macadamianut

Has anyone ever had a cat-delete test pipe fitted? Any notable gains or problems? Waste of time?

Are there exhaust systems available that produce any kind of real gains with a stock engine?

Just curious.

Damian in NJ

Here in NJ, if you delete the cat and get caught they fine you $1,000 for every year since your last inspection . . .

Stephenwz968

I'm not so sure you would see any real gains as you need some backpressure for the engine...that said, I know Rich Glickel has had great gains with his exhaust, although I'm not sure of his setup.

Steve

PorscheDude1

Check rsbarn.com
They make a nice exhaust with all the options including a test pipe.

Damian in NJ

As you can see from my signature, I have a high flow cat along with a full Cargraphic exhaust. As I recall their TuV approved claims are around 12-15hp gain, with some extra savings coming from weight loss compared to stock. Other than TuV ratings for Cargraphic I don't think any systems sold in the US (RS, B&B, Fabspeed, Powerhaus) have independent dyno testing-although they all may show gains as well.

PorscheDude1

If you go with just a test pipe, you may lose some back pressure. This may hurt performance.

luckett

Pure speculation. The 968 stock exhaust does not have a shortage of back pressure behind the cat. Have you ever see the inside of the resonator or muffler?

If you open up the exhaust flow, you get a huge increase in throttle response, which is one of the characteristics of the 968 that I most dislike. Even if there is a slight power loss (I'm not saying there is), the gain in driveability is worth it.

You're probably better off deleting the resonator before the cat.

Stephenwz968

I had an exhaust built for my coupe where I deleted the resonator, and let me tell you, it was LOUD!
Steve

luckett

louder than a cat delete?

macadamianut

I'm definately not interested in loud, and if you guys don't think it chokes the car much, I'll just leave it all alone. The exhausts I am seeing are fairly pricey for a 12-15 hp gain.

Will focus energy on some snazzy suspenders instead.

luckett

The stock 968 exhaust definitely chokes the car, but the side effect of opening it up is usually more noise. There may be systems out there that allow better flow with the same noise, but there is also a lack of unbiased comparison tests of the available exhausts.

If you want your car to perform better get:
1) autocross/track time
2) good tires
3) good alignment to performance specs
3) good shocks
4) thicker sway bars
5) better brake pads

If you want to impress your friends get:
1) expensive stainless steel exhaust
2) expensive stainless steel headers
3) wheel bling

These are fantastic cars that don't really need much to perform well.

FRporscheman

How much of that exhaust was still factory? What brand/type of muffler and cat did you use?

Anyone know how loud a stock exhaust is without the muffler? Less than 92dB?

luckett

what did you do, cut your muffler off?

FRporscheman

I would never do such a thing. I would totally unbolt it though, if there weren't so many cops and CHP around here. A disadvantage to living so near the only local freeway.

I want to take it off for Laguna Seca. Don't lots of people drive without mufflers? I know this won't give me much power... I just think it will sound cool on the track.

luckett

without the resonator and muffler it will be way too loud for laguna.