2F HOLLY SNIPER EFI (1 Viewer)

Joined
Oct 19, 2019
Messages
47
Location
Phoenix
You must have a return. Yours is good. What Jdc1, myself and a few others have done is, not use the regulator in the Sniper, cap it off and install a remote regulator. Then a return line is run from the remote regulator back to the tank. In Jdc1’s pic, the return comes off the bottom of the regulator.
Your pump puts out way over 60 psi. The regulator holds back 60 psi and the excess gets released which must be plumbed back to the tank.

Usually the cycle is like this, Tank>pump>fuel injector/rail>regulator>tank. You CAN'T have a regulator BEFORE the fuel injectors because the return line is open to tank pressure (Patm + Pvapor) and you would have no (some but insufficient, use Bernoulli) liquid fuel pressure. This is all very simple stuff and should be available in the Holley manual. If you don't approach this systematically you will/and seem to have already driven yourself nuts. Use quality parts, dot your I's and cross your T's and you will be in business.

I'm trying to reconcile these two posts. What is the benefit of using a remote regulator vs. just connecting the return from the Sniper to the stock return line to the tank?

Also, if I do use a remote regulator and inline pump, isn't the regulator installed between the pump and the Sniper? If so, I don't understand @Braden620's post.
 

Steamer

SILVER Star
Joined
Jul 20, 2009
Messages
1,409
Location
Miami, FL
What is the benefit of using a remote regulator vs. just connecting the return from the Sniper to the stock return line to the tank?
The pumps we use are high GPM and more fuel ends up getting returned than used. For me, I did not like all that fuel getting circulated through a hot engine bay, over a hot manifold and then back to the tank. Grant it, I only have a 13-gal tank but after 1-1/2 to 2 hrs. running at crawl speed, the tank was getting up 120 deg F.
With the remote regulator, all fuel going to the engine bay gets used. And I’m running the Walbro GSL 394 which puts out less GPM that the GSL 392 that’s included in the Sniper kit.


Also, if I do use a remote regulator and inline pump, isn't the regulator installed between the pump and the Sniper? If so, I don't understand @Braden620's post.
I don't understand either. With my third and final plumb job, I'm running an Aeromotive regulator. Everything is close to tank. It goes like this. Tank, pre-filter, pump, post-filter, regulator and then on to the Sniper. The return port on the regulator just goes back to the tank.
Aeromotive shows I could plumb it several ways including what I think Braden620 is referring to.
Have a look at the illustrations for the regulator I'm using
"HERE"

And I do not recommend the Holley EFI Filter/Regulator that Holley says is perfect for the Sniper.
 
Joined
Oct 19, 2019
Messages
47
Location
Phoenix
The pumps we use are high GPM and more fuel ends up getting returned than used. For me, I did not like all that fuel getting circulated through a hot engine bay, over a hot manifold and then back to the tank. Grant it, I only have a 13-gal tank but after 1-1/2 to 2 hrs. running at crawl speed, the tank was getting up 120 deg F.
With the remote regulator, all fuel going to the engine bay gets used. And I’m running the Walbro GSL 394 which puts out less GPM that the GSL 392 that’s included in the Sniper kit.


I don't understand either. With my third and final plumb job, I'm running an Aeromotive regulator. Everything is close to tank. It goes like this. Tank, pre-filter, pump, post-filter, regulator and then on to the Sniper. The return port on the regulator just goes back to the tank.
Aeromotive shows I could plumb it several ways including what I think Braden620 is referring to.
Have a look at the illustrations for the regulator I'm using
"HERE"

And I do not recommend the Holley EFI Filter/Regulator that Holley says is perfect for the Sniper.

Thank you, very helpful. My Sniper has been ordered; should be here next week (I didn't buy the kit, just the Sniper unit itself.) I'm about the pull the trigger on a Walbro GSL394 based on some other posts. But, the more I think about this, the more I'm inclined to go with this in-tank returnless system from Holley. I believe that means I could eliminate the pre-filter and the regulator as both are built-in to that unit.
 

MOTOV8R

SILVER Star
Joined
May 19, 2009
Messages
1,282
Location
Boise, ID
The pumps we use are high GPM and more fuel ends up getting returned than used. For me, I did not like all that fuel getting circulated through a hot engine bay, over a hot manifold and then back to the tank. Grant it, I only have a 13-gal tank but after 1-1/2 to 2 hrs. running at crawl speed, the tank was getting up 120 deg F.
With the remote regulator, all fuel going to the engine bay gets used. And I’m running the Walbro GSL 394 which puts out less GPM that the GSL 392 that’s included in the Sniper kit.


