What size fuel line
- Thread starter mustangdave
- Start date
-
Sponsors (?)
mdjay
Premium Sponsor
dodgestang
Active Member
3/8" line will actually handle alot more than 400hp, closer to 600 or so as i recall. the only reason we ran 1/2" line on our fuel altered many years ago was because we were running alcohol and we needed the volume. we were making around 800hp.
as i recall 5/16" line will handle about 400hp before you start having starvation issues at the top end.
as i recall 5/16" line will handle about 400hp before you start having starvation issues at the top end.
mdjay
Premium Sponsor
This is funny timing. We're finding out right now that my 3/8" hard line is not sufficient enough for my set up. I'm running a #8 braided front to back today! I intend to follow the hard line route! The #8 is 7/16 so this should get more fuel volume there. The biggest problem with the hard line that I can see is the decreasing radius bends.
monk302
Founding Member
19simmons65 said:
It is not difficult at all. I bought a roll of twenty foot 3/8ths from Summit. I already had a pipe bender for doing my brake lines. My experience is that shape the line at the rear first going to the fuel tank and then move forward.
dodgestang
Active Member
mdjay said:
I'm sure you covered this, but more than one person has been caught running larger fuel lines and then NOT remembering to increase the 5/16 line right at the tank or the size of the lines at their fuel pump also
I've always heard conflicting answers to this question myself. The only reason for such divergent answers that I can think of would be the pressure. I have heard that 400fwhp is the limit for 5/16 and 550 or so for 3/8 on a line with 4-6 PSI (carbureator). The mechanical versus electric is not the issue it is line pressure.
I put a 1/2 inch aluminum hard-line with some -8AN fittings and 1/2 braided lines; all behind a 110gph mechanical pump at 6psi...just to be sure.
I put a 1/2 inch aluminum hard-line with some -8AN fittings and 1/2 braided lines; all behind a 110gph mechanical pump at 6psi...just to be sure.
mdjay
Premium Sponsor
You can use frame clips or rubber insulated wiring loops.
My fuel pressure is much higher on mine. I'm using the carter provided by paxton which is 9lb at idle and it boosts references from there up to 12-14. The top end is where I'm having issues. Keep in mind this motor is no where near stock. 586 lift solid rolloer, big valves and lots of work on these aluminum heads. I'm still running the stock pulley on the paxton until I get all the bugs worked out. On the higher output motors, you definately need a vented gas cap at the least.
The other problem I ran into is if I have less than a 1/4 tank, the car pulls so hard that it moves the gas out of the way of the pick-up. Then I vapor lock!
My fuel pressure is much higher on mine. I'm using the carter provided by paxton which is 9lb at idle and it boosts references from there up to 12-14. The top end is where I'm having issues. Keep in mind this motor is no where near stock. 586 lift solid rolloer, big valves and lots of work on these aluminum heads. I'm still running the stock pulley on the paxton until I get all the bugs worked out. On the higher output motors, you definately need a vented gas cap at the least.
The other problem I ran into is if I have less than a 1/4 tank, the car pulls so hard that it moves the gas out of the way of the pick-up. Then I vapor lock!
mdjay
Premium Sponsor
mustangdave said:
I agree with the 3/8 on a mild build. I have a SC 302 with everything roller and openned way up. Somewhere between 550-600 crank hp (never bench dynoed) with about 457 on the ground. I'm only getting about 5-7 lbs of boost. I waiting on getting the bugs out and adding miles before I change the pulley. Don't ask me why I'm considering changing the pulley to their 10 lb upgrade, the damn thing is already too fast. I think it's the 500 rwhp goal that is pushing me. Click the link on my sig to get more specifics...
mdjay
Premium Sponsor
70_Nitrous_Eater said:
I'm not that serious about racing this thing yet so it just makes me baby it if I get low on gas. That's a good thing. This car is more set up for the corners than a launch. Too stiff out back to squat. I just baby her first gear and let her rip in second gear.
mdjay said:
I would expect you to have the same sort of problems when cornering hard on a low tank.
It sounds like your still running a carb which probably helps. I know that alot of guys who convert their classics to EFI have the same problem. Carbs are much more forgiving when it comes to air in system.
If it does start to bother you, look into a surge tank. Easy and cheap to make.
