Am I asking for trouble opening up my exhaust that way? I've been thinking long and hard about the exhaust, and what I can do to free up some ponies. Right now I have the stock manifolds into some sort of cat back. I know it's very restrictive. I don' have emissions, and noise isn't an issue for me, but will I be hurting the motor by reducing the backpressure? What I want to do is get the HEDMAN elite ceramic coated headers, a pair of 3" input, 2" output glasspacks , then run straight pipes out to the tips.

Pros? Cons? Thanks again for the help you guys provide.

 

your engine runs best with a little bit of backpressure...you wont eliminate all your backpressure with what you described.(thats good)..and glasspacks dont last all that long..headers.a good cat-back,and some good mufflers will do wonders ( shop around get a idea on them) alot of people will happily tell you what they use and how well it works
Edit: i wasnt thinking..most catbacks,if not all, come with mufflers...and get a High-flow Cat That will get you seom good gains

 

No it doesn't. Backpressure is a force that your pistons must fight on each exhaust stroke. You want to cut it down to a minimum while still maintaining air velocity. If noise and emissions aren't an issue, then just run open headers or headers with straight pipes back to wherever you want your exhaust to exit.

 

I did some more studying, and i was misinformed. but i did find that glasspacks can reduce power compared to a typical flowmaster syle muffler..i dont think it is very significant though...

 

Less back pressure will help with torque and low-end speed.. more backpressure, although limiting to torque, will help with top-end acceleration.

 

A good flowing exhaust will actually help and make HP over just running open headers. At WOT the least back pressure is usually best but for driveability,low end torque, etc you will want a nice good exhaust. i drove my car with open headers and it was a dog. after i installed my exhuast it was like night and day difference

 

What do you base this theory on? Backpressure pushes against the piston on the exhaust stroke even more at higher RPM.

 

Explain why this is the case to me scientifically and I will probably believe you if your argument is sound, but I am very skeptical of the seat of the pants dyno.

 

glass packs?wtf i thought those went out with the 80s

 

I think they are great. They reduce "some" noise, but are wide open! I don't want to kill my driveability at all. As my research and plans progress, it has become very aparent that I will be doing most of my racing on 1/8th mile tracks, where you light means everything. Everything else (for the most part) will be street driving in town. I like the thought of the low cost when it comes to headers, glass packs, and pipes, but I don't want to sacrafice drivability. I just remeber sitting at the strip, and most of the cars were running a setup similar to this (or they didn't have the mufflers). I just don't know how the TPI will react since I will be doing my exhaust before I do anythig with the intake/ignition.

 

a set of 1 5/8" coated headers (hooker and TPiS are the best), cat deletes, 2.5" pipes and a set of 40 series will not only make your car sound like a beast, but increase low end torque and mid-rpm HP. as im sure you are aware, HP is what you buy, and TQ is what you drive. hope this helps.

 

Jack where can you buy cat delets or test pipes for an 89 formula

 

truth be told, no idea. i threw that out there because that is a common set up for L-98 Corvettes. if it's good enough for a 'vette, it's more than good enough for an f-body. you may have to fab your own pipes to replace the area where your cats are. im sure somebody on here knows an alternative to that tho. but i can atest to how awesome that set-up sounds. good luck man.

 

When i still had a V6, i cut out the catalytic converter and instead put a straight pipe...the engine lost A LOT of low end torque, but was much faster at hitting the redline on the rpm... for everyday driving its good to have some backpressure..

currently on my V8 i have a free flowing muffle just after the headers, and at the end i also got a free flowing muffler, drives like a dream and isn't noisy.

 

If I pick up the headers and mufflers, a good exhaust shop can do the rest right? Why 2.5" over 3"?