Hey guys, I'm trying to get my car finished but keep running into fueling issues. Its the car in my sig with Lonnie's 340 upgraded double pumper kit, -8 Teflon feed, -6 return. Y'd at back of intake to each rail, with return off each rail to regulator. And finally, brand new FIC 2000 injectors. Base pressure is set @ 43.5psi and it follows up with boost to about 12-14 psi then falls off terrible, this is only at about 5500 rpm and 875 rwhp. Put a new filter on and didn't help much. Any other ideas, or am I at my max?

 

What kind of voltage are you feeding the pumps? 340s should be good for 500 each at the motor on e85 so you're probably right where you should be. Move up to the big turbine pumps or add a third on a switch

 

Same exact fuel system I have and was hoping for 1000 rwhp. Sorry I don't have an answer but subscribed

 

Just have the upgraded harnees it takes for the duals, no boost a pump.

 

Lots of variables to consider...
What dyno? Dynojet or Mustang?
What air fuel ratio are you running?

If using the 340lph pumps it should be good for 1000rwhp on E85. (based on Dynojet)
Twin 255's are good for about 800rwhp on E85.

As a test, try removing the boost reference & see if the pressure holds steady.. just be sure you are tuned rich enough first.

Also since you have a lot of injector, try lowering your base pressure to 35psi.
This will take some load off the pumps. You get more flow at lower pressures.

Also if you want help, call me for a faster response. I answer the phone 7 days a week.

 

You could have a pressure build up on the return side. Do you have a quick way of adding more capacity to the return?

Also could be clogged fuel filter. My small micron was trashed from the solids in the e85 jamming it up.

 

Tuner is lowering base pressure tomorrow and we'll see what happens.

 

Also I hope you are not running both pumps continuously. That will over inflate your idle pressure & throw off the readings as load increases.

 

No using Hobbs switch plumbed into a manifold with boost gauge and bov in brake booster line.

 

Can't wait to see your results

 

Mebbe, I grew up with a different idea about fuel pumps. I would want to run one to support my goal so if it stops working I dont have to consider if my other pump is coming on or not. I would also be running bigger return and feed. Make sure your regulator can support your hp as well and your injectors can be supported by Volume of the fuel pump. there is a spreadsheet somewhere where you can enter injector info and it tells you what pump volume you need to support it.

as always this is just my opinion.

 

One thing to remember is those pump ratings don't take into account the extra fuel needed to spin the procharger. Figure another 100-120 BHP to spin the F1A.

 

I was thinking about this too. Havent heard back from my tuner on anything yet with the lowered pressure.

 

Getting ready to install this fuel system in my car. Any updates on your issue?

 

Interested to see the results, I was looking at using the same fuel system.

Who is the tuner ?

 

No, lowered base to 35 psi and only made a 1000 rpm difference. Ended up brining car home to do a 4l80 swap and take back after that's done, clutch is having some issues. Looking to get things figured out after that.

 

My brother is making just around 625rwhp and it seems to be working OK. Mine made 863 and power falls off at 5600 rpms.

Andy Wicks is tuning it.

 

I am installing mine currently and will let you know how it works out.

 

FWIW, Lonnie suggested this to me as well. I run a 37psi base pressure with my 1:1 fuel reg and have no pressure issues pushing 20-22psi on my little pt7675. Not sure what power it's making though. I street drive the car a good deal and keeping the pumps healthy was important. Since I have 2000cc injectors running a lower base pressure should be ok.

 

Whatever happened here? I was planning to build a dual 340 setup and push around 800 to the wheels.