EFI question…

[aarvig]

So I am switching to EFI on my 427w. I would like to run a Holley Sniper setup. My question is about fuel pumps. I really like Aeromotives in tank Stealth 340 pump because of its internal foam baffling. The issue is the pump puts out 90 PSI. The Holley requires 58 psi. I see that the Holley EFI has its own fuel pressure regulator built into it. Does this mean that I can hook the 90 psi pump up to it and the overpressure will be returned to the tank or do I need to regulate pressure from the pump to the Holley Sniper?

[Gordon Levy]

You don't need to worry about the pump. That pump will work for for your setup, I have used it many times. I personally like running and externally regulator because the one is the snyper is a bit cheap.

[Ted G]

Curious why you are going to EFI? reliability? I am currently considering my build to be with a carbed 427 for more period correct. I do plan driving the car rather than garaging it, so I think the carb set up should be fine. Thoughts?

[aarvig]

Curious why you are going to EFI? reliability? I am currently considering my build to be with a carbed 427 for more period correct. I do plan driving the car rather than garaging it, so I think the carb set up should be fine. Thoughts?
I have had nothing but difficulty getting this carburetor dialed in. Our temperature swings are pretty large here in MN so it seems I’m constantly messing with the carb and it’s never ideal…

[weendoggy]

So I am switching to EFI on my 427w. I would like to run a Holley Sniper setup. My question is about fuel pumps. I really like Aeromotives in tank Stealth 340 pump because of its internal foam baffling. The issue is the pump puts out 90 PSI. The Holley requires 58 psi. I see that the Holley EFI has its own fuel pressure regulator built into it. Does this mean that I can hook the 90 psi pump up to it and the overpressure will be returned to the tank or do I need to regulate pressure from the pump to the Holley Sniper?

My advice is to install a return line instead of the returnless routing on a Sniper. It also has it's own internal regulator so I'd go that route first and be sure to install a fuel pressure gauge (put this at the Sniper inlet) so you can monitor actual fuel pressure along with a transducer. This way you know if the pump is large enough. I've never run a pump with pressure that low so I can't comment on that pump. You also need to decide if you want the Sniper to control timing or not. If not, you can use a RTR type distributor without a CD box or the driver module.

[FLPBFoot]

Curious why you are going to EFI? reliability? I am currently considering my build to be with a carbed 427 for more period correct. I do plan driving the car rather than garaging it, so I think the carb set up should be fine. Thoughts?

Ted G

I'm running a carb with my 427w and it works great. Was in Northern IL and now down in SW Florida and no issues I did take it out to South Dakota this Summer and the 4,000 ft+ elevation caused it to run rich and load up pretty easily. Still ran well but would have to blow it out with a high rpm run up a couple times a day. I think the big thing is get a professional to tune the carb for the elevation you will be running it at. I had mine dyno'd and tuned and all is good. I went with a manual choke and don't really have to use it unless its below 50F. When cold, just a couple pumps of the go pedal and fires right up.

If I lived in a region where I was changing elevation often I would have gone with a Sniper.

Steve

[ggunter]

I went with the Holley Sniper and switched out my Holley carb because I don't like the electric choke, and my carb had a slight stumble just off idle I could never get out. I like the turn key start of fuel injection. The only feature of the Sniper I personally don't like is the non progressive linkage, whch if you change to mechanical throttle linkage and install a longer throttle lever that becomes a non issue. You can switch to progressive in the Sniper but you loose your vacuum advance feature to the distributor. But if your using a computor controlled timing thats not an issue either. The one downfall I've had is the oxygen sensor went out after only a thousand miles. I've heard other people have run into this as well. In general I like it.

[RBachman]

Really like my Sniper and don't think you'll regret it. You can also call Mike Forte'. He's a dealer and helped me a great deal with my Sniper, including the fuel pump. Holley Technical Service is extremely helpful, but there's usually a wait to get someone.

Here are a few random things that I learned (relative to daily driving) with my Sniper, along with a "devils advocate" view for thought.

I've had more success when component design parameters match up with the rest of the system. The 340-LPH, 90-psig pump will work fine, but it's overkill. It's also much more expensive and requires increased sizes of the fuel system components. The "rule of thumb" is to multiply the HP by .38 to get an idea of maximum fuel flow (LPH) required. Remember it is not that often you'll max out the engine and couldn't use all that fuel if you tried to anyway.

I do not use an additional regulator because it's not required and I've no issues with the internal regulator. However, I'm using a pump that's closer to the Sniper design pressures.

340-LPH will typically support an 800 to 1,000 HP demand. The Sniper is limited to 600 HP. If so, over 1/3 of the flow rate and about half the pump power consumption will never provide benefit. It may also cause excessive heat build up and premature failure at the pump, particularly when fuel tank levels are low. There is also a potential for excessive foaming.

