what would happen if........

[mickmick]

the wastgate rod got stuck fully in????

or possibly out

I'm not sure which one makes the yurbo go wheeeeeee

Mick

[ailwyn]

Stuck closed (forcing all of the exhaust through the turbo).

The ECU would flip into limp home mode after the boost had been running at around 1 bar for more than 0.5 seconds.

Ailwyn

[mickmick]

ok then, next question

is there a way to set the wastegate to a fixed position to allow max useable ariflow constantly without dmage to the engine etc

[mickmick]

the reason i'm asking is because some days i get the full on 0.6 bar, and others the car maxes out at a whole 0.3 bar

its a funny one

[ailwyn]

I would think that if you "fixed" the wastegate then this would cause you more problems as I would imagine that if the wastegate is always open then the turbo would take longer to speed up.

Have you tried wiggling the actuator to make sure it's not sticking?

Have you checked elanscan to make sure the boost guage is not faulty?

Others may have other ideas.

Ailwyn

[Candles]

The variation in your boost may well be due to a gauging error rather than actual boost differences. Does the car feel different? The most likely cause, in my guesswork opinion is the earth wire to the orange transducer (on the offside wheelarch under the bonnet) coming loose or being corroded. It is a really easy one to clean up and retighten, so try that first.

The whole point of the wastegate is so that it isn't fixed, so having it fixed would be pointless. Closed = max exhaust through turbine. Open = bypass most exhaust to prevent overboost (mentioned above).

[Doug]

variation may also be due to a dodgy BSV (boost solenoid valve) or its connection. Remember the wastegate only allows 0.4 bar or so and then its the BSV that allows the full 0.65 !!

[Ashaman]

That is why some people use a spring loaded check valve inline with the actuator.

The idea is that you set the tension on the check valve so that no pressure lower than say, 8psi will ever even get to the actuator. Once you pass that point though, the ball in the check-valve will pop open, and allow all pressure to go the actuator.

The difference is that normally the wastegate opens as pressure builds. The more pressure, the more it opens (gradually) untill it is fully open. With the check valve, the hope is that it stays totally shut until you want it to open, so the valve pops, the wastegate opens fully (instantly), and spoolup is faster.

It seems like a good idea, except that I think firstly it might cause a brief surge/overboost which might trip the dreaded CEL; and secondly I have never seen proof it actually makes a difference.

It sounds good in theory though!