An air to air inter cooler is to cool intake air charge.Your problem seems to be fuel temperature.Shielding the turbo on the exhaust side would help all under hood temps.Pictures of the engine bay would help us understand the issues better.Hot air under the hood needs an exit point.This problem is why vans are so prone to cooling problems.

Hi Oldblue, I certainly do not mind being told about something I already know. Sincere thanks for the info on intercooler's function. But, yes I am aware that it is to take heat away from the compressed intake charge. But in the process, it sits in front of the radiator, and transfers that heat back into the radiator that is to take the heat out of the engine, and at best blows it back into the engine bay itself. Your thoughts on cooling things down with exit openings is right on. I have already installed a vent in the driver's fender, and it works well. I will do the same in the pass side soon. I had to put an inner vent in the inner fender to allow it to work. You know the vent well, as it is on all BMW M-3's.

It does seem as if the fueling problem and excess heat are related here. I just got back home, and will go out, jack up the car, and see if the return line dumps back into the sump, or into the tank.

Don't ever be afraid to share something you think I might already know. Even if I do, I might not be thinking along those lines at the moment. Sometimes my open minded, seemingly naive honesty is taken for scattered thinking. Maybe it is scattered, but it is also open to considering many options, and exploring many lines of thought at a time. So, if you can stand it, just hang in there with me, and keep the ideas flowing. This is bound to help others as well.

Pierre is going to post some photos soon.

Sam

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Pierre, I am telling you something you probably already knew because it shows in the photos I sent you two years ago of the fuel pump and sump. Yes indeed, the return line goes into the sump, which means it operates as an effective heater for the fuel.

Will it work to plumb the return line into one of the four vent/expansion nipples that emerge from the upper front, driver's side of the tank? Right now they do nothing much. I connected them all with a manifold and lengths of hose. The current functioning vent is from the filler tube at the top.

Am I going to create some other unintended bad consequence if I use one of the nipples for return?

Sam

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Your thinking is not scattered.You seem to think in tangents.I thought you already knew the things I mentioned.But as you said others are here soaking in knowledge.Have you tried an "old school" cool can on the fuel line?

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I have thought of that, but you have to pack those with ice, and are temporary at best; good for race day. I think a trans or oil cooler is actually a reasonable aid in this quest for cooling things down. I am not sure what pressures a tranny cooling line runs. Any auto experts out there? I know, I can look it up on line, but the forum is more fun. And has more personality.

Sam

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Good trans coolers are 200PSI. I use one on my air compressor you can see in another recent thread. Will do fine as a fuel cooler. The stacked plate types are more efficient then the finned types, so I've read. They are parallel flow instead of one long winding tube.




Sam, I can't make out the plumbing. I think I see an inline pump there which I imagine your not using any more since the tank with included pump was installed. Describe the current plumbing / regulator / filter etc please.

It looks like the turbo is already shielded. Only the intercooler output gets near the fuel rail so I don't imagine that's contributing a whole lot to the fuel rail temp. If it was the intercooler input thats a different story. Yes the intercooler may add heat into the engine bay as a whole, but I doubt its the huge change we are looking for. Your not reinventing the wheel, turbos and intercoolers are put into OEM engine bays. My thoughts still concentrate with the fuel system itself.

How hot are the pressure and return lines at the tank itself?

I don't know the anatomy of the vents. They may not allow enough volume, causing a restriction and increase of pressure. An easy way to do a return is to put a fitting in the fill pipe.

To put things in perspective - I just drove my car home for the 35 mile commute. Filled gas, another mile or so home. Ambient was perhaps low 70's. Fuel rail was cool to the touch, could hold on to it no problem. The fuel rail bracket or intake on the other hand was instant burn.

Yes, Pierre, Thanks for posting those. That photo is outdated. I am sorry. I could not tell from the thumbnails in the index. The heat shield for the turbo is gone now. John took it off, and lost it. So, I need to make a new one. The inline pump is gone as well. But the general layout of everything else is the same. The Accel ECU box is gone also. The MS is hanging inside the passengers compartment under the dash to be dealt with as it becomes a priority.

Can I put the return line back into the output from the original sending unit? It is just capped off right now. Having the return line go in low like that would fill the return line with gas when all was shut off, but I cannot see that as a problem. Wouldn't the pump simply start pushing in back into the tank as soon as pressure was up on the FPR? That would be the easiest thing to do. I could just swing the input hose down, and slip it over the tub that comes out of the sending unit then block off the.

The tranny coolers I looked at in the Summit and Jegs catalogs were listed at 30 PSI. So, it seems I need to go elsewhere. Do you have a supplier e-mail link, or part number to look at please? And, what about mounting location. I was thinking of hanging it vertically in front of the tank. I have problems with hanging exposed fuel lines out in front of the car where they could get ruptured and do mega damage in a front end crash.

