mbc
e9 bov
dp o2 dump test pipe

 

We should try modding the stock VIII actuator. It may be up to the task of 26-27#. At least it is worth a try and it won't cost you anything. If all else fails we go to an aftermarket heavy duty VIII actuator.

Did you already test to establish current wastegate spring pressure level? You have a MBC so just rotate the adjustment knob all the way out counterclockwise (-) to lowest possible boost setting. Do a WOT run in 4th and note peak boost level on your boost gauge.

 

Disconnect hose to actuator. Remove cotter pin that secures tip of actuator rod to flapper valve's pivot arm. Remove two bolts securing actuator bracket to turbo's compressor housing. Remove actuator assembly from turbo.

Secure the actuator by clamping the actuator rod in the jaws of a bench vise. Unscrew and set aside both the turnbuckle tip and its backup nut. Measure 1/4"(.250 inch) from threaded tip of actuator rod. Cut 1/4" off threaded tip of actuator rod(1/4" equates to about 4 threads) using a hacksaw or a Dremel cutoff wheel.

Reinstall the turnbuckle tip onto the actuator rod LEAVING THE BACKUP NUT OFF. Tighten the turnbuckle down as far as it will go along the threads bottoming the rod out inside the turnbuckle.

Reinstall the modded WGA assembly onto your turbo. Go for a WOT run in 4th gear. Check boost.

 

Yikes! I forgot to mention that after you install the modded actuator you must back your MBC adjustment knob all the way out counterclockwise to its lowest boost setting(-), before road testing at WOT.

The boost reading that you obtain from that test run is your new(preloaded) spring pressure level. From that base point you can increase boost via MBC knob.

 

thanks 27 psi on 4th gear zero knock

tappers down to 23-24

siiiiick

thanks for the help amigo

 

Anytime! I am glad the issue is resolved, my friend.