Fuel swirl pots, twin 044 pumps and fuel heating

[IJ.]

Where would you put the Temp Sensor Ross?

In the fuel rail.

Isn't that just going to heatsoak from the engine heat in the rail and NOT give a tank temp compensation?

Hi Chris,

I run 2 044 pumps on my GTR33 through 2 stock (supply & return) lines feeding fuel on the sides and dumping fuel from center of the rail through regulator back to the swirl port through -8 line. I used larger return line in order to have correct pressure at idle and lower loads. On previous setup with -6 return line I was unable to have the pressure lower then 3.5 bar on vacuum. Both pumps are always on together though I am thinking of implementing individual control. Did not notice any heat related problems although the swirl does get hot after couple of hours of running. My current differential pressure is at 3 bars.

One thing to note when implementing individual pump control is to make sure the fuel will not be dumped back through the second pump when it is off. Not sure about this since did not test it myself. Perhaps somebody could comment on this more. We usually remove the valves that these pumps come installed with.

I think better way would be to use Motec DHBs to do PWM pump control like OEMs do in stock cars. That way you can reduce the pump current therefore reducing the volume, heat and noise! Looking at the DHB spec sheet it seems to be possible. Motec thech gurus please comment on this.

The control table logically will be RPM x MAP.

I think that your 800cc injectors would max out before you reach the 700bhp on pump gas. Just doing easy calculation you would need 919cc at 0.6 bsfc, 80% duty on 6 cylinders to get 700bhp. So I would go with 1000cc.
If you plan to run on high octane race fuels then 800cc would be just suffice.

700bhp GTR is a beast at the streets let alone circuits! I am not sure what skills it would take to fully utilize on the circuit I do take extreme care pedaling mine in and out of the corners cold sweating in the process!

Good luck with your project

Alex

I use a pair of Aeroquip non return valves to prevent any back flow through the inactive pump Alex.

[RossB]

Isn't that just going to heatsoak from the engine heat in the rail and NOT give a tank temp compensation?

It shouldn't, it is measuring the temperature of the liquid inside the fuel rail in the same way it would measure the coolant in the engine.

[Scott@FP]

Ideal place for a fuel temp sensor for correcting for fuel density changes would be inside the injector itself, 2nd best would be as close to the injector as possible (rail or possibly regulator), least ideal place would be tank, but its just like IAT or any other comp, if its not a direct, proper sensor location, fudge the comp and use the 2nd axis if available to achieve a comp that approximates reality.

[IJ.]

Thanks for the clarification guys!