Hey, gang--

Now that my T28 is running (and running well), the time has come to let the engine breathe better. I had a section of the stock 1 and 7/8" piping still in my exhaust system.
In a nutshell...it was literally choking the engine to death. I found this out at the dragstrip last weekend, as my car was stuck in the 14s.
For short bursts of boost, the car was fine. Reversion never really had time to occur with short bursts of the T28. However...
At the dragstrip, going through four gears under full-throttle, the car literally fell flat on its face midway through second gear. No power. Choking.

So, I pieced together a 3" exhaust setup that would let her breathe, and produce a nice tone at the same time. The pieces of choice:

1.) Catco universal 2.5" catalytic converter. $59.99 through Summit Racing.
2.) Dynomax Bullet Race Series muffler, used as a resonator, in 3" diameter. $35 at Summit. Perforated core.
3.) Dynomax 7" diameter round cannister stainless steel muffler, 3" in/out. $109.99 at Summit.

Total, with $70 labor/pipes: $284.49 installed. Not bad. Here's the pics:
http://media.TheInsiders.com/Media/Other/72_caton.jpg.JPG
Here's the Catco cat going on behind the downpipe. My original, 151,000 mile cat was beyond shot, beyond clogged.

http://media.TheInsiders.com/Media/Other/72_resonon.jpg.JPG
That's the Dynomax Bullet resonator, 21" in length, being welded behind the cat. I hoped this resonator would quiet down the drone my car had before. It did.

http://media.TheInsiders.com/Media/Other/72_axleon.jpg.JPG
Here you can see my 3" aluminized piping. Yes, it is crush bent. However, with huge 3" pipes, the difference between crush and mandrel bent is minimal, if anything at all. The huge diameter of the pipe just means that bends cannot possibly be sharp at all. No shops around here offer mandrel bending. My exhaust guy told me there'd be minimal difference, and that I'd understand once I saw the pipe bent into shape. He was right. 3" pipe is pretty much THE biggest we can fit on our cars. There just isn't much room for anything bigger, without breaking out a cutting torch, IMHO.

Also...note that there are no flanges anywhere in my setup. Everything is welded together, forming one big piece.

http://media.TheInsiders.com/Media/Other/72_muffon.jpg.JPG
And finally, here's the Dynomax 3" in/out stainless steel cannister muffler. 20" overall length with 16" can length. It looks eerily like the factory muffler that came on the car when it was new. I like that. No big chrome tip or anything on the end. Sleeper-ish.

The difference? I went through the gears today and can tell a dramatic difference in the performance of the T28. The thing can breathe now. The sound? Mellow. Deep. But not loud at all. The drone that is SO common in SR20 cars with ES motor mounts has been reduced dramatically, too. It will never go away, but this setup helped to minimize it.

For under $300 out the door, I'm very happy, and highly recommend these bits for SR20 turbo cars for their combination of value, performance, and sound quality.

Nice, very nice... I especially like the price :D

you said you added a 2.5" cat....wouldnt that be a bottleneck in a 3" exhaust system?

also the crushes would be sortof like a bottleneck as well...wouldnt they?

Blair--

GOOD questions. Let me clarify for you. My downpipe is 2.5" all the way back to the cat. Which is 2.5", too. So, it's not a bottleneck up until that point.

As for crush bends vs mandrel bends: Just being honest here....but there really isn't THAT big a difference between the two when it comes to 3" exhaust pipe. The diameter is so much bigger that bends just aren't that sharp that they crush the wall down dramatically.

The tightest bend on my setup (and for all B13s) is the bend that goes up and over the rear suspension. If you look in that photo...the bend does have a *tiny* bit of crush to it. Not much.

Again...the 3" diameter makes crush bending more palatable, IMHO. That's just me, and YMMV.

-GP-

He didn't mention in the first post how big the downpipe was, but if the D/P is only 2.5", there isn't too much sense in using a 3" cat, since they have about the same frontal area. I'd think that the turbulence of going from a 2.5" D/P to a 3" cat could possibly hurt performance, too, which brings us to Point #2...

