diff --git a/src/core/lib/gprpp/time.h b/src/core/lib/gprpp/time.h
index 2c5cb42060d..a8e07790c34 100644
--- a/src/core/lib/gprpp/time.h
+++ b/src/core/lib/gprpp/time.h
@@ -200,6 +200,7 @@ class Duration {
     }
     return *this;
   }
+  Duration& operator*=(double multiplier);
   Duration& operator+=(Duration other) {
     millis_ += other.millis_;
     return *this;
@@ -287,6 +288,11 @@ inline Duration Duration::FromSecondsAsDouble(double seconds) {
   return Milliseconds(static_cast<int64_t>(millis));
 }
 
+inline Duration& Duration::operator*=(double multiplier) {
+  *this = *this * multiplier;
+  return *this;
+}
+
 inline Timestamp& Timestamp::operator+=(Duration duration) {
   return *this = (*this + duration);
 }
diff --git a/test/core/gprpp/time_test.cc b/test/core/gprpp/time_test.cc
index 0a652b45997..f1e4b783432 100644
--- a/test/core/gprpp/time_test.cc
+++ b/test/core/gprpp/time_test.cc
@@ -75,6 +75,13 @@ TEST(DurationTest, Infinities) {
             Duration::NegativeInfinity());
 }
 
+TEST(DurationTest, Multiplication) {
+  Duration d = Duration::Seconds(5);
+  EXPECT_EQ(d * 2, Duration::Seconds(10));
+  d *= 3;
+  EXPECT_EQ(d, Duration::Seconds(15));
+}
+
 TEST(DurationTest, FromTimespan) {
   EXPECT_EQ(Duration::FromTimespec(gpr_time_from_millis(1234, GPR_TIMESPAN)),
             Duration::Milliseconds(1234));
diff --git a/test/cpp/end2end/client_lb_end2end_test.cc b/test/cpp/end2end/client_lb_end2end_test.cc
index e3a03e650be..13c5d4944b0 100644
--- a/test/cpp/end2end/client_lb_end2end_test.cc
+++ b/test/cpp/end2end/client_lb_end2end_test.cc
@@ -581,7 +581,8 @@ TEST_F(ClientLbEnd2endTest, ChannelIdleness) {
   StartServers(kNumServers);
   // Set max idle time and build the channel.
   ChannelArguments args;
-  args.SetInt(GRPC_ARG_CLIENT_IDLE_TIMEOUT_MS, 1000);
+  args.SetInt(GRPC_ARG_CLIENT_IDLE_TIMEOUT_MS,
+              1000 * grpc_test_slowdown_factor());
   auto response_generator = BuildResolverResponseGenerator();
   auto channel = BuildChannel("", response_generator, args);
   auto stub = BuildStub(channel);
@@ -732,7 +733,8 @@ TEST_F(PickFirstTest, ProcessPending) {
 TEST_F(PickFirstTest, SelectsReadyAtStartup) {
   ChannelArguments args;
   constexpr int kInitialBackOffMs = 5000;
-  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS, kInitialBackOffMs);
+  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS,
+              kInitialBackOffMs * grpc_test_slowdown_factor());
   // Create 2 servers, but start only the second one.
   std::vector<int> ports = {grpc_pick_unused_port_or_die(),
                             grpc_pick_unused_port_or_die()};
@@ -758,7 +760,8 @@ TEST_F(PickFirstTest, SelectsReadyAtStartup) {
 TEST_F(PickFirstTest, BackOffInitialReconnect) {
   ChannelArguments args;
   constexpr int kInitialBackOffMs = 100;
-  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS, kInitialBackOffMs);
+  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS,
+              kInitialBackOffMs * grpc_test_slowdown_factor());
   const std::vector<int> ports = {grpc_pick_unused_port_or_die()};
   const gpr_timespec t0 = gpr_now(GPR_CLOCK_MONOTONIC);
   auto response_generator = BuildResolverResponseGenerator();
@@ -779,7 +782,8 @@ TEST_F(PickFirstTest, BackOffInitialReconnect) {
   gpr_log(GPR_DEBUG, "Waited %" PRId64 " milliseconds", waited.millis());
   // We should have waited at least kInitialBackOffMs. We substract one to
   // account for test and precision accuracy drift.
-  EXPECT_GE(waited.millis(), kInitialBackOffMs - 1);
+  EXPECT_GE(waited.millis(),
+            (kInitialBackOffMs * grpc_test_slowdown_factor()) - 1);
   // But not much more.
   EXPECT_GT(
       gpr_time_cmp(
@@ -790,7 +794,8 @@ TEST_F(PickFirstTest, BackOffInitialReconnect) {
 TEST_F(PickFirstTest, BackOffMinReconnect) {
   ChannelArguments args;
   constexpr int kMinReconnectBackOffMs = 1000;
-  args.SetInt(GRPC_ARG_MIN_RECONNECT_BACKOFF_MS, kMinReconnectBackOffMs);
+  args.SetInt(GRPC_ARG_MIN_RECONNECT_BACKOFF_MS,
+              kMinReconnectBackOffMs * grpc_test_slowdown_factor());
   const std::vector<int> ports = {grpc_pick_unused_port_or_die()};
   auto response_generator = BuildResolverResponseGenerator();
   auto channel = BuildChannel("pick_first", response_generator, args);
@@ -799,8 +804,8 @@ TEST_F(PickFirstTest, BackOffMinReconnect) {
   // Make connection delay a 10% longer than it's willing to in order to make
   // sure we are hitting the codepath that waits for the min reconnect backoff.
   ConnectionAttemptInjector injector;
-  injector.SetDelay(
-      grpc_core::Duration::Milliseconds(kMinReconnectBackOffMs * 1.10));
+  injector.SetDelay(grpc_core::Duration::Milliseconds(
+      kMinReconnectBackOffMs * grpc_test_slowdown_factor() * 1.10));
   const gpr_timespec t0 = gpr_now(GPR_CLOCK_MONOTONIC);
   channel->WaitForConnected(
       grpc_timeout_milliseconds_to_deadline(kMinReconnectBackOffMs * 2));
@@ -810,13 +815,15 @@ TEST_F(PickFirstTest, BackOffMinReconnect) {
   gpr_log(GPR_DEBUG, "Waited %" PRId64 " milliseconds", waited.millis());
   // We should have waited at least kMinReconnectBackOffMs. We substract one to
   // account for test and precision accuracy drift.
-  EXPECT_GE(waited.millis(), kMinReconnectBackOffMs - 1);
+  EXPECT_GE(waited.millis(),
+            (kMinReconnectBackOffMs * grpc_test_slowdown_factor()) - 1);
 }
 
 TEST_F(PickFirstTest, ResetConnectionBackoff) {
   ChannelArguments args;
   constexpr int kInitialBackOffMs = 1000;
-  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS, kInitialBackOffMs);
+  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS,
+              kInitialBackOffMs * grpc_test_slowdown_factor());
   const std::vector<int> ports = {grpc_pick_unused_port_or_die()};
   auto response_generator = BuildResolverResponseGenerator();
   auto channel = BuildChannel("pick_first", response_generator, args);
@@ -844,7 +851,7 @@ TEST_F(PickFirstTest, ResetConnectionBackoff) {
       grpc_core::Duration::FromTimespec(gpr_time_sub(t1, t0));
   gpr_log(GPR_DEBUG, "Waited %" PRId64 " milliseconds", waited.millis());
   // We should have waited less than kInitialBackOffMs.
-  EXPECT_LT(waited.millis(), kInitialBackOffMs);
+  EXPECT_LT(waited.millis(), kInitialBackOffMs * grpc_test_slowdown_factor());
 }
 
