MBA-Sailor

Not sure if my 996 is supposed to sound like this, but since I've had it (3 weeks) I hate the engine sound. There is no growl, no exhaust note... it just has a "whine". It sounds like an electric car... almost like a kazoo. Not sure if that's normal, or if something is screwy with my intake or exhaust (I do think I have a loose heat shield, or maybe a rattling cat), but it drives me nuts.
I listened to my friend's 996... but her car has an aftermarket exhaust so I can't compare stock to stock (her exhaust sounds AMAZING... not too loud, but very growly).
Thoughts?
(ps - I plan to do the silicone tube air box mod this week)

Spokayman

M96 and M97 engines have a distinctive sound that includes a kind of "mechanical whine" or "whirring" noise.
If the exhaust is stock, it can become the loudest thing you will hear from the engine.
But even with my stock exhaust systems, I've noticed that there is a change in sound when you are deep in the throttle and above 5K RPM.
I also have a rattling catalytic converter that sounds very strange sometimes and is definitely a poor quality sound. Perhaps that's what you're experiencing?

MBA-Sailor

Hi Spokay... yes, I think you are spot on. In low gears (so not much wind or road noise) up until about 4k or 5k RPM, the car just sounds like an old Toyota Corolla backing up in reverse... just a mechanical whine, like a transmission in reverse. I hate it.
I guess maybe it's time to either bypass my cats (I'm in FL, there are no emission controls here) or get an aftermarket exhaust...

Spokayman

MBA, Look into the Fister D or "Gundo Hack" mods to the mufflers. Lots of threads about this inexpensive and apparently very impressive sound modification. It's actually a bypass of muffler chamber/s via a welded in pipe.
I've been on the fence about doing this mod because the 996 is also driven by my wife whom I believe will not be very impressed with the sound...go figure....

MBA-Sailor

Looks like I need to find a shop in Tampa to do that...

MBA-Sailor

Or, remove my cats, since I think they may be rattling.
Anyone know what the difference in sound is between a cat bypass and a FisterD mod?

996pp

Fister kinda makes it sound like a stock 993. Cat bypass you get a nice deep growl at low rpm's and screams like a virgin at WOT.

SWK6Cup

you remove the cats, you might not pass a state inspection, if they have one in FL. Fister D, call Darin at Dipietro (sp/) Motorsports, have him ship you a set, you send him yours........inexpensive and fantastic. If you need more, check into high flow cats and an x pipe system.

frisbee91

+100

Do this. You can have your local exhaust shop do this mod for cheap (probably under $200). You will not regret it.

There is a TON of information on this if you search, and several ways to approach the mod.
Here's just one of many links:
https://rennlist.com/forums/996-foru...-fister-d.html

alpine003

In addition to the fister mod, don't forget to supplement the silicone with the buck wheat mod too.

Dennis C

I agree with the comments on Fister mufflers. They are inexpensive and they sound fantastic. Engine sound is one of the things that I really miss about my 996.

Invius

I'm also in Tampa -- I had Vortex Motorsports on Hillsborough Avenue do the Gundo Hack/Bypass Mod to mine. They had done it before and knew what they were doing -- it's probably the best $$ I spent on the car.

DS

MBA-Sailor

Country 911 - there are no emission inspections in FL. Hence, my quandary... if my cats are going bad, should i just bypass them, and not do the Fister mod (since I think with no cats and Fister mod the exhaust may be too loud). And, if I do the Fister mod, and and in the future have my cats go bad, I'd then either have to buy new cats or reverse the Fister mod...

SWK6Cup

MBA-Sailor:
Fister D mod is the way to go. Inexpensive and simply awesome, as many others in here can/will attest to. You will love it and would never have to worry about "reversing" the Fister D mod. Try it, you should love it! Talk to a reputable indie mechanic about removing the cats, altogether. I'm sure it would reduce back pressure, (might possibly effect low end torque, too), would certainly add more sound, but not sure if it would cause the OBDII to throw a code. One of the others, more learned that I, might want to chime in.
BTW: you are lucky there are no emissions inspections in FL, certainly less to worry about!

Topaz330ci

show us a sound clip so we can try to help...

When my clutch interlock switch went, the growl and the whole engine note went away... sounded kinda like what you're mentioning. When I fixed that, boom, back to normal.