C32owner

As a matter of interest ,wondering if someone has done a before and after dyno run going from stock fueling and then going to the bigger 550cc injectors with possibly looped fuel rail and upgraded fuel pump pressure what the gains are if any in power ? Is this done more for safety to prevent engine running lean after aggressive mods...or would upgrading fuel pump and injectors increase a good amount of power ?

SterlingE55

It will only increase power if your are starving the motor.

JoeNobody

existing fuel pumps are enormous. As long as the pump and sender are in good shape then there's no need to replace them.

C32owner

Thanks guys, so right now waste of money... Guess crank pulley next for more power first.

Ruthle55

Sell your s/c pulley and step down to a 73. Injectors dont magically give you more power. They give you more room for more timing, and more boost. Step up to 550s, 73mm s/c pulley and race gas.

C32owner

Thanks man, I didn't want to go the fixed pulley route due to various reasons, so got the smallest clutched pulley 77mm for now. I am toying with the idea of adding a 170mm crank pulley into the mix as my boost level is really low at the moment even with the 77mm upper. I am currently at about 8,7psi. I just had massive headers and exhaust fitted which I think has lowered the boost somewhat. We also at 5000ft altitude so that also has a major effect. I want to keep things safe and reliable though so checking out the pulley combo charts. I would say we are a good 5psi down on the numbers of the charts due to our altitude

Ruthle55

Well, honestly messing with the crank pulley sketches me out. UPD offers some pretty small clutched pulleys. So.

C32owner

I share your sentiments, I have always said no to the crank pulley, unfortunately I am forced to now if I am after more power. I have the smallest clutched pulley that UPD has to offer, the 77mm... Smaller than that you are looking at the fixed pulley, and I think it's safer to go the crank pulley route now instead of fixed upper pulley.

Ruthle55

I disagree. To each their own though.

Ruthle55

Remember, boost does not equal power.