i tried seaching but nothing found....has anyone done this??a friend of mine has done it to his turbo hatch, and sounds like a damn semi commin! but is it good or bad to run a open downpipe?(without a cat back xhaust). much info would be great

 

i've ran my car around the block a few time with no cats and no catback

sounds real mean but b/c there is no back preasure you lose a lot of torque

not worth it

 

not a lot of torque?...im not too sure of that. Turbocharged cars don't need any backpressure at all. If there is no backpressure past the downpipe, it keeps the exhaust gases further upstream moving faster. It all kindof creates a vacuum that helps utilize the turbo to its fullest extent. I think anyone will tell you that backpressure is bad, and reducing it will increase both horsepower and torque. check this web page at vishnu: http://www.vishnutuning.com/exhaust101.htm

I think the largest concern would be having your downpipe open right underneath the car, and the possiblity of fumes entering the interior. I'm not sure if it actually is a hazard, but I would at least have some pipe that directed the gases out to the side. Further, I'm not sure it would help. If you had an aftermarket dp and the stock exhaust, then, yes, I think you would probably see some improvement.

 

backpressure is only your friend if you have an n/a motor. though now that i think about it you might loose some power down low before the turbo starts creating boost. then again with no backpressure you might get rid of some turbo lag... i agree that if you were to do this, and plan on running it like that for a prolonged amount of time you should get something to route the exhaust out the side of the car. the last thing you want is exhaust fumes making their way into the car.

I definately wouldnt do this in california. thats a REALLY easy way to get fined. =)

 

yeah, i just installed a turbo xs dp and a helix uppipe, and decided to run with no catback for a few minutes. Damn did it sound beefy. Woke the neighbors up, but no cops..yet. it's sweet.

 

I agree, turbocharged cars do not need any back pressure. Running open downpipe will definetely increase your top end.

 

the bottom of the car could get a little toasted. i'm guessing that it would shoot bigger flames under the car without the catback

 

Definitely, friend of mine with a totally catless system says he's shooting fireballs out of a borla hush. lol