So I’m starting from scratch with the fuel system on my L92 as part of an engine swap. I’m aiming for hopefully around 500hp (at the flywheel) with the initial build, but I don’t want to seriously restrict myself in the future. I generally prefer to do it once do it right where possible, so long as it makes some semblance of financial sense (and frankly even sometimes when it doesn’t).

So my first big conundrum is whether to go dead-head or full return.

I’ll be using BTR rails (BTR Trinity intake) and 42lb LS3 injectors. I’ve been thinking of going dead-head for ease of plumbing, so the system would be:

Deatschwerks DW300C (340lph, in tank) -> 8AN line -> Radium 6μm Filter -> 8AN line -> Radium MP-RA Multi-Port Fuel Regulator (1 in to 2 out + return)

There would then be two separate 6AN lines, one to each rail, along with a 6AN return back to the tank.

The car is a “fast road” build, so won’t be seeing prolonged track/race use. At best the odd track day here and there. Would there be any advantage to going with a full return system over this? As far as I can tell this should already give me quite a bit of headroom over the 500hp initial build aim in terms of fuel supply. Is there anything else I should be considering when designing this?

 

On my LS swaps one -6 return line works fine.
On my 67 Nova with a stroked LS2 to 427 cubes with 495 RWHP on the chassis dyno I used -6 on all fuel lines. Ran great. No fuel issues. I was running a Bosch 044 external pump with a C5 FFR.

 

I’m putting down 650 wheel in the Chevelle with -6 supply and return. Single 450 pump in tank, to filter, to rails. Then return out of rails, to FPR, to tank. Super simple and it works flawlessly.
Moving this to external…..

 

If you do go deadhead id recommend a pwm driver for the pump. Turns your pump into variable speed output to match engine demand.

 

Check out VaporWorx. They make excellent dead head systems that use PWM on the fuel pumps to control pressure. They were recently integrated into Aeromotive. I've used a VaporWorx system w/ CTS-V2 fuel pump module on my supercharged LSx for ten flawless years.

 

Thanks for that shoutout, I think the VaporWorx system might be perfect for what I’ve decided I might go for instead. Thinking of going totally mad and going double pump with one pump feeding each rail. Then I could use the Vaporworx 66166 ReturnX Dual Pump PWM Controller to stop them overheating the fuel in traffic etc.

Totally mad for my requirements, but no harm in over building right? FPR would be the Deatschwerks DWR1000 - https://deatschwerks.com/products/6-1000-frb-86

 

The guy who installed my motor did a really nice job on the fuel plumbing, so consider this...



From the pump it goes through a filter, then a Y block, then separate lines to each fuel rail..

The front of the driver side rail has a 2" ORB extension, and then a Fore regulator.
The front of the passenger side rail has a fuel pulse damper, and then a crossover line that goes to the second input on the regulator.
All of that is -8. The regulator return line (with the 90 degree fitting, at the top of the pic) is -6.

I made the crossover line - the zig-zag on the passenger side was needed to clear the throttle body. Brian at Brad's Custom Auto in Seattle deserves credit for coming up with the rest of it, especially the 2' ORB extension - that made the regulator part of the fuel rail which made the rest of the plumbing a lot simpler than most LS setups I've seen.

(The only catch is that I'm losing some pressure at full throttle and high RPM. I'm pretty sure that's either a clogged fuel filter or an undersized pump, but a Walbro 400 should be plenty for the pump so I'm going to try replacing the fuel filter element soon. It could also be a wiring problem but that was upgraded and should be more than sufficient.)

 

In actual practice I have never seen it matter, but I can't get my head past the idea that I want fuel flowing through my rails instead of to them. Whatever microscopic **** gets past the filter will in theory be flushed through instead of building up in the rails. In spite of how much easier it would be, I can't bring myself to build a deadhead system, simply out of theoretical paranoia.

 

Keep it simple, chief:

 

...............Simply Genius. The above diagram has everything you need, and nothing extra to leak or break.