Technical Help Please!
Discussion
I'm running a Mitsubishi Lancer Evo1 and have just started to tweak it a little.
Runs 10psi boost standard, but I've put a decent exhaust, uprated fuel pump and fancy plugs in.
Trying to get to 15psi, but it won't go higher than 12.5psi. Even disconnected the pipe going to the actuator, so it should run unlimited boost - guess what? 12.5psi.
Even replaced the actuator - guess what? 12.5psi!
Any ideas why it won't go higher anyone?
Runs 10psi boost standard, but I've put a decent exhaust, uprated fuel pump and fancy plugs in.
Trying to get to 15psi, but it won't go higher than 12.5psi. Even disconnected the pipe going to the actuator, so it should run unlimited boost - guess what? 12.5psi.
Even replaced the actuator - guess what? 12.5psi!
Any ideas why it won't go higher anyone?
Check the obvious things first such as a leak in the induction system (including a leaking dump valve), leaking exhaust manifold, igntion breaking down under boost etc.
Does the Evo have some kind of overboost protection that causes a fuel cut or retards the ignition above a certain pressure?
Does the Evo have some kind of overboost protection that causes a fuel cut or retards the ignition above a certain pressure?
To eliminate the idea that its the ecu, or to confirm it, i would disconnect the pressure pipe to the actuator, and go for a very careful drive, to see if the boost will rise over the 12.5 psi you say is all you can get.
DO NOT go clogging it, as the engine will not be protected from the huge pressure spike that is sure to occur with a non functioning wastegate.
If it STILL wont go above 12.5, id say there could be either a restricted exhaust, possibly collapsed baffle?...or the turbo has some sort of internal fault, maybe eroded blades on either the compressor or the turbine, or some other turbo related fault.
If it does go above 12.5 psi, then the symptom sounds vety like the scenario i currently enjoy on the GT4.
The turbo actuator is fed a modulated air stream by an electric valve in the line to the actuator, the excees pressure being bled off to the intake, so as the boost can rise. If the valve is continually stuck open then the boost will never exceed the factory level, as it will be applying FULL boost to the actuator whenever it gets any pressure fed to it.
As others have suggested, check the induction path for colapsed filters and hoses etc BEFORE trying what ive said.
Let us know how you get on.
DO NOT go clogging it, as the engine will not be protected from the huge pressure spike that is sure to occur with a non functioning wastegate.
If it STILL wont go above 12.5, id say there could be either a restricted exhaust, possibly collapsed baffle?...or the turbo has some sort of internal fault, maybe eroded blades on either the compressor or the turbine, or some other turbo related fault.
If it does go above 12.5 psi, then the symptom sounds vety like the scenario i currently enjoy on the GT4.
The turbo actuator is fed a modulated air stream by an electric valve in the line to the actuator, the excees pressure being bled off to the intake, so as the boost can rise. If the valve is continually stuck open then the boost will never exceed the factory level, as it will be applying FULL boost to the actuator whenever it gets any pressure fed to it.
As others have suggested, check the induction path for colapsed filters and hoses etc BEFORE trying what ive said.
Let us know how you get on.
Thanks for all responses guys.
I know the turbo should be able to produce 15psi, cos I know other people with Evo 1,2,3 running 15psi.
I've disconnected the electronic boost controller, which is the only limit on allowed boost - it's inline between turbo and actuator and is effectively an electronic bleed valve.
Wastegate opens at 12.5psi whether the actuator is connected or not.
Seems like a leak somewhere is the most likely culprit, but wouldn't I be able to hear it?
I've followed what other people have done before me, and they seem to get the required boost level no problem..................
I know the turbo should be able to produce 15psi, cos I know other people with Evo 1,2,3 running 15psi.
I've disconnected the electronic boost controller, which is the only limit on allowed boost - it's inline between turbo and actuator and is effectively an electronic bleed valve.
Wastegate opens at 12.5psi whether the actuator is connected or not.
Seems like a leak somewhere is the most likely culprit, but wouldn't I be able to hear it?
I've followed what other people have done before me, and they seem to get the required boost level no problem..................
Mr2Mike said:
Rob Plummer said:Even disconnected the pipe going to the actuator, so it should run unlimited boost - guess what? 12.5psi
deltaf said: i would disconnect the pressure pipe to the actuator, and go for a very careful drive...
Think he's been there already...
OOPS! dam glasses!
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