89Formula3

Iv'e decided to get some flowmasters on my 89 firebird is it best to get it from the muffler on or all the way down with 2 cats


And will it affect smog if i get it done all the way?

LowStyleII

Hopefully I have your answer. Buy the Flowmaster 80 series muffler from either Jegs or Summit its like $1 difference but whatever. Go to an exhaust shop and since you have an 89 have them re-do the pipes from the cat backwards. Actually get rid of the cats too put a 3" pipe in place. With a new pipe, no cats, and a sweet Flowmaster you will be glad you did it. Any other questions let me know.

89Formula3

Will that affect smog check?

camaro86

i think you wont be able to pass smog because in cailfornia you cant take out the cats.

91 camaro racer

iTrader: (2)

yeah, with no cat u will fail smog tests, just buy a hi-flo cat to replace it with...

five7kid

iTrader: (14)

You cannot change the location or type of cat(s) in California. If you have factory dual cats now, you will have to stick with factory dual cats or certified replacements. If you have a single cat now, you can only change to dual cats if you do it like the factory did (or certified replacements), and you have all of the equipment that the factory put on with dual cats.

What you do after the cat(s) is up to you as far as emissions is concerned, as long as you aren't in violation of any safety or noise codes.

89Formula3

Damn California and their rules.

So what about if i just get the flowmasters from the muffler on, will that give me any kind of added power and or good deep sound?

1989GTATransAm

iTrader: (3)

Best to get the cat backs. This will include the muffler. Also check out the Magnaflow product. Yes you will fail California smog without the dual cats. I have them on my car and it runs pretty good.

Fixing to install the Mufflex 3.5" exhaust system on the car as soon as the Magnaflow muffler shows up. Allen

Nytmayr

There are no companies that make a full exhaust system for use with dual converters. Several say they do, but after calling one (SLP) I found out that they don't. What they have is a cat back system.(I suspect that it is the same with the others.) This is for my 1991 1/2 to 1992 F code powered Formula. Don't know about the other years, though. You can get a flowmaster cat back system, or you can get just the muffler and use the stock turn down style pipes. (That is what I did, and I love the sound. Not nasty, but a healthy rumble.) If you do go with a Flowmaster muffler, here is some info. If you have a three inch intermediate pipe, Flowmaster has two Series 80 mufflers. One is part # FLO-53083 and the other is FLO-43083. (Both are summit Racing part numbers.) The 53083 is 5 inches thick instead of the normal 4 inches. It is thicker so it should give you more of a rumble. With dual converters, the 5 inch muffler and stock tailpipes, I think is sounds very nice.

About removing the cats. Don't. More and more places will not even work on the car if they don't have them, forget about them removing the cats. Plus the car probably won't pass smog without them. Also, since some states have a visual inspection, they will look and see no cats, automatic failure. You can try fooling them by using a gutted cat (or cats), but if it fails, you still have to go and get the car "repaired." The small benefits you may get from no cats isn't worth the trouble. Plus, unless you are talking a semi-serious race car(at least. More like a full on race car.), you probably won't notice the difference. You can get good mileage with clean emissions from a car with good horsepower and performance.

five7kid

iTrader: (14)

www.summitracing.com

P/N FLO-17228, under "Application", it says: "Application Notes For models with dual catalytic converters."

Same for P/N FLO-17150.

89Formula3

Finally decided what im gonna go with.

Thanks to everyone for all the help.

Nytmayr

five7kid: True it does say that the application is for dual converters, but what I said was that there are no companies that make a FULL exhaust system for the dual converter cars. The FLO-17150 is a cat back system for dual converter cars. Also, if the picture is an actual picture of the system, it wouldn't work on the third gen cars. It has dual inlets and they are on both ends of th muffler. F body cars haven't had exhausts like that since the 1981 model year. With the 1982 model year they all went to a single inlet muffler. For the performance cars the inlet diameter should be 3 inches. (This would be for the dual converter cars. The dual converter setup is part of the R6P Performance Enhancement Package. At least that was what it was called in 1992 when I special ordered my car.)

five7kid

iTrader: (14)

What do you mean by a "full" exhaust system, then?

"Image is a representation of this part. Actual part may vary." It is a weird-looking system, and the description says 2-1/2" I-pipe. That one would require further investigation.

For the FLO-17228, it's a single inlet, dual outlet pictured.

Summit hasn't been very reliable with their pictures, but they seem to have gotten better lately.

Nytmayr

A FULL exhaust system would consist of down pipes(from the exhaust manifolds, or headers) a "Y" pipe(which connects the two down pipes to the catalytic converters) the intermediate pipe(which connects the converters to the muffler) the muffler and either one or two tailpipes.

A "Y" pipe may or may not contain the down pipes, although they usually do.

The problem for the dual converter cars is that there is no "Y" pipe in front of the converters. A single pipe comes from the exhaust manifold and goes to a single converter. The pipe coming from the left side of the engine goes to one of the converters, and the pipe coming from the right side of the engine goes to the other. They pass through their respective converter and are joined into one single pipe which goes back to the muffler. (If you go to the YearOne catalog for the 1982 to 1992 Firebirds and look on page 111 at the bottom right hand corner you will see what I mean.)

Many people simply go with a cat back system, not a full exhaust system simply because it is easier and cheaper.

pilot

I'm thinking about updating my muffler but I'm confused on the size. I have a 3" intermediate pipe but it looks like the size is reduced where it goes into the muffler.
The 43083 has the 2.5" inlet and outlets.
The 53083 has the 2.5" outlets and 3" inlet.
Also the 53083 is 17" long which is close to existing muffler's length.
The 43083 is about 3 " shorter than my existing muffler.
What's confusing is when I measure the OD of my tail pipes I get close to 2.5". The inlet measures a little bigger but not 3". I know I have a 3" intermediate. I replaced the cat recently and it was a direct fit replacement with a 3" exit.
I'm leaning towards ordering the 53083 because the length is correct and I don't want the tail pipes to interfere with my trailer hitch. Yes, a custom hitch, and no it's not ugly. I wonder if I'm the only one with a hitch.

Nytmayr

Just remember, it can all be in how everything is measured, as compared to how you measured. But if you are close, the pipes can be expanded if necessary. (Or the muffler inlet)

I like the setup I had done, but have gotten in a wreck and will need to replaced the tailpipes. (They are the originals, so it is about time anyway.) This time however, I will have the pipes tucked up a little closer to the body which should give it a cleaner look, along with not such an extreme angle for the final bend on the tailpipe. I hope to have about a 45 degree angle instead of almost 90 degrees like the stock is.

Just remember, it is your car so you know what you want for it. Go ahead and do it, just PLEASE don't butcher the car. There are enough of them out there as it is.