I posted last week about issues with my fuel system overheating. I was given plenty of great info and one of the most reccommended things was to reroute the fuel lines more effectively. How have you guys done your system. I cant remember how the stock lines were looked. Right now my feed line is coming up from the firewall and up to the rails (pretty close to the header) and the return line goes through the hole in the shock tower. can you post some pics of your set up and give ideas on how to re route the lines. I also have the braided steel lines, where can I get more of this? Would it make more sense to go back to stock like plastic lines, or is there an advantage to using the braided one's. Here is the link to my previous post if you are interested.
http://web.camaross.com/forums/showthread.php?t=361420

thanks miles

 

I run a single -6AN line up the firewall to the back of the engine, then split into a -6AN line into each rail. The return comes off a -6AN fitting welded to the cross-over pipe on the front of the rails, runs back to a Weldon AFPR under the cowl, and then down the fire wall. I have never had a problem with heat buildup in the system, even though the lines are not all that far from the muffler bolted to the drivers side collector. I have dual 205 liter/hour pumps, but the system normally runs on a single pump, with the second pump being activated with the nitrous "arm" switch. But even if I run both pumps continuously, I haven't seen a problem with heat buildup.

In my opinion the problem is your fuel system is just way too big, and the huge amount of fuel being circulated is picking up heat just from being circulated so fast through the system.

First, you claim a "1000 gallon per hour pump".... that is simply wrong. The guy from Aeromotive picked up on that and assumed you mean 100 gallons per hour (375 liters per hour), and that sounds more reasonable.

Second, a -12AN supply line is ridiculous. It would be OK from a sump on the tank to the pump suction. But not from the pump to the engine. A "too large" fuel line actually hurts you, since on a hard launch, the entire "mass" of the fuel in the line pushes back on the fuel pump, and you start to lose pressure in the line, at exactly the time when you need max fuel.... the pressure is going to bounce. I run a -6AN feed and return for a nitrous motor making 800 flywheelHP. The system supports injectors that flow 78#/HR at the system's 58psi operating pressure.

I have seen a 1,325 flywheelHP blown 383, and it only used a -10AN supply line. -12AN is overkill. With a slightly smaller version of that engine (~1,125HP) he had a problem with the fuel heating up... simply because of the huge volume the pumps were capable of flowing, and all the heat they picked up as they circulated, and the heat input from the pump and the friction in the lines. His solution was a simple fuel cooler. Solved the problem completely.

 

Injuneer,

thank you for the informative reply and based upon your expertise I should look into a smaller pump and change the lines to -6 to and from. As I research further I began to think the system was too large and wondered if it could be the problem. Since I bought the car this way i would like to do it right even if it means starting over. What would you reccommend as far as a newer pump? and where can I get the lines?

 

racetronix sells a very nice kit, with a walbro pump and plug and play harness. May want to check them out...they are a registered vendor.

 

I would check out the pump before replacing it.... it is unlikely that is is a "1,000 gallon per hour pump"..... maybe John Force uses one (or two) of those

But a 255-350 lph pump would appear to adequate for what you have. I make 500 flywheelHP on a single 205 lph pump. I wouldn't worry about changing out the AN line at this point.... a pair of 15-ft lengths of -6AN fuel line are going to be expensive. Look into a fuel cooler. Make sure you aren't pulling suction on a line that goes into the top of the tank, as Mark (??) from Aeromotive suggested. You shouldn't have a high point in the line from the tank to the pump. That's why they put the stock pump IN the tank. If you add an outboard pump, you need to put a sump at the back/bottom of the tank to make the connection.