ella94

Which is better for power..

-3" open dp
-3" dp straight piped catback
-3" dp 3" inlet/outlet high flow cat and catback

Ive seen dyno sheets that claim to produce more power with a random tech. high flow cat vs. straight piped.

Or is a open downpipe ultimatly the best, providing the most unrestricted exhuast?

GS-R Civic

In theory open dp would be the best, but depending on how much power you are making you may not be able to tell the difference.

On a lower hp set up 250-300ish there may not be a large difference between the 3" straight back or with a 3" cat. I made 272whp with 3" a hiflow cat and straight back exhaust. Then I replaced the cat with a testpipe and I have not noticed any changes in power. I think that if i was making 400-500whp and removed it I would definatly see some change, but it all depends on the set up.

Hope this helps somewhat, maybe someone else will have a little more concrete info. Good luck!

ella94

Yeah, in theory a open dp would be best, producing the least amount of backpressure. But engines dont always listen to mathmatical equations.

My goal is 400whp. I currently have a 2.25" dp, god knows why the expletive turbonetics puts those in a kit designed to make 300+whp but that sure as hell did.

I guess i'll wait to hear some other peoples thoughts and experiences with this.

ella94

ttt

yee SERIOUS

iTrader: (1)

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Or is a open downpipe ultimatly the best, providing the most unrestricted exhuast?

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yeps, theorically...but it's noisy as hell. i would just run an ecutout to save the life of my ears. lol

GS-R Civic

Well what will this car be used for? Daily driving? Track car? Weekend fun?

If its a DD the amount of tickets will add up really quick to the cost of a full exhaust system.

If its a track car, don't worry about exhaust unless you are trying to get into a street muffled bracket.

Weekend fun car, you could run open dp but it is still risky on the street.

Good luck !

ella94

Yeah forgot to add, its a weekend beater. Never sees rain/cold weather.

So, 3"dp with 3" straightpiped catback?

boostfeen

4 inch Downpipe

ella94

A good free flowing 3" catback wouldnt create enough backpressure to really bog down the motor vs. a open dp, would it? Been reqading some on this, and a good mandrel bent exhaust only produces a good 3-6 psi of backpressure, right?

Im thinking straight piped now.. dont feel like getting tickets for a open dp