Another option would be an engine oil cooler. They would likely be rated at 70 PSI or more. My engine runs 50 PSI when cold, and when above an idle.

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Sam look at summit for the B&M Supercooler series. They are rated to 200 PSI per www.bmracing.com website. My air compressor runs 150+ PSI and it handles that just fine. They have 1/2" NPT fittings. They also have a "Transmission Supercooler" which I believe has hose barbs which appear to be similar construction so I am assuming they hold similar pressure as well.

More tonight, gotta run to work.

Just for the record, it would be easy to add the return line to the filler tube.
And I don't mind doing that if it is better. It is more work, but I designed this so I could take the top of the tube out separately.

Sam

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Definitely want to add that heat shield back on.

How close is the stock tube to the hole in the sump? The stock port on the sender could work as a return as long as its not close to the input hole on the sump. The idea is you don't want to disturb the input to the sump. For one obviously you don't want the pump to suck hot fuel back into it. Second, the return may have bubbles etc. I imagine there's sufficient flow into the return line that it shouldn't be a problem pushing fuel bank into the tank. Watch the pressure - if you switch the return line and the pressure goes up significantly then its too much a restriction. Sounds like its pretty easy for you to do / undo the switch so I say go for it before getting into the more complex solutions. Even if it isn't ideal it will still lead you down the right path if it makes a significant change in rail temp.

Is the fuel rail dead-ended?

Meaning fuel flow goes to the regulator; then from the regulator fuel either goes to the rail or back to the tank thru the return line.


Or does the fuel go from the pump to the fuel rail, thru the fuel rail, then it hits the fuel regulator so that there's constant flow thru the regulator due to the fuel return line?

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yea Sam describe the plumbing layout. When you said everything else is the same I'm not sure what that means. I know (and can see in the outdated pics) that you were using the semi truck sized fuel filter but not sure what goes where.

Once again, Thanks for the ideas. Multiple brains are always better , and more balanced than one. Hi Ems, Nice to hear from you.

Fuel supply line is 3/8" and comes from the rear to the front along the frame via mostly hard line. There is a flare tube to AN fitting right near the bell housing, and the #6 AN rises to the fuel filter which sits right above the oil filter. From there it parallels the heater hoses and wraps around to the front of the head to the fuel rail. The fuel flows from front to rear through the rail. It exits the back of the rail, where it takes a 90 towards the regulator sitting on the pass inner fender. The return line exits the bottom of the regulator, and #6 AN line joins into 5/16" return hard line which lies parallel to the supply line against the frame box going back to the tank, which flex line goes back up to the return nipple on the sump.

I can see that having the fuel line next to the heater hose is big mistake number one. I will try to relocate that. It is cooler there than near the turbo, so it is best still on that side, but I will just separate it as much as possible.

The big truck oil filter and in line pump are gone. Other than that , it looks about the same. Return exit at the rear, supply in the front coming up the pass side.

I went back to the thread in the forum regarding the fuel pump and sump and looked at the photos there. BTW it is from Ricks Rod Shop not Tony's as a stated somewhere else lately. It looks like the sending unit tube is maybe a foot or two from the sump, depending on how deep the tube goes into the tank. I cannot remember how the sump gets filled. It seems there are holes in it up the side. I was just wondering if the return line is an important part of the flow into the sump. I guess maybe this slant will never be using fuel fast enough to worry about that.

I will re-rout the supply line away from the heater hose and reconfigure the return entry for now, and check it out. Any other thoughts? Thanks.

Sam

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Went out and worked this morning before going to work on the fuel supply line and discovered another source of excess heat in the fuel. This is fixable, and reason for hope. The supply line runs across in front of the valve cover, and then takes a 90 back into the fuel rail. The way things are configured, the lateral portion of the line is pulled hard against the front of the radiator hose and thermostat housing. E-gads. Why did I do that?

So, I have purchased a nipple and coupling to extend that forward 3 or 4 inches to get it away from the housing and hose. It will hanging out half way between the radiator and the thermostat housing. That has to be one of the MAJOR sources of heat here. So, I will go ahead and add that tonight, and start it up and try things out again, before I make any changes in the tank return. I am feeling very hopeful about this. I was wondering about making a bracket from plastic to tie the line to. I wonder what kind of material I can use that will not get melted by the radiator heat. And, what kind of material can I insulate the fuel line itself with?

Sam

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You could get the foam pipe insulation from the hardware store.

Might not last very long, but should be long enough for testing purposes.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes