TDS911

Looking for just a tad more higher rpm power and a tad more exhaust sound volume from my 3.2 but don't want obnoxious and unrefined. I plan to stick with the stock main muffler.

Straight pipe car bypass or the one with the pre-muffler?

Thanks in advance.

SoCalRayRay

I couldn't be happier with my cat delete and Fabspeed 1 in 1 out exhaust. It's not very loud or drone in the car and everyone says it sounds awesome outside.

Amber Gramps

Cat bypass and pre-muffler is the same animal. If you are looking for horsepower loose some weight. I had the bypass and took it off because of the smell. I didn't want to deal with the smell. I gained far more by putting the car on a diet. Some don't want to go that route, but man, I ain't looking back.

Hunt3R

A cat bypass really does make a noticeable difference in power on a 3.2, assuming your A/F is tuned right, but it won't make much difference in noise if you run the stock banana muffler. I remember when I first changed out to a Dansk premuffler and kept the stock muffler I noticed an ever so slightly more throaty tone in acceleration, but it was barely noticeable. I wanted to actually hear the exhaust so I eventually changed the muffler too.

A straight pipe bypass will possibly be slightly louder since it doesn't have the baffled chamber like a premuffler. If you're really worried about noise then just go for the premuffler because neither will be different in power really. And if you decide to get a different muffler later then the premuffler will help keep the muffler a little quieter too.

TDS911

Thanks. The car is very low miles and extremely original, including paint, so I am not looking to hot rod it too much, just looking for a tiny bit extra.

So stock muffler will stay on. Is the non-muffled cat bypass the way to go then? A bit more top end, and little more growl? Not looking for tinny or raspy sound.

And I need to adjust air/fuel with a cat delete?

Thanks again for the insight, first aircooled Porsche.

JonSnow83

The M&K straight by-pass + muffler will be a BIG weight reduction of the tail of the car (probably 20+ lbs total) and be a little power boost AND SOUND AWESOME. My ROW 3.2 has the set up from the PO who had it built as a 1 into 2 with one of the exits capped. It sounded very nice with 1 exhaust, sounds really really nice with both pipes open. It's not too loud unless you're at wide open throttle and has a really good gurgle as rpm's fall.

race911

In the wheelhouse of running 3.2L cars we found that it made basically zero difference on a ~72-~120 pull up the front straight at Thunderhill. No data back in those days, unfortunately. But I was satisfied with my testing. In our time trial series you could stay in a "stock" class with anything but headers, so there had to be a serious gain to want to bump up into the world of (near) full suspension mods.

Reiver

Agree, makes more noise and is a weight saving. Will probably move your rpm sweet spot a bit higher on your tach too.
I believe most butt dyno's are also attatched to one's ear...if it's louder and sounds faster it must be.