? on internally wastegated turbos...

[starscream5000]

Can you set the stock boost level below what the wastegate spring actuates at by the use of a MBC or something similar? I have a project that I want to try out, but the wastegate on the turbo I want to use is set in between 6-8 psi and I only want to use 5 psi tops. Anyone know of a way to lower the boost?

 

[Nick M]

If you made a different actuator yes, but no. It isn't enough pressure to move against the spring.

 

[starscream5000]

So basically it looks like I would have to find an actuator with a weaker spring and customize the arm to fit on the wastegate flapper?

 

[Supra]

You can disconnect the actuator arm so the flapper is free to open. Boost would be minimal.

 

[boostadikt]

lol^^^ as said the pressure forces the spring to compress pushing the gate open. you may be able to take the spring out and cut it.

 

[starscream5000]

You can disconnect the actuator arm so the flapper is free to open. Boost would be minimal.

:nuts:

That will work... Not!

lol^^^ as said the pressure forces the spring to compress pushing the gate open. you may be able to take the spring out and cut it.

I may try this, but It's going to be difficult to seal back up the wastegate again...

 

[IJ.]

SS5: You can unpreload the actuator so there is the barest pressure on the flapper, doing this will give you the very minimu that the gate can supply and an MBC can't change this.

It will cause Lag as the gate will blow slightly open with any boost, a better alternative would be a part throttle open actuator if you can find one to suit as it's open/open at part throttle then pulls closed for boost control but you'd need some way to control it.

 

[mattjk]

or just add a coil spring in the opposing force

best thing to do is what IJ said. I would cut the actuator shaft and thread it with a die, then use a tube nut with jam nuts on both sides to add length/reduce spring tension.

 

[boostadikt]

^^^ I Didn't think of that.... Great idea

 

[IJ.]

I set mine with as little preload as I can and then rely on the AVCR to prevent the Lag down low it chops 200 rpm off spool and keeps the gate to 1 bar so it's safer to drive on wet days....

 

[starscream5000]

That's actually what I was thinking of doing, set the actuator bar to where the wastegate flapper is just barely open, then adjust from there. This is what you are talking about right Ian? A controlled small boost leak?

 

[IJ.]

SS5: I set mine with half a hole preload any less and it leaks.