Simon928

I was just curious about what everyone's opinions were about getting a y-pipe on my otherwise stock US '84 without upgrading the headers. I ask because I might have the opportunity to swap some spare parts I have lying around for a Y pipe, but I can't really justify spending a bunch more money right now on headers. Almost all of the reviews and explanations of performance gain for the Y pipe seem to be from people who upgraded their headers as well, and most reports seem to say that it would lead to less torque off the line but more power in the 4000+ RPM range. Would roughly the same hold true if I just got the Y Pipe on its own, or would it give significantly less results? Right now I'm leaning towards selling my spare parts for money and putting the returns toward my 928 emergency fund, but if the y pipe is worth it I might just bite.

Mike LaBranche

About all it will do is make it sound better; you probably won't notice much improvement in performance. I ran one for a few years on my 84, went back to the stock cat when I got to California. I don't miss it.

PorKen

A Y-pipe can make a big difference. (With a L-Jet intake, you'll mostly increase torque.)

You can get most of the benefit of '85-'86 exhaust manifolds by doing an hour's worth of grinding.
16V manifolds have a nice internal shape. The outlet is too small, though.
Grind it out to the 32V gasket size.

16V down pipes are too small. Even bolting on 32V cats will help.

I made a Y-pipe from 32V down pipes, and bits from a 16V cat back for my '81 auto.
It made a huge difference.

928nut

.... and I've got a brand new Y-pipe waiting for you - right in your backyard ;-)

Let me know if you decide to go ahead with it, maybe we could work out a deal.

The Fixer

I installed a Y pipe leaving the rest of the exhaust stock on my US '83.
I believe it runs better and a few degrees cooler.
The Y pipe is considerably lighter than the o.e. cat.
Early cats do not flow like the new ones do. But i am not saying i gained much power, it feels like a small gain but it does run great with the Y.
For the weight savings and great sound it was worth the cheap admission for me.
I ordered mine thru Auto Atlanta and was pleased with the fit.

Simon928

Thanks for all of the info guys--that does clear up a lot of the questions that I had. I assume that S4 headers don't fit, is that correct? I'm guessing no, but I only ask because I have access to the exhaust system from an '87.

Landseer

S4 downpipes and cats can be made to fit. S4 manifold pipes, no, wrong connection to heads using 3 bolts per cyl instead of 2.

I have an 84 that uses stock manifold pipes, to 85 downpipe and cats.

Also an 84 Euro using 85 manifolds and 87 downpipe and cat.

A little bending and some welding is what it takes, but the parts are solid starting pieces..

Simon928

Cool, thanks! Maybe if I can scrounge up some 85/86 headers for a decent price I'll actually do this.

Barry Chan

Pls post when changes are made, i may be interested to do the same if there's improvement

Simon928

Will do!

Barry Chan

I see winter storm/blizzard over there right now, hope your shark is dry and warm!

Simon928

Oh yeah, it's friggin' nuts right now. I have a couple feet of snow on my yard. Last year I never even had to shovel my driveway, so I guess this is some kind of karmic retribution. Thankfully my 928 is sitting all cozy on jack stands in my garage awaiting a few more winter fixes. One of the (very) few benefits of wintertime.

Hvithaien

Here is a short video sample of mine.
'84 US with y-pipe. The rest is stock.

I don't think I have much performance gain, but the sound is much better in my opinion.

Five-8

I have a y pipe fitted to a stock setup.I did notice an immediate improvement in low end grunt( not a huge difference, but unmistakeable).Sound is loud, but not too loud, although it does have a somewhat "unrefined" note to it. I sometimes feel the sound is too "truck-like", but the 944 guys i met last summer in Kingston all said they liked the "burble".
Simon, you are not far away from here, you are welcome to come have a listen for yourself come Spring (there IS going to be a Spring-right?)

Cheers,

Simon928

That sounds great!

I might just take you up on that! I'm always looking for a good excuse to go for a nice drive, and looking and listening to other 928's is as good an excuse as they come. Thanks!