I've had my inlets covered up since I installed them to keep dirt/dust out of the tanks. Today most of my fueling parts (low/high pressure pumps, regulator, 75/10 micron filters, hose fittings, etc.) arrived and I when I removed the cover over the tank outlet I noticed it was only 4AN in size. To me, that seems very small for a 500HP engine but before I go cutting, and replacing, I'd like to hear from others as to the size they have hooked up to their low pressure pump pulling fuel out of the tank.
Size of fuel tank outlet.
- Thread starter darrinps
- Start date
Never mind...ran across this little chart. Looks like I have some surgery to perform on my tanks. Ugh.
From tank to pump (suction)
Tube ID
.180" = 110hp
.243" = 200hp
.319" = 335hp
.444" = 675hp
Note that I think these numbers are low as I am sure a 3/8" line will support well in excess of 500HP. That's what I am going to go with. 3/8 with a 6AN fitting.
From tank to pump (suction)
Tube ID
.180" = 110hp
.243" = 200hp
.319" = 335hp
.444" = 675hp
Note that I think these numbers are low as I am sure a 3/8" line will support well in excess of 500HP. That's what I am going to go with. 3/8 with a 6AN fitting.
Well EFI should be fed from a swirl so it's kind of irrelevant unless you're going flat out for some time. You might want to run a large swirl pot though.
If you're talking single line then you should be able to run -4 for about 500HP but best go to -6 for a 500-550HP motor.
Looking at the area of the different sizes
-4 is .22in ID so 24.5mm^2
-6 is .34in ID so 58.6mm^2
-8 is .44in ID so 98.1mm^2
So if you're running dual pumps or link the two into one pump you should be fine as the two -4's are very nearly equivalent to one -6.
Main thing I guess to consider though is that you really don't want to weld a used fuel tank, if you're unsure get 8AN fittings put in before you fill it, you can always use an adapter to drop them down a size or two.
FWIW I'm planning on running -8 to the swirl but I know it's total overkill, the original lines to my engine were I think -4.
If you're talking single line then you should be able to run -4 for about 500HP but best go to -6 for a 500-550HP motor.
Looking at the area of the different sizes
-4 is .22in ID so 24.5mm^2
-6 is .34in ID so 58.6mm^2
-8 is .44in ID so 98.1mm^2
So if you're running dual pumps or link the two into one pump you should be fine as the two -4's are very nearly equivalent to one -6.
Main thing I guess to consider though is that you really don't want to weld a used fuel tank, if you're unsure get 8AN fittings put in before you fill it, you can always use an adapter to drop them down a size or two.
FWIW I'm planning on running -8 to the swirl but I know it's total overkill, the original lines to my engine were I think -4.
The tanks are brand new and have never been filled. Going to just pull from one tank (although I am linking the two tanks...just not pulling from both).
Just put in my order for some 6AN to 10mm fittings and some Ducati fuel line to go over the 10mm push fittings. Will be a pain but it should do it.
I'm going with 6AN because my low pressure pump (which is good to 700HP or so) is fed via a 6AN.
Just put in my order for some 6AN to 10mm fittings and some Ducati fuel line to go over the 10mm push fittings. Will be a pain but it should do it.
I'm going with 6AN because my low pressure pump (which is good to 700HP or so) is fed via a 6AN.
Seymour Snerd
Lifetime Supporter
Keep in mind that a single under-sized fitting is a lot better than an entire line that is undersized. So if after a (say) 4AN fitting the tubing or hose is (say) 8AN you're probably fine.
Regardless, if you can have larger fittings put on the tank definitely do so. FWIW Superformance puts 8AN fittings on both tanks. And as someone pointed out, you can always adapt down for whatever size fittings the downstream fuel pumps and carb inlets have.
Regardless, if you can have larger fittings put on the tank definitely do so. FWIW Superformance puts 8AN fittings on both tanks. And as someone pointed out, you can always adapt down for whatever size fittings the downstream fuel pumps and carb inlets have.
Agreed!
The 6AN should be fine for everything I will ever need though. I've seen calculations showing that line supporting well over 700HP and all I am looking at is 550 or so.
The 6AN should be fine for everything I will ever need though. I've seen calculations showing that line supporting well over 700HP and all I am looking at is 550 or so.
