anyone have any experience? i have a bolt on (non o2) downpipe currently and am doing a turbo and other stuff shortly to my X for the next year racing season. i am curious what kinda gains if any are out there going from my current setup to a o2 downpipe. I am mainly worried because if there isn't much gains vs. a stock o2 then i want to leave my stock o2 there for maximum reliability cause the car is gonna be raced a lot.
dave

 

From the first dp's that came out that were non 02 had NO GAINS, where as the 02 dps you made power.

 

An open dump downpipe will make the most power. Of course these are very loud, so I went with the AMS widemouth o2/downpipe.

 

It would be nice to see an unbiased back to back dyno of a standard downpipe with the stock o2 housing and then one with something like the AMS cast piece. I just have a UR downpipe with stock o2 and didn't think there would be much power in replacing it, but it would be nice to know for sure.

I'm sure someone has tested this?

I did do some testing of running a full exhaust vs an open dump (stock o2 housing) and it was a consistent 7hp difference with no exhaust, via Data Log Lab

 

yeah i am just looking for some solid figures

 

AMS had a thread about the downpipe. They reported no gains what so ever. Ill see if i can find it.

Edit- here it is
https://www.evolutionm.net/forums/ev...zero-gain.html

 

That's not a thread about an o2/downpipe though that is simply the downpipe section with stock o2 housing. As previously mentioned replacing the o2 housning AND downpipe will yield extra power.

 

Well if you actually browsed through it, you would find a dyno graph on there regarding the 02.
hint-page 8

 

so they took a stock evo x and dyno'd it , swapped the downpipe out and then retested it? if so i am not suprised they didn't make any gains enlarging the front portion of the exhaust and leaving the stock restrictive cat and catback. i want someone with a modded car like mine (intake, bc, intercooler and piping, 3 inch o2 and back and a tune ,cams ) then swap to a o2 downpipe ....thats where i want to see gains. Otherwise do you have a ams test of a stock car only adding the o2 downpipe and gaining 10-15whp with all else the same?

 

since your going with a bigger turbo, i say go for it. even if the stock o2 isnt really restrictive now, its def going to be a bottle neck with a bigger turbo.

Just my .2 cents

 

Well if YOU actually read the thread you would see the AMS o2 downpipe dyno graph shows a gain of 22whp and 21wtq.

 

BR said there is really no to minimal gain from doing a downpipe on stock turbo, since the stock one can flow fine. It's after 400 whp or so that a upgraded is recommended. If you plan on doing a larger turbo a upgrade might show just cause. Probably something like the BBX would gain since it can flow 30 psi at 7000rpm.

 

I never said the 02 didnt make power? im confused.

 

Haha, gotchya. My bad... just the way you mentioned that it was a thread proving there is no gain for downpipes then I pointed out that it's not including o2 downpipes which DO increase power you say 'well there are o2 dynos on page 8' kind of came off like you were referring to them not making power.

I apologize

 

haha its all good. My first post was a bit off topic tho. I should read a bit better.