I know how to turn the boost up but how do I stop it from getting to high. Do I adjust the length of the wastgate arm so it opens earlier or something.
olboy

how are you controlling the boost for turning up and down and what sort of motor is it .

A15 and I'm using one of those adjustable restrictor valve thingies. You can adjust it so that the wastgate gets less boost and dosn't open, thus more boost but you carn't give it more boost than the turbo is making in the first place to make it open any earlier. I think that makes sence
olboy

The hose that goes from the waste gate avator to (the snail of the turbo or the cross over pipe)you need to blead air from that hose or put a t piece in and run the hose in the car so you have ajustible boost you will have to put a tap on the end of the hose do you have a boost gage running of yor manifold if not it will go boom from too much my web add is datsun1200post @hotmail.com

yeh ok I have an adjustable boost thingy but assuming the wastgate opens at say 12lb how do I get it to open at say 8lb. Screwing the adjustable boost thing (whatever you call it)down won't make it read 12lb when the turbo is only making 8lb.
You carn't have 12lb at the wastgate and 8lb at the turbo. The adjuster thing can turn the boost up but I carn't see how it can turn it down.
olboy

the spring in the actuator will resist pressure upto 7psi as t28 for example.

the T piece can hold 7psi and only give the actuator 3psi to allow the wastegate to stay closed longer increasing boost. to reduce boost you will therefore have to reduce the spring rate so the actuator opens on smaller pressure levels.

if the turbo boosts 7psi without T piece that is its default pressure it cant go lower than that. from what i understand and this is very difficult to try explain

so yes... screw the waste gate actuator to make it longer and see what your boost does then...

screw it the other way if it goes higher...

2qk4u is right u have a default setting that u cant go below. maybe you could change the length of the actuator arm, still may have same problem. 7psi is good for a15 why u eanna go lower?

I don't want to go lower, I just want to cap it at about 9lb.