I don't understand either. With my third and final plumb job, I'm running an Aeromotive regulator. Everything is close to tank. It goes like this. Tank, pre-filter, pump, post-filter, regulator and then on to the Sniper. The return port on the regulator just goes back to the tank.
Aeromotive shows I could plumb it several ways including what I think Braden620 is referring to.
Have a look at the illustrations for the regulator I'm using
"HERE"

And I do not recommend the Holley EFI Filter/Regulator that Holley says is perfect for the Sniper.

That's interesting about the heating. I bought the Holley 12-886 regulator but I have been thinking about not using it. I read that dead heading the sniper can lead to higher fuel temps at the unit since the fuel isn't being circulated.
 

Steamer

SILVER Star
Joined
Jul 20, 2009
Messages
1,409
Location
Miami, FL
That's interesting about the heating. I bought the Holley 12-886 regulator but I have been thinking about not using it. I read that dead heading the sniper can lead to higher fuel temps at the unit since the fuel isn't being circulated.
Yes, the fuel moves slower to the Sniper & has more time to warm up. But Holley does recommend & promotes a remote regulator in the video in the link above. The whole Sniper unit gets pretty hot under the hood anyway. I just know now my tank stays cool and most important so does the pump. I wanted to drop down a size from 3/8 OD to 5/16 OD to increase the velocity so the fuel spent less time getting warmed up, but -5 AN fittings aren’t easy to find. I did insulate that single line to the Sniper with “THIS”
 

Steamer

SILVER Star
Joined
Jul 20, 2009
Messages
1,409
Location
Miami, FL
I'm inclined to go with this in-tank returnless system from Holley. I believe that means I could eliminate the pre-filter and the regulator as both are built-in to that unit.
I think I'd like to hear some reviews on that unit before cutting a big hole in my tank. Quite pricey. Sometimes "all in one" can be nice, and sometimes not. I'd give it a lot of thought. I just have a bad taste in my mouth after buying that $164 filter/regulator and discovering the engineering flaws in it.
 
Joined
Oct 19, 2019
Messages
47
Location
Phoenix
I think I'd like to hear some reviews on that unit before cutting a big hole in my tank. Quite pricey. Sometimes "all in one" can be nice, and sometimes not. I'd give it a lot of thought. I just have a bad taste in my mouth after buying that $164 filter/regulator and discovering the engineering flaws in it.

I think @Will Van used one? How’s it working, Will?
 
Joined
Feb 15, 2016
Messages
287
Location
Somerset KY
I would steer clear from a return less system on a retrofit application. I'm not going to get into all the details. There needs to be some basic understanding of fluid mechanics to discuss the ins and outs of these fuel systems. You guys are going to do what you want anyhow. Good luck!
 
Joined
Feb 15, 2016
Messages
287
Location
Somerset KY
It's not returnless. It's just a matter of where the return is located. Whether the regulator is in the Sniper or if it's back at the tank, the regulator simply maintains 60psi in the Snipers fuel chamber.
Having the regulator BEFORE the injectors partially defeats the purpose of the regulator. Again, no free lunch in fluids. The pump can't properly maintain the fuel pressure in the "chamber" because the pump is of a constant velocity type. Modern return less systems control fuel pressure as a function of pump velocity, which is constantly monitored by ECU and pressure sensors. The Holley system is not that complex. Better to stick with the return as it was intended.
 

Will Van

GOLD Star
Joined
Aug 18, 2017
Messages
1,864
Location
Austin, TX
I think I'd like to hear some reviews on that unit before cutting a big hole in my tank. Quite pricey. Sometimes "all in one" can be nice, and sometimes not. I'd give it a lot of thought. I just have a bad taste in my mouth after buying that $164 filter/regulator and discovering the engineering flaws in it.

I think @Will Van used one? How’s it working, Will?
I had previously used the Aeromotive Phantom fuel bulkhead and hated it. It leaked constantly.

I switched to the Holley returnless in-tank setup and love it. It works very well and is easy to plumb. I deleted the FPR on the Sniper assembly itself. The fuel pump is noisy in the tank. But no more noisy than the cab of the truck at any speed above 7 mph.

