I am desinging a fuel system for a car that is gonna make 700+rwhp w/forced induction. The easy route is to go with a sumped tank and a big external pump. The owner of the car wants to avoid a sumped tank if at all possible. This is a street car and we want to keep it as "street" appearing as possible. so what are my in-tank options. I know many people run dual walbro 340's. how much HP are these good for? The injectors are gonna be in the nieghborhood of 80lbs.

Any help is appreciated. what works,what doesnt etc. thanks

 

TTT

I want answers to this too. Interested in twin walbros as well.

 

Might want to speak with Jack @ Racetronix as I think they have such a kit. Jack seems very knowledgable and does post in the LT1 tech forum.

-Alex

 

For the most part, on FI setups way too much is made of this. Stock fuel lines only result in 3-4psi loss at 600-700hp worth of fuel, and for the most part it's much easier to get satisfactory results with small fuel lines and large fuel rails.

The ammount of actual fuel you need depends on the BSFC of the engine, just multiply the bsfc by the HP produced and you'll get your requred flow, then you just need to find a pump that can flow in excess of that at the pressure that you're expecting to see. The pressure is important (don't forget any increases as the reasult of boost refrencing...) since pump capacities drop dramatically as pressure increases.

As your required fuel flow increase so does your need for regulator and return line capacity. If you can't send back what you're pumping then you won't be able to control your FP at idle. If you have dual intank pumps staged setups (the second turns on when you hit 4psi boost or something similar) help this immensly by not flowing nearly as much at idle with only one pump going.

If I was starting from scratch I'd probably run 1/2" or AN-8 lines with dual intank pumps and a paxton style FPR (plumbed so that the return doesn't actually go through the fuel rails first). If I was starting with a stock fuel system I'd try dual intank pumps with the stock lines... and a 2 or 4 psi hobbs switch to turn the second pump on.

 

When last dynoed I was at 733rwhp with the following system. The car is making actually making ~50rwhp addtional, but it hasn't been to the dyno with the larger nitrous jets (they were a one time thing for the last day of the year, the motor was coming out anyway).

stock tank, line, FP regulator
Bosch 255lph intank
Kenne Bell "Boost-a-Pump" (available from my friend Bob Kennedy at www.kennedysdynotune.com)

If I needed more (and I may this year) I would get the Racetronix system as the next step. Unless you are making huge hp you can use stock lines and tank.

Rich Krause