Exhaust setup problem dc 4-1 and 2.5inch please help!!

[mugen_rr]

hellow guys so i have an exhaust issue with my ek9, my car was running on a standard exhaust just a decat delete and aem v2 and was tuned on crome and made 180whp, now i got a new jdm dc 4-1 manifold and a 2.5 inch pipe with a resonator and a rear muffler, today i went for a remap and found out that my ek was running rich instead of lean, and it went down 10bhp down, My mechanic told me that maybe its the resonator wich is very restrictive, all i can say is that i made the resonator because it was too loud as hell on a stright pipe, and when i installed the resonator it came very quiet even more then it was with the standard exhaust thaths why he suspected in the resonator, so what are your thoughts

 

[elchunk]

sounds pretty self explanitory to me, have you tried it without the resonator? probably could do with a remap to make the best of your mods too!

 

[mugen_rr]

for your reply mate i havent tried a remap without the resonator yet, but i have to start from the manifold itself i think maybe the gasket got a little bit in the way and is closing the the exhaust ports a little bit, but after a remap and loosing 10 bhp the restriction is big after a 4-1 and a 2.5 inch exhaust everybody says that you have to go for a remap quickly because it gets very lean, and my ek became rich instead the opposite of what should happened,i will tryto check the header first of all cause allthough the sound is resonated very very good its a stright through resonator so everything is a possibility

 

[Vtec6000]

Has the 4-1 mani 2.5" collector? tbh I would have went with a 4-2-1 manifold they suit the shorter stroke of the b16 better than a 4-1 in most cases. I'd pull the catback off and see if power improves atleast you can narrow it down to catback been the problem or not.

 

[mugen_rr]

yes it has a 2.5 inch collector, usually it will loose power because it s open too much and it will become very lean and the opposite happened, its running rich so there is big restriction so restrictive that its holding more than the factory manifold and exhaust, i will check the header primeries if they are the exact match, im supposed to notice because of the black deposits left from the burned fuel then will move on by removing the resonator andwel move from there, im really afraid cause i never can believe that this straight through resonator could make such a big differnce, i mean the factory exhaust had a big resonator and the piping was 2.2 inch so there comes the haddeace