prime exhaust set-up???

[DSM24]

i hear that a 2.5 inch downpipe, and a 3inch cat-back is the prime set-up for exhaust is this true?????

[Mirage]

3" from the turbine outlet to the tip is a prime exhaust system for anything less than a 9 second pass...

The less post-turbine backpressure, the better.

Marcus Martinez

[wildfire0310]

ok marcus, I got a question, I known the 3" exhaust but what do you think is good for a car with a less then 9 sec time slip, 4"???

[Mirage]

ok marcus, I got a question, I known the 3" exhaust but what do you think is good for a car with a less then 9 sec time slip, 4"???

Open exhaust :D .

3.5" piping would probably flow all that you'd ever need for street use. It's LOUD though. Just ask Dave. If you're that fast to where you are running sub-9 second passes, chances are that you have at least a 3 1/2" side dump exhaust fabbed up for it.

Marcus Martinez

[96gst]

i have heard that 2.5 is better for the first half of the downpipe, because the hot gases flow better,then to open up to 3" after the flex section.

[evildsmr]

trizuuuuuuuuuuuueeeeeeeeeeee..........



Josh
93 TSI AWD

[Mirage]

i have heard that 2.5 is better for the first half of the downpipe, because the hot gases flow better,then to open up to 3" after the flex section.

If you like backpressure...

Marcus Martinez

[KeltonDSMer]

Us with turbo motors don't have to worry about correctly sizing the piping, bigger will always make more power.

For an NA application, backpressure is needed and the size of the pipes is very important.....I knew a kid with a Honda that lost 20WHP and a lot of torque when he got a bigger exhaust.

[v413nc3]

You can talk thermal velocity, thermodynamics, backpressure, etc. all day long, the point of the fact is, the best you can have is none, so larger is ALWAYS better.

Turbos don't spin off gas, they spin off of thermal difference. It's the hot gas coming in combnied with a cooler area beyond the turbine that makes it spin. If you were to eliminate the DP completely that would mean that ambeint temperature would normalize the exhaust leaving the turbine faster, causing it to spool tremendously faster. Smaller piping heats up faster, and evacuates gas slower, causing a slower spool time.

Now all these rules change when you're talking non-turbo (not N/A because a supercharger type system works like N/A when you're talking exhaust). But then again, we're not talking NT.