[DorsoDuroJohn]

Hi all, 2021 LT1. 20k miles, wet rainy cold evening.

Had the rear seats down so the sound is probably more noticeable, but have never heard this before or since.

Sounded like a damn supercharger when i would get on the gas coming from the rear of the car, it was a higher pitch whine, and sounded awesome. But as quickly as it was there, it was gone, probably 45 seconds later after coming to a stop sign.

NPP exhaust
No mods

any ideas?

[FlukeSS]

Originally Posted by DorsoDuroJohn

Hi all, 2021 LT1. 20k miles, wet rainy cold evening.

Had the rear seats down so the sound is probably more noticeable, but have never heard this before or since.

Sounded like a damn supercharger when i would get on the gas coming from the rear of the car, it was a higher pitch whine, and sounded awesome. But as quickly as it was there, it was gone, probably 45 seconds later after coming to a stop sign.

NPP exhaust
No mods

any ideas?

Sound tube probably, it amplifies intake suction sound and engine sound inside the car.

It sounds like the car is taking huge gasps of air when the car shifts right? Almost like a waste gate or blow off valve but not as hissing high pitched. More like if you clinched your teeth open your mouth and breath in fast through the sides of your mouth it would sound similar.

That's normal sound if that is how you describe it.

[DorsoDuroJohn]

I guess it could be that, it literally sounded like a supercharger to me. Not exactly like a blow off or waste gate. It was while on throttle, not shifting. For sure from the rear of the car.

[FlukeSS]

Originally Posted by DorsoDuroJohn

I guess it could be that, it literally sounded like a supercharger to me. Not exactly like a blow off or waste gate. It was while on throttle, not shifting. For sure from the rear of the car.

Weird maybe its not what I thought it was. Sure someone else will chime in if they have other ideas.

Turbo maybe? Not all turbos are loud or voicetress. More so smaller turbos. Have you driven a stock camaro before, would you know if you had a turbo?

[DorsoDuroJohn]

LOL, it's an LT1 with the V8. No turbo's, no superchargers stock. Now if somebody said the factory installed one i wouldn't complain.
I've had a couple subaru wrx and STi's, so i'm familiar with the turbo sounds.

[FlukeSS]

Originally Posted by DorsoDuroJohn

LOL, it's an LT1 with the V8. No turbo's, no superchargers stock. Now if somebody said the factory installed one i wouldn't complain.
I've had a couple subaru wrx and STi's, so i'm familiar with the turbo sounds.

Fair enough, just that some cars have turbos and you wouldn't know they had them.

A 2016 Chevy Trax LTZ has a turbo, and no one would know it if they didn't look up the specs (*cough* also why Chevy stopped building them, because it was taking sales away from the Equinox because they were cheaper and had better specs than the base model Equinox)

Pontiac Grand Prix GXP or GTP has a turbo and no one would know it if they didn't look up the specs.

I guess what I mean is if you bought your car used, doesn't mean it doesn't have a turbo. But I guess you bought it new.

[NotFast]

I've found that DOHC V8's sound like they've got a supercharger when you wind them out... a sound that the OHV small block does not.

[JSH]

Put LT, hi-flows, and AB on it, and you won't hear it!

Originally Posted by DorsoDuroJohn

Hi all, 2021 LT1. 20k miles, wet rainy cold evening.

Had the rear seats down so the sound is probably more noticeable, but have never heard this before or since.

Sounded like a damn supercharger when i would get on the gas coming from the rear of the car, it was a higher pitch whine, and sounded awesome. But as quickly as it was there, it was gone, probably 45 seconds later after coming to a stop sign.

NPP exhaust
No mods

any ideas?

[easttxss]

Originally Posted by FlukeSS

Pontiac Grand Prix GXP or GTP has a turbo….

Nope, those were supercharged


Sent from my iPhone using Tapatalk

[FlukeSS]

Originally Posted by easttxss

Nope, those were supercharged


Sent from my iPhone using Tapatalk

Were they supers? Either way point remains the same, You don't hear them.

[N Camarolina]

I heard a somewhat similar noise from the rear diff (high pitched like gear whine, like the gears were "singing") after I tracked the car for the first time. It went away after I changed the rear diff fluid (2nd change, shortly after that first track event). In my case, I'm guessing it was the fact that giving the rear diff a work-out on the track wore the grears in and created debris in the diff fluid, and changing out the fluid fixed the issue. The rear diff fluid on SS 1LEs gets dirty rather quickly! Not sure about LT1s.

You said you heard yours on a cold, wet evening. That was probably a low traction environment and gave your rear diff a workout, thus leading to some debris and the noise. Not sure why it went away on it's own. Maybe it took a while for the debris "sludge" to get diluted out in the pool of (realatively more clean) diff fluid, which sits in the bottom of the diff and acts like a resevoir).

If you are handy, you can always change the diff fluid yourself before the normal required service interval.

[DorsoDuroJohn]

Rear diff fluid was recently changed, maybe 3k miles ago.