Fuel set up advice (hot swirl pot)

[ashley]

Looking for some advice on my fueling set up...

Currently I am running a standard fuel pump in the tank lifting fuel to a boot mounted swirl pot, then a Bosch fuel pump running from the swirl pot to the fuel rail, with a retun line back to the swirl pot.

The Bosch pump is running at full whack continuously.

I've found my swirl pot is getting quite hot, especially after a longer run. I'm guessing the pump is just cycling fuel through the rail continuously, and at idle/ low load the same fuel is just going round and round getting hotter and hotter.


I was thinking of trying to reduce the flow rate of the pump at lower loads, either by reducing the voltage to the pump or by pulsing the power to the pump. But I've heard that lowering the voltage to a 12v dc pump can damage it, and I've heard reservations about pulsing the power to the pump and what that might do to my fuel pressure.


I was also thinking of introducing a mocul oil cooler into the return line before the swirl pot to actively cool the fuel, but I'm not sure whether introducing the larger bore of an oil cooler into my fuel system will be a problem.


I'm guessing that this is not an unusual problem, so how have other people gone about it? Not sure which way to jump!

[djpkins]

not sure if it's applicable here but cold fuel increases the chance of det doesn't it, thats why the throttle body is heated from the coolant supply...to prevent fuel droplets forming in the pot.

[RyanRs]

I think thats more to do with the cold engine parts, cold inlet ports providing surfaces for the fuel to condense on, warming the intake air slightly will keep the fuel in an atomized state. I dont run any TB warming, just use a little more enrichment on cold start, not had any problems with this.

Im pretty sure that fuel should be kept cool for the same reasons as intake air. The warmer the fuel, the less its density and therefore the leaner it will burn for the same volume of A/F ratio. So the denser the fuel the more boost you could run. Also the colder the fuel, the more efficiently the cooling of the cylinders will be.

Is your fuel return line going back to the tank or the swirl pot? if it is the swirl pot then i can defo see why your fuel is getting so hot! Try adding one of these to your Setup..
http://www.summitracing.com/parts/FLX-4130/?rtype=10

[bobhatton]

Looking for some advice on my fueling set up...

Currently I am running a standard fuel pump in the tank lifting fuel to a boot mounted swirl pot, then a Bosch fuel pump running from the swirl pot to the fuel rail, with a retun line back to the swirl pot.

The Bosch pump is running at full whack continuously.

I've found my swirl pot is getting quite hot, especially after a longer run. I'm guessing the pump is just cycling fuel through the rail continuously, and at idle/ low load the same fuel is just going round and round getting hotter and hotter.


I was thinking of trying to reduce the flow rate of the pump at lower loads, either by reducing the voltage to the pump or by pulsing the power to the pump. But I've heard that lowering the voltage to a 12v dc pump can damage it, and I've heard reservations about pulsing the power to the pump and what that might do to my fuel pressure.


I was also thinking of introducing a mocul oil cooler into the return line before the swirl pot to actively cool the fuel, but I'm not sure whether introducing the larger bore of an oil cooler into my fuel system will be a problem.


I'm guessing that this is not an unusual problem, so how have other people gone about it? Not sure which way to jump!

You need to run a dead head setup as its called, the fuel does not flow through the fuel rail.

You come out of the high pressure pump to the FPR, the return goes back to the swirl pot. From the other side of the FPR feed both ends of your fuel rail.

With the swirl pot getting hot it shows the pump in the tank is not flowing enough fuel as that should be flowing more than the high pressure one and would keep the swirl pot cool until the fuel tank got to the same temp

[T.F.S.]

My swirl pot is cool to the touch and its located in the engine bay!!

[Peter Gidden]

You need to run a dead head setup as its called, the fuel does not flow through the fuel rail.

+1. Exactly as i have plumbed Simon's Brighton car!

Ash - PM received, i'll reply later.

[ashley]

Is your fuel return line going back to the tank or the swirl pot?

Yes- back to the swirl pot, pretty much a standard set up I thought...one option on the table is to run the return to the fuel tank, and replace the standard in-tank pump with a Walbro to lift to the swirl pot... but then I might as well stick two walbro's in the tank and lose the swirl pot altogether.

You need to run a dead head setup as its called, the fuel does not flow through the fuel rail.

You come out of the high pressure pump to the FPR, the return goes back to the swirl pot. From the other side of the FPR feed both ends of your fuel rail.

With the swirl pot getting hot it shows the pump in the tank is not flowing enough fuel as that should be flowing more than the high pressure one and would keep the swirl pot cool until the fuel tank got to the same temp

Thanks Bob, I had read about the dead head setup- think I need to do some more research on it, I don't have an FPR in there at the moment and I'm still on a single feed rail (which hasn't been a problem at the power levels I'm at).


