Hot Gas Tank
 

I took my Camaro on a road trip yesterday that lasted for about two hours. It was the longest trip that I had taken it on. Most are half hour to an hour. When I got home after the two hour drive, I noticed a weird sound. It was a low hiss that I tracked down to the vented gas cap on my gas tank. I slowly removed the cap and it sounded as though the fuel in the tank started to boil. Needless to say, that scared me a little. I touched the bottom of the stainless tank and I couldn't hold my hand there for more than a couple of seconds. There isn't any source of heat close to the tank, my exhaust dumps in front of the rear axle and isn't closet to any fuel lines. The only thing that I can guess is that my fuel pump is circulating the fuel so much that the gas isn't cooling off in the tank like is should. I run a MangaFuel ProStar EFI 600 pump that is rated at 850GPH. I bought this pump so that when I do twin turbos in the car I wouldn't have to buy a new pump. Am I thinking right that the fuel isn't allowed to cool off properly and also that the vented cap and the vent in the top of the tank aren't big enough to relieve the pressure, which is higher because the tank is so hot? It's definitely only going to be short trips until I can figure out what is going on.

I guess if I put cooling fins on the gas tank I'd have a second radiator.:lol:

Sounds like vapor lock... anyone else?

What brand is it?

-Paul

Hey Mike, where's your return plumbed?

Wow, sounds spooky.

Fuel pump generated heat sounds like a likely scenario but I can't say with any certainty.
What is your fuel line routing like?
I sure wouldn't drive the thing till you sort it out.

The guy that I bought it off of said it was a Rock Valley, but when I called them about tank straps they didn't think it was one of theirs. So, I'm not sure who made it. I don't think that the tank is causing the problem though.

Hey Matt, Haven't talked to you in a while. How's it going? The return is plumbed back in to the top front of the tank. It's the line that goes in above the fuel filter in this picture:
http://www.camaroheaven.org/images/a...rebuild623.jpg

That's exactly how I feel!

I have the pump mounted between the rear axle and the tank and it's connected to the tank with -10 braided with a filter in between. A short piece of -10 braded connects to 5/8" stainless that runs up to the front. Then braided to another fuel filter to hardline that goes to the fuel rails then back to the tank using -8 braided and 1/2" stainless. The return line follows the feed line back to the tank and dumps in to the tank through a fitting in the top-front of the tank. I have more pictures of my fuel system on my site.
Pictures of the back of the system are on this page
http://www.camaroheaven.org/modules....id=2&start=616
and for the front are on this page
http://www.camaroheaven.org/modules....id=2&start=560

Thanks for the help guys.

You've got a big pump which bypasses a lot of fuel. Compound that with the fuel running through the heated fuel rails before being bypassed to the tank. There are a couple things that would help a lot.


#1 Get the regulator bypassing before the fuel rails. That way the engine doesn't get to heat all the fuel.

#2 You may need to install a pump controller on that pump to lower the voltage during cruise/idling conditions. This creates a lot less heat in the pump and heats the fuel less.

#3 Install one of these nifty cool cans on the return line to the tank to cool the fuel!

http://www.yenko.net/photos/data/548...r_2005_055.jpg



Jody

Thanks Jody. The oversized fuel system is all because of the turbo headers I bought off of you:D .

I might try the regulator before the fuel rails. I set the system up accourding to the MagnaFlow (now MagnaFuel) diagrams and they put the pressure control unit after it flowed through the fuel rails.

MagnaFuel says on their website not to use a voltage step-down device and now looking at the page that is on (http://www.magnafuel.com/support/index.htm) they say that the tank vent needs to be at least a -8 which it isn't close to. I will try that first to at least get it up to their specifications.

If I can't figure it out, I'll definately be mounting a big fuel cooler box in the trunk. I think that instead of ice, I'll have my A/C system dedicated to cooling it off. :lol:

Regulation prior to the fuel rails is a good idea. Send only the fuel you need to the engine compartment.

Another thing to look at is the number and type of fittings you have in the entire circuit. The more fittings (especially if they are 90deg) and the more tubing bends you have the greater the restriction. This may be contributing as well.

My question about the routing was aimed at the lines and their proximity to your engine/trans and exhaust.

Thanks True.

I tried to use only a couple of 90* fittings to try and cut down on restriction but there are quite a few bends in the system because of the way I followed the frame. I think that the lines are far enough away from the exhaust. They run on the inside of the frame just up to the subframe connectors and then they run outside all the way to the front. The closest that they might get to the exhaust is by the front of the header. This is the best picture that I could find.

http://www.camaroheaven.org/images/a...rebuild653.jpg

It's hard to tell how close it is. I'll measure it tomorrow and let you know.