question for technical know-it-alls :)
#5
I think what your are referring to is actually a Amal Valve .
So called cos its made by a company called Amal who used to/still? make carburettors.On a Scooby I think you must be refering to the boost control solenoid.
Steve
So called cos its made by a company called Amal who used to/still? make carburettors.On a Scooby I think you must be refering to the boost control solenoid.
Steve
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#8
Chris and Niall ....
It is a serious question, which is why it's not been posted in the Muppet forum funnily enough
Steve, it's spelt anvil on the Subaru job sheet when it was fitted about two years ago but they didn't know what it was for when I asked recently) ... but thanks
#14
I'm a technical know-****-all, so I really couldn't help with this one
Nick
Well muppet me sideways!
[This message has been edited by Mr Footlong (edited 04 April 2001).]
Nick
Well muppet me sideways!
[This message has been edited by Mr Footlong (edited 04 April 2001).]
#16
Yes, Pete I did want a serious answer
Shark, thanks, if I get a chance I'll shoot round for piccie (don't know how easy it'll be to take one tho)
John,
Thanks for the answer .... adyhicut sent me a website with details of it on for an RS ... and that talked of a switch on the dashboard somewhere, and as far as I'm aware I don't have one, does that mean it's "on" all the time? And does this mean that the ECU has had to have been altered too, ie. it's no longer standard?
And, how common are they? And, why didn't the Subaru dealer where I bought the car not know what it was (and spelt it wrong ) ???
[This message has been edited by Rebecca (edited 05 April 2001).]
[This message has been edited by Rebecca (edited 05 April 2001).]
Shark, thanks, if I get a chance I'll shoot round for piccie (don't know how easy it'll be to take one tho)
John,
Thanks for the answer .... adyhicut sent me a website with details of it on for an RS ... and that talked of a switch on the dashboard somewhere, and as far as I'm aware I don't have one, does that mean it's "on" all the time? And does this mean that the ECU has had to have been altered too, ie. it's no longer standard?
And, how common are they? And, why didn't the Subaru dealer where I bought the car not know what it was (and spelt it wrong ) ???
[This message has been edited by Rebecca (edited 05 April 2001).]
[This message has been edited by Rebecca (edited 05 April 2001).]
#17
Hi rebecca
Its an AMAL valve your refering to, called that because its made by AMAL, simple really.
Very simply it is a solonoid that controls the flow of air from the turbo compressor to the waste gate actuator.
In order to control the boost levels the engine produces, the ECU controls this valve to give the correct presure on the diapram in the waste gate actuator. Once the boost level is at its highest allowed level the valve is opened by the ECU and this opens the waste gate, causing the exhaust gasses to bypass the turbo exhaust blades, therefor not driving the turbo, therefor not producing infinate boost levels.
This is a process that is happening all the time the engine is under load and demanding boost from the turbo. It must be controlled by the ECU so there should be some wires onto the valve from the ECU output.
If you need more info just fire away.
Its an AMAL valve your refering to, called that because its made by AMAL, simple really.
Very simply it is a solonoid that controls the flow of air from the turbo compressor to the waste gate actuator.
In order to control the boost levels the engine produces, the ECU controls this valve to give the correct presure on the diapram in the waste gate actuator. Once the boost level is at its highest allowed level the valve is opened by the ECU and this opens the waste gate, causing the exhaust gasses to bypass the turbo exhaust blades, therefor not driving the turbo, therefor not producing infinate boost levels.
This is a process that is happening all the time the engine is under load and demanding boost from the turbo. It must be controlled by the ECU so there should be some wires onto the valve from the ECU output.
If you need more info just fire away.
#19
All,
The Amal valve (yes, it is called an Amal valve because it's made by Amal, AND it's actually written on the valve!) is used to control boost, as john says. Subaru do not use Amal valves, they are found on Cossies (and we affectionately nicknamed them "**** valves" for obvious reasons). Subaru use a Denso solenoid for boost control.
An Amal valve is like a small round tin (like they use for tuna but smaller) with three ports coming out radially, and two electrical posts on the top axially but off centre. It can switch between ports thereby connecting the wategate actuator either to pressure from the turbo or to atmosphere (back to the intake) to release pressure from the actuator. It is used by the ECU to open the actuator when a preset boost has been reached by allowing pressured air onto the wastegate actuator, thereby allowing air to bypass the exducer and holding the boost.
In a Subaru the Denso unit is a cylinder which is attached to the driver's side suspension turret. It can have either two or three ports on it depending on the model year of the car and its origin. It is used in the same way as described above. Basically it allows more boost than would be possible by just connecting the wastegate actuator directly to the turbo exit, by reducing the pressure at the actuator (in essence, it needs more boost at the turbo exit for the same pressure at the actuator).
If it breaks it will almost certainly break in a fail safe state, that is it wllows air onto the actuator thereby preventing the car from making more boost than the actuator opening pressure (typically around 0.5 bar on a Subaru). If it failed in the other position then the car would overboost chronically and the overboost fuel cutoff should save the engine....
Cheers,
Pat.
The Amal valve (yes, it is called an Amal valve because it's made by Amal, AND it's actually written on the valve!) is used to control boost, as john says. Subaru do not use Amal valves, they are found on Cossies (and we affectionately nicknamed them "**** valves" for obvious reasons). Subaru use a Denso solenoid for boost control.
An Amal valve is like a small round tin (like they use for tuna but smaller) with three ports coming out radially, and two electrical posts on the top axially but off centre. It can switch between ports thereby connecting the wategate actuator either to pressure from the turbo or to atmosphere (back to the intake) to release pressure from the actuator. It is used by the ECU to open the actuator when a preset boost has been reached by allowing pressured air onto the wastegate actuator, thereby allowing air to bypass the exducer and holding the boost.
In a Subaru the Denso unit is a cylinder which is attached to the driver's side suspension turret. It can have either two or three ports on it depending on the model year of the car and its origin. It is used in the same way as described above. Basically it allows more boost than would be possible by just connecting the wastegate actuator directly to the turbo exit, by reducing the pressure at the actuator (in essence, it needs more boost at the turbo exit for the same pressure at the actuator).
If it breaks it will almost certainly break in a fail safe state, that is it wllows air onto the actuator thereby preventing the car from making more boost than the actuator opening pressure (typically around 0.5 bar on a Subaru). If it failed in the other position then the car would overboost chronically and the overboost fuel cutoff should save the engine....
Cheers,
Pat.
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