Ducman82

well, i have had lots of cars and both good and bad exhausts. on this girl, id like to do headers, x-pipe to dual muffler (s), then tips out. i might do the full flow cats being that im in Albuquerque and they do testing. funny thing is i just got this car and it tested so clean you can almost breath it! and the air pump was not hooked up!

id like to do stainless with vand clamps. i might do it like i did my diesel. make it so i can interchange the cat with a stright pipe for performance when needed.

im just not sure if headers are worth the extra $$ over late model manifolds.

GlenL

That's what I was wondering. Thanks.

GlenL

Sounds like a good plan.

But...

Ya gotta get rid of the stock, cast manifolds. As Landseer confirms, the '85-'86 "Shorty headers" won't flange up to an off-the-shelf X pipe. Too bad as those followed by this:

http://www.928motorsports.com/parts/xpipe.php

would be really effective. Can always adapt the X pipe to the position of the better manifolds.

Headers are better still but that puts you into totally custom work.

Duals will fit but the S4 dual exhaust requires changes to the body and tranny member (IIRC) to make the pipes clear. You can do duals down the middle.

I'm plenty happy with the later manifolds tapped into a stock Euro exhaust. That's got dual pipes and three mufflers. I figure about 10 HP and it's still quiet. One of them could be a cat, but it ain't. I've passed smog where they look underneath.

If I had a stock US system I'd put on the '85 manifolds and gut the cats.

jleidel

On my new build, I'm refurbing a set of MSDS headers I recently bought. I'm having a collector made to pull the two 3" header endpoints into a single 4" down tube. I'll run it back to the factory rear muffler location into a Borla muffler [single 4" in, 4" out] with a single tip. [no cats... registered as an antique] I've always enjoyed the sound and rumble from the Borlas on the 16V cars. I wanted to keep the tubing simplistic yet get extremely good flow.

Ducman82

that should be a nice set up. i might just due one pipe, a bigger pipe

LEADASS

OK, I'm going to install 928 Motorsports headers with header-x pipe. I have to have cats for inspection... so I'll install 2 hi-flow cats. Question... should I go straight pipe back, or muffler? It's an 86 32-valve auto, I'll do all street driving... but loud and fast! I'm worried about enough backpressure, and loosing any low end power. A buddie has told me that the oem manifold is as good as it gets and I'm wasting $$.

sweet928

I've got a 79 5 speed with a header and full stainless steel system with Borla. I have high flow CATs - not sure of the make, as the PO put the whole set up in.

Sound is perfect IMHO -- loud when your "on it" and mellow when your not. Love going under an underpass, etc, and hearing the echo effect. Have not dyno'd it yet, but feels/sounds like more HP then it probably is. Honestly more fun (for me) then my previous two S4's. Maybe it's my midlife crisis, but my little OB might just be my fav toy of all time.

Ducman82

noob question, what does OB mean

GlenL

An "OB" is an "old bugger" or "old buggah" in a New England accent.

It is a 78 or 79 car. One with the CIS injection system and no spoilers at all.

Some people confuse the term to mean "Not S4" but that's wrong.

Ducman82

so an 81 with L jet is not an OB but an SOB, Semi Old Bugger

GlenL

Funny. I like it. This should be added to 928 jargon.

Ketchmi

I have set up several systems using 85'-86' headers, our "Y" pipe (using our adapter) and a Borla cat back with great results. I have not seen significant gains using headers and a full custom exhaust over that setup with stock engines. It also sounds great!

I did develop a 3" single cat-back exhaust for the 16 valve engines using dual mufflers. It lost torque on 219 hp engines with little gain on the top. It was reasonable down low on 240 hp engines with noticable gains on the top end. The 300/310 hp engines were unleashed using it, from almost idle up to redline. It was very bassy sounding, one of the best OB exhausts I have ever heard.

You have to remember, most exhausts do nothing more than release restricted horsepower. They do not create horsepower. It is possible to put on too much of a free flowing exhaust and lose horsepower and torque. A big exhaust on a 219 hp engine is pretty much a waste of time, energy and money. The setup I initially talked about will work great for every 16 valve from a 79' auto to an 84' US. The euro's can use a better exhaust, they love to breathe.

There was not enough interest so we shelved the idea.

atb

Dave,
Just got your Y pipe for Maurice's car ('79). We installed the '85-'86 headers and saw the passenger side "gap" that other's have mentioned. What is your fix for that, do you just sandwich a thick header flange inbetween the manifold and the Y pipe to act as a spacer to fill the gap, or have you guys manufactured a specific fix?

Ducman82

got a link to this pipe? im interested.

Ketchmi

Hey Adam,

We make a dual flange setup that fills the gap nicely. We make them in stainless and mild steel, give me a call.

Ducman, you can get our "Y" through either Roger @ 928srus or Carl @ 928 Motorsports or call us directly.