# Fuel system configuration



## x47544F (Apr 11, 2012)

I have been collecting parts over the last year and reading a lot of threads from numerous sites but one thing that I have not put a lot of thought into is the fuel system. My plans are to run the stock LS2 block normally aspirated (maximum effort) for its life then reuse the majority of parts I buy on either a centrifugal supercharger or turbo 408 LQ9 build or LSX build in the distant future.

Car: Pontiac GTO 2005 A4

So far I have the following parts: (None of which have been installed yet)
SNL 4" CAI, SNL 100mm MAF, S&B filter & brackets
LSX-R 102mm intake manifold [#146302]
Nick Williams 102mm DBW Throttle body (Hooks directly to the ls2 harness) NW102TBDBW
FAST LSX-R fuel rails [#146033-Kit]
Kooks 1 3/4" x 1 7/8" x3" stepped signature series headers w/ (Jet Hot 1700 Sterling coating)
Kooks 3"<->3" Mid Pipes w/Catalytic Converters

The next parts I am looking to spec. out are heads and a mild to moderate cam and under drive pulley. Figured I would shoot for 68cc or 72cc combustion chamber AFR 225cc heads. Granted they may be a little large on the engine but during racing the engine sees higher RPM anyway. The cam I haven’t put much thought into yet…

What flywheel power do these builds typically produce? 525-hp? Let me know what you think and any suggestions for heads and cam. Heads have to be cathedral port due to the fact that I got a cathedral port intake manifold. Also, can one get 6 bolts per cylinder and still install it on the LS2? I don’t see why not…

I realize there are calculations for fuel consumption which I have done below:

BFSC = .45 to .37 (Otto cycle engines) Internet said so, must be right. (So lets round to 0.5 for worst case scenario.)

My guess on the na build is 525-hp @ flywheel…
525-hp*0.5 lb/hp-hr = 262.5 lbs/hr of fuel total

262.5 lbs/hr / 8 = 32.8125 lbs/hr for each injector minimum.

Shoot for 80% duty cycle
32.8125 lbs/hr/ 0.8 = ~41 lbs/hr for each injector

41*8 = 328 lbs/hr total

328 lbs/hr / 6 lbs/gal = 54.7 gal/hr (Fuel pump flow rate)

Which this converted is:
218.8 L/hr (Fuel pump flow rate)

So my thoughts are 1x Walbro 255 lph connected to stock fuel line. Fuel line out of firewall is connected to a dual fuel feed splitter and runs to both FAST billet fuel rails. This should support my needs as it is with the na build. Are there any other configurations people are running? Any feedback would be appreciated. Thanks,


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