 TEST_F(ClientLbEnd2endTest,
@@ -854,8 +861,9 @@ TEST_F(ClientLbEnd2endTest,
   // Create client.
   const int port = grpc_pick_unused_port_or_die();
   ChannelArguments args;
-  const int kInitialBackOffMs = 5000 * grpc_test_slowdown_factor();
-  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS, kInitialBackOffMs);
+  const int kInitialBackOffMs = 5000;
+  args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS,
+              kInitialBackOffMs * grpc_test_slowdown_factor());
   auto response_generator = BuildResolverResponseGenerator();
   auto channel = BuildChannel("pick_first", response_generator, args);
   auto stub = BuildStub(channel);
diff --git a/test/cpp/end2end/xds/xds_end2end_test_lib.cc b/test/cpp/end2end/xds/xds_end2end_test_lib.cc
index 8a3e0df7be8..007167db320 100644
--- a/test/cpp/end2end/xds/xds_end2end_test_lib.cc
+++ b/test/cpp/end2end/xds/xds_end2end_test_lib.cc
@@ -791,7 +791,8 @@ std::shared_ptr<Channel> XdsEnd2endTest::CreateChannel(
   // TODO(roth): Remove this once we enable retries by default internally.
   args->SetInt(GRPC_ARG_ENABLE_RETRIES, 1);
   if (failover_timeout_ms > 0) {
-    args->SetInt(GRPC_ARG_PRIORITY_FAILOVER_TIMEOUT_MS, failover_timeout_ms);
+    args->SetInt(GRPC_ARG_PRIORITY_FAILOVER_TIMEOUT_MS,
+                 failover_timeout_ms * grpc_test_slowdown_factor());
   }
   if (GetParam().bootstrap_source() == XdsTestType::kBootstrapFromChannelArg) {
     // We're getting the bootstrap from a channel arg, so we do the
@@ -1004,7 +1005,8 @@ absl::optional<AdsServiceImpl::ResponseState> XdsEnd2endTest::WaitForNack(
     std::function<absl::optional<AdsServiceImpl::ResponseState>()> get_state,
     const RpcOptions& rpc_options, StatusCode expected_status) {
   absl::optional<AdsServiceImpl::ResponseState> response_state;
-  auto deadline = absl::Now() + absl::Seconds(30);
+  auto deadline =
+      absl::Now() + (absl::Seconds(30) * grpc_test_slowdown_factor());
   auto continue_predicate = [&]() {
     if (absl::Now() >= deadline) {
       return false;
@@ -1023,6 +1025,14 @@ absl::optional<AdsServiceImpl::ResponseState> XdsEnd2endTest::WaitForNack(
   return response_state;
 }
 
+void XdsEnd2endTest::SetProtoDuration(
+    grpc_core::Duration duration, google::protobuf::Duration* duration_proto) {
+  duration *= grpc_test_slowdown_factor();
+  gpr_timespec ts = duration.as_timespec();
+  duration_proto->set_seconds(ts.tv_sec);
+  duration_proto->set_nanos(ts.tv_nsec);
+}
+
 std::string XdsEnd2endTest::ReadFile(const char* file_path) {
   grpc_slice slice;
   GPR_ASSERT(
diff --git a/test/cpp/end2end/xds/xds_end2end_test_lib.h b/test/cpp/end2end/xds/xds_end2end_test_lib.h
index 1b98f92146c..b214bd70650 100644
--- a/test/cpp/end2end/xds/xds_end2end_test_lib.h
+++ b/test/cpp/end2end/xds/xds_end2end_test_lib.h
@@ -720,6 +720,7 @@ class XdsEnd2endTest : public ::testing::TestWithParam<XdsTestType> {
     // Dev note: If a timeout or Deadline Exceeded error is occurring in an XDS
     // end2end test, consider changing that test's timeout instead of this
     // global default.
+    // Will be multiplied by grpc_test_slowdown_factor().
     int timeout_ms = 1000;
     bool wait_for_ready = false;
     std::vector<std::pair<std::string, std::string>> metadata;
@@ -747,6 +748,11 @@ class XdsEnd2endTest : public ::testing::TestWithParam<XdsTestType> {
       return *this;
     }
 
+    RpcOptions& set_timeout(grpc_core::Duration timeout) {
+      timeout_ms = timeout.millis();
+      return *this;
+    }
+
     RpcOptions& set_wait_for_ready(bool rpc_wait_for_ready) {
       wait_for_ready = rpc_wait_for_ready;
       return *this;
@@ -884,6 +890,7 @@ class XdsEnd2endTest : public ::testing::TestWithParam<XdsTestType> {
     // If true, resets the backend counters before returning.
     bool reset_counters = true;
     // How long to wait for the backend(s) to see requests.
+    // Will be multiplied by grpc_test_slowdown_factor().
     int timeout_ms = 5000;
 
     WaitForBackendOptions() {}
@@ -1012,6 +1019,10 @@ class XdsEnd2endTest : public ::testing::TestWithParam<XdsTestType> {
         gpr_now(GPR_CLOCK_MONOTONIC));
   }
 
+  // Sets duration_proto to duration times grpc_test_slowdown_factor().
+  static void SetProtoDuration(grpc_core::Duration duration,
+                               google::protobuf::Duration* duration_proto);
+
   // Returns the number of RPCs needed to pass error_tolerance at 99.99994%
   // chance. Rolling dices in drop/fault-injection generates a binomial
   // distribution (if our code is not horribly wrong). Let's make "n" the number
diff --git a/test/cpp/end2end/xds/xds_fault_injection_end2end_test.cc b/test/cpp/end2end/xds/xds_fault_injection_end2end_test.cc
index 96591d49f3e..39b8b33d104 100644
--- a/test/cpp/end2end/xds/xds_fault_injection_end2end_test.cc
+++ b/test/cpp/end2end/xds/xds_fault_injection_end2end_test.cc
@@ -204,8 +204,8 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionPercentageAbortViaHeaders) {
 
 TEST_P(FaultInjectionTest, XdsFaultInjectionPercentageDelay) {
   CreateAndStartBackends(1);
-  const uint32_t kRpcTimeoutMilliseconds = 10000;
-  const uint32_t kFixedDelaySeconds = 100;
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(10);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(20);
   const uint32_t kDelayPercentagePerHundred = 50;
   const double kDelayRate = kDelayPercentagePerHundred / 100.0;
   const double kErrorTolerance = 0.1;
@@ -225,14 +225,13 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionPercentageDelay) {
   auto* delay_percentage = http_fault.mutable_delay()->mutable_percentage();
   delay_percentage->set_numerator(kDelayPercentagePerHundred);
   delay_percentage->set_denominator(FractionalPercent::HUNDRED);
-  auto* fixed_delay = http_fault.mutable_delay()->mutable_fixed_delay();
-  fixed_delay->set_seconds(kFixedDelaySeconds);
+  SetProtoDuration(kFixedDelay,
+                   http_fault.mutable_delay()->mutable_fixed_delay());
   // Config fault injection via different setup
   SetFilterConfig(http_fault);
   // Send kNumRpcs RPCs and count the delays.
-  RpcOptions rpc_options = RpcOptions()
-                               .set_timeout_ms(kRpcTimeoutMilliseconds)
-                               .set_skip_cancelled_check(true);
+  RpcOptions rpc_options =
+      RpcOptions().set_timeout(kRpcTimeout).set_skip_cancelled_check(true);
   std::vector<ConcurrentRpc> rpcs =
       SendConcurrentRpcs(DEBUG_LOCATION, stub_.get(), kNumRpcs, rpc_options);
   size_t num_delayed = 0;
@@ -249,8 +248,8 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionPercentageDelay) {
 
