Hey there, I am new to these cars and I have a 1985 svo. The problem with the car is that I installed a dual stage boost controller from Turbo XS to turn up the boost, but the thing will only hit 15 p.s.i. max. I noticed that it will first build to 18 p.s.i. for about a second, then level off to 15. Any sugestions would be great!

 

You don't need a dual boost control, but make sure its seeing boost from the turbo and the other line is going to the wastegatte and not flowing through the actuator that comes stock on your SVO to limit boost

 

I took the wastegate hose and hooked it up directly to the bcs. The other hose I took and plugged it into the the turbo. Now I am getting good boost, but it will spike, and then level down to 18 lbs. When on boost it will go up to 20-22 lbs. then drop down to 18. What could be causing that?