I'm thinking it's a toss up between binning the swirl pot and using twin in tank pumps, or sticking a larger single pump in tank to feed the swirl pot, and then considering a dead head set up.

My swirl pot is cool to the touch and its located in the engine bay!!

Great! How have you set it up?

You need to run a dead head setup as its called, the fuel does not flow through the fuel rail.

+1. Exactly as i have plumbed Simon's Brighton car!

Ash - PM received, i'll reply later.

Cheers buddy- looking forwards to hearing your wisdom, thanks

[T.F.S.]

I's plumbed up so when the swirl pot if full it returns to the tank mate.

http://www.balancemotorsport.co.uk/imag ... lation.gif

It would have to heat all of the fuel in the tank to raise the fuel temp...the tank is dumping the heat whilst the rail is trying to heat it

[RyanRs]

If your willing to remove the fuel tank, and considering you already have a bosh 044, perhaps consider copying my setup -its very simple and works perfectly!

Its a deadhead setup like bob and pete have advised. Basically i made my own pickup from the tank, then ran a -8 line to the 044 fuel pump in the boot with an inline filter before it, then from the pump to the FPR Left side with an inline check valve, Right side of the FPR goes to the rail which is dead headed and bottom FPR port is an AN-6 line back to the tank. Simple!

[bobhatton]

Keep the swirl pot, dead head the fuel rail and fit a 044 in the fuel tank with -8 flow lines and -6 return and that will do 650hp if you have a 044 feeding the fuel rail.

I will do a drawing later this week if that would help you

[RyanRs]

Im not too keen on the idea of fitting an 044 in the tank ever since mine developed an internal electrical fault causing the whole outer casing and connected aeroquip fuel lines to become live! After some investigation with the supplier of my pump, it turned out 1/2 the pumps on the shelf were also like it! and what was most worrying was my pump is a year older than the ones on the shelf. Seems a bad batch is out there somewhere!

[ashley]

Thanks guys- much food for thought, I need to go and do some research of my own and check the pricing on some stuff...think I have a plan brewing, and it will almost certainly involve a dead head setup.

Thanks for all the advice, I will update once I've got a final plan together

[bobhatton]

Thanks guys- much food for thought, I need to go and do some research of my own and check the pricing on some stuff...think I have a plan brewing, and it will almost certainly involve a dead head setup.

Thanks for all the advice, I will update once I've got a final plan together

Do not forget 25% discount on all Goodridge hose and fittings. We have also just fitted a 044 with -8 lines into my sons car and going to do the same with -10 lines on my one.

There are lots of fake fuel pumps out there made in China so cheap is not the best way to go with fuel pumps, this could have been what you had Ryan

[RyanRs]

Certainly wasnt Bob! its was an authentic pump with proper sealed box part numbers etc etc, paid full price from camskill! and they get it from the UK bosch dealer. camskill was very helpfull and involved me in the discussions with the dealer and it was the dealer whom tested (iirc) 10 to find 6 with issues!

[bobhatton]

Certainly wasnt Bob! its was an authentic pump with proper sealed box part numbers etc etc, paid full price from camskill! and they get it from the UK bosch dealer. camskill was very helpfull and involved me in the discussions with the dealer and it was the dealer whom tested (iirc) 10 to find 6 with issues!

Oh right, not good for Bosch. I know the fake ones are very good and come in boxes too.
I had better check out our ones

[RyanRs]

Exactly what i thought. Test that there is no continuity between the +12v terminal and the pumps outer casing.

[ashley]

Right, I think I'm hatching a plan that looks something like:

Twin walbros in tank running to an FPR, FPR outputing to a dead head rail, and to the fuel tank return.

Swirl pot & external pump set up is probably coming out, but not fully decided yet...

I might tweak the above as Bob suggests to incorporate the swirl pot: so in tank walbro flowing to the pot, the external bosch pumping to the FPR, FPR outputing to a dead head rail, and to the return to the fuel tank.

The only concern I have about dead-heading the rail is the potential to heat soak the rail when running at low load...has anyone had problems with this??

[bobhatton]

The 044 return via the fpr should go back to the swirl pot.
The swirl pot should have a flow from the tank into the bottom, an outlet from the bottom to the 044 pump the return from the fpr goes into the top, the return to the tank comes from the top as does the vent back to the tank vent. All should be -8 fittings in the swirl pot apart from the vent, that can be smaller.

The only fuel flow you have in the rail is what is being used by the engine so no heat soak problems

[ashley]

[RyanRs]

What sort of bhp are you aiming for Ash? thats a lotta fuel pumps!! i've heard of quite a few walbro pumps packing up, tis quite a lot of work getting the tank off to replace if one did go!