 TEST_P(FaultInjectionTest, XdsFaultInjectionPercentageDelayViaHeaders) {
   CreateAndStartBackends(1);
-  const uint32_t kFixedDelayMilliseconds = 100000;
-  const uint32_t kRpcTimeoutMilliseconds = 10000;
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(10);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(20);
   const uint32_t kDelayPercentageCap = 100;
   const uint32_t kDelayPercentage = 50;
   const double kDelayRate = kDelayPercentage / 100.0;
@@ -275,13 +274,14 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionPercentageDelayViaHeaders) {
   SetFilterConfig(http_fault);
   // Send kNumRpcs RPCs and count the delays.
   std::vector<std::pair<std::string, std::string>> metadata = {
-      {"x-envoy-fault-delay-request", std::to_string(kFixedDelayMilliseconds)},
+      {"x-envoy-fault-delay-request",
+       std::to_string(kFixedDelay.millis() * grpc_test_slowdown_factor())},
       {"x-envoy-fault-delay-request-percentage",
        std::to_string(kDelayPercentage)},
   };
   RpcOptions rpc_options = RpcOptions()
                                .set_metadata(metadata)
-                               .set_timeout_ms(kRpcTimeoutMilliseconds)
+                               .set_timeout(kRpcTimeout)
                                .set_skip_cancelled_check(true);
   std::vector<ConcurrentRpc> rpcs =
       SendConcurrentRpcs(DEBUG_LOCATION, stub_.get(), kNumRpcs, rpc_options);
@@ -299,8 +299,8 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionPercentageDelayViaHeaders) {
 
 TEST_P(FaultInjectionTest, XdsFaultInjectionAbortAfterDelayForStreamCall) {
   CreateAndStartBackends(1);
-  const uint32_t kFixedDelaySeconds = 1;
-  const uint32_t kRpcTimeoutMilliseconds = 100 * 1000;  // 100s should not reach
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(30);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(1);
   // Create an EDS resource
   EdsResourceArgs args({{"locality0", CreateEndpointsForBackends()}});
   balancer_->ads_service()->SetEdsResource(BuildEdsResource(args));
@@ -314,14 +314,14 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionAbortAfterDelayForStreamCall) {
   auto* delay_percentage = http_fault.mutable_delay()->mutable_percentage();
   delay_percentage->set_numerator(100);  // Always inject DELAY!
   delay_percentage->set_denominator(FractionalPercent::HUNDRED);
-  auto* fixed_delay = http_fault.mutable_delay()->mutable_fixed_delay();
-  fixed_delay->set_seconds(kFixedDelaySeconds);
+  SetProtoDuration(kFixedDelay,
+                   http_fault.mutable_delay()->mutable_fixed_delay());
   // Config fault injection via different setup
   SetFilterConfig(http_fault);
   // Send a stream RPC and check its status code
   ClientContext context;
   context.set_deadline(
-      grpc_timeout_milliseconds_to_deadline(kRpcTimeoutMilliseconds));
+      grpc_timeout_milliseconds_to_deadline(kRpcTimeout.millis()));
   auto stream = stub_->BidiStream(&context);
   stream->WritesDone();
   auto status = stream->Finish();
@@ -332,12 +332,11 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionAbortAfterDelayForStreamCall) {
 
 TEST_P(FaultInjectionTest, XdsFaultInjectionAlwaysDelayPercentageAbort) {
   CreateAndStartBackends(1);
+  const auto kConnectTimeout = grpc_core::Duration::Seconds(10);
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(30);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(1);
   const uint32_t kAbortPercentagePerHundred = 50;
   const double kAbortRate = kAbortPercentagePerHundred / 100.0;
-  const uint32_t kFixedDelaySeconds = 1;
-  const uint32_t kRpcTimeoutMilliseconds = 100 * 1000;  // 100s should not reach
-  const uint32_t kConnectionTimeoutMilliseconds =
-      10 * 1000;  // 10s should not reach
   const double kErrorTolerance = 0.1;
   const size_t kNumRpcs = ComputeIdealNumRpcs(kAbortRate, kErrorTolerance);
   const size_t kMaxConcurrentRequests = kNumRpcs;
@@ -360,23 +359,22 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionAlwaysDelayPercentageAbort) {
   auto* delay_percentage = http_fault.mutable_delay()->mutable_percentage();
   delay_percentage->set_numerator(1000000);  // Always inject DELAY!
   delay_percentage->set_denominator(FractionalPercent::MILLION);
-  auto* fixed_delay = http_fault.mutable_delay()->mutable_fixed_delay();
-  fixed_delay->set_seconds(kFixedDelaySeconds);
+  SetProtoDuration(kFixedDelay,
+                   http_fault.mutable_delay()->mutable_fixed_delay());
   // Config fault injection via different setup
   SetFilterConfig(http_fault);
   // Allow the channel to connect to one backends, so the herd of queued RPCs
   // won't be executed on the same ExecCtx object and using the cached Now()
   // value, which causes millisecond level delay error.
   channel_->WaitForConnected(
-      grpc_timeout_milliseconds_to_deadline(kConnectionTimeoutMilliseconds));
+      grpc_timeout_milliseconds_to_deadline(kConnectTimeout.millis()));
   // Send kNumRpcs RPCs and count the aborts.
   int num_aborted = 0;
-  RpcOptions rpc_options = RpcOptions().set_timeout_ms(kRpcTimeoutMilliseconds);
+  RpcOptions rpc_options = RpcOptions().set_timeout(kRpcTimeout);
   std::vector<ConcurrentRpc> rpcs =
       SendConcurrentRpcs(DEBUG_LOCATION, stub_.get(), kNumRpcs, rpc_options);
   for (auto& rpc : rpcs) {
-    EXPECT_GE(rpc.elapsed_time,
-              grpc_core::Duration::Seconds(kFixedDelaySeconds));
+    EXPECT_GE(rpc.elapsed_time, kFixedDelay * grpc_test_slowdown_factor());
     if (rpc.status.error_code() == StatusCode::OK) continue;
     EXPECT_EQ("Fault injected", rpc.status.error_message());
     ++num_aborted;
@@ -393,12 +391,11 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionAlwaysDelayPercentageAbort) {
 TEST_P(FaultInjectionTest,
        XdsFaultInjectionAlwaysDelayPercentageAbortSwitchDenominator) {
   CreateAndStartBackends(1);
+  const auto kConnectTimeout = grpc_core::Duration::Seconds(10);
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(30);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(1);
   const uint32_t kAbortPercentagePerMillion = 500000;
   const double kAbortRate = kAbortPercentagePerMillion / 1000000.0;
-  const uint32_t kFixedDelaySeconds = 1;                // 1s
-  const uint32_t kRpcTimeoutMilliseconds = 100 * 1000;  // 100s should not reach
-  const uint32_t kConnectionTimeoutMilliseconds =
-      10 * 1000;  // 10s should not reach
   const double kErrorTolerance = 0.1;
   const size_t kNumRpcs = ComputeIdealNumRpcs(kAbortRate, kErrorTolerance);
   const size_t kMaxConcurrentRequests = kNumRpcs;
@@ -421,23 +418,22 @@ TEST_P(FaultInjectionTest,
   auto* delay_percentage = http_fault.mutable_delay()->mutable_percentage();
   delay_percentage->set_numerator(100);  // Always inject DELAY!
   delay_percentage->set_denominator(FractionalPercent::HUNDRED);
-  auto* fixed_delay = http_fault.mutable_delay()->mutable_fixed_delay();
-  fixed_delay->set_seconds(kFixedDelaySeconds);
+  SetProtoDuration(kFixedDelay,
+                   http_fault.mutable_delay()->mutable_fixed_delay());
   // Config fault injection via different setup
   SetFilterConfig(http_fault);
   // Allow the channel to connect to one backends, so the herd of queued RPCs
   // won't be executed on the same ExecCtx object and using the cached Now()
   // value, which causes millisecond level delay error.
   channel_->WaitForConnected(
-      grpc_timeout_milliseconds_to_deadline(kConnectionTimeoutMilliseconds));
+      grpc_timeout_milliseconds_to_deadline(kConnectTimeout.millis()));
   // Send kNumRpcs RPCs and count the aborts.
   int num_aborted = 0;
-  RpcOptions rpc_options = RpcOptions().set_timeout_ms(kRpcTimeoutMilliseconds);
+  RpcOptions rpc_options = RpcOptions().set_timeout(kRpcTimeout);
   std::vector<ConcurrentRpc> rpcs =
       SendConcurrentRpcs(DEBUG_LOCATION, stub_.get(), kNumRpcs, rpc_options);
   for (auto& rpc : rpcs) {
-    EXPECT_GE(rpc.elapsed_time,
-              grpc_core::Duration::Seconds(kFixedDelaySeconds));
+    EXPECT_GE(rpc.elapsed_time, kFixedDelay * grpc_test_slowdown_factor());
     if (rpc.status.error_code() == StatusCode::OK) continue;
     EXPECT_EQ("Fault injected", rpc.status.error_message());
     ++num_aborted;
@@ -450,10 +446,10 @@ TEST_P(FaultInjectionTest,
 
