Pipe dimensions of exhaust

[Porschebenny]

Hi!

I have put a 3,6 engine from the 996 in my Boxster S with help from tholyoak from this forum! Thank you Tod :)

Now I need to upgrade the exhaust so it's fit the new engine. I got headers from Fabspeed with new 200 cell metallic catalysts with 2.5" tubes.

My question: Should I continue with 2.5 "tubes, or go down to 2"-2,25?

Gretings from Sweden

Benny

Edited February 16, 2010 by Porschebenny

[Guest]

I would say biger is better. Get some cheap mid pipes without cats like NHP and you choice of mufller. It's a british guy on eBay that has great stuff, but to mailit to us was touch for me.

Sergiu

[Porschebenny]

I do not think it's so easy to just have the biggest pipe! :rolleyes:

I only need one cat per side here in Sweden!

Edited February 16, 2010 by Porschebenny

[catmanluge]

I do not think it's so easy to just have the biggest pipe! :rolleyes:

I only need one cat per side here in Sweden!

\

I have 2.5 inch stainless steel pipes with HiFlow Cats on each side they were made with a pipe bender and not that diffeercult. I would love to have a 3.8 instead of my 3.4.. Next swap maybe!

[tholyoak]

Benny, I would assume you are using the 987 headers from Fabspeed. I really don't like their short primary design but they are beautiful pieces to look at. Based upon what I have read on exhaust fabrication for the 3.6L engine, I think 2.5" tubing is on the large side. The 3.6 and 3.4 from the factory use 55mm tubing. For ease of use, I like the pipes from Supersprint (55mm), although they are getting kind of expensive for a simple piece of bent stainless pipe.

-Todd

[Porschebenny]

Hi Todd! The headers is for the 986. I need to replace the cats on them, and the new one have bigger pipes, 63 mm instead of 51 mm, so if I use 2,25" (57 mm) tubing it should be ok, or?

[tholyoak]

Benny,

You don't want to use 986 headers as the port sizes are too small to match the ports in the 3.6 heads. Are you having custom ones made or are you just welding on larger cats and collectors?? All my conversions use 987 based headers and pipe routing. Typically I use headers without cats to get better primary design and the cats are located in the mid-pipes, similar to how the cats were placed in the early 2.5L cars.

Send me an email or PM and we can talk more about it if you like.

-Todd

[Porschebenny]

Ok Todd! You got mail :)