82-T/A

Well, unfortunately, it's just not possible to get a V8 sound from a 4 cyl. Being what it is, a 4 cyl produces a certain type of resonance that can make it sound ricey. A perfect example is my 2006 Pontiac Solstice. I have a totally stock cat-back exhaust, but an aftermarket hi-flow cat, a tubular shorty header, and a cold air intake. It goes like hell (high 14s), but sounds like the most ricey thing I've ever heard. It kills me.

There are a few things you can do to reduce the noise. There are two things to look at, 1) reducing the noise as YOU hear it, 2) reducing the noise eminating from the exhaust.

For #1, there are many things you can do inside your car to help eliminate the sound. You can lay dynamat in many places in your car. The Porsche already comes with some sort of factory dynamat in strategic places (inside of the outter door panel, inside of the rear quarters, floor boards, etc). What came with the car is better than what most cars come with, but it's still not very substantial. One of the things I've noticed too is that over time, it will dry up, and peel away from the metal. The factory rubber tar sheets also are not full-sized panels. In the door, for example, it only takes up maybe 2/3rds (if even that) of the inside of the door panel. You can correct this by buying your own dynamat, filling in the spaces, and then spraying all the other spaces with some rubberized undercoating (also serves to help deaden sound). The ONLY thing I don't like about this is, in your case, a convertible 944 S2 is a fairly uncommon car. It's not like a normal 944 and holds much more value. If this is just a regular daily driver to you, then I'd go for it, but it's somewhat more of a collectible car than anything. I'd do this to a Porsche 914, but not to a 1973 Porsche 2.7 RS Carerra.

So, you can do that. You can ALSO have an upholstery shop put an additional layer of fabric in the headliner of your convertible top, this will also significantly reduce road noise. As with anything, you can also help reduce noise by replacing your rubber gaskets if they're worn and have shrunk.


Now, for #2, you can add a resonator to the exhaust before the muffler. Also, if you have a K&N air filter in your car, you would want to replace that with a stock filter (believe it or not, a K&N air filter DOES contribute to more air intake and exhaust noise).

Other than that, any more that you do to the exhaust will really start to have an affect on power.


Todd

ejsaenz

Thanks for all the info Todd.

I guess I'll probably go the Dynamat way. I know the hood has no insulation or sound deadening on it. Just a little piece of foam type stuff near where the distributor cap is when the hood is closed. I guess that may help a bit.

The resonator sounds like a good idea too.

I had a buddy that in the late 80's had a Ford Courier mini-truck that he put a "Sonic Turbo" brand muffler on it and it sounded very deep, almost like a V8 under the hood. It was kinda funny because all sorts of V8 Camaros,Novas, and Mustangs always wanted to race him. He just laughed and told them that it was only a 4 banger. He ALWAYS lost, 'cept when they dropped the clutch too soon and stalled!!

Oh well, I hope the one that holds the purse strings will allow me to spend some money and make it quieter.

dede944

Turbo it

Turbo will eat some exhaust sound...

ejsaenz

I'd love to turbo it, but only if and when the engine dies. either that or a V8!

I dunno if the cabrio can handle the torture I would give it. My mechanic claims that I can't really put too stiff a suspension because it may crack my windshield.

Then again all that is in the future sometime, right now I just want to enjoy it and try and make it quieter.

billthe3

Rock seems to be having no issues with his turbo cab, aside from the blown trannies...

Cory9584

These should do the trick

http://www.omarksafety.com/category....ff_NRR_25_.cfm

Yabo

BTW you can put a sub in the trunk and it will work fine... thats what most cars have..

Yummybud924

yeah I hate loud exhausts as well. whenever I see someone reving their rice exhaust I don't get it.

the stock exhaust on my 944 is fine, not to loud and doesn't sound ricey.

I saw some kid today with a double exhaust on his protege with 2 huge ricer mufflers sticking out the back and it was crazy loud in a really bad way, sounded like he was reving a huge blender.

Dynamite 76

Maybe your car has an exhaust leak.

JohanvdWalt

I had great success by replacing my rear muffler with a bigger unit. Only way to absorb more sound is by going bigger. The exhaust guy explained something about changing the frequency to get away from a resonance - I don't understand a thing but it worked wonders.

Dan Shea

you may not have an exhaust leak but the internals on the muffler could be shot. might try replacing with a new stock setup

Robby

I can't believe I just waded through all those messages- I want my 5 min back!!!

Ok, I've worked on this a LOT!!! I absolutely HATE LOUD CARS!!! If I wanted a bullseye on my back for every cop in KnoxVegas, I'd just get a Supra TT w/a big F&F sticker on the back & be done w/it.... Several things Todd said are true, as are several other comments... But, you can go a lot further...

