Thread: Fuel Tanks
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Old 10-25-2009, 08:45 AM
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Quote:
Originally Posted by GregWeld View Post
Regulator is after the fuel rails -- so the fuel is fed to the front of the passenger rail - out the back - looped to the front driver rail - out the back to the regulator mounted on the firewall - where it returns to the tank.

I ASSumed the fuel was moving continuously through the system... only "stopping" / or "slowing" as required to build pressure (the regulator - doing it's job ala a thermostat on the coolant side of things).

If the pump is whirring away without any fuel movement -- then wouldn't we have another issue --- CAVITATION?
although the stainless hard lines and braided lines look good they do act like a heat sink. The fuel is moving through the system, but getting heated quite a bit in the hard lines and rails.

Usually if you enter in the front then you'd use a short line from rear of one rail to the other and exit in the front also (opposite rail you entered). So if you wanted the regulator hidden in the rear then enter in the rear also. Your way works, just adds even more stainless hard line to heat the fuel though. Bottom line, if you're not having problems with the fuel pressure dropping on long runs you should be fine. Large pumps aggravate the situation, but you do have some of the ingredients of the problem scenario with all the hard lines and front mounted regulator.

Not sure what you meant by the cavitation issue....... were you speaking of a rear mounted regulator? In that case the regulator still bypasses to the tank, just at the rear of the car, not the front. Still fuel moving through the pump like your setup, but without the hot fuel back to the tank. If you want to see if you might have an issue you need to take a 100-150 mile drive down the freeway, watch the fuel pressure, or pull over and feel the tank. If the fuel is heating the tank you'll know it, the tank will be hot to the touch. There are tons of cars with front mounted regulators that have no problems, it just takes the right combo of parts and conditions to cause the issues we had. Big pumps running full speed, hard lines and rails heating the fuel, long runs, etc. I've been mounting the regulators in the rear for years without any issues. Many people have said you can't do that, I don't argue with them. I know the later Vettes, GTO's, etc. all had the regulator in the filter on the frame rail, with the bypass off of that, only one line to the front and work fine. They do bump the fuel pressure, probably to help guard against any fuel boiling from the fuel in the rails; I've run from 43 to 58 psi at idle, never seemed to make any difference, no problem either way.

Jody
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Last edited by camcojb; 10-25-2009 at 08:49 AM.
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