Low Power with Large Turbo

[A.J.]

Did you run a dedicated set of wires back to the pump? Is this a return style fuel system? I will be interested to know how far the 120's will get you when you make the switch to e85. Great info thanks for sharing.

I have not yet run dedicated wires to the fuel pump. I was going to check the voltage at the pump today. We were messing with it until 9:30 last night. It is a return style system. The pump feeds the rail, then the rail to the regulator, then the regulator back to the tank.

[contraption22]

Curious, do you have a picture of your turbocharger?

[cordes]

I would definitely check the voltage at the pump. I've heard of as much as 2-3 volts for a drop from front to back. That will kill your pump's ability to work for sure. I would think that a 255 should be able to flow enough for your boost levels though. When I did some calculations back when I was going to go with 120lb injectors, but I was going to stick with the 255 pump.

[A.J.]

Curious, do you have a picture of your turbocharger?

Kind of:




I have the duel ball bearing Zeta 2.8 with a .75 twin scroll turbine housing: http://www.agpturbo.com/agp-zeta-2-8-ball-bearing/

[contraption22]

That's a Forward Motion Stage 3?

[A.J.]

That's a Forward Motion Stage 3?

AGP Zeta 2.8

I have the duel ball bearing Zeta 2.8 with a .75 twin scroll turbine housing: http://www.agpturbo.com/agp-zeta-2-8-ball-bearing/

[contraption22]

Ah sorry! I was asking the OP.

[A.J.]

Made another discovery today that everyone ought to check on their vehicles because we're dealing with 25 year old stuff.

I borrowed a 340 lph pump from a friend because either the 255 lph pump in my van is either going bad (which I think it is) or can't keep up. I put it in, using the same tune that I couldn't get better than AFR of 12's with the 255 is now in the 9's. Put put a fuel pressure gauge on and I'm still dropping pressure at 25 psi of boost. I forgot to check voltage drop at the pump. At idle the voltage at the battery in 13.8v and the voltage at the pump is 12.3v, a 1.5v drop. I take it for a road test and at 15 psi of boost it drops to 11.95v. I had planned on running 10 gauge wire from the battery to the the pump with the ASD relay power to the pump tuning on another relay that will feed the pump. Now I have to do it even sooner. I was going to try to dyno tune so I can race next Saturday but that isn't going to happen. This is the second time this week I've had to drop the tank so I'm making access panels in the floor. I ASSUMED fuel pressure and volume was good, I was wrong. I ASSUMED voltage to the pump was good, I was wrong. Assumption is the mother of all F ups.

[cordes]

Glad to hear that you have it figured out. Any time there are multiple problems at once things are a real pain.