isn't no pipe, better than ANY pipe?

[ds475]

isn't having no kind of muffler on my car better than having ANY kind of restriction, such as a muffler? the less restriction there is, the better, right?

[ae1969]

On Turbo vehicles the theory holds true........too much back pressure and the turbo does not spool up as efficiently as it should

On NA vehicles you need a certain amount of back pressure. You can actually loose power with the wrong exhaust set up.

[ds475]

so the RIGHT kind of exhaust helps? is the stock one not a good one?

are there some cheap but good ones out there?

[afx]

There is nothing really wrong with the exhaust on the NA. From what people have done, there is not all the big of an increase in horsepower from changing the exhaust. The biggest reason people seem to do it on the NA is to get a different sound out of the car. If you put a new intake and exhaust on it will completly change the way the car sounds.

[Scootin159]

Actually no restriction gives more high-rpm horsepower, more restriction gives more low-end torque (or low-rpm horsepower, however you want to say it). Both of these have extremes however.

To see how the exhaust restriction can add horsepower: First you have to realize that the exhaust isn't really a "flow" as much as "ocillations" with 2 exhaust bursts per revolution of the engine. The way the exhaust can add power is it puts those ocillations into harmonics with each other so that the exhaust "pulse" is timed just right to actually PULL the air out of the pistons (thus better than no restriction). At high-rpm's those occilations become closer to just a continuous flow, and that's when just an open exhaust is better.

For around town you'll want the low-end torque of a good exhaust system to give ya more power, but at the track an open exhaust could be a LITTLE better. Really the stock exhaust is about as good as you'll find (other EXPENSIVE systems MAY add 3-5hp, but probably sacrifice an equal amount of torque). As said above, you can change the sound with a different exhaust though.

Anyways, you'll always want at least some type of exhaust system if only to just keep the exhaust gasses from getting into the car (notice even NASCAR & Formula 1 use exhaust systems).

[SoCal Driver]

In other words: Save your money. Keep it stock.

[ds475]

well, i didn't plan on spending money... i've just been driving without exhaust on my car for a while...

[perfecto951]

i bet it sounds not so good. even for a 944.

[ds475]

well... i admit, it is rather loud.

[repoman]

you need a nominal amount of exhaust back pressure

[fty]

Ok so running MSDS headers which promise 14% more HP and running a testpipe wont increase HP that much? -chris

[Paul Glasson]

I have always been led to believe you will burn valves if you run long term with insufficient back pressure. Perhaps guys like Scootin will be able to elaborate, he had some interesting stuff to say about oscillations and harmonics.

[repoman]

I'm with Paul on this

[profssr2017]

I'm surprised you drove it without an exhaust system - they are extremely loud! painfully loud.