ATB

Need picture of stock FC exhuast from header to tailpipe. Anyone snap a photo when they did an upgrade?

Specifically, I am needed to know the positioning of the cat in relation to the stock manifold.

Post here or send me a shot to:

andy AT flatout-motorsports.com

Thanks!

SirCygnus

iTrader: (1)

uh... the cat bolts to the catback. no relation to the stock manifold. there are precats that go right after the manifold. then the cat, then catback.

ATB

Right. What I am trying to learn is the POSITIONING of the cats in relation to the manifold. Literally, I want to see WHERE stuff is on a stock S5 throughout the system.

Icemark

Here is a drawing of the layout... the 89-91 non turbo uses the same layout as the Turbo picture in the drawing (just actual part numbers are different) with only two cat converters.

ATB

Many thanks. To be clear, the 86-88 NA had 3 cats? And the 89-91 had two cats.

Anyone know of a real high-performance pre-cat?

I am building a car for a class within SCCA that requires all the cats to be in place. They can be high flow (as long as they have EPA certs).

I can do any header as long as the cats are in the same location as stock. After the cats, I can do any muffler setup as long as it is somewhat quiet.

I don't want the shop guys to have to fab this whole thing from scratch if I don;t have too!

Icemark

Yes, 86-88 non turbo engines have three cats, while 89-91 non turbo and all Turbo engines have only a pre-cat and main cat.

RX7.com has bonz high flow cats designed for rotary engines and a cool pre-cat main cat down pipe. There are probably other places as well.

Fault Bucket

The way the cats are arranged the best you'll be able to do is a good cat-back. The pre-cat comes right off of the stock exhaust manifold, so a header is out. I assume you're building up for STS?

The pre-cat itself is not very restrictive AKAIK. The one that came off of my '89 had pretty much nothing in it, just some metal mesh stuff around the outer wall. You should be able to get a good high-flow main cat like the Bonez unit to replace the main, then go 2.5" back from there. I'm looking into a 2.5" fabbed single myself.