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Okay, having a problem and it has led to some thoughts.

I have a Boyd fuel tank with a rear sump that feeds into an A1000 pump mounted on the front of the tank. The fuel line runs up the tunnel to the fuel regulator on the firewall and then the return line runs back down the tunnel to the tank.

I have had issues with the car dying (usually will start up pretty quick after it dies) . . . never at highway speeds, just when driving around town on hot summer days. This was not happening before we installed the new Boyd tank and fuel lines. I have been told that most likely I am having a heat problem because the pump is too close to the hot pavement. Another suggestion was that the regulator and return line are getting hot from the headers and the heat running down through the trans tunnel. Someone suggested I install the regulator back near the tank so the return line is less than a foot long (this would make the engine bay a bit cleaner too). This thought intrigues me. Is there any reason not to do this?

Also what about drilling a hole in the main frame tube to pass the stainless fuel line through (With an angled heavy duty rubber grommet of course) and then having it come back out right at the firewall and run up to my carb. This isn't for heat but just to clean everything up a bit under the car.

Thoughts? Advice? Suggestions? Open to all feedback.

Thanks!

Bill
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The air in the transmission tunnel is not hot. How do I know? A mod I've used on several builds is air scoops in the tunnel that allow air into the cockpit. Something I saw on a build 10 years or so ago. Actually works reasonably well, and the air is basically ambient temp. I don't know how close your headers are to the fuel lines. But unless they're extremely close, I doubt that's an issue either.
 

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My concern would be that, due to length of run and restrictions caused by fittings w/ bends, the pressure at the engine might be less than at the regulator. Of course you could check that w/ a temporary gauge up front. I do know that Toyota/Lexus around 2006 started running just one fuel line to the engine w/o a return. At least one person said that running the fuel up to the engine and back again heated the fuel more than dead heading it at the engine but I don't know if that is actually true. Does the new tank have a vent?
 

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I agree with Craig. You really want the max pressures near the induction system then the regulator to the induction if dead heading. Or the following config.

I've run an Aeromotive bypass regulator on the firewall after the carb. This configuration provided regulated pressure at the carb and then the return to the tank. This configuration is well documented in pressure regulator installation instructions. This solved multiple overpressure problems even when running a mechanical pump that in theory didn't need a regulator.

In the past my cars had fuel lines between the frame rails in the trans tunnel, no serious heat issues but I did install a heat shield between the main fuel line and the headers. This seemed to work well for me and friends that did the same.

While I like the idea of running a stainless line through a frame rail I wonder if there will be vibration issues inside the frame that you'll not be able to see, secure or protect.

Jim
 

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GM has been doing that for decades. The pressure regulator/filter is mounted in the rear of the car. The fuel line kits that Breeze sells are GM parts.

That being said, I don't think that's your problem. The A1000 pump moves a massive amount of fuel. At 50-60 psi, the odds of developing vapor lock from overheated fuel is really low. I would look elsewhere for the problem.

As for running the fuel line through the frame, a lot of people have done that.
 

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Don't like the idea of having a fuel line where It's not easy to see.
 

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1. Hydraulic systems can run hot if the oil is aerated. As the bubbles are compressed, heat is generated. The heat is transferred to the oil. Could this be an issue in your fuel system?

2. With a return system, the fuel tank acts as a radiator of sorts, cooling the return fuel. This does depend on air flow over the tank. I am unsure if it is as important for petrol powered vehicles. It is certainly necessary for common rail and unit injection diesels. I have worked on stationary engine applications where the fuel tank got so hot that you couldn't hold your hand against it.

On my coyote powered mk4, I ran the fuel lines through the transmission tunnel about 2 inches down from the top. At the time it seemed pointless to take the fuel lines from the top of the fuel tank down to the frame rails and then back up again to a regulator under the hood.
My understanding is the coyote engine is a cool runner. Regardless, there are no heat issues in the trans tunnel even after extended driving. I also don't think there is enough continuous load on the gearbox to generate a lot of heat either -could be different in race conditions.
I have a dash mounted, calibrated fuel pressure gauge and pressure is rock solid. I have a Mallory fuel pressure regulator that is vacuum referenced to the engine.
I used the standard fuel lines that are supplied with the kit. Even under heavy acceleration the fuel pressure is maintained at 55 psi.
One point worth mentioning; on a couple of occasions I have caught myself short and nearly run out of fuel. Once the tank is below a quarter full I have noticed that the fuel pressure starts to drop down to ~25 psi when braking or pulling away from a stop. Although the engine seems to cope with this quite well, it seems that the supplied tank probably isn't the best design.

I don't feel that running the fuel line through the chassis rail is necessarily a good idea as it will be both unsupported and unable to be inspected. Also if heating is an issue, then running the line inside the frame rail prevents any sort of air cooling. I could be completely wrong on these points, after all, some might say I'm a stooge for running my fuel lines in the transmission tunnel.

Don't know if any of this helps, but best of luck getting your issue sorted.

Cheers, Nigel in South Oz
 
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