What capacity fuel pump for a desired amount of horsepower/boost?

[T-TopFlyer]

Is there a reference anywhere that gives an indication of what capacity fuel pump (liters/hr, gallons/hr, PSI) that's required for a given application such as desired amount of horsepower, boost, etc?

[Keller]

http://www.gnttype.org/techarea/fuel.../fuelpage.html

Look at the "Injector vs. ET" charts. Think about how much fuel will be burned/required. Work backwards from there, converting the injector flow ratings over to something more sensical and getting them to mesh with pump flow ratings.

Actually, most of the European and Japanese injector flow ratings are in cc/min, which is a bit easier to handle. No matter what, some math will be needed. And I haven't done it all.

Basically, by low-11's a single in-tank is pretty much done. The Walbro 340 or "169" is 255 lph for reference. Many externals blow this away. On both capacity and price.

[T-TopFlyer]

Originally Posted by Keller

http://www.gnttype.org/techarea/fuel.../fuelpage.html

Look at the "Injector vs. ET" charts. Think about how much fuel will be burned/required. Work backwards from there, converting the injector flow ratings over to something more sensical and getting them to mesh with pump flow ratings.

Actually, most of the European and Japanese injector flow ratings are in cc/min, which is a bit easier to handle. No matter what, some math will be needed. And I haven't done it all.

Basically, by low-11's a single in-tank is pretty much done. The Walbro 340 or "169" is 255 lph for reference. Many externals blow this away. On both capacity and price.

Great reference! Not gonna do Walbro until it's confirmed the issues with those are fixed. On paper, it looks like with a Syclone/TTA Pump and larger injectors it would be possible to get in the mid to high 11s.........this is on paper.....In reality, is it safe to push that pump to those limits? The setup I plan to go with is the TTA/Syclone pump, SMC alky kit, and 60 lb injectors....Would like to run ~20 PSI boost.....any thoughts for or against?

[T-TopFlyer]

Ran 20+ PSI today with Syclone Pump, 60 lb inj, SMC alky, FP set at 43 PSI hose off. Strange thing is I got knock before in the same equation when the only difference was that the fuel pump was a Walbro instead of the Syclone pump. Fortunately no knock today. Got log files both ways if anyone wants to view them.

Based on the data I've observed in this case, I'm thinking the Walbro was showing it's current and true colors......Failing over various demands and voltages, and giving weird knock at various points due to inconsistency in supply vs demand is a major issue, especially for an aspirated car.

[Keller]

Probably good judgment. Sound like the Walbro was not delivering the goods when it was being called upon.

Is your pump a GM one, or aftermarket?

I'd suspect its delivery is a little weaker than the high capacity Walbro is supposed to be. I think we have some charts somewhere...

[T-TopFlyer]

Originally Posted by Keller

Probably good judgment. Sound like the Walbro was not delivering the goods when it was being called upon.

Is your pump a GM one, or aftermarket?

I'd suspect its delivery is a little weaker than the high capacity Walbro is supposed to be. I think we have some charts somewhere...

Aftermarket....and yes I know that's risky, but so are Walbros right now.........got it because of the 1 year warranty. Everything else I found was either a 3 month or no warranty. Got a Walbro on hand if this one craps out.

I would say it's delivery is weaker than a Walbro that is running top notch and was made in the U.S. ~ 2 years ago.....unfortunately I haven't had any of those in about a year and a 1/2 and I would say out of the 3 that I've had in that time period most of them were on par with a stock pump at best and very intermittent pretty much shutting down when warm and failing on both high and low demand. Were adequate at a cruise speed though. Showed knock under full throttle, and when I would stop at a stop light the car would quit running. Let it cool down a while and it would recrank. If you could get through the low demand part back up to cruise speed I could make it home running stop lights and stop signs. That's my Walbro experience. How's that for safety, dependability and performance from a "high performance" fuel pump.

Charts show a max of 38 gal/hr for this pump which on paper is good for mid to high 11s.

To add even more risk to this equation. It's going through stock wiring with no hotwire.

What's more is that all this time everyone I talked to said tune to desired boost with no knock. Adjust fuel, timing, and alky. Did all this, a lot of times tuned the exact same way as someone else, but could never get rid of that minimal KNR usually around 1.2 no matter what I did. I think I realize now why. I had a great combo, but the fuel pump was the weakest link and hindered everything.

http://www.autozone.com/selectedZip,.../selectZip.htm