i have a 2004 evo, with an RMR intake, 3" Nvidia exhaust & greddy turbo timer, the guys from the NTevo owners club (evotexas.org) said my next step should probably be a downpipe, or downpipe+hi flow cat? will this add a significant amount of power? also, there are about 1million different downpipes available, ranging from $100-$400 or more.

whats the difference?

which do you recommend? price/performance wise.

thanks

hez

 

Just think of a downpipe as a bigger pipe let air get out of the turbo quicker, you will gain some power by putting one on. In my opinion the only difference is price and since you do not have an 05 fitment should not be an issue. Get the cheapest three inch you can.

 

All downpipes are not created equal. Some "3 inch" DPs start smaller to match the o2 housing. These are not true 3". Some Taper at the Cat. You need to know if you are going to go with an aftermarket 3" O2 housing, if you are going to remove the CAT or not. These answers will make a big difference.

 

The down pipe is about useless unless you shed that cat....the cat is still the bottleneck.

Turbo cars should be modded from the tailpipe forward.

I purchased a megan exhaust , testpipe, and downpipe from Zeus. I put on the cat back first then a week later installed the DP and testpipe. The biggest gain I felt was in spool and then power above 6k .....midrange felt the same.