(Hi Comp788!)

My exhuast system is ailing. I have OEM hedders, an old *** cat, and the pipe going to the muffler is splitting longitudinally along the top. I'm planning on getting new headers and just making the entire exhaust 3 inch but the timing isn't totally right yet and I don't know which hedders to buy exactly (do I have AIR or not?).

My question is, can I go with a 3 inch exhaust from the collecter back without replacing the hedders at this point? In other words, all I want (need?) to do is replace the pipe under the car and the cat.

I can do that, right?

What's a good hi-flow cat to get?

 

Give me a call tomorrow. If your free Tuesday night come by the shop and we can figure out what you need and get all the stuff on order.

Happy Superbowl Sunday!
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P.S. To answer your question. Yes we can change out the exhaust from the cat back and not do the headers now.

 

Yes, you can buy a replacement catalytic converter and cat-back (a catback consists of the intermediate pipe [the pipe between the cat and the muffler], the muffler, and tailpipes) and keep your factory manifolds and y-pipe. Any exhaust shop should be able to take care of adapting/welding everything into place. Later on you can add headers and their specific y-pipe and have that adapted to your new or existing cat.

And yes, you do have AIR.

I would go with a Carsound or Magnaflow cat. I've heard bad things about the Catco brand lately.

 

Jeremy,

I will be the exhaust shop for the installation.

Also I love the fact that everyone now makes catalytic converters. The funny thing is there are only a couple of companies that make the internals and they just sell them. Then companies have a shell made and stuff the internals into the converter housing.

FYI a high flow cat does not work as good (from and an emissions point) as a standard cat. The difference is that thet honeycomb is of a larger opening and lets air pass through it quicker. Hence it does not work as well.

 

Ever thought about having flanges welded to the cat and use a straight pipe for the rest of the time? Here's mine:

 

That's fine. It still never hurts to get opinions from people other than the one that will be profiting from the person who wants to upgrade their car.

I suspected that much, that is very true throughout the aftermarket equipment industry. Do you happen to know who supplies each company with their substrates? It just seems that I have read about a great number of bricks coming loose inside of Catco converters. Could just be the way they adhere them inside of the shells, I do not know.

That's interesting, since some high flow cats still meet stringent California Air Resource Board requirements. So, those products must still do the necessary conversions I would think. Do you agree?
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Yes, I have dual test pipes that I built. Mine look pretty much the same as yours except I used lower profile two bolt flanges to get a bit more ground clearance.

 

I have dual catcos and they knock REALLY loud. They're about 6 months old too.

 

Jeremy,

1) I was offering to help him / teach him how to install his exhaust. I was going to do it for N/C. I do agree it is important to shop around so people do not get taken advantage of.

2) I do not know who makes the substrates for the shells. I have noticed that the shape of the housing and how it fits in the shell seems to effect how the converter holds up. The honeycomb comes in large blocks that are cut and then installed into the shells. It could be the cutting process or the method that they hold it in the shell. I do not really know. I have anasumption that the larger companies might have the cutting process down better.

3) I agree that they do meet the strict CA standards but what I was getting at is they are not as efficient as a standard cat.

Im my opinion a good running FI car will just about pass california emissions with no cat assuming it is running correctly, with no tune up issues, and a stock mild cam.I can remember when I was working as a mechanic and we had a 74 Pinto come in and it would have passed 2007 emissions. That car had basically no smog on it.
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If they are knocking they are starting to come apart. See if the shop that you purchased them from will warranty them.

 

They were on the car when I bought it last week. I picked up soem magnaflows for it. It started knocking around so bad once that it would not rev past 3,200 rpms. I held the revs up for a few seconds and then the cat popped and blew smething out of the tailpipe and it ran fine. It sits in the garage now waiting for the new ones.

 

I really ought to look into having a flange setup 2 years from now when I have to smog again.
I have been cutting my cat and re-welding.

 

Be sure then when it went through the exhaust that it did not plug up the muffler.

 

I have been doing that for years on cars.

 

It was just a little piece of something, it's all out. I'm puting a Magnaflow catback on it anyway. It has an American thunder catback on it now that I'm going to sell.

