hobbs switch psi recommendation
05-28-2012, 11:28 AM
#1
hobbs switch psi recommendation Fuel system is dual 255's intanks, 60# inj, stock everything else. yes i know its not ideal but its what im working with until i upgrade the lines, rails, reg, etc which isnt happening at the moment.
prior setup was the same with a single walbro 255, made 600 rwhp on a mustang dyno seeing 10#'s and approx 80% idc on the injectors. I dont want to slam the regulator with a ton of fuel when its not needed so I was thinking a 7 psi swtich should work well since I know the single can handle 10#'s on my setup and it should only hit the second pump after the fuel demand is high and be a little easier to tune around.
any thoughts?
prior setup was the same with a single walbro 255, made 600 rwhp on a mustang dyno seeing 10#'s and approx 80% idc on the injectors. I dont want to slam the regulator with a ton of fuel when its not needed so I was thinking a 7 psi swtich should work well since I know the single can handle 10#'s on my setup and it should only hit the second pump after the fuel demand is high and be a little easier to tune around.
any thoughts?
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05-28-2012, 01:44 PM
#8
reason trying to tell myself, since im not running an aftermarket reg the pressure spike will be less and easier tune to around since the demand is higher at 7#'s. also still wont be near the end of the first pump
real reason, the 3-4 psi switch i originally ordered is on backorder from where i ordered it from for a few weeks and i want to get my car back together. (ordered a bunch of stuff to complete my fuel system and wiring, not just the switch)
the more i think about it, the more a higher switch makes sense to me, of course only without an adj reg and return, and not near the single pump power level. with an adj reg I would likely have it come on immediately in boost
real reason, the 3-4 psi switch i originally ordered is on backorder from where i ordered it from for a few weeks and i want to get my car back together. (ordered a bunch of stuff to complete my fuel system and wiring, not just the switch)
the more i think about it, the more a higher switch makes sense to me, of course only without an adj reg and return, and not near the single pump power level. with an adj reg I would likely have it come on immediately in boost
05-28-2012, 03:23 PM
#9
It seems to be the best for tunning to have it come on sooner then later.
If you have it come on at 5 psi or later, it will add a funny "ridge" to your tables.
Maybe that was just me and how I tune but I do not like it coming on after 5 PSI and prefer 1-2 PSI
If you have it come on at 5 psi or later, it will add a funny "ridge" to your tables.
Maybe that was just me and how I tune but I do not like it coming on after 5 PSI and prefer 1-2 PSI
05-28-2012, 04:09 PM
#10
mine kicked on at ~5-6psi. The only reason i know this is because my boost was spiking to 9lbs and then settling back to around 5lbs. when it got near 5lbs my AFR had a slight step in the lean direction so we realized the second pump was turning off. Im running them both all the time right now and the AFR is rock solid. Im on a completely aftermarket setup though
08-15-2012, 10:55 PM
#12
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I run a 4psi switch. Boost comes on really fast, so the way I see it there's not much difference between a 4 or a 6. But I also don't see any reason why a 7psi one wouldn't work.
I would say it also depends how much boost you are building before you launch. If you are building 4-5psi while staging, you probably wouldn't want your 2nd pump running during that time.
I would say it also depends how much boost you are building before you launch. If you are building 4-5psi while staging, you probably wouldn't want your 2nd pump running during that time.
08-16-2012, 06:22 AM
#14
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I had mine come on at 1psi until my hobbs switch failed on me and stuck open, then i said screw it, if im not gonna control them with the computer, im not using another "switch".
I run 2 walbros full time right now.... and did the whole time i had the GTO going.
I run 2 walbros full time right now.... and did the whole time i had the GTO going.
