FWIW, I posted this here because I wanted a reply from someone who has experience in this area, and from what I have read LT1 tech is not that section. Hopefully this thread will quailify for this section.

My new engine is done and its time to get the car ready, so I need suggestions about what to do with the fuel system.

Just so you get an idea of what I need, The engine is a 11:1 383 LT1 built by Fast Times motorworks with JE pistons, Scat 4340 forged crank, Scat H beam rods, custom ground Hyd roller w/rev kit, with AFR190 cyl heads proted by HVH. etc etc. This engine is estimated to make roughly 700hp (on nitrous). I have been contemplating using a fogger or even the new NOSzle kit. When I built this engine it was with the intent to be able to spray 300 if necessary. Realistically I am going to do what I need to achieve my horsepower/ E.T. goal.

Will I be alright with a 255lph in tank with a T rex and the stock fuel lines? or will I have to up grade to larger braided fuel lines? I am sure the stock line would be adequate on horsepower, but I question if the stock lines will support the volume I need when I spray the car. Please help.

 

The T-rex will hurt, not help. It flows less than your intank.

Rich Krause

 

If you are going with a wet nitrous system, use the 255lph pump (assuming that is the flow rating at 43.5psi, and that is the pressure you are running) for the N/A application. The stock fuel lines are fine. You don't need the T-Rex. I use -6AN lines for 800HP (dry nitrous), and that is the same inside diameter as the stock lines.

Set up a seperate fuel system for the wet nitrous, small cell, maybe the T-Rex (what is the flow rating at the fuel pressure required by the nitrous system?), adjustable pressure regulator for spraying. Hook up the pump to only come on when the nitrous system is armed.

 

Fred, how big are your injectors? I was considering using twin Bosch pumps (Doug Rippie bottom filter-style) in-tank. I don't want to hear fuel pump whine if I can help it, so I don't want a big inline pump out of the tank, plus my tank already has an internal baffle and sump system, so I might as well make use of it.

I planned on using -08 feed and -06 return lines, which with the two pumps should be ample to feed my MSD 50 lb/hr. injectors to ~675 horsepower. Possibly overkill, but I'd rather have too much fuel than not enough, if you know what I mean.

I am surprised, though, that you're using a -06 feed line for 800 horsepower. Is there anywhere that you know of that has calculations for fuel line size? Sort of along the lines of calculating power cable size for length of the run and that sort of thing. I'd rather use twin -06 lines if I don't have to use anything bigger. It'd keep them lower profile, and I could use my stock fuel line covers on the underside of the car, probably.

Thanks!

 

The following fuel system is currently supporting ~775rwhp in my car.

Bosch 255lph intank.
Stock lines and regulator.
Kenne Bell "Boost-a-Pump"

Rich Krause

 

Jim:

I am running Bosch 64# injectors at 4bar, so in effect they are 74#/HR. Duty cycle is a shade under 70% at peak fuel demand.

I always take the "bigger is better" approach, and often find that people can prove me wrong. The logic for the -6AN fuel supply line lies in the fact that my application, particularly with the nitrous flowing, is strictly 1/4-mile. The way they talked me out of the -8AN or -10AN line was to point out that when you launch, you can easilly generate short term loads of up to 3G's, and when that happens, the entire mass of fuel in the lines is suddenly pressing back against the fuel pump discharge. That will cause the last thing you want on launch... a loss of fuel pressure. Not a complete loss, but a reduction the computer can't compensate for.

I know it sounds extreme, but when these guys show me that they practice what they preach in their sub 7-second Pro 5.0 Mustang, it gets my attention.... .

 

Thank you Fred and everyone for your replies.

Your suggestion was similar to an Idea I had. My car is a convertible and I have little space for a fuel cell or pump in the trunk for a dual system. I was trying to avoid this but in the back of my mind I knew it was inevitable. My car currently has a stock intank pump and a t rex pump because I used to run a S trim, would that be adequate for the new enigne on horsepower? Should I take the t rex off and install a 255lph in tank pump? Moving to the nitrous fuel system, I figure a cell & pump could be finessed in the spare tire well by a chassis shop. Any suggestion on a fuel pump to run on the nitrous side? I probably could run a carburator style pump (low pressure, high volume ex: BG 280) succesfully and the run the NOS recommended jet sizes for the fogger. However, If I use the NOSzle style kit could you suggest a pump that would work with the high pressure?

Just out of curiosity, what if I decided to run a dry kit? A good friend of mine runs NMRA Real Street and he has recently switched to a dry system with encouraging results. However, the fuel system on his car is a bit more than I wanted to deal with IE: Sumped tank Weldon pump -10 feed lines, you get the picture. I see that you run a dry kit, What would you suggest in my situation?

Also, could you suggest an injector size for both a wet and dry application? I really appreciate your help.

 

I tend to be a minimalist, I'm using a Racetronix pump/harness with stock lines and afpr, but I'm not at your HP level. I'm 550 with a 150 shot. You might try the racetronix kit and if it's not adequate, add a second fuel cell/pump like Fred said.