You can read more about it here: Builds - 1977 Freeborn Red FJ40 Patina Build - https://forum.ih8mud.com/threads/1977-freeborn-red-fj40-patina-build.1146933/page-12#post-13202489
 

Steamer

SILVER Star
Joined
Jul 20, 2009
Messages
1,409
Location
Miami, FL
Having the regulator BEFORE the injectors partially defeats the purpose of the regulator. Again, no free lunch in fluids. The pump can't properly maintain the fuel pressure in the "chamber" because the pump is of a constant velocity type. Modern return less systems control fuel pressure as a function of pump velocity, which is constantly monitored by ECU and pressure sensors. The Holley system is not that complex. Better to stick with the return as it was intended.
Well I could agree with you, but then we'd both be wrong. WAIT! I'm Just kidding. Don't wanna argue. I think maybe we're not talking about the same thing.
Anyway, my regulator back at the tank maintains 60 psi at the Sniper. I have a gauge at the inlet. I'm sure if I put a gauge at the outlet where the return used to be, I'd show 60psi there as well.
Holley promotes a remote regulator with just one line to the Sniper. "HERE"
 
Joined
Feb 15, 2016
Messages
287
Location
Somerset KY
Well I could agree with you, but then we'd both be wrong. WAIT! I'm Just kidding. Don't wanna argue. I think maybe we're not talking about the same thing.
Anyway, my regulator back at the tank maintains 60 psi at the Sniper. I have a gauge at the inlet. I'm sure if I put a gauge at the outlet where the return used to be, I'd show 60psi there as well.
Holley promotes a remote regulator with just one line to the Sniper. "HERE"
I suspect the only reason this works is because the volume of fuel required for these engines is so small compared to the capacity of the pump, and there is only one or two injectors in the system. What I am telling you, is that the laws of fluid mechanics are unshakeable. There is NO advantage to a return less system other than not having to plumb in a return. In terms of properly engineering a fuel system a return is the only correct way.

I think if you study how the components of an EFI fuel system are configured and you draw a diagram showing the pressures you will understand. The key to you understanding this is in that the return is open to the atmosphere which in fluid mechanics means that the pressure there (at the outlet) is 0!

Imagine a rubber garden hose capped at one end with the water turned on (pressure). The hose is firm (pressure forces act in all directions). Now you uncap the end of the hose and let the water freely run onto the ground... the hose is NOT as firm as it was before (pressure drop, force drop).

Now what if we cap the hose again (this is our regulator) and we poke a tiny pin hole (fuel injector) somewhere along the length of the hose? We get a nice stream of water spraying out of the hole. But what if we uncap the hose? The pinhole now loses flow due to the now open end of the hose, pressure drop.

What if we move the capped end of the hose BEFORE the pin hole and then open the cap slightly (return), pressure drop at injector!!!!!!

Or you could just forget trying to use an analogy and use a Bernoulli equation and all will become clear.
 

MOTOV8R

SILVER Star
Joined
May 19, 2009
Messages
1,282
Location
Boise, ID
The 12-886 regulator is a spring driven regulator. It basically acts as a pressure relief valve. Also the input/output lines are marked I/O, meaning it doesn't care which is which. Essentially the entire line is pressurized to 58 psi and anything above that pressure pushes the spring and releases flow to the return. Holley says it can be mounted before or after the EFI. In fact there would be no need to an output port unless you put it before the EFI (as shown the output is capped if ran after the EFI). I do think that some pressure drops can be seen the further away from the EFI that the regulator is mounted (probably not anything significant on a 2F unless its a Mosley cop motor). Holley says to mount it as close as possible to the EFI unit.

8ED88650-98EE-4C92-9241-CEA2D6AB19BD.png
 

Steamer

SILVER Star
Joined
Jul 20, 2009
Messages
1,409
Location
Miami, FL
I think that's what @Braden620 is getting at - the sniper doesn't really have the capability to properly run a returnless system
Again! Let me make it clear. I'm not suggesting a return less system. The remote by-pass regulators we're talking about have a return. It's just plumbed from the regulator back to the tank. A by-pass regulator has 3 ports. Inlet, outlet and return. The pump is capable of 100 psi plus, if you dead head it. The by-pass regulator releases anything over 60 psi which goes out the return port. The outlet port to the Sniper is maintained at 60psi.
 

AussieHJCruza

SILVER Star
Joined
Jul 8, 2013
Messages
1,833
Location
New South Wales, Australia
Again! Let me make it clear. I'm not suggesting a return less system. The remote by-pass regulators we're talking about have a return. It's just plumbed from the regulator back to the tank. A by-pass regulator has 3 ports. Inlet, outlet and return. The pump is capable of 100 psi plus, if you dead head it. The by-pass regulator releases anything over 60 psi which goes out the return port. The outlet port to the Sniper is maintained at 60psi.
Sure, I'm not familiar enough with the sniper setup on a 40 to understand the setup totally, but I would say Holley would know how their system should work
 

Users who are viewing this thread

Top Bottom