With your chosen pump, make sure the additional regulator is able to bypass that much fuel while maintaining steady performance at lower/idle fuel demands. Return and supply lines are another consideration. 340 LPH is roughly 1.5 gallons per minute. Aeromotive recommends 1/2" lines with AN-8 size fittings for 340 LPH. Other sites recommend even larger 5/8" lines and AN-10 fittings for a 340-LPH flow rate. The pump hanger lines also need to be large enough not to restrict flow, so those will have to be larger than what the Sniper/Engine would otherwise require. Holley has a max allowable return line pressure design of 3 psig. (A 3/8" return with that flow rate can quickly exceed 3psig with fittings and routing.)

Make sure that your power feed wires are large enough for the pump. You may also need to bump up the fuse rating for the pump circuit.

Get the install manual from Holley and go through it very carefully. (https://documents.holley.com/199r11031r.pdf)

It's not necessary, but a fuel pressure gauge (electronic) is very beneficial in diagnosing fuel flow and pressure issues. Put the sensor as close to the Sniper supply line as reasonable. Mine is on the Sniper just after the final filter. I installed the gauge on my dash and it's come in very handy. Speed Hut has the matching gauges.

Don't forget the filters. Snipers are dependent on good filters and it's a must have for these systems. So be careful not to allow debris from the lines, installation, or elsewhere entering the Sniper. It's not a bad idea to blow out the new lines and "dust off" or flush the filters with a little compressed air. Mount the final filter as close to the inlet as reasonable. The pre filter is mounted by the tank. Make sure whatever filters you choose can handle the pump flow rate.

[aarvig]

Really like my Sniper and don't think you'll regret it. You can also call Mike Forte'. He's a dealer and helped me a great deal with my Sniper, including the fuel pump. Holley Technical Service is extremely helpful, but there's usually a wait to get someone.

Here are a few random things that I learned (relative to daily driving) with my Sniper, along with a "devils advocate" view for thought.

I've had more success when component design parameters match up with the rest of the system. The 340-LPH, 90-psig pump will work fine, but it's overkill. It's also much more expensive and requires increased sizes of the fuel system components. The "rule of thumb" is to multiply the HP by .38 to get an idea of maximum fuel flow (LPH) required. Remember it is not that often you'll max out the engine and couldn't use all that fuel if you tried to anyway.

I do not use an additional regulator because it's not required and I've no issues with the internal regulator. However, I'm using a pump that's closer to the Sniper design pressures.

340-LPH will typically support an 800 to 1,000 HP demand. The Sniper is limited to 600 HP. If so, over 1/3 of the flow rate and about half the pump power consumption will never provide benefit. It may also cause excessive heat build up and premature failure at the pump, particularly when fuel tank levels are low. There is also a potential for excessive foaming.

With your chosen pump, make sure the additional regulator is able to bypass that much fuel while maintaining steady performance at lower/idle fuel demands. Return and supply lines are another consideration. 340 LPH is roughly 1.5 gallons per minute. Aeromotive recommends 1/2" lines with AN-8 size fittings for 340 LPH. Other sites recommend even larger 5/8" lines and AN-10 fittings for a 340-LPH flow rate. The pump hanger lines also need to be large enough not to restrict flow, so those will have to be larger than what the Sniper/Engine would otherwise require. Holley has a max allowable return line pressure design of 3 psig. (A 3/8" return with that flow rate can quickly exceed 3psig with fittings and routing.)

Make sure that your power feed wires are large enough for the pump. You may also need to bump up the fuse rating for the pump circuit.

Get the install manual from Holley and go through it very carefully. (https://documents.holley.com/199r11031r.pdf)

It's not necessary, but a fuel pressure gauge (electronic) is very beneficial in diagnosing fuel flow and pressure issues. Put the sensor as close to the Sniper supply line as reasonable. Mine is on the Sniper just after the final filter. I installed the gauge on my dash and it's come in very handy. Speed Hut has the matching gauges.

Don't forget the filters. Snipers are dependent on good filters and it's a must have for these systems. So be careful not to allow debris from the lines, installation, or elsewhere entering the Sniper. It's not a bad idea to blow out the new lines and "dust off" or flush the filters with a little compressed air. Mount the final filter as close to the inlet as reasonable. The pre filter is mounted by the tank. Make sure whatever filters you choose can handle the pump flow rate.

Boom! Massively helpful. Thank you. So I have ditched the aeromotive idea and am going to go with an in-tank Holley Sniper pump that matches my HP needs 607x.38 is 230LPH.