 TEST_P(FaultInjectionTest, XdsFaultInjectionMaxFault) {
   CreateAndStartBackends(1);
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(4);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(20);
   const uint32_t kMaxFault = 10;
   const uint32_t kNumRpcs = 30;  // kNumRpcs should be bigger than kMaxFault
-  const uint32_t kRpcTimeoutMs = 4000;     // 4 seconds
-  const uint32_t kLongDelaySeconds = 100;  // 100 seconds
   const uint32_t kAlwaysDelayPercentage = 100;
   // Create an EDS resource
   EdsResourceArgs args({{"locality0", CreateEndpointsForBackends()}});
@@ -464,15 +460,15 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionMaxFault) {
   delay_percentage->set_numerator(
       kAlwaysDelayPercentage);  // Always inject DELAY!
   delay_percentage->set_denominator(FractionalPercent::HUNDRED);
-  auto* fixed_delay = http_fault.mutable_delay()->mutable_fixed_delay();
-  fixed_delay->set_seconds(kLongDelaySeconds);
+  SetProtoDuration(kFixedDelay,
+                   http_fault.mutable_delay()->mutable_fixed_delay());
   http_fault.mutable_max_active_faults()->set_value(kMaxFault);
   // Config fault injection via different setup
   SetFilterConfig(http_fault);
   // Sends a batch of long running RPCs with long timeout to consume all
   // active faults quota.
   int num_delayed = 0;
-  RpcOptions rpc_options = RpcOptions().set_timeout_ms(kRpcTimeoutMs);
+  RpcOptions rpc_options = RpcOptions().set_timeout(kRpcTimeout);
   std::vector<ConcurrentRpc> rpcs =
       SendConcurrentRpcs(DEBUG_LOCATION, stub_.get(), kNumRpcs, rpc_options);
   for (auto& rpc : rpcs) {
@@ -498,9 +494,8 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionMaxFault) {
 
