fedmax

Hi all

I recently put a Tuning Exhaust from Tubistyle (Italy) on my 996 Turbo MJ 2002. The exhaust is ok from the outside, not too loud but I have a huge issue in the cabin: with low revs (1500-2500rpm) I get deep tone resonance inside the cabin to a level that is not fun to drive long distances. The exhaust is cool but I need to get rid of that resonance.

Does anyone of you have experience with sound insulation for the cabin? What material would you use and where would you place it? E.g. is there enough room underneath the carpets behind the back seats?

Any hints or links are helpful.

Thanks
Ronny

TT Surgeon

I think you need a different exhaust. The tubi 997tt exhaust is exceptional and has zero drone/resonance, the 996 version is completely different.
I would try and find a used europipe quiet or the like.

fedmax

The thing is I got the exhaust with my car and I quite like the sound. The engine tuning is configured for the sport cats of the tubi.
It puts a huge smile on my face whenever I go above 4000rpm, specially in a tunnel . If there is any good insulation material that limits the drone/resonance I'd like to go for that route even if I need to add weight to the car.

Any ideas apart from changing the exhaust ?

adam_

IMO it is folly to add pounds and pounds of 'stuff' to try and change the resonance frequnency of the cabin.


Strip out the interior and add 40+ lbs of dynamat, reinstall all the matting, and maybe it will change it.

A

tvurt

dynamat will not help that.

1) get a new exhaust
2) don't drive at that rpm. Just rev through it and cruse in a lower gear, like 5th instead of 6th. ect.

I use method #2 and just rev the car a bit higher, like 2900 rpms for highway.

Tom

JG 996T

So, did you just add the exhaust, or did it come with the car?

If the former, go back to stock (or other); the latter, get a different exhaust (lots of debate on here, and 6speed about exhaust "drone" and "resonance"). I agree with everyone else that insulating the cabin is not a good solution.

fedmax

It came with the car plus stock exhaust. What I'll try before going back to stock is to check if I can change anything to the mounting of the exhaust i.e. add a damper/rubber piece to decouple it from the chassis...what do you guys think?

vanHunks

I had a Tubi exhaust on a BMW M5 (the E39 V8 model) which removed the standard exhaust's resonators. Had the same effect as you're experiencing but it wasn't not bad enough to prompt me to do anything about it. I suggest you consult Tubi themselves or a local exhaust specialist to look into the possibility of altering the exhaust in some way (adding resonators - ?).

fedmax

I did add some Alubutyl insultation about 2 weeks ago...little effect about 10% better. The good effect is that I do not hear the relays vibrating anymore. Anyway I'll take the exhaust off this Thursday, will do a performance tes with the driftbox to see how much power I loose.