What point should a different lift pump be added such as a FASS??? I have a friend that has a 97 12v that dynos 600hp and he is thinking the fuel pressure from the stocker may be low. Anyone have some suggestions?

 

not that i know if he should upgrade or not but what mods is he at??im about to get a 2nd gen 12v also so am very curios,tryin not to jack your thread here

 

He should install a fuel pressure gauge to make that decision. The great thing about the mechanical pumps is that the more fuel you move, the higher the rpm, the more fuel they pump. If he sees a significant fuel pressure drop, then he might want to think about going a different route but I would stick with the stock setup as long as he can.

 

I know several people that have dyno'd in the 500-600 range on the stock 12v lift pumps with out a problem, and Joe D over on TDR got his 12v all the way into the 800's on fuel only with the stock lift pump.

 

What pressure is good for a mechanical pump??? I will have him hook up a gauge and check his.

He has DDP sticks, industrials twins with the k31, Industrial tuned pump, oringed and ported head, Helix camshaft.

 

well what has he done to the pump? fuel plate, dvs?

 

he has the bigger barrels..12mm i think. The plate is a 5 he thinks, it was setup at Industrial so he is not sure.

 

He should be seeing around 18psi at idle and around 25 or so wide open. If it is below 20 psi wide open, try pinching off the return line to see if the overflow valve is worn out. Along with the lift pump being a limiting factor, all of the fuel lines and fittings are limiting. If he is seeing low pressure, it may make sense to redo the fuel system for less restricted flow rather than trying to put on a fass or something else.

 

Mine runs right at or just a hair below 20 psi at WOT. Is that to low?

 

I run 24psi at idle and about 35 or so while at higher rpms but not while I'm in it. It doesn't drop past 20

 

Mine started dropping down to single digits once I got over 600. I added a second pump to use when i play.