Fuel Pump Pressure At Dyno

[edizio]

Hi!

Just had a car on the dyno! It did really well but had to stop the boost at 1.8bar as the three pumps are not working properly. The car can boost a lot more but not without the fuel system working properly!

At 7k rpm, the fuel pressure drops from 6bar to 4.5bar!

I have 2x bosch 044s and 1x walbro 450 (all genuine) in the boot of the car.

Does anyone have any bright ideas on the best way to test them? The condition only seems to happen after being thrashed on the dyno. The fuel pumps seem to work fine now so it could be that they are getting too hot, in which case, I need to think of a way of verifying this and sorting the problem. One of the ideas was to have two guys sit in the back with multimeters checking the voltage of each pump when the condition occurs whilst I monitor the overall fuel pressure to rule out a voltage problem. Seems a bit crazy though; any other ways?

The swirl pot, metal tubing, pumps and filters were all hot to touch but the car was on the dyno for a good time so if the heat is effecting them this much, should the pumps be positioned underneath the car so they have air flow or do I just need to keep the tank filled? The tank had reached 1/4 left at this point.

Thanks!

[scotty nm35]

We don't know your configuration, what pumps are supplying the engine? At what power is the pressure dropping? Are you running stock lines etc?

What is your base fuel pressure with the vac line to the reg disconnected?

If the fuel is getting hot you are returning too much fuel to the surge, without cooling it sufficiently. Might want to sort that out.