Class 6100 rules are out on BITD

[OldGreen]

If that is the way it works, it shouldn't be an issue with the fuel itself. . .more likely with the way it is plumbed or the pumps.

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[FlyHiFlyLo]

RG had Vapor lock during qualifying....

haha that's what he told you?

[Byrdracing]

I have no idea of how your truck is set up, but how we figuired it out on my 7s (stock 4.0 sohc)was running 2 tandem faucet pumps directly below the cell (acting as pushers) and having the high pressure pump and regulator as close to the fuel rail as possible. The high pressure pump(stock ford 110 psi) is up front away from major heat sources and the fuel lines are shielded. Faucet pumps more or less run cooler and do not pressurize the fuel line as much as having the high pressure pump next to the cell (safer deal)
Never had a problem running pump gas and ive got it hot enough to blister my feet on the pedals. Hope this helps

[FlyHiFlyLo]

Hey fish, does your Mac Movie editor have a vapor lock? LOL

[Jacob7672]

From my understanding the vapor lock happens on the suction side from trying to suck it from the bottom of the tank. The pumps are lubricated from the fuel. When it vapor locks the pumps are run dry and can cause damage to them. If you mount the pumps in the bottom of the tank this can't happen.

Exactly, this is what happened to my "fuel injected" prerunner a couple months ago. Eventually the pumps were just sucking air and I had to crack the lines to release the pressure and prime the pumps again.

[FlyHiFlyLo]

Exactly, this is what happened to my "fuel injected" prerunner a couple months ago. Eventually the pumps were just sucking air and I had to crack the lines to release the pressure and prime the pumps again.

This can't happen if you run an open loop, only if you dead head it..

[CRAIG_HALL]

With the only change being race fuel I'd guess the pumps are still creating the same heat but the pump gas fuel boils at a lower temp and you'll get vaporlock. That means the pumps are probably creating too much heat in the first place. I saw the different ratings for the fuels but what is the actual boil temp. difference ? is it that drastic or have we been on the edge the entire time ?

[FlyHiFlyLo]

With the only change being race fuel I'd guess the pumps are still creating the same heat but the pump gas fuel boils at a lower temp and you'll get vaporlock. That means the pumps are probably creating too much heat in the first place. I saw the different ratings for the fuels but what is the actual boil temp. difference ? is it that drastic or have we been on the edge the entire time ?

If your fuel is circualting it won't boil.

[Jerry Zaiden]

Jerry, on those cold days, by chance did you actually physically touch the pumps to see how hot they were? Only asking cause as I said in my story above, I kind of assumed it was vapor locking on me but I also wondered if the pumps working to suck the fuel were actually just over heating. It was always in the back of my head that when I wrapped them in a wet rag or put a bag of ice on them all I was doing was cooling them down enough to work again. Heck, maybe they were actually vapor locking right inside the pump from the heat it built up? It was always a summer issue for me though so I automatically assumed vapor lock. On those cold days though you speak of, it would be interesting if the pumps were physically hot? Would a small low pressure high volume in take pump to supply to your high pressure inline pump help?

Yes the pumps were not hot and the fuel was also cold to the touch.

If I'm not mistake the fuel enter rear of one rail, crosses over at front, thru other rail, exits at rear. there's a regulator on the exit right ? I'd have to check with Jason at shop to confirm..

Yes the regulator is correct and yet it backs up pressure to the rails.

[FlyHiFlyLo]

if you don't run the pump in the tank keep as close to that tank as you can and below it.