Going with slightly smaller pulley - need new chip burned?

[Z's Cobra]

I'm gonna post this here and the D-1 area. I have the D1-SC and the motor is the stock cobra except for pro-m mass air meter, 42lb injectors, offroad exhuast, ati adjustable fmu and shorty headers. I have a mail order jms chip set-up for my current boost level. I'm running a 3.55" pulley and seeing 10lbs of boost. I'm going with a 3.35" pulley. I'm running a fairly safe tune. Do I need a new chip? Can I give it more fuel with the fmu and maybe retard the timing to avoid detonation? Thanks guys.

Brian

[Four eyed stang]

When you got your tune was your meter maxing out?

It never hurts to put the car on a wideband right after a mod like that. It is peace of mind.

[Z's Cobra]

Originally posted by Four eyed stang
When you got your tune was your meter maxing out?

It never hurts to put the car on a wideband right after a mod like that. It is peace of mind.

I don't know if the meter was maxing out. How do you tell? I probably should be safe and check the a/f ratio right after the mod but I'm running it at a new track and would like to see 120mph traps. Right now my best trap has been 114, so maybe 120 is unlikely with only a couple more pounds of boost but at least 118mph. Maybe I should wait on the pulley swap until I can check the a/f ratio. Thanks for the reply.

Brian

[paluka21]

Originally posted by Z's Cobra
I don't know if the meter was maxing out. How do you tell? I probably should be safe and check the a/f ratio right after the mod but I'm running it at a new track and would like to see 120mph traps. Right now my best trap has been 114, so maybe 120 is unlikely with only a couple more pounds of boost but at least 118mph. Maybe I should wait on the pulley swap until I can check the a/f ratio. Thanks for the reply.

Brian

Brian,
see my post in the d1 forum.
If your making 10#s now, then I would say with 13-14#s you should see 117-118mph.
I went 119 on 10#'s, and 123 on 13#'s.

Later
Dan

[SnakeIs]

I would definitley have your car hooked to a wideband just for the peace of mind, to know that its safe. I would say that with an FMU and 42's you should be fine, but I have learned not to assume...we both know what happens when you do that!

[WA2FAST]

Any time you ADD more boost to your combo, it is best to put it on a dyno with a wideband and do a re-tune. You are gambling if you just throw more boost on and go. I would play it safe and possibly save yourself a few grand.