Hi guys. I need some advice. We just installed a powerdyne supercharger on my friends 88 IROC. This is a custom kit, so we have no directions or recomendations on tuning. Evenutally we will get him a custom prom, but we leave for the Power Tour in 2 days, so its old fashion tuning for now. We are trying to adjust the timing and fuel pressure, but could use some recomendations. What do you guys with centrifugal units run? Its more or less a stock motor, with minor mods. We installed the charger, getting about 6 pounds of boost, also an inline pump with a fmu.

Thanks,
Ben

 

set the base pressure at 45 or so if possible and max fuel pressure under boost around 75-80

also, keep the base timing stock......you should look into a BTM box that retards timing via boost since you have no intercooler

 

next day air a FMU about a 6:1 and get a recal kit at the same time for a 4:1 so you can change it if you have to. call vortech now, order next day air. tell them you need it with the kit like it comes in thier TPI kit. install it in return line after the stock fuel pressure regulator (it is the smaller fuel line). here is what an FMU and a recal kit looks like.

 

Well, we got back from the trip and there is deffinitely something wrong with the car. Before the car made 225hp and about 300 ftlb at the wheels on a dynojet. Now that the charger is on, with 3 pounds of boost (vac cap blew off), it made 160hp. Fixed the leak and with 6 pounds, it made 160hp. So to me, with 3 more pounds of boost and no power increase, we have some other major issues somewhere. Gas mileage was also down. I am leaning towards the Maf possibly, bad or maybe maxed out? We are going to get a scanner to check out all the readings, but lets just see his is very unhappy. It just blows my mind that you double the boost amount and there is no increase at all.

 

horrible gas mileage sounds like you are running horribly rich which will drop your A/F ratio and hurt power