Though crush-bent 3" pipe may not be significantly smaller than mandrel-bent, it's the turbulence that hurts performance the most. Look especially at the first 90* bend in the b-pipe; see those three ridges on the inner radius? You can say several milliseconds of spool lag with each ridge.

Now that I've totally insulted your intelligence, experience and budget, I'd like to apologize. Your exhaust system flows WAAAY better than stock, and you did it on the cheap; BRAVO!!!

Several milliseconds of spooling? Geez. Now I feel terrible. ;)

Just kidding.

Yes, most would prefer mandrel bends. As would I. Time to order some up just wasn't on my side, really. And once I saw the bends, it didn't really mean all that much to me any more.

The car just rips now. Simple as that. Worth every penny. :D

-GP-

Also, for the step between the cat and the bullet (and I'm just being an asshole, now ;)), I'd probably want to use a long-tube reducer instead of the rough ledges that appear to be in place. The same kind of reducer that you'd use to go from a 3" header collector to a 2.5" H-pipe on a domestic V8 car would be perfect, though it would add to the time and expense of the installation.

Again, GOOD WORK! :D (No, I'm not being sarcastic.) That over-axle bit can be a real bitch, can't it?

Originally posted by CowboyDren
That over-axle bit can be a real bitch, can't it?

Especially in 3" piping, it is a nasty bitch. There just isn't much room...

-GP-

Looks awesome -GP- ! Keep up the good work!!

Yeah!!!!!! I think it looks great, nice job :)

Yes it looks fantastic!!

The only thing I'm concerned about is if you need to get it off the car considering the lack of flanges.

Chuck--

Good point. However, this is not my daily driver. It drives to the dragstrip and to the autocross course and back. This exhaust setup should last quite a long time, IMHO.

But if the need *does* arise to remove it, I do have access to the greatest tool ever made: A Sawz-All by Milwaukee Tools. :D

-GP-

Just curious... why did you replact the cat, the stock one is actually over 2.5 inches as a 2.5 inch pipe slips inside the inlet or outlet.

. My original, 151,000 mile cat was beyond shot, beyond clogged.

I still don't know why you spent the money to get the new cat. Just gut the old cat and weld a pipe in it. It will be far less restrictive and if a cop pulls you over and does the mirror test, he will think you are running a cat.


PS: My 3" mandrel fits dandy over the rear suspension. :)

Originally posted by sobert
Just curious... why did you replact the cat, the stock one is actually over 2.5 inches as a 2.5 inch pipe slips inside the inlet or outlet.

The original cat is 2.5" ID, yes. My new one is, too. :D


Originally posted by 92SE-R
I still don't know why you spent the money to get the new cat. Just gut the old cat and weld a pipe in it. It will be far less restrictive and if a cop pulls you over and does the mirror test, he will think you are running a cat.


PS: My 3" mandrel fits dandy over the rear suspension.

Terrin, we do not have any emissions testing or inspection here in West-by-God Virginia. So, I could have gotten away with no cat, no problem. But, I like to do things by the book. That's just me.

-GP-

Yeah, I think I'd also rather have a cat to help control emissions. And it would be great if you could get a Turbo car to pass emissions (I would like to do it, although I don't need to)

Originally posted by 92SE-R
I still don't know why you spent the money to get the new cat. Just gut the old cat and weld a pipe in it. It will be far less restrictive and if a cop pulls you over and does the mirror test, he will think you are running a cat.

Even though his State may not have a legal requirement for emissions (due to a less dense population) its a good thing to keep to help the world that we ALL live in be cleaner. Less emissions = less smog and acid rain for everyone. Plus the free flowing Catco cat will probably not reduce hp/torque by anything significant.

Steve (environmental consultant)

Originally posted by thepep

a less dense population

LMAO. Some folks would say that West Virginians are dense, Steve.

Just not in the way you referenced. ;)

-GP-
Not an environmental consultant, but hey.

You guys honestly think our cars pollute that much nowadays? Even without a cat. Also, have you seen the study where there are platinum particles in the air now because of 30 years of catalytic converters? I think big semi diesel trucks and big waste producing plants are the cause of a lot of pollution.