Would like to know if anyone here is running a 2.75" stock cat-back with stock muffler and tips from an LT1 on a 3.4L V6?

-Did it bolt right up?
-How did it sound?
-Did you have to do anything special to make it fit?
-How was the power increase? I know that the stock 3.4L I-pipe is 2.25, and the LT1 is 2.75.

Thanks for the help cuz I know SOMEONE here has this set-up.




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1993 V6
1993 Z28
2002 SS

 

i dont have a stock Z setup , so i cant awnser your questions on power or sound , but yes the stock pipe is 2.25 and the Z pipe is 2.75" and it will bolt up fine, but you will have to get another hanger for the extra exhaust tip

 

Thanks, yeah I know exactly what bracket your talking about. Anyone else here?

 

Maybe the exhaust hanger? That is what they told me they had to add to get it to fit. I had stock take off one and it sounded nice. Not to loud or too soft. No drone what so ever either. But a bigger pipe might help out. In terms of gain, since I only did the muffler, I did not feel a damn thing. Since your doing catback, would be a minor increase, but not too much.

 

Well, the different size of the I pipe is making me nervous. I dont want to loose any torque by doing this. whats your guys opinion on torque loss? I have stock headers and cats.

 

I heard it was not much since you gain a bit on the top end. I think 2 1/2 would be better all the way since it is only a minor increase so it would affect the low end much. Never got to try it though.

 

you wont loose power by going to a bigger I pipe

i dont care what people say about backpressure on a V6 , i think the #'s prove it, i ran 12 times at the track 1 day, the 3 passes i made with my cutout closed were the 3 worst passes of the day, they were .2 and .3 slower than my other passes

feel free to argue, but im convinced that a Z i pipe is a good thing for a V6

 

hehe you will be fine with the catback, hell I thought the stock muffler on the stock catback I had was too restrictive.

Depends on the year catback you have, I ran one off a 95 or 96 z28 on my 94. The pipe started right at the tail of the tranny, and went all the way back, I did not need any special hangers, I used all my stock ones.

However I did need a custom S-pipe, to line up and fill in the gap, I had one made out fo 2.5 in. pipping(same as Cat, and Y-pipe)

I ran numerous exahsut setups, only time I ever had backpressure problems was with the open -y-pipe, open cutout(mine was mounted in front of the cat, so basically an open y-pipe)

I put in block off plates on my cutout to give it a little bit more backpressure ans ran some 15.6s-15.8s, depending how I had it set up.

An idea of the backpressure you need is I ran my best times with a $15 muffler (thrush form dynomax) on my y-pipe.

stock z28 catback was alot better then my stock 2.25in. i-pipe, and flowmaster muffler.

And it sounds nice, deep, mellow but nto insanely rough, sounds definetely like and aftermarket exhasut, but nearly as loud and raspy.

 

Guys, I just decided not to go with the catback. I bought a muffler and tailpipe from a 02 LS1 Z28. The only thing I should need is a reducer for the inlet and a hangar for the passengers side. Im going to take it to a quality exhuast shop anyway. Anything else I need to be aware of? This muffler that I got has like 10K miles on it so Im happy. No rust on that or the tips.

 

I have the muffler back from a Z28 on my 3.4 firebird. It sounds pretty good, didn't really notice any gains in performance, but it has been on there for several years, so who knows. I like the way it looks and sounds so i guess it wasn't a bad investment considering i got the muffler, pipes, and tips for 30 bucks

 

Yeah, I think it should sound good. Do you have a muffler from a LT1 or LS1? I know that the LS1 mufflers are quieter.

 

I think you guys shoudl go with the I-pipe as well, thats where the gain is from. Stock I-pipe is 2.25 in, stock v8 I-pipe is 2.75 in. a pretty big difference.