 TEST_P(FaultInjectionTest, XdsFaultInjectionBidiStreamDelayOk) {
   CreateAndStartBackends(1);
-  // kRpcTimeoutMilliseconds is 10s should never be reached.
-  const uint32_t kRpcTimeoutMilliseconds = grpc_test_slowdown_factor() * 10000;
-  const uint32_t kFixedDelaySeconds = 1;
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(20);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(1);
   const uint32_t kDelayPercentagePerHundred = 100;
   // Create an EDS resource
   EdsResourceArgs args({{"locality0", CreateEndpointsForBackends()}});
@@ -510,13 +505,13 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionBidiStreamDelayOk) {
   auto* delay_percentage = http_fault.mutable_delay()->mutable_percentage();
   delay_percentage->set_numerator(kDelayPercentagePerHundred);
   delay_percentage->set_denominator(FractionalPercent::HUNDRED);
-  auto* fixed_delay = http_fault.mutable_delay()->mutable_fixed_delay();
-  fixed_delay->set_seconds(kFixedDelaySeconds);
+  SetProtoDuration(kFixedDelay,
+                   http_fault.mutable_delay()->mutable_fixed_delay());
   // Config fault injection via different setup
   SetFilterConfig(http_fault);
   ClientContext context;
   context.set_deadline(
-      grpc_timeout_milliseconds_to_deadline(kRpcTimeoutMilliseconds));
+      grpc_timeout_milliseconds_to_deadline(kRpcTimeout.millis()));
   auto stream = stub_->BidiStream(&context);
   stream->WritesDone();
   auto status = stream->Finish();
@@ -530,8 +525,8 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionBidiStreamDelayOk) {
 // for description.
 TEST_P(FaultInjectionTest, XdsFaultInjectionBidiStreamDelayError) {
   CreateAndStartBackends(1);
-  const uint32_t kRpcTimeoutMilliseconds = grpc_test_slowdown_factor() * 500;
-  const uint32_t kFixedDelaySeconds = 100;
+  const auto kRpcTimeout = grpc_core::Duration::Seconds(10);
+  const auto kFixedDelay = grpc_core::Duration::Seconds(30);
   const uint32_t kDelayPercentagePerHundred = 100;
   // Create an EDS resource
   EdsResourceArgs args({{"locality0", CreateEndpointsForBackends()}});
@@ -541,13 +536,13 @@ TEST_P(FaultInjectionTest, XdsFaultInjectionBidiStreamDelayError) {
   auto* delay_percentage = http_fault.mutable_delay()->mutable_percentage();
   delay_percentage->set_numerator(kDelayPercentagePerHundred);
   delay_percentage->set_denominator(FractionalPercent::HUNDRED);
-  auto* fixed_delay = http_fault.mutable_delay()->mutable_fixed_delay();
-  fixed_delay->set_seconds(kFixedDelaySeconds);
+  SetProtoDuration(kFixedDelay,
+                   http_fault.mutable_delay()->mutable_fixed_delay());
   // Config fault injection via different setup
   SetFilterConfig(http_fault);
   ClientContext context;
   context.set_deadline(
-      grpc_timeout_milliseconds_to_deadline(kRpcTimeoutMilliseconds));
+      grpc_timeout_milliseconds_to_deadline(kRpcTimeout.millis()));
   auto stream = stub_->BidiStream(&context);
   stream->WritesDone();
   auto status = stream->Finish();
diff --git a/test/cpp/end2end/xds/xds_outlier_detection_end2end_test.cc b/test/cpp/end2end/xds/xds_outlier_detection_end2end_test.cc
index 194f8a08809..6321f92fdec 100644
--- a/test/cpp/end2end/xds/xds_outlier_detection_end2end_test.cc
+++ b/test/cpp/end2end/xds/xds_outlier_detection_end2end_test.cc
@@ -63,23 +63,15 @@ TEST_P(OutlierDetectionTest, SuccessRateEjectionAndUnejection) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  base_time->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(1);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_base_ejection_time());
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(100);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(100);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -135,20 +127,13 @@ TEST_P(OutlierDetectionTest, SuccessRateMaxPercent) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(1);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(100);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(100);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -239,29 +224,21 @@ TEST_P(OutlierDetectionTest, SuccessRateStdevFactor) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  base_time->set_seconds(1 * grpc_test_slowdown_factor());
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_base_ejection_time());
   // We know a stdev factor of 100 will ensure the ejection occurs, so setting
   // it to something higher like 1000 to test that ejection will not occur.
   // Note this parameter is the only difference between this test and
   // SuccessRateEjectionAndUnejection (ejection portion, value set to 100) and
   // this one value changes means the difference between not ejecting in this
   // test and ejecting in the other test.
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(1000);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(1);
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(1000);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(100);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -310,28 +287,20 @@ TEST_P(OutlierDetectionTest, SuccessRateEnforcementPercentage) {
   CreateAndStartBackends(2);
   auto cluster = default_cluster_;
   cluster.set_lb_policy(Cluster::RING_HASH);
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  base_time->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(100);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_base_ejection_time());
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(100);
   // Setting enforcing_success_rate to 0 to ensure we will never eject.
   // Note this parameter is the only difference between this test and
   // SuccessRateEjectionAndUnejection (ejection portion, value set to 100) and
   // this one value changes means the difference between guaranteed not ejecting
   // in this test and guaranteed ejecting in the other test.
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(1);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(0);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -382,25 +351,18 @@ TEST_P(OutlierDetectionTest, SuccessRateMinimumHosts) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(100);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(100);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(100);
   // Set success_rate_minimum_hosts to 3 when we only have 2 backends
   // Note this parameter is the only difference between this test and
   // SuccessRateEjectionAndUnejection (ejection portion, value set to 1) and
   // this one value changes means the difference between not ejecting in this
   // test and ejecting in the other test.
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(3);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(1);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(3);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -451,26 +413,19 @@ TEST_P(OutlierDetectionTest, SuccessRateRequestVolume) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(1);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(100);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(100);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(1);
   // Set success_rate_request_volume to 4 when we only send 3 RPC in the
   // interval.
   // Note this parameter is the only difference between this test and
   // SuccessRateEjectionAndUnejection (ejection portion, value set to 1) and
   // this one value changes means the difference between not ejecting in this
   // test and ejecting in the other test.
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(4);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(4);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -527,23 +482,15 @@ TEST_P(OutlierDetectionTest, FailurePercentageEjectionAndUnejection) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  base_time->set_seconds(3 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(1);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(3),
+                   outlier_detection->mutable_base_ejection_time());
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -606,20 +553,13 @@ TEST_P(OutlierDetectionTest, FailurePercentageMaxPercentage) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(1);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -707,28 +647,20 @@ TEST_P(OutlierDetectionTest, FailurePercentageThreshold) {
   CreateAndStartBackends(2);
   auto cluster = default_cluster_;
   cluster.set_lb_policy(Cluster::RING_HASH);
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  base_time->set_seconds(1 * grpc_test_slowdown_factor());
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_base_ejection_time());
   // Setup outlier failure percentage parameter to 50
   // Note this parameter is the only difference between this test and
   // FailurePercentageEjectionAndUnejection (ejection portion, value set to 0)
   // and this one value changes means the difference between not ejecting in
   // this test and ejecting in the other test.
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(50);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(1);
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(50);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -778,28 +710,20 @@ TEST_P(OutlierDetectionTest, FailurePercentageEnforcementPercentage) {
   CreateAndStartBackends(2);
   auto cluster = default_cluster_;
   cluster.set_lb_policy(Cluster::RING_HASH);
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  base_time->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_base_ejection_time());
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
   // Setting enforcing_success_rate to 0 to ensure we will never eject.
   // Note this parameter is the only difference between this test and
   // FailurePercentageEjectionAndUnejection (ejection portion, value set to 100)
   // and this one value changes means the difference between guaranteed not
   // ejecting in this test and guaranteed ejecting in the other test.
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(1);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(0);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -851,14 +775,11 @@ TEST_P(OutlierDetectionTest, FailurePercentageMinimumHosts) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
   // Set failure_percentage_minimum_hosts to 3 when we only have 2 backends
   // Note this parameter is the only difference between this test and
   // FailurePercentageEjectionAndUnejection (ejection portion, value set to 1)
@@ -922,26 +843,19 @@ TEST_P(OutlierDetectionTest, FailurePercentageRequestVolume) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
   // Set failure_percentage_request_volume to 4 when we only send 3 RPC in the
   // interval.
   // // Note this parameter is the only difference between this test and
   // FailurePercentageEjectionAndUnejection (ejection portion, value set to 1)
   // and this one value changes means the difference between not ejecting in
   // this test and ejecting in the other test.
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(4);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(4);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -995,37 +909,20 @@ TEST_P(OutlierDetectionTest, SuccessRateAndFailurePercentage) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_max_ejection_percent()
-      ->set_value(50);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_max_ejection_percent()->set_value(50);
   // This stdev of 500 will ensure the number of ok RPC and error RPC we send
   // will make 1 outlier out of the 4 backends.
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(500);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(1);
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(500);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(100);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(1);
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -1120,7 +1017,7 @@ TEST_P(OutlierDetectionTest, SuccessRateAndFailurePercentage) {
 }
 
 // Tests SuccessRate and FailurePercentage both unconfigured;
-// This is the case where according to the RFC we need to instruct the picker
+// This is the case where according to the gRFC we need to instruct the picker
 // not to do counting or even start the timer. The result of not counting is
 // that there will be no ejection taking place since we can't do any
 // calculations.
@@ -1130,14 +1027,11 @@ TEST_P(OutlierDetectionTest, SuccessRateAndFailurePercentageBothDisabled) {
   CreateAndStartBackends(2);
   auto cluster = default_cluster_;
   cluster.set_lb_policy(Cluster::RING_HASH);
-  // Setup outlier failure percentage parameters.
-  // Any failure will cause an potential ejection with the probability of 100%
-  // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  base_time->set_seconds(1 * grpc_test_slowdown_factor());
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_base_ejection_time());
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -1186,37 +1080,20 @@ TEST_P(OutlierDetectionTest,
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_max_ejection_percent()
-      ->set_value(50);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  outlier_detection->mutable_max_ejection_percent()->set_value(50);
   // This stdev of 500 will ensure the number of ok RPC and error RPC we send
   // will make 1 outlier out of the 4 backends.
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_stdev_factor()
-      ->set_value(500);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_success_rate()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_success_rate_request_volume()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(1);
+  outlier_detection->mutable_success_rate_stdev_factor()->set_value(500);
+  outlier_detection->mutable_enforcing_success_rate()->set_value(100);
+  outlier_detection->mutable_success_rate_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_success_rate_request_volume()->set_value(1);
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
@@ -1293,23 +1170,15 @@ TEST_P(OutlierDetectionTest, DisableOutlierDetectionWhileAddressesAreEjected) {
   // Setup outlier failure percentage parameters.
   // Any failure will cause an potential ejection with the probability of 100%
   // (to eliminate flakiness of the test).
-  auto* interval = cluster.mutable_outlier_detection()->mutable_interval();
-  interval->set_seconds(1 * grpc_test_slowdown_factor());
-  auto* base_time =
-      cluster.mutable_outlier_detection()->mutable_base_ejection_time();
-  base_time->set_seconds(3 * grpc_test_slowdown_factor());
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_threshold()
-      ->set_value(0);
-  cluster.mutable_outlier_detection()
-      ->mutable_enforcing_failure_percentage()
-      ->set_value(100);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_minimum_hosts()
-      ->set_value(1);
-  cluster.mutable_outlier_detection()
-      ->mutable_failure_percentage_request_volume()
-      ->set_value(1);
+  auto* outlier_detection = cluster.mutable_outlier_detection();
+  SetProtoDuration(grpc_core::Duration::Seconds(1),
+                   outlier_detection->mutable_interval());
+  SetProtoDuration(grpc_core::Duration::Seconds(3),
+                   outlier_detection->mutable_base_ejection_time());
+  outlier_detection->mutable_failure_percentage_threshold()->set_value(0);
+  outlier_detection->mutable_enforcing_failure_percentage()->set_value(100);
+  outlier_detection->mutable_failure_percentage_minimum_hosts()->set_value(1);
+  outlier_detection->mutable_failure_percentage_request_volume()->set_value(1);
   balancer_->ads_service()->SetCdsResource(cluster);
   auto new_route_config = default_route_config_;
   auto* route = new_route_config.mutable_virtual_hosts(0)->mutable_routes(0);
diff --git a/test/cpp/end2end/xds/xds_ring_hash_end2end_test.cc b/test/cpp/end2end/xds/xds_ring_hash_end2end_test.cc
index 616974c19d8..2e7a146fdd8 100644
--- a/test/cpp/end2end/xds/xds_ring_hash_end2end_test.cc
+++ b/test/cpp/end2end/xds/xds_ring_hash_end2end_test.cc
@@ -285,7 +285,8 @@ TEST_P(RingHashTest,
   // Increase subchannel backoff time, so that subchannels stay in
   // TRANSIENT_FAILURE for long enough to trigger potential problems.
   ChannelArguments channel_args;
-  channel_args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS, 10000);
+  channel_args.SetInt(GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS,
+                      10000 * grpc_test_slowdown_factor());
   SetUpChannel(&channel_args);
   // Start an RPC in the background.
   LongRunningRpc rpc;
diff --git a/test/cpp/end2end/xds/xds_routing_end2end_test.cc b/test/cpp/end2end/xds/xds_routing_end2end_test.cc
index 32c81f7d2d7..93a4f5ace80 100644
--- a/test/cpp/end2end/xds/xds_routing_end2end_test.cc
+++ b/test/cpp/end2end/xds/xds_routing_end2end_test.cc
@@ -1882,12 +1882,12 @@ TEST_P(LdsRdsTest, XdsRoutingClusterUpdateClustersWithPickingDelays) {
 }
 
