Well I want to change the exhaust up on the cheap. Ive heard of people using the duel exit GT exhaust to replace the single exhaust on the Iron Duke. Where is it blended into the stock exhaust? Also is the Fiero Store Cat delete worth it?

[This message has been edited by bkaab (edited 08-31-2012).]

IDK about TFS cat delete, seems a straight pipe from autozone for 7$ would be cheaper. No good can come from using a cat.

the duel exhaust fieros just have a muffler with 2 outlets instead of one. you can go to your local auto parts store and get a 2 foot piece of exhaust pipe, remove the cat and install the exhaust pipe you just bought.

i keep hearing people say glasspack mufflers sound great on the 4clys.

The sound will be LOUD without the cat. Just a warning. I did this on two 4 cyls, so I speak from experience.

quote Originally posted by jaskispyder: The sound will be LOUD without the cat. Just a warning. I did this on two 4 cyls, so I speak from experience.

Even wit the muffler?

quote Originally posted by Stainless1911: Even wit the muffler?

yes... even with a new OEM exhaust system... it is loud. The cat quiets the exhaust a lot.

Indys and 4-cylinder SE's came with dual outlet mufflers, so putting one on a 4 is nothing new. And if you replace your cat with either a straight pipe or a high flow cat, the exhaust will be louder. (Please note that it is against federal law to replace the cat with a straight pipe.)
I put a dual outlet muffler on my 88 coupe, and I did it this way. If you look under the car at where the pipe goes from the muffler to the cat area, you will see a part of the pipe that is straight. I cut mine in the middle of the straight part, and cut the doner muffler's pipe in the same place. Then I joined the "new" dual outlet muffler to my existing pipe at the cut place with a short pipe and clamps. It was quick and easy that way.

quote Originally posted by jaskispyder: yes... even with a new OEM exhaust system... it is loud. The cat quiets the exhaust a lot.

[/QUOTE]

yes... even with a new OEM exhaust system... it is loud. The cat quiets the exhaust a lot.

Thanks for the info. I have to replace the entire system on a Fiero Im bringing back from the grave. I'll add a second muffler now, where the cat should go. Thank you again

I made this 2.5” baffle and put it in the center of a swaged test pipe to lower the noise level coming from the walker turbo muffler on my 88 L4. Made a BIG difference. Didn’t see any drop in performance or MPG, but with a 4500 redline, you wouldn't expect any. Just another option if the dual outlet muffler on the 4 is to loud for your taste.

quote Originally posted by Stainless1911: It is against Fed law for a licensed repair facility to do it, but you can do it yourself if you wish. If you have a legal claim, please provide a cite to the law for reference.

http://www.epa.gov/enforcem...ile/exhsysrepair.pdf

FACT SHEET: EXHAUST SYSTEM REPAIR GUIDELINES

The EPA has prepared this fact sheet to answer some of the
most commonly asked questions about the types of exhaust work a
repair shop can legally perform.

Question 1.
Under what conditions or circumstances can a catalytic
converter be removed from a vehicle and a converter replacement
pipe be installed?

Answer 1.
Under federal law, catalytic converters may not be removed
and replaced with "converter replacement pipes" by any person.
The 1990 Clean Air Act Amendments even prohibit private
individuals from installing "converter replacement pipes" on their
own vehicles. Anyone who installs such pipes would violate section
203(a)(3)(A) and (B) of the Clean Air Act (Act).

What TopNotch said above about EPA rules and
Current Cat designs won't cause a flow problem. Engine won't see much, if any, exhaust restriction.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

quote Originally posted by Stainless1911: Even wit the muffler?

Now I will say that my duke with the stock muffler on and the cat off isn't that loud but then again my neighbors seem to disagree...but it sounds good at low rpm, at least to me inside the car.

[This message has been edited by Mcfleev-O (edited 08-31-2012).]

quote Originally posted by TopNotch: http://www.epa.gov/enforcem...ile/exhsysrepair.pdf FACT SHEET: EXHAUST SYSTEM REPAIR GUIDELINES The EPA has prepared this fact sheet to answer some of the most commonly asked questions about the types of exhaust work a repair shop can legally perform. Question 1. Under what conditions or circumstances can a catalytic converter be removed from a vehicle and a converter replacement pipe be installed? Answer 1. Under federal law, catalytic converters may not be removed and replaced with "converter replacement pipes" by any person. The 1990 Clean Air Act Amendments even prohibit private individuals from installing "converter replacement pipes" on their own vehicles. Anyone who installs such pipes would violate section 203(a)(3)(A) and (B) of the Clean Air Act (Act).

Thank you.

If I get rich, Im going to buy a Prius brand new, take it to a salvage yard, crush it and put it on youtube.

[This message has been edited by Stainless1911 (edited 08-31-2012).]

Ya I took the cat off my 96 Grand Prix with a 3100 and even with the stock resonator and 2 turbo mufflers and it got really raspy and a lot louder. My 01 Grand Prix has no cat and just turbo mufflers and its pretty loud too. No stranger to exhaust work. Ive always had louder cars and the Fiero is just too quite right now.

But anyway does anyone have and videos of 4cyl exhaust post them up. Please list what ya have for an exhaust.

Here's a pic for you of my 88 2.5's exhaust. Ok, it's been modified to fit on my 4.9 but the PO said it was a Ocelot performance 4cyl exhaust he ordered in. I was running it on the fiero as I got it and it was pretty loud. When I pulled the engine I found a few of the exhaust manifold bolts loose in the head and that there were no bolts connecting it to the exhaust pipe! That explained the knock sound it would make under hard acceleration. If you check out my swap thread https://www.fiero.nl/forum/Forum2/HTML/122389.html you can see what's inside the muffler when I cut it open to change the intake tube from the small 4cyl tube for a 2.5"exhaust tube to handle the added 4.9 output. Just thought it might be of interest given your topic.

I have an 88 2.5 with GT exhaust. It is 4cyl just past the engine mount, then GT from that point on. Used a small section of pipe for the joint so I could lap weld it vs. but weld it.


Here is a sound clip. I just started it up so it was in idling high.

[This message has been edited by fieroguru (edited 09-01-2012).]

My experience with most cars is the same, remove the cat and the car is louder.
Even my wifes 91 Buick is loud with no cat. The resonators do not muffle as well as a muffler.
My Fieros have had cat failures with the plugs that are in the bottom. When the plug rusts out, I replace the plug with a 'T' bolt and fender washer.
So far, I only had one 'T' bolt failure, but since I make my own, they are cheap.
I wonder how many empty cats are on cars to bypass the federal law? The cat is there, it just doesn't work, and we don't have to test them...

quote Originally posted by crashyoung: I wonder how many empty cats are on cars to bypass the federal law? The cat is there, it just doesn't work, and we don't have to test them...

I had a 91 Suzuki Swift where the internal material in the cat broke apart and began rattling around. Eventually most material blew out the exhaust but an egg shaped piece got lodged in the pipe which choked off the engine. I peeled back the heat shield, cut open the cat and removed the remaining material. Welded it back up including the heat shield and still passed government emission testing with flying colors! Can't say the car was any louder though...all 1.3 liters of displacement.