As many here know, I'm a weight fanatic. You have a rear seat, right? any opposition to pulling it out? You can shed a few pounds AND make it quieter- a lot of noise comes through the transaxle & the rear wheel wells, although your's, being a convertible, probably holds the wheel well noise back a touch but then also lets in noise through the convertible top. BTW- adding a turbo will not help much- C&D & R&T tests when these cars were brand new only showed 1-2Db dif b/t turbo & NA at all speed ranges. It's something, but not what people usually think.

Anyway, Kuhl951 put me onto several things. Polyken tape 360-35 & Nuprene. You can get the Polyken at Merco Tape online & I can forward you info to get the Nuprene in big sheets (for very cheap) on ebay- fuseguy.net or fuseguy something... anyway, they are big 4x6ft sheets for ~$10/ea. the Polyken comes in rolls- the 35 means 35mils thick & it also comes in 45mils, but is harder to find- I have 35mils & it sticks better than DMat, is lighter, & is a lot cheaper too & much easier to work with. Put it inside your doors & then lay a layer of Nuprene (a Neoprene type substance- very light- open cell on one side closed on other- used for quieting jets) down on top of Polyken. Then, do the side of the door that the door panel will lay down on in Polyken- Nuprene will be too thick to get the door panels on over it, so Polyken will do there, but on the innermost inside panel, use both. THEN, do the entire hatch (trunk in your case) area, underneath the carpet, as well as rear wheel wells & the entire seat bottom (IF removing seats) & carpet over like Rich Sandor did....

You can use some Nuprene under the hood probably or buy one of the pads that Rob Budd is selling- they aren't foil-type so wont reflect heat back to engine.

THEN, it's muffler time. I JUST saw an S2 from underneath today & this guy had an ODD system. I would need to see pics of yours (or stock S2) from underneath, but IIWY & had some money to spend, I'd get a Bursch 2.5" test pipe (~$250) & weld a free-flow cat (~$175 + <$20 labor) into it, nearer to one end, & a resonator (as long as will fit- ~$50 + <$20 labor) right after it (actually, I'd do the resonator BEFORE the cat). THEN, you can do a a 2.5" catback of some sort. I'd find a place to make one in the exact shape & length of your stock setup (probably less than $300) & then weld another muffler (Borla XR1 probably- ~$130 from Summit + <$20 labor) into the diagonal section. THEN, you can use a quieter type (but still unrestrictive) muffler (<$100) for the end. THEN, you could even put a short resonator on for a tail pipe (~$50 + <$20 labor), as my SFR 3" Catback has a 17" long tailpipe- not sure why everyone makes the tailpipes so long on these cars- it's really sort of odd. But you could easily weld a cheap $50 resonator onto the end of a muffler & weld the hangars onto the outside of it, then use a short section of pipe to finish the tip. In short, piece together an exhaust full of various mufflers & resonators & KEEP a cat, only a freer-flowing one, preferably. NA cars actually NEED a little bit of back-pressure anyway... I MAY just be selling a 2.5" Bursch here pretty soon, but not sure how much life will be left in it until I get it off, but it DOES have a 12" resonator welded into it at this time. I'm only mentioning 2.5" instead of 3" b/c your's is an NA & 2.5" is still larger than stock...

Last- the exhaust manifolds on these cars are notorious for cracking- especially turbos, but NA's too & THAT makes it really loud- get the manifold checked & weld cracks if needed (OR if you're made of $, get SFR headers or something...)....

Yes, I've put WAY too damn much thought into this...


JohanvdWalt - do you have a full-size copy of that test in your signature? Is it in English...? Could I get a copy...?

JohanvdWalt

JohanvdWalt - do you have a full-size copy of that test in your signature? Is it in English...? Could I get a copy...?
__________________

I do have it in Pdf but its Afrikaans, I've got the CAR test in english though if you want that.

Robby

Thanks- you have PM... :-)

82-T/A

Robby,

I'm like you, for the most part in that I don't like loud cars. That said, if it's appropriate, then I don't mind loud and obnoxious. I have a 1981 Pontiac TransAm with a 1969 Oldsmobile 455 big block in it. It's profusly loud and obnoxious. But on a more refined car, like my 944, or even my Crown Victoria... I want it to be quiet, but powerful.

One thing I wanted to ask you about though... is in the trunk area. (84/944). The factory trunk area only has a single square of sound deadening material, and it appears as though it was installed prior to painting. It's REALLY REALLY clean looking, and even though it's covered by carpet, I would hate to stick dynamat to those painted panels. Do I have any other options? Perhaps attaching it to the underside of the carpet?

Or maye I just need to buy some more jute backing?

I've attached dynamat in the areas that I will NEVER see... but there may be times that I'll expose the rear trunk area, when I'm messing around in the spare tire well, and I'd hate to see tacky dynamat attached to the panels.

let me know what you think...


Thanks!!!

Todd,
2006 Pontiac Solstice
2002 Ford Crown Victoria LX-P74
1987 Pontiac Fiero SE / V6
1984 Porsche 944
1981 Pontiac TransAm WS6
1973 Volkswagen Type-2 Transporter