Multiple fuel pumps and check valves
Thread Starter
Joined: Aug 2011
Posts: 4,729
Likes: 814
From: Portland, OR
Multiple fuel pumps and check valves See what you guys think.
I have the Holley12-1800 as my main pump. Both halves running full time.
I added the Holley 12-890 little brother as a secondary pump on a hobbs set to 15psi.
Wasn't sure if I needed a check valve for the second pump so I added one. A Summit valve.
What happens as I approach 80psi pressure, top of second gear only, and it's consistent, I lose 10psi for less than a second. From there on it's solid.
55psi base, I'm running 24 psi boost.
Comes right back, but causes a bit of a lean area.
So, if the main pump makes more pressure than the secondary pump. check valve needs 1 psi to open, any chance that the differential pressure ie main pump is more than 1 psi higher than the secondary pump for a brief period, the second pump can't add?
I'm going to remove the check valve. And test. Then wire around the hobbs, it's an expensive Honeywell unit. But nothing is failure prone.
Thoughts?
Ron
I have the Holley12-1800 as my main pump. Both halves running full time.
I added the Holley 12-890 little brother as a secondary pump on a hobbs set to 15psi.
Wasn't sure if I needed a check valve for the second pump so I added one. A Summit valve.
What happens as I approach 80psi pressure, top of second gear only, and it's consistent, I lose 10psi for less than a second. From there on it's solid.
55psi base, I'm running 24 psi boost.
Comes right back, but causes a bit of a lean area.
So, if the main pump makes more pressure than the secondary pump. check valve needs 1 psi to open, any chance that the differential pressure ie main pump is more than 1 psi higher than the secondary pump for a brief period, the second pump can't add?
I'm going to remove the check valve. And test. Then wire around the hobbs, it's an expensive Honeywell unit. But nothing is failure prone.
Thoughts?
Ron
Is it a sumped tank? I ran a 12-1400 for 3 years, staged the 2nd pump to come in under boost (also as a backup if pri failed on the road)
Orig forgot to fuse the 2nd pump, but the pri was keeping up with 12 lbs boost, lol-I would think the 1800 should handle it, IF both pumps are working (there was a little history with the 1800's)
Is there a voltage drop as the third pump comes on, until the alt can pick it back up.
Does the second pump use the same line from the tank, or a sep one-I guess if one pump had a diff pressure it might cause a slight cavitation in another pump-my first thought was the 1800 could be pushing fuel back thru the other pump (path of least rest.) but with a ck valve it wouldn't happen.
I am guessing your data logging, any other event happen at the same time
Yep, on my second cup of coffee and wired, lol
Orig forgot to fuse the 2nd pump, but the pri was keeping up with 12 lbs boost, lol-I would think the 1800 should handle it, IF both pumps are working (there was a little history with the 1800's)
Is there a voltage drop as the third pump comes on, until the alt can pick it back up.
Does the second pump use the same line from the tank, or a sep one-I guess if one pump had a diff pressure it might cause a slight cavitation in another pump-my first thought was the 1800 could be pushing fuel back thru the other pump (path of least rest.) but with a ck valve it wouldn't happen.
I am guessing your data logging, any other event happen at the same time
Yep, on my second cup of coffee and wired, lol
TECH Fanatic
Joined: Jun 2013
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From: Avon, Ohio
Thread Starter
Joined: Aug 2011
Posts: 4,729
Likes: 814
From: Portland, OR
I tested with all three pumps on with the engine off and triggering the second pump only upped pressure 1psi.
Voltage during a run is rock solid.
For next year I’ll get a lower pressure Hobbs.
For the test and tune Sunday I’ll just put a switch in so I can turn all three on prior to a pass.
I agree I shouldn’t have picked 15psi for the Hobbs. It’s adjustable, but only a few psi.
I tested with all three pumps on with the engine off and triggering the second pump only upped pressure 1psi.
Voltage during a run is rock solid.
For next year I’ll get a lower pressure Hobbs.
For the test and tune Sunday I’ll just put a switch in so I can turn all three on prior to a pass.
I tested with all three pumps on with the engine off and triggering the second pump only upped pressure 1psi.
Voltage during a run is rock solid.
For next year I’ll get a lower pressure Hobbs.
For the test and tune Sunday I’ll just put a switch in so I can turn all three on prior to a pass.
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Thread Starter
Joined: Aug 2011
Posts: 4,729
Likes: 814
From: Portland, OR
I should try reducing base pressure a tad as well.
Thread Starter
Joined: Aug 2011
Posts: 4,729
Likes: 814
From: Portland, OR
That has been said. Not sure if it’s proven. I’ve read all the diatribes on the pumps. Myself I’ve had no failures. Or issues until this odd behavior. Which didn’t happen until I upped the boost.
Teching In
Joined: May 2012
Posts: 14
Likes: 0
From: Regina, Saskatchewan, Canada
I run the same 1800 pump, and trigger the one side after 6psi and 3500rpm. I had a pump failure when I had both sides running all the time. Was also told to lower base pressure so not to exceed 75psi in boost. Logs show rock solid and running fairly similar times in your signature.
Thread Starter
Joined: Aug 2011
Posts: 4,729
Likes: 814
From: Portland, OR
Mellow, sneaking in here?
My logs show it making it to 80 psi....barely. So I'll lower it to 52 base and live with over 100% idc. My 1800 has performed flawlessly for 5 years now.
I'll know tomorrow.
68 degrees, sunny, prepped track and I'm going for it.
My logs show it making it to 80 psi....barely. So I'll lower it to 52 base and live with over 100% idc. My 1800 has performed flawlessly for 5 years now.
I'll know tomorrow.
68 degrees, sunny, prepped track and I'm going for it.
Cut your losses and throw the holley trash pumps in the garbage. Just saw youve had it for 5 years, its a unicorn pump lol.
Stock ecu? Ive been running a magnafuel 4301 with no pump controller. Rock solid fuel pressure. Also running ID1300s at 43.5 base fuel pressure. Love the setup.
Stock ecu? Ive been running a magnafuel 4301 with no pump controller. Rock solid fuel pressure. Also running ID1300s at 43.5 base fuel pressure. Love the setup.
Thread Starter
Joined: Aug 2011
Posts: 4,729
Likes: 814
From: Portland, OR
I'll follow up.
I turned the base down to 52 psi and had no issues.
Max pressure hit 77 psi, boost was wavering between 24-25.
I believe Stevieturbo was correct on the 80psi internal pressure relief. I think those can be removed.
Vince, I can do that. Simple relay trigger wire switch. But on the other hand it's working.....
Ron
I turned the base down to 52 psi and had no issues.
Max pressure hit 77 psi, boost was wavering between 24-25.
I believe Stevieturbo was correct on the 80psi internal pressure relief. I think those can be removed.
Vince, I can do that. Simple relay trigger wire switch. But on the other hand it's working.....
Ron
Thread Starter
Joined: Aug 2011
Posts: 4,729
Likes: 814
From: Portland, OR
Cut your losses and throw the holley trash pumps in the garbage. Just saw youve had it for 5 years, its a unicorn pump lol.
Stock ecu? Ive been running a magnafuel 4301 with no pump controller. Rock solid fuel pressure. Also running ID1300s at 43.5 base fuel pressure. Love the setup.
Stock ecu? Ive been running a magnafuel 4301 with no pump controller. Rock solid fuel pressure. Also running ID1300s at 43.5 base fuel pressure. Love the setup.
My experience with that magnafuel pump in my buddies car that I tune has been horrible.
So I guess we pick our poison.