mr.mustang214

iTrader: (6)

OK so I have been searching the site for a while but have not found a definite answer. Does anyone run the flex fuel pump with boost? If so, how much boost? I recently purchased a P1SC for my 08 5.3 flex fuel and am trying to gather all my fuel parts. The pulley I have is a 3.4" so i'm assuming around 9-10 psi? correct me if i'm wrong please. So will 44# injectors and the stock flex fuel pump hold up with that amount of boost? Help will be greatly appreciated!

sureshot

iTrader: (5)

I'm not sure on the pump, but you'll be close to the limit of those injectors.

08cheyennesc

iTrader: (2)

I don't know much about flex fuel ,but in a stock 5.3 (IDK if yours is) , a P1 with a 3.4" pulley should give you 12# or more,I also think you should go with 60# injectors. My truck is not flex fuel and I'm still using the stock pump at 9-10# with a 3.6" pulley. I also have the cam in my Sig .

mr.mustang214

iTrader: (6)

Yes it is a stock 5.3, so looks like i need to find me a larger pulley. Will my 44# injectors work fine with 8-9psi? Obviously the stock flex fuel pump will hold up if you are still running yours.

08cheyennesc

iTrader: (2)

I got 52# injectors at 9-10# of boost ,I'm not sure if your 44s are enough ,I would say
A 3.7 or 3.8 pulley will get you 9-10#.

Doobie

iTrader: (2)

I'm at 8 psi with a flex fuel pump in my Tahoe.

mr.mustang214

iTrader: (6)

Well I already have the injectors so looks like the cost effective way to go is to just get a bigger pulley. I'm sure i'll still see a pretty good power gain with 8 psi still.

bad cutt

iTrader: (5)

I run 12 psi with 42 # objectors and haven't had any problems. I have ran up to 16 psi with an a/f ratio of about 10.9

mr.mustang214

iTrader: (6)

I may just set it all up and see how it acts during tuning. If I lose fuel pressure or the injectors are running too high of a duty cycle then i'll grab a bigger pulley.

marlboroman71818

Trade for a 4" pulley?