second fuel pump switched for boost
second fuel pump switched for boost Hey guys,
Building my first turbo car... My 6.0 lq4 with bw s475 e85 non intercooled. I have a holley dominator fuel pump which is actually two pumps in one, with two separate trigger wires. Pump is louder when both are running so I was considering having the second come on when necessary. Somehow referencing boost? How can this be done safely?
Building my first turbo car... My 6.0 lq4 with bw s475 e85 non intercooled. I have a holley dominator fuel pump which is actually two pumps in one, with two separate trigger wires. Pump is louder when both are running so I was considering having the second come on when necessary. Somehow referencing boost? How can this be done safely?
I have the Dom. 1400 pump, and have it set to come on with boost
Since I have the Holley HP, I just picked sec. pump and set it up for
the boost I wanted it to come on-I also wired it thru a 3 way switch,
on/off/on, so if I had a pump failure of the pri pump, I could just flip
the switch and fire up the other pump-also use it testing for leaks
You could use anything to turn on the sec pump, Hobbs sw., etc
Since I have the Holley HP, I just picked sec. pump and set it up for
the boost I wanted it to come on-I also wired it thru a 3 way switch,
on/off/on, so if I had a pump failure of the pri pump, I could just flip
the switch and fire up the other pump-also use it testing for leaks
You could use anything to turn on the sec pump, Hobbs sw., etc
The device your looking for is called a hobbs switch. IMO they are an unnecessary risk. Some guys will swear by them though. I have always had two pumps running all the time on my cars and never once had an issue.
I was thinking about doing the same thing. Do you see a lot more fuel consumption having them both run all the time? Glad you dont have any issues.
No, You should never see an increase. The motor will only use what it needs/called for, Thats what the regulator is for. For the guys with return less fuel systems or inadequately sized return lines i could see an issue with fuel overheating or straining the pump. Even when i was N/A i was running dual Walboro 255's and i never had issues. (-10 feed -8 return)
i personally don't like the idea of cycling fuel up to the hot engine only to return it to the tank.
i try to use a throttle trigger if possible to stay ahead of the demand... or low low boost like zero.
cavitation is a very real thing and i stay as far from it as possible
i try to use a throttle trigger if possible to stay ahead of the demand... or low low boost like zero.
cavitation is a very real thing and i stay as far from it as possible
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i personally don't like the idea of cycling fuel up to the hot engine only to return it to the tank.
i try to use a throttle trigger if possible to stay ahead of the demand... or low low boost like zero.
cavitation is a very real thing and i stay as far from it as possible
i try to use a throttle trigger if possible to stay ahead of the demand... or low low boost like zero.
cavitation is a very real thing and i stay as far from it as possible
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TECH Apprentice
Joined: Dec 2004
Posts: 358
Likes: 1
I believe the MS can trigger the second pump based on the MAP sensor which is the way I'd go
parts left out don't break (hobbs switch) and for sure the Map will be a reliable trigger
hobbs switches are pretty reliable too if installed properly
BUT if that second pump doesn't come on the car could run dangerously lean
I'd think of a simple safeguard in case that happens
the MS stuff is really cool and cost effective with the plug and plan harness
TECH Apprentice
Joined: Feb 2012
Posts: 360
Likes: 3
From: Montreal
Pretty sure a hobbs switch is more reliable than the pump itself. Yet to have or hear of a problem with one if wired properly.
I run a Z06 pump with a BAP, which handles all normal daily driving. I then have a Holley 12-1800. One pump comes on at 7 psi, and the second at 15 psi. Having pumps running all the time when not needed just adds heat, and wear on the pump.
If using a hobbs try and use one like the ones racetronix sells that use proper metripak connections. If done properly they wiring on this is as the same as OEM stuff.
I run a Z06 pump with a BAP, which handles all normal daily driving. I then have a Holley 12-1800. One pump comes on at 7 psi, and the second at 15 psi. Having pumps running all the time when not needed just adds heat, and wear on the pump.
If using a hobbs try and use one like the ones racetronix sells that use proper metripak connections. If done properly they wiring on this is as the same as OEM stuff.
Pretty sure a hobbs switch is more reliable than the pump itself. Yet to have or hear of a problem with one if wired properly. I run a Z06 pump with a BAP, which handles all normal daily driving. I then have a Holley 12-1800. One pump comes on at 7 psi, and the second at 15 psi. Having pumps running all the time when not needed just adds heat, and wear on the pump. If using a hobbs try and use one like the ones racetronix sells that use proper metripak connections. If done properly they wiring on this is as the same as OEM stuff.
Last edited by oscs; Mar 4, 2015 at 09:09 AM.
TECH Apprentice
Joined: Feb 2012
Posts: 360
Likes: 3
From: Montreal
Same here and my constant fluid transfer has yielded great results with no failures in any of the vehicles I have ever owned.
TECH Apprentice
Joined: Feb 2012
Posts: 360
Likes: 3
From: Montreal
Have a great day. !!!
Last edited by oscs; Mar 4, 2015 at 09:36 AM.
i personally don't like the idea of cycling fuel up to the hot engine only to return it to the tank.
i try to use a throttle trigger if possible to stay ahead of the demand... or low low boost like zero.
cavitation is a very real thing and i stay as far from it as possible
i try to use a throttle trigger if possible to stay ahead of the demand... or low low boost like zero.
cavitation is a very real thing and i stay as far from it as possible
On pumps that can take advantage of it, I like to use a speed controller for both pumps.
fuel pumps fail! everybody stop using them.
use what you like. recommend what you have success with.. lots of ways to do it.
i recommend a test button so I know the pump will come on-line when i ask!
use what you like. recommend what you have success with.. lots of ways to do it.
i recommend a test button so I know the pump will come on-line when i ask!