Personally, I don't even see why those multiple inline external pumps are necessary. Rich said he's making 730+ rwhp on a single 255 lph intank, and I know Derrick Redd is making 550ish on the stock bottom end with a single 255 lph intank. My friend has a Vette with a few inline external pumps. When one goes out, the total system pressure drops to crap. It's completely retarded. I don't see the point, really.

All you need is a single bad-*** intank, or if you feel the need to: a single bad-*** external - friend has a 1000 hp-compatible external Aeromotive on his Mustang which sounds like a chainsaw All of this multiple external inline stuff is for the birds.

Mike

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Part of it has to do with the use the car sees. In a street car, that has to operate at very low fuel demand, a "1000HP pump" is going to be recirculating an awful lot of fuel... that fuel gets heated up in the pump, heated up in the lines when it passes the exhaust system, and heated up in fuel rails. Heat it up enough, and you are going to generate excessive vapor loads in the tank, and eventually heat up the entire fuel supply. I have seen it happen, and it required a fuel cooler to correct. More weight.... more plumbing.

A pure track car doesn't have this problem, and can handle the short periods of high recirculation. A "chain saw" sound might also be more acceptable on a track car than on a street car.....

A properly sized fuel system, with the correct fuel pressure regulator will not vary in pressure when the extra (parallel) pump is turned on or off. Mine doesn't. You might see the needle on the gauge "twitch" one psi or so at most, but the pressure stays in complete control.

 

Fred: Thanks for the run down on the injectors, looks like I will need to address that and look for some slightly bigger ones.

For those that wondered whether bypassing the T-Rex has helped I honestly can't say yet. I haven't had a chance to really hammer on the car as 2 new problems have surfaced, one stemming from me and a buddy apparently running the MSD fuel pump voltage booster incorrectly and possibly frying the sender in the tank for the fuel level gauge. Might be the time to drop the tank and put the better 255lph Walbro in instead of the standard 255lph that I currently run.

Either way, with Fred's explanation it looks like I will be running out of injector.

 

You don't want to be running 100% DC for long but there is nothing wrong with it.

80 to 85% is a good range for prolonged use but for a street/strip burner 100% is fine. We aren't normally doing high speed runs with these cars. People go hogwild with injectors alot of the time when then aren't needed.

 

That I understand...

Currently though I am seeing near 100% duty cycle just barely over 5000 rpms. By 5800 it was at 110%.

Also, not sure how this factors in to Fred's equation but the injectors were flow tested at 44.7-44.9 lbs I think at 80% duty cycle.
I don't want to go too big but I would like some nice headroom to work with.

 

Two Aeromotive 1000hp EFI fuel pumps in parallel. One pump will serve as the primary pump and the secondary pump speed will vary based on engine rpm. Both pumps are controlled by their own Aeromotive billet fuel pump controller. -10 AN fuel feed line, and a -08 AN fuel return line.

http://www.montygwilliams.com/fuel_pumps_filters.jpg

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Hey guys, what about inline pumps that are higher than intank pumps.

Say, a 255lph intank, with a 405lph inline. Will that cause a problem?

 

From the experience Rich had, id say you'll be fine since the inline flows more than the intank.