Sorry search didn't turn up with this combo, I just know it's probably the 18 or 22 psi spring. So my wastegate actuator arm broke off of my BBK 3B. I think I'm getting a Turbosmart internal wastegate to replace it, but I'd really appreciate a bit of guidance over which spring pressure to choose.

The car is Tscomptuned's old 2.4 motor, ported BBK 3B, ported Megan o2 housing, tuned on E85 at about 26psi peak at 450-500whp (430 dyno dynamics). I may go a bit higher to 30 psi peak in the future.

18 psi spring? 22psi? More?

Also it's pretty funny driving like this, no boost, but not as bad as you'd think.

http://www.turbosmartdirect.com/Prod...shi-Actuators/

 

Two ways to look at it IMO. If you are going to be on pump fuel at times and like to beat on the car then put a 18psi spring with normal preload on. This will be base boost to work up from and less likely to have a spike on shifts. A good rule to live by is pump fuel =low boost and ethanol = high boost. Things live a better life when they aren't rattled.

If you are going to really max it out and have E85 then a 22psi or even 25psi spring would be good. The stiff spring will help keep the wastegate door closed and have good spool up.

Also from my experience a softer spring yields more stable boost control with the MHI housing but may give up some spool up and top end.

I ran an 18psi spring on my red setup (recirculated) and with my old downpipe it would make 20psi. Boost control was good but over 530whp /30 psi it wouldn't hold well up top. I moved to a 25psi spring and would get 23psi and wouldn't beat on it on pump fuel(high compression and no need for me). That setup would make 40psi and hold out the top. It also kept the door closed on spool up better but boost control wasn't as precise.
I moved from a 2.75" DP to a 3" DP and now get 19-20psi base with the 25psi spring.

 

Rule of thumb is to run a spring around half the weight of your peak boost so in this case either of those will work fine. The above advice is also pretty good. If I were you I'd get the 18psi and see how it feels. Can't remember but I thought TS actuators were serviceable so you should be able to swap out the spring in it.

 

Thank you both for the advice, Chad from CBRD also recommended the 22 psi version as a replacement for the original high pressure unit that came with the 3B. I'm on 100% E85 so I'll go with that.

Looks like the springs can be swapped out too, didn't know that, thanks.