I'm almost done getting all the parts for my Dailey driver Amc V8 turbo build. I'm thinking a belt drive fuel pump would be the way to go. Quiet, reliable, no high amp draw (60-amp alt stock) but can't find alot of info in these for EFI, using a holley Sniper. And especially can't find any info on using one on an Amc V8. Couldn't find anything on the-amc-forum either.

I did email Aviaid about a drysump oil system awhile back. So i know i can get a block mount for that which is very similar and use the same type of belt system.

I'm still curious if I'll need a remote sump to have a constant fuel supply ready. As the factory tank in the Jeep is for a carb. No baffling. Or will the pump pull enough it won't matter? Though i am probably going to a smaller 15g tank from the stock 20g as I'm pushing the rear axle back. And that tank is an efi baffled tank from genright.

So what type, brands, system, mounts, pieces would be best?

 

IMO you’d be better off using an electric fuel pump since you plan on moving the axle back and installing the efi baffled tank . Upgrading the alternator would be a wise decision if you are adding EFI to it. What vehicle is this? What engine?

 

84 CJ7, Amc-401 t, the alternator will get upgraded at some point. But there's not alot of electronics in a jeep as it is. And I thoughtiI read big fuel pumps could pull as much as 60-amps?i could be wrong on that. But the stock system should be fine to run the holley efi I think.

The axle will only be going back 4" give or take. Short as the jeep is, it shouldn't be a problem.
But there's no sound dampening, and the fuel tank is only like 2 feet from the driver seat. So i really don't wanna listen to a big pump buzzing or reverbing off the floorboards. Which I've read can be a problem with high hp builds/pumps

 

An in tank pump isn’t that loud. Since it is a Jeep idk if you plan on adding more lighting or winch etc but a higher amp alternator would be needed especially with efi . Run all your accessories at once lights,radio,wipers etc and who knows if your alternator will keep up.

 

Higher amp alternator seems like a much easier upgrade than a belt driven pump... what is your fuel need? A 525lph fuel pump is only going to draw 20-25 amps at peak output. You could get one of the baffled EFI drop in conversion kits, or run a remote sump if your going to be 4 wheeling often.

Belt driven fuel pumps are more like race car stuff than DD stuff, and its going to do nothing for the inevitable vapor locking you will experience with modern fuel, so your still going to have to run a low pressure electric inline pusher which is going to whine and cry much more than an in tank deal.

My cj has custom tanks that cannot be replaced or modified, they are essentially part of the body work. So I run an inline electric pusher with a sump, the sump is full recirculate and you can barely hear either pump even at idle because there is no resistance on the low pressure pump and the 340lph in the sump is muffled by the fuel and sump body. Once you get some wind and tire noise your not going to hear anything over the 401 and the other miscellaneous jeep sounds.

 

Isn't vapor lock directly related to the fuel heating up? Which the electric pumps contribute to?

The 401 will be intercooled and between 7 and 10 psi.. 650-700hp. Along with 1 ton axles and 37s. I think that qualifies as racecar stuff? There may be plans to drysump it in the future as well. (it's getting an accusump for now) Hardcore offroading isn't where i want oil or fuel issues to arise.. If a pump dies on a hillclimb..
And If every offroad vehicle had a drysump system they'd live alot longer.

A belt pump just seems deadnuts reliable and won't heat the fuel. I've thought about using the factory block fuel pump to fill the a sump uo front. Then just one high pressure pump. Which may be the easiest route.

 

I'll agree with Ben, and 91 on this, electric is reliable with the proper pump, and electrical. Belt driven is typically found on 1500+ hp with ethanol, or methanol fuels. That aside, if you're dead set on belt driven, check out Motion Raceworks for universal stuff as I believe bolt on AMC stuff is going to prove tough to find, and they're the only ones that come to mind. Another thing to keep in mind is that most pumps don't pull fuel worth a darn so you'll need a cable driven if looking at a rear fuel tank, or a second tank upfront.

 

You compress any fluid it’ll heat up but that’s beside the point. A fuel pump that is submersed in fuel would be more reliable by keeping it cool. The fuel pump mat can help in off camber situations too.

 

Vapor lock is caused by fuel boiling in the lines, that could be from heat but the equilibrium vapor pressure of modern fuel is so low you can make it boil just by putting vacuum on it, and its worse in warm weather. My 78 would vapor lock any time i got on the highway if I didn't turn the little pusher on, even if it was cool out. You will find just about any vehicle with a fuel pump at the front has some sort of pusher at the rear. Adding 3-4 psi positive vs a little bit of draw vacuum is enough to push the boiling point out to where you wouldn't ever notice. When you start talking EFI pressures you increase the boil point dramatically.

As far as a pump failing... When was the last time you heard of a modern in tank pump failing? It doesn't happen often.

7-800 hp used to be race car stuff, pretty common hot street territory these days. I am not sure what "1 ton axles" have to do with racing, they are heavy power wasters, I can't imagine a serious race application that uses them at this point, the custom axle world has flourished in the last decade. "37 inch tires" don't really have anything to do with racing, that's just a size.

The heat compression of fuel is just about a wash, because its going to loose exactly the same amount of heat when its injected.

 

I don't hear of OE pumps failing, but occasionally custom builds. What pump would you all recommend?

Aren't fuel pumps sized oddly, don't want one too big or too small having it run at full tilt?

While on that, they aren't common.. But i believe fuel coolers are a thing too? Maybe just an extruded aluminum tube cooler used for power steering to pull some heat out?

Motion race works has some neat stuff.

 

Size your pump to have at least 20% overhead at your hp goal and pressure. Most quality pumps have a flow/ pressure/ current draw graph for comparison.

 

If your running a return style system you can put in quite a bit of overhead. Don't worry about the fuel heating thing too much, as said before any heat added by compression will be released by decompression.

 

A single Walbro 525 might do the job. Don’t know if it’ll give you enough cushion for 700hp .You can always put a pair of smaller intank pumps in if you want

 

My opinion is to use two EFI type pumps in parallel. Especially on a new fabricated fuel system.
That way if you are out on the trail you might not be as fast but you can get home and do the repair later.
I only know of one racer who is running a cable drive pump. Most have the fuel system in the front or
they use EFI style electric pumps in the rear.
Tom V.