I have a 94 camaro m6 lt1. I currently have the lt4 hot cam installed, shorty headers, no cats, with the loudmouth exhuast. I recently had my Pcm tuned by pcmforless. When I drive under 3k my car builds up backpressure and makes a loud backprssure sound. It's affecting my performance like its imissing everytime it builds up backpressure. Could chaning my exhuast to a muffler help slove that problem, Since I running headers with no cats off a loudmouth exhuast. If your fimilar with the loudmouth its like a straight pipe almost not even condsider a muffler. Could that build up backpressure. ALSO if I took it to a real place to get it dyno and tuned. Could they find the problem and give my car more performance. - Mike

 

Well, have you had any work done to the heads....ported and polished or valve job?? To me...if you were to put cats and mufflers back on you would build up MORE back pressure...I dont think you are lettin enough exhaust out of the motor...

 

Are you sure thats what the problem is? Your car isn't makeing THAT much power to be suffering from high back pressure. Its just a guess but maybe somethings blocking it, you could try and just run off headers and see if that makes a difference.