Dump valve = lack of power
#1
Dump valve = lack of power
I took my dump valve off and stuck a standard recirc one back on, after doing this my car drove like a bag of **** it would not boost to max 1.2 bar that I have set it struggled to reach 1!! and felt very hesitant.
My question is this, is that normal?, I thought they were just toys really to get on peoples nerves with that release of air and I have read on here they reduce power and you should not fit them!! this seems to be the opposite with my car, It really didn't like it, do they need mapping on and off to stop the loss of power as I understood you did not need a map to fit these.
Cheers
Brian
My question is this, is that normal?, I thought they were just toys really to get on peoples nerves with that release of air and I have read on here they reduce power and you should not fit them!! this seems to be the opposite with my car, It really didn't like it, do they need mapping on and off to stop the loss of power as I understood you did not need a map to fit these.
Cheers
Brian
#5
Nah OE one went on fine not much to get wrong there, sounds like it's working but who knows though, I was offered a few by people off here for £20 so may well go back to some of the others now and buy another one, for that price it's worth a punt just to make sure it's working right.
I am right in thinking they don't require mapping though ???
I am right in thinking they don't require mapping though ???
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#8
Depends entirely on the context, doesn't it, and whether the car has already been mapped for the aftermarket one that's coming off. It would be easier to provide you with relevant advice if you had included a fair bit more info in your post(s).
If a previous owner has simply bolted on an aftermarket DV without having it mapped, then clearly you won't need to alter/remap anything if you go back to a standard valve (that works properly).
If the car has been mapped properly with the VTA valve in place, there may have been some changes to the high rev/low load fuel map zones to eliminate lift-off overfuel. Under these circumstances you might find it goes a bit lean with the standard dumpvalve back on.
Clearly none of us here can guess what's been done to your car, so if it has been custom tuned, the best person to speak to would be the mapper responsible.
If a previous owner has simply bolted on an aftermarket DV without having it mapped, then clearly you won't need to alter/remap anything if you go back to a standard valve (that works properly).
If the car has been mapped properly with the VTA valve in place, there may have been some changes to the high rev/low load fuel map zones to eliminate lift-off overfuel. Under these circumstances you might find it goes a bit lean with the standard dumpvalve back on.
Clearly none of us here can guess what's been done to your car, so if it has been custom tuned, the best person to speak to would be the mapper responsible.
#9
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Did you blank off the unused pipe that goes to the inlet when you fitted the VTA valve?
Did the small vacuum hose to the dump valve get refitted?
Did the small vacuum hose to the dump valve get refitted?
#11
Thanks for the helpful replies guys
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as long as your other scoob runs over 1bar as it is now then yeah that will tell you if the valve is at fault. (I'm guessing the valve starts to leak at/above 1bar)
but as said above its nothing to do with the map under full throttle.
but as said above its nothing to do with the map under full throttle.
#19
What about what splitpin has said above about the map
"If the car has been mapped properly with the VTA valve in place, there may have been some changes to the high rev/low load fuel map zones to eliminate lift-off overfuel. Under these circumstances you might find it goes a bit lean with the standard dumpvalve back on."
would this not effect it at full throttle, I might just buy another OM valve and try it like I have said It's only £20.
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I don't suppose the wrx boosts to 1bar does it(standard car).
What about what splitpin has said above about the map
"If the car has been mapped properly with the VTA valve in place, there may have been some changes to the high rev/low load fuel map zones to eliminate lift-off overfuel. Under these circumstances you might find it goes a bit lean with the standard dumpvalve back on."
would this not effect it at full throttle, I might just buy another OM valve and try it like I have said It's only £20.
What about what splitpin has said above about the map
"If the car has been mapped properly with the VTA valve in place, there may have been some changes to the high rev/low load fuel map zones to eliminate lift-off overfuel. Under these circumstances you might find it goes a bit lean with the standard dumpvalve back on."
would this not effect it at full throttle, I might just buy another OM valve and try it like I have said It's only £20.
if its a older wrx and standard then I doubt it will hit 1bar.....so thats no good to you.
what splitpin has mentioned has nothing to do with the issues your having, hes on about when you lift off the throttle.
just buy/borrow another and try that on there
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