Thunder22

I have a 2023 HTC with just under 700 miles on it and I can hear what I can best describe as a "mechanical clutch" sound when the car swtiches from V8 to V4. When I hear the sound, i usually look down at the dash and can see the V8 icon change to V4.

Is this normal? do any of you hear similar?

SoCal C8

Some hear it, some don’t…..I don’t and anyone else in the car haven’t mentioned it. I wouldn’t even know it switched other than the green V4 that appears below the rev counter.

Thunder22

my bad, the subject line should have read from V8 to V4.

jovette

Same for me.

Kvou812

6 months and 3k miles and I haven't heard the switch in mine

brocco

The only thing I hear is the sound change from the AWE exhaust I put on when it goes into V4 mode. As a result of that and other driving habits, I mostly stay in manual mode.

DebRedZR1

fixed

Thunder22

Thanks Deb.

dahogan

This, for my '21 with over 6000 miles.

rkrupka

I can hear a very slight 'wooosh' when switching to V4 only if the car is very quiet and a very light pedal - no stereo, no top down, no windows open, no road noise, usually between loke 20 and 40 mph as any other speeds have too much noise to hear the valves closing.

Andybump

I don't so much hear the "transition" as hear the actual difference in the engine sound between V4 and V8. I have never heard the swoosh sound but more than one poster has reported that. The NPP valves in the exhaust system close, and if you have NPP those valves close as well. So there may be a noticeable change in exhaust note, particularly if you have an HTC. It comes right out of V4 if you take your foot off the gas, or if you press the throttle just a little more. Anyway, what I hear, although subtle, is more like the sound of an engine lightly lugging. I am NOT saying that it is lugging, nor that it is any problem for the engine. Its just the sound that I hear, with the top down on the HTC. When I take a leisurely drive on back roads with periods of hills and flats, in tour mode, it will frequently shift in and out of V4. While it does not generally bother me, I prefer not to hear it. I more often use Z mode with engine/shift set to track - this prevents V4 mode.

There is supposed to be some Active Noise Cancellation that is supposed to reduce whatever unpleasant sound V4 mode makes. It is in you manual, but its does not explicitly say its purpose is to mask the V4 mode. But Tadge said that verbally in a discussion a while back. In any case, I believe that cancellation, if it exists, can only work if the top is up. I rarely drive with the top up, but I do not recall ever noticing any sound associated with V4 mode with the top up.

Thunder22

The sound is the same top up or top down, and it's not a whoosh, it's a mechanical sound, like when you pop a clutch and the RPMs are too low for the gear you're selecting, like a mild clunk. The ANC doesn't mask this noise.

Reading the responses so far, I'm betting it's the NPP valves.

Andybump

You can test that by listening to the NPP valves open and close with the engine off, if you want. Without starting the engine, put the car in service mode, by pushing and holding the start button without pressing the brake, until the car fully wakes up. I think it may have to be held for 5 seconds or more (page 191 of the 2023 manual). In that mode I can then move the drive mode between Tour and Track and I can hear the NPP valves clicking and moving, sometimes with a creaking sound. Or, I can also using Z drive mode, switch the engine sound between the different settings, and also hear the NPP valves move, click, and creak. Its not loud on mine but clearly audible with the engine off. I do not believe this causes the other set of valve, the AFM valve in the exhaust system to move. I have done all this - so not making it up.

I agree that ANC will not mask the type of noise you are describing. I don't hear what you are describing - it may not be normal.

TwoTime

2023 Z51 w/ 6,000 miles on it since June.
There is a distinct "clunk" as the system shuts down the 4 cylinders and the V-4 light turns on.
I spend most of my time without the radio on when I am road tripping so I have become very used to the quiet in the cabin.
I'm guessing that it is the solenoid shutting off the additional cylinders.
Never bothered me.a bit.
Absolutely LOVE driving this car.

NAVY_LDO

Sometimes I hear it and sometimes I don’t but what I hear is the audible tone shift from the exhaust, nothing mechanical. Same on 21 coupe and 23 HTC.

LT2/3LT

If it wasn't for the illuminated, green, V4 symbol on the display, I'd never know when it switches from 8 to 4!

Mike's LS3

My 2021 has 7000 miles and I cannot hear any difference between V8 and V4 engagement. I turned off the radio and tried listening for it while watching the V4 green light illuminate and I hear nothing.

RKCRLR

I can hear it if I'm listening for it. If I'm not focusing on it when driving I don't notice it.

Bob Paris

This is my experience as well.

gabsdad5