 TEST_P(LdsRdsTest, XdsRoutingApplyXdsTimeout) {
-  const int64_t kTimeoutMillis = 500;
-  const int64_t kTimeoutNano = kTimeoutMillis * 1000000;
-  const int64_t kTimeoutGrpcTimeoutHeaderMaxSecond = 1;
-  const int64_t kTimeoutMaxStreamDurationSecond = 2;
-  const int64_t kTimeoutHttpMaxStreamDurationSecond = 3;
-  const int64_t kTimeoutApplicationSecond = 4;
+  const auto kTimeoutGrpcHeaderMax = grpc_core::Duration::Milliseconds(1500);
+  const auto kTimeoutMaxStreamDuration =
+      grpc_core::Duration::Milliseconds(2500);
+  const auto kTimeoutHttpMaxStreamDuration =
+      grpc_core::Duration::Milliseconds(3500);
+  const auto kTimeoutApplication = grpc_core::Duration::Milliseconds(4500);
   const char* kNewCluster1Name = "new_cluster_1";
   const char* kNewEdsService1Name = "new_eds_service_name_1";
   const char* kNewCluster2Name = "new_cluster_2";
@@ -1928,11 +1928,10 @@ TEST_P(LdsRdsTest, XdsRoutingApplyXdsTimeout) {
   listener.mutable_api_listener()->mutable_api_listener()->UnpackTo(
       &http_connection_manager);
   // Set up HTTP max_stream_duration of 3.5 seconds
-  auto* duration =
+  SetProtoDuration(
+      kTimeoutHttpMaxStreamDuration,
       http_connection_manager.mutable_common_http_protocol_options()
-          ->mutable_max_stream_duration();
-  duration->set_seconds(kTimeoutHttpMaxStreamDurationSecond);
-  duration->set_nanos(kTimeoutNano);
+          ->mutable_max_stream_duration());
   listener.mutable_api_listener()->mutable_api_listener()->PackFrom(
       http_connection_manager);
   // Construct route config.
@@ -1944,20 +1943,17 @@ TEST_P(LdsRdsTest, XdsRoutingApplyXdsTimeout) {
   route1->mutable_route()->set_cluster(kNewCluster1Name);
   auto* max_stream_duration =
       route1->mutable_route()->mutable_max_stream_duration();
-  duration = max_stream_duration->mutable_max_stream_duration();
-  duration->set_seconds(kTimeoutMaxStreamDurationSecond);
-  duration->set_nanos(kTimeoutNano);
-  duration = max_stream_duration->mutable_grpc_timeout_header_max();
-  duration->set_seconds(kTimeoutGrpcTimeoutHeaderMaxSecond);
-  duration->set_nanos(kTimeoutNano);
+  SetProtoDuration(kTimeoutMaxStreamDuration,
+                   max_stream_duration->mutable_max_stream_duration());
+  SetProtoDuration(kTimeoutGrpcHeaderMax,
+                   max_stream_duration->mutable_grpc_timeout_header_max());
   // route 2: Set max_stream_duration of 2.5 seconds
   auto* route2 = new_route_config.mutable_virtual_hosts(0)->add_routes();
   route2->mutable_match()->set_path("/grpc.testing.EchoTest2Service/Echo2");
   route2->mutable_route()->set_cluster(kNewCluster2Name);
   max_stream_duration = route2->mutable_route()->mutable_max_stream_duration();
-  duration = max_stream_duration->mutable_max_stream_duration();
-  duration->set_seconds(kTimeoutMaxStreamDurationSecond);
-  duration->set_nanos(kTimeoutNano);
+  SetProtoDuration(kTimeoutMaxStreamDuration,
+                   max_stream_duration->mutable_max_stream_duration());
   // route 3: No timeout values in route configuration
   auto* route3 = new_route_config.mutable_virtual_hosts(0)->add_routes();
   route3->mutable_match()->set_path("/grpc.testing.EchoTestService/Echo");
@@ -1968,55 +1964,45 @@ TEST_P(LdsRdsTest, XdsRoutingApplyXdsTimeout) {
   // Test grpc_timeout_header_max of 1.5 seconds applied
   grpc_core::Timestamp t0 = NowFromCycleCounter();
   grpc_core::Timestamp t1 =
-      t0 + grpc_core::Duration::Seconds(kTimeoutGrpcTimeoutHeaderMaxSecond) +
-      grpc_core::Duration::Milliseconds(kTimeoutMillis);
+      t0 + (kTimeoutGrpcHeaderMax * grpc_test_slowdown_factor());
   grpc_core::Timestamp t2 =
-      t0 + grpc_core::Duration::Seconds(kTimeoutMaxStreamDurationSecond) +
-      grpc_core::Duration::Milliseconds(kTimeoutMillis);
-  CheckRpcSendFailure(
-      DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED, "Deadline Exceeded",
-      RpcOptions()
-          .set_rpc_service(SERVICE_ECHO1)
-          .set_rpc_method(METHOD_ECHO1)
-          .set_wait_for_ready(true)
-          .set_timeout_ms(
-              grpc_core::Duration::Seconds(kTimeoutApplicationSecond)
-                  .millis()));
+      t0 + (kTimeoutMaxStreamDuration * grpc_test_slowdown_factor());
+  CheckRpcSendFailure(DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED,
+                      "Deadline Exceeded",
+                      RpcOptions()
+                          .set_rpc_service(SERVICE_ECHO1)
+                          .set_rpc_method(METHOD_ECHO1)
+                          .set_wait_for_ready(true)
+                          .set_timeout(kTimeoutApplication));
   EXPECT_THAT(NowFromCycleCounter(), AdjustedClockInRange(t1, t2));
   // Test max_stream_duration of 2.5 seconds applied
   t0 = NowFromCycleCounter();
-  t1 = t0 + grpc_core::Duration::Seconds(kTimeoutMaxStreamDurationSecond) +
-       grpc_core::Duration::Milliseconds(kTimeoutMillis);
-  t2 = t0 + grpc_core::Duration::Seconds(kTimeoutHttpMaxStreamDurationSecond) +
-       grpc_core::Duration::Milliseconds(kTimeoutMillis);
-  CheckRpcSendFailure(
-      DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED, "Deadline Exceeded",
-      RpcOptions()
-          .set_rpc_service(SERVICE_ECHO2)
-          .set_rpc_method(METHOD_ECHO2)
-          .set_wait_for_ready(true)
-          .set_timeout_ms(
-              grpc_core::Duration::Seconds(kTimeoutApplicationSecond)
-                  .millis()));
+  t1 = t0 + (kTimeoutMaxStreamDuration * grpc_test_slowdown_factor());
+  t2 = t0 + (kTimeoutHttpMaxStreamDuration * grpc_test_slowdown_factor());
+  CheckRpcSendFailure(DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED,
+                      "Deadline Exceeded",
+                      RpcOptions()
+                          .set_rpc_service(SERVICE_ECHO2)
+                          .set_rpc_method(METHOD_ECHO2)
+                          .set_wait_for_ready(true)
+                          .set_timeout(kTimeoutApplication));
   EXPECT_THAT(NowFromCycleCounter(), AdjustedClockInRange(t1, t2));
   // Test http_stream_duration of 3.5 seconds applied
   t0 = NowFromCycleCounter();
-  t1 = t0 + grpc_core::Duration::Seconds(kTimeoutHttpMaxStreamDurationSecond) +
-       grpc_core::Duration::Milliseconds(kTimeoutMillis);
-  t2 = t0 + grpc_core::Duration::Seconds(kTimeoutApplicationSecond) +
-       grpc_core::Duration::Milliseconds(kTimeoutMillis);
+  t1 = t0 + (kTimeoutHttpMaxStreamDuration * grpc_test_slowdown_factor());
+  t2 = t0 + (kTimeoutApplication * grpc_test_slowdown_factor());
   CheckRpcSendFailure(
       DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED, "Deadline Exceeded",
-      RpcOptions().set_wait_for_ready(true).set_timeout_ms(
-          grpc_core::Duration::Seconds(kTimeoutApplicationSecond).millis()));
+      RpcOptions().set_wait_for_ready(true).set_timeout(kTimeoutApplication));
   EXPECT_THAT(NowFromCycleCounter(), AdjustedClockInRange(t1, t2));
 }
 
-TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenXdsTimeoutExplicit0) {
-  const int64_t kTimeoutNano = 500000000;
-  const int64_t kTimeoutMaxStreamDurationSecond = 2;
-  const int64_t kTimeoutHttpMaxStreamDurationSecond = 3;
-  const int64_t kTimeoutApplicationSecond = 4;
+TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenXdsTimeoutExplicit) {
+  const auto kTimeoutMaxStreamDuration =
+      grpc_core::Duration::Milliseconds(2500);
+  const auto kTimeoutHttpMaxStreamDuration =
+      grpc_core::Duration::Milliseconds(3500);
+  const auto kTimeoutApplication = grpc_core::Duration::Milliseconds(4500);
   const char* kNewCluster1Name = "new_cluster_1";
   const char* kNewEdsService1Name = "new_eds_service_name_1";
   const char* kNewCluster2Name = "new_cluster_2";
@@ -2047,11 +2033,10 @@ TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenXdsTimeoutExplicit0) {
   listener.mutable_api_listener()->mutable_api_listener()->UnpackTo(
       &http_connection_manager);
   // Set up HTTP max_stream_duration of 3.5 seconds
-  auto* duration =
+  SetProtoDuration(
+      kTimeoutHttpMaxStreamDuration,
       http_connection_manager.mutable_common_http_protocol_options()
-          ->mutable_max_stream_duration();
-  duration->set_seconds(kTimeoutHttpMaxStreamDurationSecond);
-  duration->set_nanos(kTimeoutNano);
+          ->mutable_max_stream_duration());
   listener.mutable_api_listener()->mutable_api_listener()->PackFrom(
       http_connection_manager);
   // Construct route config.
@@ -2063,20 +2048,17 @@ TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenXdsTimeoutExplicit0) {
   route1->mutable_route()->set_cluster(kNewCluster1Name);
   auto* max_stream_duration =
       route1->mutable_route()->mutable_max_stream_duration();
-  duration = max_stream_duration->mutable_max_stream_duration();
-  duration->set_seconds(kTimeoutMaxStreamDurationSecond);
-  duration->set_nanos(kTimeoutNano);
-  duration = max_stream_duration->mutable_grpc_timeout_header_max();
-  duration->set_seconds(0);
-  duration->set_nanos(0);
+  SetProtoDuration(kTimeoutMaxStreamDuration,
+                   max_stream_duration->mutable_max_stream_duration());
+  SetProtoDuration(grpc_core::Duration::Zero(),
+                   max_stream_duration->mutable_grpc_timeout_header_max());
   // route 2: Set max_stream_duration to 0
   auto* route2 = new_route_config.mutable_virtual_hosts(0)->add_routes();
   route2->mutable_match()->set_path("/grpc.testing.EchoTest2Service/Echo2");
   route2->mutable_route()->set_cluster(kNewCluster2Name);
   max_stream_duration = route2->mutable_route()->mutable_max_stream_duration();
-  duration = max_stream_duration->mutable_max_stream_duration();
-  duration->set_seconds(0);
-  duration->set_nanos(0);
+  SetProtoDuration(grpc_core::Duration::Zero(),
+                   max_stream_duration->mutable_max_stream_duration());
   // Set listener and route config.
   SetListenerAndRouteConfiguration(balancer_.get(), std::move(listener),
                                    new_route_config);
@@ -2088,12 +2070,13 @@ TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenXdsTimeoutExplicit0) {
                           .set_rpc_service(SERVICE_ECHO1)
                           .set_rpc_method(METHOD_ECHO1)
                           .set_wait_for_ready(true)
-                          .set_timeout_ms(kTimeoutApplicationSecond * 1000));
-  auto ellapsed_nano_seconds =
+                          .set_timeout(kTimeoutApplication));
+  auto elapsed_nano_seconds =
       std::chrono::duration_cast<std::chrono::nanoseconds>(system_clock::now() -
                                                            t0);
-  EXPECT_GT(ellapsed_nano_seconds.count(),
-            kTimeoutApplicationSecond * 1000000000);
+  EXPECT_GT(
+      elapsed_nano_seconds.count(),
+      (kTimeoutApplication * grpc_test_slowdown_factor()).millis() * 1000);
   // Test application timeout is applied for route 2
   t0 = system_clock::now();
   CheckRpcSendFailure(DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED,
@@ -2102,15 +2085,16 @@ TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenXdsTimeoutExplicit0) {
                           .set_rpc_service(SERVICE_ECHO2)
                           .set_rpc_method(METHOD_ECHO2)
                           .set_wait_for_ready(true)
-                          .set_timeout_ms(kTimeoutApplicationSecond * 1000));
-  ellapsed_nano_seconds = std::chrono::duration_cast<std::chrono::nanoseconds>(
+                          .set_timeout(kTimeoutApplication));
+  elapsed_nano_seconds = std::chrono::duration_cast<std::chrono::nanoseconds>(
       system_clock::now() - t0);
-  EXPECT_GT(ellapsed_nano_seconds.count(),
-            kTimeoutApplicationSecond * 1000000000);
+  EXPECT_GT(
+      elapsed_nano_seconds.count(),
+      (kTimeoutApplication * grpc_test_slowdown_factor()).millis() * 1000);
 }
 
-TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenHttpTimeoutExplicit0) {
-  const int64_t kTimeoutApplicationSecond = 4;
+TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenHttpTimeoutExplicit) {
+  const auto kTimeoutApplication = grpc_core::Duration::Milliseconds(4500);
   // Populate new EDS resources.
   EdsResourceArgs args({{"locality0", {MakeNonExistantEndpoint()}}});
   balancer_->ads_service()->SetEdsResource(BuildEdsResource(args));
@@ -2133,32 +2117,32 @@ TEST_P(LdsRdsTest, XdsRoutingApplyApplicationTimeoutWhenHttpTimeoutExplicit0) {
   auto t0 = system_clock::now();
   CheckRpcSendFailure(
       DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED, "Deadline Exceeded",
-      RpcOptions().set_wait_for_ready(true).set_timeout_ms(
-          grpc_core::Duration::Seconds(kTimeoutApplicationSecond).millis()));
-  auto ellapsed_nano_seconds =
+      RpcOptions().set_wait_for_ready(true).set_timeout(kTimeoutApplication));
+  auto elapsed_nano_seconds =
       std::chrono::duration_cast<std::chrono::nanoseconds>(system_clock::now() -
                                                            t0);
-  EXPECT_GT(ellapsed_nano_seconds.count(),
-            kTimeoutApplicationSecond * 1000000000);
+  EXPECT_GT(
+      elapsed_nano_seconds.count(),
+      (kTimeoutApplication * grpc_test_slowdown_factor()).millis() * 1000);
 }
 
 // Test to ensure application-specified deadline won't be affected when
 // the xDS config does not specify a timeout.
 TEST_P(LdsRdsTest, XdsRoutingWithOnlyApplicationTimeout) {
-  const int64_t kTimeoutApplicationSecond = 4;
+  const auto kTimeoutApplication = grpc_core::Duration::Milliseconds(4500);
   // Populate new EDS resources.
   EdsResourceArgs args({{"locality0", {MakeNonExistantEndpoint()}}});
   balancer_->ads_service()->SetEdsResource(BuildEdsResource(args));
   auto t0 = system_clock::now();
   CheckRpcSendFailure(
       DEBUG_LOCATION, StatusCode::DEADLINE_EXCEEDED, "Deadline Exceeded",
-      RpcOptions().set_wait_for_ready(true).set_timeout_ms(
-          grpc_core::Duration::Seconds(kTimeoutApplicationSecond).millis()));
-  auto ellapsed_nano_seconds =
+      RpcOptions().set_wait_for_ready(true).set_timeout(kTimeoutApplication));
+  auto elapsed_nano_seconds =
       std::chrono::duration_cast<std::chrono::nanoseconds>(system_clock::now() -
                                                            t0);
-  EXPECT_GT(ellapsed_nano_seconds.count(),
-            kTimeoutApplicationSecond * 1000000000);
+  EXPECT_GT(
+      elapsed_nano_seconds.count(),
+      (kTimeoutApplication * grpc_test_slowdown_factor()).millis() * 1000);
 }
 
 TEST_P(LdsRdsTest, XdsRetryPolicyNumRetries) {
@@ -2252,11 +2236,10 @@ TEST_P(LdsRdsTest, XdsRetryPolicyLongBackOff) {
       "5xx,cancelled,deadline-exceeded,internal,resource-exhausted,"
       "unavailable");
   retry_policy->mutable_num_retries()->set_value(kNumRetries);
-  auto base_interval =
-      retry_policy->mutable_retry_back_off()->mutable_base_interval();
   // Set backoff to 1 second, 1/2 of rpc timeout of 2 second.
-  base_interval->set_seconds(1 * grpc_test_slowdown_factor());
-  base_interval->set_nanos(0);
+  SetProtoDuration(
+      grpc_core::Duration::Seconds(1),
+      retry_policy->mutable_retry_back_off()->mutable_base_interval());
   SetRouteConfiguration(balancer_.get(), new_route_config);
   // No need to set max interval and just let it be the default of 10x of base.
   // We expect 1 retry before the RPC times out with DEADLINE_EXCEEDED.
@@ -2285,19 +2268,17 @@ TEST_P(LdsRdsTest, XdsRetryPolicyMaxBackOff) {
       "5xx,cancelled,deadline-exceeded,internal,resource-exhausted,"
       "unavailable");
   retry_policy->mutable_num_retries()->set_value(kNumRetries);
-  auto base_interval =
-      retry_policy->mutable_retry_back_off()->mutable_base_interval();
   // Set backoff to 1 second.
-  base_interval->set_seconds(1 * grpc_test_slowdown_factor());
-  base_interval->set_nanos(0);
-  auto max_interval =
-      retry_policy->mutable_retry_back_off()->mutable_max_interval();
+  SetProtoDuration(
+      grpc_core::Duration::Seconds(1),
+      retry_policy->mutable_retry_back_off()->mutable_base_interval());
   // Set max interval to be the same as base, so 2 retries will take 2 seconds
   // and both retries will take place before the 2.5 seconds rpc timeout.
   // Tested to ensure if max is not set, this test will be the same as
   // XdsRetryPolicyLongBackOff and we will only see 1 retry in that case.
-  max_interval->set_seconds(1 * grpc_test_slowdown_factor());
-  max_interval->set_nanos(0);
+  SetProtoDuration(
+      grpc_core::Duration::Seconds(1),
+      retry_policy->mutable_retry_back_off()->mutable_max_interval());
   SetRouteConfiguration(balancer_.get(), new_route_config);
   // Send an initial RPC to make sure we get connected (we don't want
   // the channel startup time to affect the retry timing).
@@ -2400,10 +2381,9 @@ TEST_P(LdsRdsTest, XdsRetryPolicyRetryBackOffMissingBaseInterval) {
   retry_policy->set_retry_on("deadline-exceeded");
   retry_policy->mutable_num_retries()->set_value(1);
   // RetryBackoff is there but base interval is missing.
-  auto max_interval =
-      retry_policy->mutable_retry_back_off()->mutable_max_interval();
-  max_interval->set_seconds(0);
-  max_interval->set_nanos(250000000);
+  SetProtoDuration(
+      grpc_core::Duration::Milliseconds(250),
+      retry_policy->mutable_retry_back_off()->mutable_max_interval());
   SetRouteConfiguration(balancer_.get(), new_route_config);
   const auto response_state = WaitForRdsNack(DEBUG_LOCATION);
   ASSERT_TRUE(response_state.has_value()) << "timed out waiting for NACK";
diff --git a/test/cpp/end2end/xds/xds_server.h b/test/cpp/end2end/xds/xds_server.h
index 066629b101b..12e226c33c3 100644
--- a/test/cpp/end2end/xds/xds_server.h
+++ b/test/cpp/end2end/xds/xds_server.h
@@ -853,7 +853,8 @@ class LrsServiceImpl : public std::enable_shared_from_this<LrsServiceImpl> {
           }
         }
         response.mutable_load_reporting_interval()->set_seconds(
-            parent_->client_load_reporting_interval_seconds_);
+            parent_->client_load_reporting_interval_seconds_ *
+            grpc_test_slowdown_factor());
         stream->Write(response);
         CountedService<typename RpcApi::Service>::IncreaseResponseCount();
         // Wait for report.