Hs981

I have a 93 F150 with the 302 V8 in it, got her as my first car little over 2 years ago and put about 800-1000 bucks into a nice exhaust, headers, y-pipe, the whole deal. Yesterday got the itch for earsplitting loudness, so I chopped it right before cat and wow it is loud. My only concern is back pressure, how I know if there isn't enough? As I was told by some friends that it could potentially damage the engine.
Could post a video of her givin' hell if anyones interested.

sdmartin65

Should be fine just don't suck water in. Save the portion you cut off, won't take long to get tired of the ear splitting sound.

construction ford

This whole myth of needing back pressure is all about EPA bull****. The reason you need back pressure is to keep the cats hot witch in turn burns the excess gasses off so if your not worried about EPS then less restrictions the better!

93Bandit

More back pressure questions... Put simply, back pressure hurts engine performance. An engine never benefits from back pressure. The reason people think back pressure is needed is because they put too big of exhaust on their car and they loose low end, so they thing the smaller exhaust is providing back pressure and increasing power. Back pressure is not the problem, its the flow characteristics of the exhaust being used.

Hs981

Oh so, if no back pressure is needed then she should be gaining from this right? I swear there's more "oomph" in 2-3rd gears now and can put you back in the seat up to about 85 or so.

My parents keep telling me that "loud exhausts mean less mpg" is this true? I've seen little difference, if not higher mpg now, and I know I'm doggin her cause it gets LOUD

justintendo

there is a difference between "backpressure" and a "tuned length" of pipe. no vehicle thats a four stroke needs ANY backpressure..a two stroke does need back pressure in the form of a stinger and diverging cone, but thats a whole different animal..backpressure is equal to cupping your hand over the exhaust. a tuned length is different and much harder to explain, but you do need it. the best exhaust would be straight pipe with no obstructions in it, but of the proper diameter and length to keep velocity high..too high of diameter will cool the gas too quickly.
i think "cutoff in front of cat" isnt long enough, lol..
in this case, you are losing power and the added boost is in your head because of the noise.. buy a performance cat and run straight pipe out to the bumper..that will work much better
check out some books by david vizard..easy to read and very informative..he explains the misuse of the term "backpressure" and is a super smart tuner.