Hello all, I have a 1996 Z28 which is perplexing me some.

It appears that there are two cats, one right off the exhaust manifold on the left side that looks like an old coffee can, and on lower down by a combination pipe for the right sidethat looks like a real cat.

After getting underneath, it looks like someone added a flowmaster muffler and possibly aftermarket style rectangular tips.

My biggest questions, is why the f**k did GM design this thing with one dinky pipe to the muffler in the rear?

I want to add a high flow cat (I guess now I have to get two of them) and a Edelbrock SDT muffler, but have not found anyone offering a complete cat back for the 1996.

Are all of you running a single pipe from the front cat to the muffler, or is anyone running true duals with an x pipe.

I'm going to have to buy a post lift just to get under mine.

 

i have the same thing and its going to be hard to get a high flow cat in place of that drivers side cat. what i did was gutted the drivers side and replaced the passenger side with pipe. i have a magna flow catback and it really didnt fit that well. i had to slip the i pipe that comes in the kit way over the stock ypipe i would say a few inches at least and didnt even use the spipe which is meant to bolt to the 94-95 cat.

 

There are several catback options for your car. There is no real difference either between the catbacks of the 96-97 cars and the 93-95s except the 93-95s have an extra piece of s-shaped piping that connects the y-pipe to the catback. Hooker, Flowmaster, Edelbrock,SLP, Borla, Magnaflow, and GMMG are several of the catbacks offered. There are other options as well in terms of aftermarket headers and y-pipes, or as you noted, the true dual route as well.

 

Well, I would like this to be true, but if you look on Edelbrock's page of exhausts,
http://www.edelbrock.com/automotive_...ust_auto.shtml

they do not list the 96-97 LT1 in their part numbers. Oddly enough, they DO list the 1995-1997 3.8L.

I could be missing something, but if I can't get the WHOLE exhaust from edelbrock, I will probably end up piecing one together with the local muffler shop. I did that twice before and have had good luck, as long as I was very, very specific as to what I wanted.
The local shop even did mandrel bends up to a godawful 5 or 6 inches, I believe for diesels, but that large pipe could be used for supercharger or turbocharger tubing also...

Is your 97 a LT1 or LS1? When did the LT1 die 1998 in the F body?

 

1997 was the last year for the LT1. I had the Edelbrock catback before switching to the Magnaflow. Check out some of the supporting vendors, you'll find plenty of full catback options. I'll try to dig up an Edelbrock vendor for you.

 

What are your long-range plans for the car? You're getting a Golen 383. Are you planning on headers, or are you trapped by the the CARB limitations/inspections?

What is the feature of the Edelbrock stuff that makes you feel its the one for you?

If you have to stick with the stock exhaust configuration, with a high HP 383, you might want to look at something more aggressive, like a Mufflex 3.5" catback. They make them as large as 4", but that might be overkill.

 

I plan on running the 383 for a while, then sticking a mild blower on it after I make sure nothing breaks in my drivetrain, and everything is broken in properly.

I suppose I should ask at what point does a 2.5" or 3" single pipe from the front to the muffler become a restriction? My old 1976 chevy six cylinder had a 2.5" pipe from the cat to out behind the bed, but maybe that was overkill for that vehicle.

I believe I want to put CARB Exempted headers on it for the upcomming SMOG test, with the stock cats and exhaust. Then I will put a complete exhaust from high flow cats back to the exhaust tips.

I know from previous experience I don't want to go too big, because I don't want to hurt my low end torque, especially since this will be my daily driver. Did that on my Durango some years ago, and when I totally opened it up with true 3.5" duals, it was a pig from the stop light. I finally went back to 2.5" pipes, same muffler and it was much, much better.

Like most people in large cities, are stuck with CARB of one sort or another. I had my Mustang done with all CARB legal items, and it still failed the technical inspection cause they were shiny. (I kid you not, the dufus running the place looked at it and said.... it don't look stock, its too shiny, and we can't test it) I had CARB E.O. numbers for everything I put on it, as I was extra careful because at the time, I wanted it to be my daily driver.
Turns out after asking around, the local Mustang club had a list of knowledgeable SMOG centers that actually knew more than the hole that was their butt, and it passed with flying colors after I got it on the dyno.

 

Oops, forgot to actually answer a part of the question.... I heard CamaroUK's car on youtube with that (those?) mufflers, and I was hooked. For me, it was music to my ears!

http://www.youtube.com/watch?v=BctTd6cEIQg

Unfortunatly, Edelbrock does not list the catback for the 1996, and his car is a 1995.

 

You're not going to lose low end torque with a large exhaust system. I used to run the 4" Mufflex, and now have dual 3" pipes dumped in front of the axles. I need a big exhaust to handle the 300-shot of nitrous. But using your theory, the engine would be a dog running without the nitrous (500HP NA).... and it isn't. Mufflex was thinking maybe I should be running something bigger than the dual 3"......

The only CARB-EO headers you will find for your dual-cat 96 will be something like the ones from SLP (if they still make them.... they have sort of abandoned the LT1 market). The primaries on the driver's side get all scrunched up and twisty because of the need to keep the driver's side cat (or coffee can as you appropriately call it) in the stock location. As a result, the headers aren't going to be a huge improvement.

I left CA, with my Formula in 1995.....

 

Technically, if you're talking about a catback systems...it's all the exhaust parts "after" the cats. Lots of companies make a complete catback for LT1s...I have a 96, like you do and chose Corsa.

Now if you want to replace with high flow cats, I didn't have much luck finding a replacement for the coffee can either...I chose to go with Random Tech's y-pipe with dual cats to replace the entire stock y-pipe in my 96. But a word of warning...I COULD NOT PASS SNIFFER with the RT y-pipe with high flow cats. I ended up putting the stock y-pipe with cats back on to pass smog.

There are a few cars locally..mostly LS1s that I've seen that have done true duals, but most stick with the y-pipe. Tough to be in CA. I've heard rumors of folks putting cats downstream from long tubes that pass sniffer...but never saw one in person.