I made 6 pulls 5 good ones. without nos it had 331.7rwhp and 381.6rwhp with nos. now the air fuel ratio was all messed up. at 3200 rpm he hit it and the ratio was at 18.4 but then from 3400 to 4600 it stayed aroud 11.9-12.2 then from 4800 on when it at 9 1/2psi boost, the hp fell off and the ratio started climing back up to 14.9-16.0. the way it was explained to me was 12.4 is were it needs to be and thats why I'm losing so much hp. before I send my pcm back what do i need to tell them? anyones help would be great!!

 

need more info, what kind of blower, max boost? fuel presure gauge? injector pulse width? fuel pump? can you post the dyno sheet?

 

Ryan, the 18.4 is not too unbelievable before you went to WOT. Sounds like it was progressively getting richer with rpm increase which it should to prevent cat burnup but than ran out of fuel. Did you look at fuel pressure?

 

its a powerdyne sc and i got it at 9lbs. i have a fuel presure guage. at idle its a about 55. i can adjust it 5lbs up or down. i didnt watch during the run though. i dont know what you mean by injector pulse width? in tank fuel pump 255lph. i will sen you the dyno sheets. i will have to scan them first. give me a day or two. its in the shop right now to get the mas read. we think it might be maxed out. also the fuel gauge is running off the fuel rail. thats right isnt it? and what should the fuel be at wot and at idle?

 

i see lots of things wrong here.

didn't know a powerdine would run that much boost(is that what the boost gauge is reading? how fast is the blower spining and are you way out of spec's?

you are probably seeing some KR, lots of it i bet, 99's are over sensative and then you are running alot of non intercooled boost. the most i could run on pump gas was 6-7psi, what kind of gas are you using?

you have your fuel presue gauge hooked up in the right spot.

what intank pump do youhave? if it is a gss340m(thats in inline number but it will be close) then i am sure it is pleanty, i went to 9psi and a 75shot on a 6.0 with that pump and it wasn't maxed yet.

i am not sure how your tune works with your fuel preuse but if it were me i would leave the FP stock, and then tune it that way, if you can adjust the tune there is no need to mess with the fuel presure. stock would be a base presure of 58-59psi, to do this you unhook the vacume line to the regulator and adjust. then you should see something like hight 40's at idle and low 60's under boost.

i doubt you are maxing your maf but who knows, i went to 8psi on a cold day on a 6.0 and didn't max mine out but it was close.

it is my oponion if you want that truck to run and you intend to boost and spray it you should invest in tuning tools like atap, ls1edit and even a wideband if you got the bank for it. keep the questions coming.