Returnless fuel systems variable pump output

[hodge]

I've Been reading a book called "Engine management and advanced tuning" and there's a section on fueling I've found very interesting in hindsight of Jamies issues with overheating fuel issues.

The part that rang bells was about having a returnless fuel system which would reduce fuel temps from engine bay heat etc.

 

Instead of the fuel pump running at 100% output all the time it is governed by the ECU depending on load/RPMs boost pressure etc. The pressure is monitored by a sensor directly in the rail so this would remove the need for a fuel pressure regulator in the engine bay also if I read article correctly.

 

What's you opinions on this??

 

Can a Bosch 044 be ran as a variable output pump??

 

I've seen speed control pumps on the market with variable outputwhich I would imagine would if connected to the ECU (I'm running a Syvecs) could be controlled any way wished as it would just increase flow with a voltage increase generated by a speed signal.

 

So say with the issue Jamie had with his pumps overheating in traffic, the pump heat could be dramatically reduced if the pump was only running at say 10% output.

 

I am seriously considering giving this a go at the latter part of the year.

 

Opinions and views would be great.

Thanks

John

[johnny g]

I'm not sure on the Bosch, but the Fuelab Prodigy pumps can be switched via PWM output. Might be worth a look...

[hodge]

I'm really liking the whole concept of this. I'll have an in-depth chat with Ryan about it on Thursday to see if there would be any issues with the Syvecs running such a system.

Johnny when you contacted fuelab a while back did they let you know if the pump could be submersible in the tank.

[johnny g]

I'm really liking the whole concept of this. I'll have an in-depth chat with Ryan about it on Thursday to see if there would be any issues with the Syvecs running such a system.

Johnny when you contacted fuelab a while back did they let you know if the pump could be submersible in the tank.

 

Yep, they can be submersed without a problem. It might be easier to sump the tank though, to keep the fuel cooler and the pump.

[hodge]

I'd just have a direct replacement for the 044 and just cap the return hole on the hanger.

[Tricky-Ricky]

The variable speed pump concept has been around for a long time, a lot of cars use a two speed pump anyway.

My Skyline has a return less fuel system, but if you go FI its always changed to a return system, although no doubt the Syvecs could handle the control, my question would be is how many fuel pumps out there are capable of variable speed control fine enough to control pressure with the precision needed?

With the FPR control the pressure is always mechanically increased with the onset of boost, and is a pretty simple and foolproof system, whereas with electronic control you are dependant on a lot more factors, and also i would expect a fuel pump with a precision motor to be on the expensive side.

Personally i would go for a mechanical system, but with two speed control of the pumps to prevent any overheating when there is not so much fuel demand.

[hodge]

As Johnny said the fuelab prodigy pump has variable speed/output. I think it's around the 300 pound mark and will flow enough fuel for over 1000hp. The whole concept does interest me a lot.

I think I need to find out some more about the pump and whole setup first though.

[Ian C]

Sounds a) expensive and b) something else to go wrong that can cause an even more expensive engine failure

 

Or am I being a luddite? If it saved weight/economy/emissions/gave more power etc I'd understand it, but really it appears to have no actual practical application. The fuel overheating issue looks to be from running two big pumps constantly and can (and is being) easily be solved by running only one when off boost.

 

Sometimes elegant engineering is based around simplicity, not the most trick setup