 

Yeah, that is a pain. Some may argue that it gives yet another potential source for leaks versus welding, but I run reusable composite gaskets or aluminum depending on availability for the particular flange, along with some red high-temp silicone. No leaks whatsoever, and the exhaust can be changed around or removed in minutes. My entire exhaust is that way, since I got tired of fighting the exhaust when removing the transmission, gas tank, etc.

 

When I built my exhaust I used v-band clamps. Quite a bit more money then bolt together flanges but no gaskets to leak and they last forever. They also are much thicker then bolt together flanges and never leak.

 

I'll call/see you soon Brett. Although I like the sound coming from the car, the wife is getting concerned that there is too many fumes coming into the cab.

 

Alrighty... I got AIR and I am chucking the Flowmaster 80.

I'm going with Magnaflow on some good advice so the question I have now is about what catback system to get. Will this one fit?

Summit 15620

JEGS 15620



Both sites say for 4th gens and for 5.7's. Am I missing the system I need or is this it?

 

MPE-15658

http://store.summitracing.com/partde...5&autoview=sku

Way too pricey and it's 2.5" it seems.

I'd personally stick with a Hooker, Flowmaster or SLP complete 3" system.

 

No way... that can't be the right Magnaflow system for a direct replacement.

3 inch pipe is a requirement.

 

Check out the Magnaflow website, they don't sell any 3rd gen kits besides what I posted.

I'm thinking you just want a Magnaflow muffler (+ tips/cat) and just 3" piping all the way down.
Any shop with a mandrel bender can just make it for you.

It's a good sound I'm sure, my Supra is Magnaflow.
I like the Flowmaster American Thunder kit on my GTA.

 

There's also a dual-cat setup: MPE-23479

I guess you could put that 15620 on as well, I'm sure Brett is magical with a welder.

 

You got that right. His work is pretty clean and professional. I'd hate to buy a kit that make it harder than it needs to be though. I'm sure he'll weigh in here soon and I'm in no hurry...

You oughta see his Z. I've never seen a 4 inch exhaust with a custom SpinTech muffler.

 

jegs is a 3" exhaust but they use their own "turbo" muffler.

jegs PN 555-30415

I have TraviZZZZZ old spintech that never made it into the 84 if you need it
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summit also sells 3" an I-pipe and over axle pipe for about $150 for both

 

Personally, I hate "Magna-Blow" and think they all sound like azz on any thirdgen.

But whatever you go with, headers and full 3" is going to be a huge improvement and you will love it bro

 

I'm in it for the performance gain.

After we address the cat and catback, I'm looking at these:

JBA Shorty headers

 

Del, you posted up the corvette system. The 15620 is the one he wants, that's the system I'm buying, and it's $388 from Summit. All that needs to be modded is the hangers in the rear (universal 360* hangers) and a 15" section of pipe to go from the I pipe to the cat. I'm buying this system for the formula as soon as the t/a sells.

 

What do you have on the black beast Vin?

Yeah I just saw that in the application tab Steve, I'm sure it will sound decent on yours and Mike's banshees.

 

I don't know about Mike but I've had Flowmaster on all my hirdgens so it's time to try something new. I heard a soundclip of the magnaflow on an lb9 and it sounded great. Plus it's pretty.

 

Well they might look pretty, shiny and all, but they sound all "fourth-genny" to me and personally I wouldn't install a Magnaflow on my lawnmower.

I've got the new style Hedman shorties with their sweet y-pipe and full 3" (no cat) to a Flowmaster dual chamber.

If it blows eardums and sets off car alarms it is good enough for me.

 

Ditto.

Remember this clip? (Click me) That's the 80 series on the car now.

The Magnaflow does look nice.

 

Well how often are you under there looking at your muffler?

I'd rather have a Flowmaster and have something that sounds good than something shiny under there that will just get mucked up by mud and dirt anyways.

IMO your current muffler will sound loads better with the added compliment of headers / Y / Full 3" intermediate. Not that it sounds bad at all, I think if it ain't broke, don't fix it.

You already have a Flowmaster, not much gain to be had there.

That's what I'd do at least.

 

No offense but with the Magnaflow the information I am seeing is that there is less restriction than the Flowmaster. Additionally, I get the straight pipes out the back and can finally depart from the stock turn downs. At the very least, I will have a good comparison between the two sounds to allow everyone to make their own choice.

