fuel line size

[zelatore]

Went out to put the fuel pump in the boat tonight when a question occurred to me:

Is the stock 3/8" fuel line large enough for the 502/procharger application, and should I step it up to 1/2"?

So I did some digging. I pulled the pick-up out of the tank and realized that even if I change the hose, the pick-up will still be 3/8". At least it's a nice short run.

Of course, in the process of unscrewing the shut off valve out of the pick-up you can guess what happened. 2 aluminum fittings that have been untouched since 2001. Yeah, it galled. :nilly:

[VetteLT193]

You'll be fine with 3/8", assuming a non crazy setup.

[ITTLFLI]

boost=1/2" lines

[BUIZILLA]

+1 .............

[SilverBack]

You need to go ahead and run a 1/2" line. You will need to change the pickup also if it is anything like mine was. I ended up using my line as a return line and I installed a new pickup and new line for the supply line.

[BigGrizzly]

ZEL, I just made a 1/2 pickup and ran AN10 (1/2) line from it to the pump. Now in reality,a true 3/8 lin. should do 67 gallons per hour at 12 psi. However with every bend in the line there is a restriction. I do know for a fact that 1/2 line will feed 1,400 hp just fine. I saw this again last Thursday. You can talk to Catch22 on this subject since he has a similar setup and no issues at all. Better yet PM him and he will get back, he is always ready to help anybody and is a great guy. BTW he is bouncing off 93+ mph at this point.

[zelatore]

OK, change to 1/2" line. I had my suspicions. (no wonder this project never seems to get done!)

Should be easy enough to do .... assuming the bigger line will pull through the stock routing. I should be able to pick up most of the parts this morning once places start opening up.

But changing the pick-up, that's another story. Not sure where I'd find that hardware.

[Air 22]

Don...if get the chance post some pic's of ur project:) :wink:

[zelatore]

I got pics....they're just on another thread.
http://www.donzi.net/forums/showthread.php?t=56721

I scrounged up some 1/2" fuel line and most of the other bits I need for the change, but the only ball valve I could find is much too big to fit under the little tank access hatch. Plus, it looks like pulling the new line isn't going to be straight-forward since it's too big to just slide in where the old 3/8" stuff was.

So for now at least, it's going to stick with the stock 3/8". It's a short run without too many bends or restrictions (that I can see) so I'm hoping it will do on my relatively mild motor. With the time crunch coming, I'm going to have to make this a 'later' project, when I can make a bigger pick-up and figure out how I'm going to pull the larger line from tank to pump.

[VetteLT193]

I got pics....they're just on another thread.
http://www.donzi.net/forums/showthread.php?t=56721
I scrounged up some 1/2" fuel line and most of the other bits I need for the change, but the only ball valve I could find is much too big to fit under the little tank access hatch. Plus, it looks like pulling the new line isn't going to be straight-forward since it's too big to just slide in where the old 3/8" stuff was.
So for now at least, it's going to stick with the stock 3/8". It's a short run without too many bends or restrictions (that I can see) so I'm hoping it will do on my relatively mild motor. With the time crunch coming, I'm going to have to make this a 'later' project, when I can make a bigger pick-up and figure out how I'm going to pull the larger line from tank to pump.

When I put my last post I said non crazy setup... so, what's the boost and expected power?

3/8 is easily good for 500 HP, and you should have no problems in the mid 500's. If you are running what I consider a standard marine pulley I figure you won't be much more than 525... if you are trying to get the most out of the engine you could be in the 600+ range so you'll need to upgrade. Especially if you really run WOT for long periods.

[Mr X]

You need to go ahead and run a 1/2" line. You will need to change the pickup also if it is anything like mine was. I ended up using my line as a return line and I installed a new pickup and new line for the supply line.
Exactly!

[DonziJon]

Anybody here ever had a Fuel Flow Meter/Scanguage or something like that to really measure fuel flow in real time? :lookaroun: John

[The Hedgehog]

When I put my last post I said non crazy setup... so, what's the boost and expected power?
3/8 is easily good for 500 HP, and you should have no problems in the mid 500's. If you are running what I consider a standard marine pulley I figure you won't be much more than 525... if you are trying to get the most out of the engine you could be in the 600+ range so you'll need to upgrade. Especially if you really run WOT for long periods.

My experience is consistent with this. 1/2" is definately better and will demand less from your pump. You can feed 500-600hp just fine with a 3/8" line. Many do. You can get by on 3/8 and get in the water just fine. It will increase your margin of error and you will be better off in the long run with 1/2.

[BigGrizzly]

Zel your biggest problem is going to be the tank bung. My tank was aluminum and the bung was bug enough to up the size. It was a bear but persiverence and a drained tank helped. as for chips in the tank use a grease heavy tap to catch tie chips, clean often and re grease. My filter took care of the rest. I used angle right angle pipe with an AN on it.