RS3 Vibration when letting off throttle... is this normal?

Hi everyone. I purchased an RS3 in August and have loved it so far. I’ve recently been wondering about a few things my car has been doing and am not sure if it’s normal or not. The car is on stage 2 Unitronic running full supporting mods, including a Unitronic yellow dog-bone mount. First thing I’ve noticed is the car makes a transmission whine noise similar to the sound of straight cut gears when past 4th gear; it doesn’t do it in any of the first 3, just the last 4. I’ve also noticed some noticeable vibration when I let off the throttle in the lower RPM in some gears. Again, it doesn’t happen in the earlier gears, and it also doesn’t happen every time, but does happen multiple times per drive. You can really feel the vibration in the steering wheel. I’ve checked through forums and haven’t been able to find concrete answers to my question, so I thought I’d ask if anyone has had similar experiences with their Audi models. Thank you!

I’d probably start with tires being out of balance. It’s cheap to have a shop check the balance, and in my experience, it’s more pronounced while cruising at a constant speed or at higher speeds (60 mph).

@Heath
That makes sense. I’ll definitely get the tires checked. Thanks for the suggestion!

If that’s not it, maybe the diverter valve is failing? It can fail in a few ways, but one way is it can get stuck, preventing boost pressure from being evacuated when you let off the throttle. This forces the air to bounce against the compressor. With an intake, you should be able to hear it as a flutter on the turbo instead of the nice PSSSHHHH noise of air being evacuated. This is kind of a long shot, but I figured I’d throw it out there.

@Asher
I actually replaced the diverter valve in November since the last one was mid-fail. So hopefully that’s not the issue.

With a newer RS3 like yours that’s heavily modified, I’d see about getting a dedicated motorsport garage in the area to take a look. There’s a lot that could be going on, and having a pro deal with it for a couple hundred bucks is probably cheaper in the long run.

@Dakota
Yeah, I’ll definitely consider that. I want to make sure everything is in good shape.

Keep me posted if I can help further. I’m not SUPER intimate with the RS3, but I can definitely try. Wheel balance issues you should feel most pronounced in your steering wheel, although the whole car should vibrate some. I suggest it because I’ve had wheel weights fall off my wheels before.

@Dez
Thanks! That’s good to know. I’ll keep an eye out for that.

Definitely a possibility, especially if you tracked yours in Sebring in September. Looking to get suspension and tires done anyway? I’ll for sure keep you updated.

Cary said:
Definitely a possibility, especially if you tracked yours in Sebring in September. Looking to get suspension and tires done anyway? I’ll for sure keep you updated.

Absolutely! I’m planning to get the suspension and tires checked soon.