any1 got 1 if so where an how?!
thanx
thanx
Phil R32
MarkyG explains
Dump vavles get rid of INLET air when theres too much pressure in the inlet tract (ie when you close the throttle and theres still a lot of air backing up between the turbo and the throttle plate) to stop damage to the turbo. BUT diesel turbos are too low boost to need one, the air can find its way round the turbo without knackering it. If you put a normal "whoosh" dump valve on the car, youll be loosing air that youve already metered with the AFM, and fuel incorectly = black/blue/white smoke and a pancake?
Wastegates get rid of EXHAUST air into the exhaust pipe after the turbo, to stop more exhaust spinning the turbo when theres already enough boost in the inlet. So a wastegate deals with exhaust gas but takes its signal from the inlet (normally the inlet side of the turbo from factory, nearer the throttle in aftermarket for better response).
Dump vavles get rid of INLET air when theres too much pressure in the inlet tract (ie when you close the throttle and theres still a lot of air backing up between the turbo and the throttle plate) to stop damage to the turbo. BUT diesel turbos are too low boost to need one, the air can find its way round the turbo without knackering it. If you put a normal "whoosh" dump valve on the car, youll be loosing air that youve already metered with the AFM, and fuel incorectly = black/blue/white smoke and a pancake?
Wastegates get rid of EXHAUST air into the exhaust pipe after the turbo, to stop more exhaust spinning the turbo when theres already enough boost in the inlet. So a wastegate deals with exhaust gas but takes its signal from the inlet (normally the inlet side of the turbo from factory, nearer the throttle in aftermarket for better response).
they are only neccessary on big diesel turbos that have been live mapped as said it will deal with the excess presure caused by the new map boosting to twice the normal level.
I think only the PD150 and 170 engnes are compatable.
In short on a vauxhall.
AHAHAHHAHAHAHAHAHHAHAHAHAAH,
but also dont get a fake one it sounds horrible and very un lifelike. If you must have one they are on ebay but they will screw your engine up and possibly looking at a new turbo every 20k miles.
I think only the PD150 and 170 engnes are compatable.
In short on a vauxhall.
AHAHAHHAHAHAHAHAHHAHAHAHAAH,
but also dont get a fake one it sounds horrible and very un lifelike. If you must have one they are on ebay but they will screw your engine up and possibly looking at a new turbo every 20k miles.
wastegate chatter sounds nice but not really a good sign issit?
diesel dump valve's exist but i'm fairly sure they are electronicly controlled and cost a fair bit more than usual DV's.
diesel dump valve's exist but i'm fairly sure they are electronicly controlled and cost a fair bit more than usual DV's.
a dv isnt any use on a derv as it doesnt need to get rid of the excess pressure like a petrol forced induction does
i feel the need to correct some people on here, the 1.7 cdti acually has very high boost preesure at 1.18 bar (about 17psi) which is nearly twise that of most turbo petrol cars for exampel standerd boost on the escort rs turbo is 7psi,
Also chatter is not from the waste gate, it is the sound of cropresser stall, basical as the throtel buterfly is clossed the exsees boost is then caused to go bakwards throught the spinning compresser blades hens the fluttering as boost presher bulds and ecuallised rapidly
As derv do not have throtal buterflys they do not chatter,
as for derv dump valvs they do the same as they would on a petrol car, releses exesss boost pressure but as there is no vacume wen the throtel is closed like on petrols u need an electronc contol box and a throtel pedel sensor for them to work which r quite expensive
derv doctor would b a gud place to look tho,
plz excuse my spelling
thanks nick
Also chatter is not from the waste gate, it is the sound of cropresser stall, basical as the throtel buterfly is clossed the exsees boost is then caused to go bakwards throught the spinning compresser blades hens the fluttering as boost presher bulds and ecuallised rapidly
As derv do not have throtal buterflys they do not chatter,
as for derv dump valvs they do the same as they would on a petrol car, releses exesss boost pressure but as there is no vacume wen the throtel is closed like on petrols u need an electronc contol box and a throtel pedel sensor for them to work which r quite expensive
derv doctor would b a gud place to look tho,
plz excuse my spelling
thanks nick
that just illustrates how **** diesls are. 17psi into a 1.7 petrol would be around 300hp.
you are right in that diesels don't have a wastegate, as they are free floating turbos, the maximum gas speed is low enough (capacity x revs = not a big number because of the low revs) that the turbo will never produce uncontrolable boost, excess boost is recirculated via the recirculation valve, so if you replace this with a dump valve, you don't only **** up the perfomance post gear change, you also mess it up pre gear change, probably one of the times you don't want the power curve to be jumping all over it's place, or unburned fuel to be bogging the engine down.
you are right in that diesels don't have a wastegate, as they are free floating turbos, the maximum gas speed is low enough (capacity x revs = not a big number because of the low revs) that the turbo will never produce uncontrolable boost, excess boost is recirculated via the recirculation valve, so if you replace this with a dump valve, you don't only **** up the perfomance post gear change, you also mess it up pre gear change, probably one of the times you don't want the power curve to be jumping all over it's place, or unburned fuel to be bogging the engine down.
ah i understand that.. (im quite suprised bout that! :lol
never new how high that pressure was :| but with the tuning box being fitted the turbo has more whistle to it when going alone so with a tuning box i could be running more pressure?! :look:
i dont think dervs are **** though.. considering they are actually better for the environment then petrols as they pollute less and easy get better mpg
But at least i get why a dump valve is a bad thing unless it was the full hog with all the other things needed as well..
never new how high that pressure was :| but with the tuning box being fitted the turbo has more whistle to it when going alone so with a tuning box i could be running more pressure?! :look:
i dont think dervs are **** though.. considering they are actually better for the environment then petrols as they pollute less and easy get better mpg
But at least i get why a dump valve is a bad thing unless it was the full hog with all the other things needed as well..
Diesel do have watse gates tho, u can see the actuator on the cdti, they dont have throtel a buterfly
To be honest i wudent say there a bad thing, ****in up performance is more of a mith, while the valve is open there is less chance of lowing rpm at the turbo compresser turbine as it can flow boost pressure out into the atmosfire, and not b slowed by back pressure meanin after the gear change when the throtel is opened again the turbo is or ready spining frealy and not havein to spool up again,
1 of the biggest reasons y dervs have turbos is tho because exhaust gas temps r around 200 oC iirc cooler than petrol because of compresion ignition ova spark for petrol, as the gasses r cooler the air is more dence, hence bigger boost pressure for such small turbos, T1.5 iirc
oh and dervs arnt ****e :x:lol:
To be honest i wudent say there a bad thing, ****in up performance is more of a mith, while the valve is open there is less chance of lowing rpm at the turbo compresser turbine as it can flow boost pressure out into the atmosfire, and not b slowed by back pressure meanin after the gear change when the throtel is opened again the turbo is or ready spining frealy and not havein to spool up again,
1 of the biggest reasons y dervs have turbos is tho because exhaust gas temps r around 200 oC iirc cooler than petrol because of compresion ignition ova spark for petrol, as the gasses r cooler the air is more dence, hence bigger boost pressure for such small turbos, T1.5 iirc
oh and dervs arnt ****e :x:lol:
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