What size headers for 3.6L 993?

[scca_ita]

Hi

I have been to two things, 1 3/4 and 1 7/8 OD? I am going to use mild steel in the $400 - $600 range. The car will be for street and track but motor will remain stock for now, maybe chip and intake cone at most.

So what size is best?

Thanks

[Ted Stringer]

I would think that bigger is better, but I could be wrong.

[Clark Griswald]

For a dual purpose car that is otherwise stock, I would go with the 1 3/4. The larger tubes will put the power way up top at the expense of low-end torque, great on the track but not so fun on the street. You will enjoy the smaller pipes everyday.

[Bill Verburg]

For the rpm range that dual purpose street/track cars use 1.75" is great. For an all out race engine that has some wild cams and operates above 6000 most of the time 1.875 is ok. there is an accoutic effect that you are trying to take advantage of. The bigger the diameter and shorter the tube, the further up the rev range the resonance point moves.

For a street 3.6 that is never or rarely taken to redline and is often lugged, 1.5" may actualy be better.

I use the 1.75" on my 3.6 and have found them to really wake the engine up above 4000.

[Jack Olsen]

What size are the Carrera pipes? I've always assumed 1 5/8. It's what I've got now, but I've been planning on 1 7/8 inch headers. Maybe 1 3/4 would be better?

[Bill Verburg]

Jack, the C2/4 did indeed use 1 5/8"(1.625") primary tubes(never had a set of 993 headers in my hot little hands). The problem is the disparate lengths of the tubes, no coherent acoustic tuning effect is the result. A buddy that has a maxed out RS America bought some genuine early PMS headers froma source in Germany, they measure out at 42mm(~1.65"). The later cars and 993 RS & Cup cars for the most part went to 1.75" with a few(at times ) using 1.875. The length of the straights at a given track was a major factor in chooseing between 1.75 and 1.875.

[scca_ita]

The 993 has a elliptical collector or flat collector. The collector measures 1.25 x 2.75. The pipes appear to be 1.75 OD.

This is suppose to be the most recent Porsche Tuned exhaust since the early heat exchangers.

[Jack Olsen]

But I currently have 3.2 pipes. Are they 1 1/2 or 1 5/8? I like the low-end torque, but I know I'm paying in terms of peak HP.

[Bill Verburg]

The elliptical collector is for ground clearance only. The Nascar boys do the same.

I have no idea as to the size of the 3 or 3.2 factory(6 into 1) exhausts. Anybody got some laying around?