High pressure fuel pumps

Nero

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Good morning y'all,

I've been reading up about switching my mechanical lift pump to electric, because there's a chance it may not be able to keep up with the 90cc pump, so I just want to be prepared.

It seems like going high pressure pump is the way to go, especially with the poor quality it seems like Holley is having lately.

I am mostly referencing this thread here when it comes to research, but there's a few others too.


I mainly want to discuss high pressure systems with a regulator that has a return line to it.
From what I gather, most people who have done this setup only use one tank. I definitely do not want to replace my rear tank with a larger one, and would like to keep my dual tanks functioning. Has anyone ran this type of setup before? I assume having the high pressure return flow, if tapped near the injectors, would cause too much return pressure and cause timing curve issues.
 

Lumberjackchuck

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I assume having the high pressure return flow, if tapped near the injectors, would cause too much return pressure and cause timing curve issues.

Yup, I tried it and can tell you that I had wayyy too much return pressure, literally a geyser of fuel squirting out of return rails. I tried then running a larger line and tee’ing it into the return along the frame right before fuel tank selector valve to see if that would help…. It didn’t help much, still about 7psi when return line is supposed to be less than 1 psi.

The problem is the orifice diameter in the fuel tank selector valve, it is too small and you will always have high pressure in the return system to squeeze that amount of flow through the valve.

The solution is to bring the regulator return back to the supply side of the pump. I’ve been warned that it can cause an issue with constantly circulating air in the fuel system and possibly over heating the fuel, which is supposed to cool the IP. I haven’t had an issue with either of these things, but it would be easy to add a fuel cooler if needed.
 

Lumberjackchuck

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I assume having the high pressure return flow, if tapped near the injectors, would cause too much return pressure and cause timing curve issues.

Yup, I tried it and can tell you that I had wayyy too much return pressure, literally a geyser of fuel squirting out of return . I tried then running a larger line and tee’ing it into the return along the frame right before fuel tank selector valve to see if that would help…. It didn’t help much, still about 7psi when return line is supposed to be less than 1 psi.

The problem is the orifice diameter in the fuel tank selector valve, it is too small and you will always have high pressure in the return system to squeeze that amount of flow through the valve.

The solution is to bring the regulator return back to the supply side of the pump. I’ve been warned that it can cause an issue with constantly circulating air in the fuel system and possibly over heating the fuel, which is supposed to cool the IP. I haven’t had an issue with either of these things, but it would be easy to add a fuel cooler if needed.
 

Nero

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I would go Bosch 7.3 powerstroke lift pump (which tend to have a long life) and a regulator.
First time I've heard of this, I'll look into it.

@Lumberjackchuck well it sounds like going high pressure may be out of the question for me then. Either that or break down and get the 38 gallon rear tank. My only concern is I lose the spare tire location.
 

hacked89

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I would read my fuel math thread if you haven’t as well as let me know if you have any specific design questions. I think that is also the thread where I cut a fuel selector valve in half and measured why you can’t draw high volume fuel through it. I also had to make tweaks to the return system and multiple versions if you are interested in that specifically.
 

Nero

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I would read my fuel math thread if you haven’t as well as let me know if you have any specific design questions. I think that is also the thread where I cut a fuel selector valve in half and measured why you can’t draw high volume fuel through it. I also had to make tweaks to the return system and multiple versions if you are interested in that specifically.
That looks like exactly what I need to read. Funny it didn't come up in the search.
With a 90cc pump Justin said it may or may not work. I'll leave the mech pump for now and have an electric backup plan.
 

Nero

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Read through it, definitely a lot of good info in there. Thanks for the link!

Question I have for you guys running larger rear tanks, where do y'all keep your spare now?
 

jwsfarrier

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I thought one of those roof racks might be a good place for the spare. I recently swapped over to 38 gallon and have been trying to find a place other than the bed.
 

Nero

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See that's the conundrum I'm in when it comes to the larger tank. 90% of the time I have my camper on my truck, so bed is not an option.
 

Old Goat

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I found one of these OEM Ford mounts.
Just those 2 pieces in the first picture, got from guy that didn`t need it for $25.

I used the long bolt that holds the spare under the truck in from the back side of the verticle slot. Then a 1/4" X 3" flat plate with a hole in the center for the bolt, and then a Lug nut.
Sits in the corner of the bed out of the way.


Goat
 
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IDIBRONCO

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See that's the conundrum I'm in when it comes to the larger tank. 90% of the time I have my camper on my truck, so bed is not an option.
How big is your camper? Does it have a very big drop at the back?
 

nelstomlinson

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Since this is devolving into "how to carry your spare," has anyone adapted one of the Bronco swing away spare carriers to our trucks? Or made a swing away mount for the rear bumper?

Nero, to bring this back on topic, it sounds as if high pressure isn't the goal here. A couple weeks ago I switched my daily driver to a Walbro FRB-13. Mine, at least, was made in America. So far so good. It's not high pressure, doesn't even need a regulator.
 
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