Fuel Cooler

[TheMonkey]

plumbing an EFI system with a return line. i don't think i'll have heat problems, but i also don't want to worry if interstate driving in the Summer. i seen this fuel cooler that might be worth putting in the return line before dumping back in the tank.

it's -6an in & out, and core is 9" wide. any guesses how much temps could possibly drop through something like this? worthwhile?

http://store.summitracing.com/partdetail.asp?autofilter=1&part=FLX%2D4136&N=700+115&autoview=sku

https://static1.pt-content.com/images/pt/2007/10/flx4136-1.jpg

[DeltaT]

In good airflow I would expect only maybe a 10 degree drop. It's pretty small.

I used a small B&M stacked-plate Supercooler on my EFI fuel return line, up behind the rearend. It doesn't get great airflow there, but my temps dropped quite a bit - I estimate 25 degrees. They have a lot more internal and external surface area which is needed for effective heat transfer.

Jim

[Samckitt]

Maybe this is a dumb question, but..... I can understand transmission oil cooler, engine oil cooler, power steering cooler, air intercooler, but wouldn't warmer / hot fuel be more apt to evaporate better than cooler fuel? Will it really make that much of a difference?

[TheMonkey]

Scot-

several people have had problems with fuel return lines getting too hot. the problem is usually a combination of a really big pump designed to feed WOT requirements, but used on a hot day on an interstate drive with the fuel tank getting lowish (maybe < 1/2 tank depending on the setup).... the fuel is pumped up into the engine compartment, soaking up heat from the fuel rails, headers, and friction from travel & pump. so, the return line is pumping back fuel that is much hotter than when it started it's round trip, and the tank fuel gets hotter and hotter. with a high volume pump, it cycles through this a lot and brings back a lot of heat into fuel tank. can hardly put your hand on the gas tank or lines. then.... it becomes too hot for the pump from vapor and the pump cavitates and driver pulls over.

some people have solved this with pulsing the voltage to the pump at lower fuel demands. i'm building my system now, and really don't know if i'll have these probs. i seen this cooler at summit, and figured i'd ask if it worked for others.

[TheMonkey]

oh yeah.... and i'm not sure if hotter fuel atomizes better, but i've read several times that cooler fuel makes better power. :bananna2:

[Samckitt]

Ahh I see. Is that why GM went with a fuel system on the LS1 Camaro that didn't have a return line but the PCM regulated the speed of the fuel pump to vary fuel pressure?

[CamaroAJ]

Ahh I see. Is that why GM went with a fuel system on the LS1 Camaro that didn't have a return line but the PCM regulated the speed of the fuel pump to vary fuel pressure?

can you back that up woth some proof? only reason i ask is because i have the LS1 wireing in my car plus i'm a tech at a dealer and have never come across anything that says that. i know they do it on the supercharged W-bodys with relays and resistors.

[TheMonkey]

Ahh I see. Is that why GM went with a fuel system on the LS1 Camaro that didn't have a return line but the PCM regulated the speed of the fuel pump to vary fuel pressure?

no idea. i'm usually cautious about making any assumptions about why oem does something or how they are able to do it. but, i do know that they are in a highly engineered and tested environment. i figure if i can have a full return system and keep it cool, most my risks are mitigated.

for me, without the benefit of extensive R&D, most my decisions are made with risk control in mind which usually ends up to be extra money, time, and always over-engineered.

[Samckitt]

I'm sorry, I was going by something I read in another car forum. Looks like the system I was referring to has the regulator in the fuel filter near the tank & doesn't route the fuel all the way to the front & back. I am still looking though, I thought I read what I posted before in more than one place.

[TheMonkey]

here's a thread with some very good reading: https://www.pro-touring.com/forum/showthread.php?t=22935

[matthimself456]

My Mercedes recently had some fuel line rust issues and while fixing it I came across something "cool." It has a fuel cooler in the return line that is around one of the ac lines. In a PT car this would obviously only work with the ac on but mine, like many newer cars, constantly cycles the compressor whether the ac is on or not. I would bet that drops the return fuel temps a lot since those ac lines are always ice cold. Doubt that specific cooler could be adapted but its an idea.

[DeltaT]

Yes, MB stuff is well built. My '90 300CE has a heater coil in the windshield washer fluid jug as well!

Jim

[CHRIS67]

I don't know if they still make it this way, but Jaguars used to have the fuel lines running through the AC before it hit the intake to add some HP by cooling down the fuel while the AC was on.

[thedugan]

I used the Barry Grant

http://thedugan.net/images/HPIM1981.JPG