I have a built 97 Miata running an efr 6258. Currently I have a turbosmart dual port actuator on a 4port Mac valve for electronic boost control. I had the boost control down well on my mkturbo kit, but now with the efr I keep overboosting. Even with the electronic boost control turned off and a 7psi spring in the actuator, I am still getting around 14psi on WOT pulls. Anyone know what could cause this? The wastegate is opening when I hook an air compressor to the wastegate actuator, but not sure if it's opening enough.

 

Check the alignment of the wastegate canister. With the nuts loose on the wastegate arm it shouldn't be side loaded and should be a straight shot to the hole in the wastegate arm. I had to put washers behind my canister where it mounts to the bracket on the turbo to correct the angle. Before I figured it out it would bind and boost creep.

-Mike.

 

I checked the alignment and it seems good. Do the wastegate springs crack open at their rated psi? Or are they supposed to be fully open? Inhave a 7psi spring and when hooked up to the air compressor it starts opening at 7 but doesn't fully open until 12-14psi. Is that normal?

 

reference the BW manual, it has a nice chart that explains all of that. Quick google search should do

 

I had a crazy overboost problem using the turbosmart actuators. Mine did not have the same overall stroke length as a stock EFR cannister. Hook some air up to both the stock and TS cannisters and see if they are opening the wastegate the same amount.

 

I've recently worked through the same issue. I started with a medium pressure canister and couldn't get it below 14psi on my car. I switched to a low boost canister and couldn't get below 13-14psi. On my car I have to run as little preload as possible after ensuring that the linkage would literally fall off the wastegate rod without the securing nut.

 

this is pretty accurate, my tuner reduced the preload so the nut was almost falling off -- the problem is that if you increase the preload, you actually reduce the effective opening angle of the wastegate, so much so that it becomes ineffective in allowing all the gasses past

 

Another consideration is the turbo will be destroyed if the nut comes off.