The stanless steel and polished pipes for the 'bling' is just an added bonus.

 

Yep, Magnaflow is much less restrictive and those tips are going to look sweet hanging out of the back with the red cars. Flowmaster, been there, done that. I too will post up sound clips of the difference between the American thunder and the magnaflow with the 350.

 

Sorry to get in here so late. Looks like I almost missed all of the fun. LOL

I need to look at the links and see what is going to be the best choice. If you go from a Flowmaster 80 to a Magnaflow you will get approx about 25 HP.

I have a good friend who owns an exhaust shop. One of his customers came in with a 4th gen with a Flowmaster 80 who had just had the car on a Dyno. He changed out the Flowmaster 80 to a Magnaflow and picked up 26 HP.

This was one of the main reasons that I mentioned to use the Magnaflow system.
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Del, I know my way around a welder. Weather it is Tig or mig. I can get by.

I completed up my exhaust last night but have to drop the rear end out of the car to finish weld it. It came out sweet!!

4" Stainless with a custon stainless Spintech muffler.

WOOHOO!!

 

He dyno'd before and after at the same exact dyno with no other changes but swapping a muffler?
His old muffler must have been rotten solid letting 0 air through, because I find picking up a 26 RWHP gain from exhaust alone to be unbelievable.

Like I said before though, I'm a fan of both brands and of getting rid of restrictive factory crimps and parts.

 

Brett,

My credit card is dying of neglect. Tell me which one to pull the trigger on.



Now I have to go read the "Itchy Bitchy Spider" to the little gals.

Mike

 

Mike, I called Magnaflow/Carsound and they do not make a bolt in kit for your car. They make 86 to 91 and 93 and up. 92 seems to be an off year unless you have two cats which you do not have. I want to make a couple more calls in the AM. Flowmaster also does not offer a kit for your car. They also only have one for two cats.

I was going to call Mufflex in the AM. They have a bunch of cool stuff and I think they will have something to make it work.

I'll send you an IM tomorrow morning.

 

Well took some pictures after work of my exhaust. It need to be finished welded in the back but otherwise the exhaust is complete.

Del you were talking about welding. Here are some pics of my exhaust and my custom Spintech muffler.

 

A couple of pictures of the muffler.

 

don't think theres any difference between years, other than the way the cats bolt up

 

Both of the exhaust companies say that it is the way the tail pipes mount and the location of the cat.

 

FWIW, I have a '91. What about Terrell's idea of getting the Magnaflow muffler and pipes with the Summit I-pipe and axle pipe?

I'll wait for your PM.

(Incredible pics BTW!)

 

Nice lookin' work man, I had no doubts.

The last time I did any tig/mig welding was in HS (~9 years ago).
I'll leave it to the experts now.

 

So I did some checking and it looks like a nice set up would be the Dynomax I pipe and Dynomax over axle pipe. They are both 3" and should fit nice. This will allow you to use any muffler. I think Terrell said he had an old Spintech muffler. That might sound really cool. You will still need tail pipes but that should be looked at when you chose a muffler.

Let me know on your thoughts.

 

You got a PM.

I think I'll go ahead and get the "I" and axle pipe to go along with a new cat. At this point pipes sticking straight out the rear might not look too good on my car with the ground effects. I'll stick with the stock turn-downs and we can re-evaluate after it's all together.

Steve: What are you going to do? Pipes straight out the back, single pipe out (SLP style), turn downs, or what?

Terrell: What are the details on the spintech again? Is it available?

Here are some examples of pipes on the Firebird with and without ground effects:



Looks good but no ground effects on this car.



Hawt, but integrated and no ground fx.



This is just wrong to me. Everyone on the thread I pulled this from seems to agree.

In short, the stock turn downs are what belong on my car.

 

I'm going with the Magnaflow catback with the polished tips sticking right out of the back. I've thought about turn downs just outside of the muffler but I doubt it.
Here's both gfx and no gfx, wait, you have those funny 91-92 gfx huh?

 

Ayup. Makes me special I spose.

 

Sorry, not trashing them or anything, they just look funny to me after mine.
I would say tips out of the back on yours, not real long ones and tucked up close to the body.

 

Kinda like the last picture?

 

Im not really a fan of your current tips.

how about these, I think they would "go" a little beter then the regular tips.