street demon2k3

last time i dynoed 253hp/269tq through the muffler and 269hp/284tq with a cutout. last night i got my headers on and today i put the y-pipe and the rest of the exhaust on. i dynoed only w/ cutout closed through same muffler and i hit 274hp/285tq. but the guy at the shop said my car was running too lean and if i took off the cutout i would damage the motor. the A/F was at 13.3-13.5 all through the run, my friend told me it could be my O2's(bosch) fuel filter, fuel pump. could i just get my car tuned to get the A/F up. i know my car has more than what i dynoed, what do you guys think?

i'll post the dyno sheets later on tonight.

stereomandan

It's not THAT lean. Most guys shoot for 12.9-13.2 I believe. I don't know why the cutout would matter since it's quite a ways after the O2 sensors.

HP looks o.k., maybe a little low, but the TQ seems low.

Dan

T/A#4

Try changing your fuel filter & check out the bracket behind it for fuel line pinching

SStrokerAce

Cutout doesn't matter with A/F ratio, too bad you didn't get a run with that!

Bret

street demon2k3

i wanted to see what i got witht he cutout too, but these guys were serious about me getting that A/F up. i gained 15hp over this same muffler through a cutout, so i would say it has around 280hp or maybe a little more. i also thought my tq #'s were low but i think its because of the 3000 stall. im shooting for 310hp with a tune and 1.6rr's, which should be sone within the next month.

stereomandan

Well, since your A/F isn't far off from optimal, I would way 310 rwhp with your mods is a pretty big stretch, even with 1.6 RR's.

If I were you, I'd shoot for 290-295 rwhp.

Dan

MarkyMark

If you dont already have a tune then I would highly reccomend one. Also I have heard of the O2's going bad right after a header install, like within 1-2 weeks of install. If I was you I would get a tune, change fuel filter and then change out the o2's to ac delco brand after the longtubes have been on for about 2-3 weeks.