if i got a greddy profec b spec 2, and want low boost to be, say 5psi and high boost to be, say 15psi but my external wastegate acutator is set to 9psi, how can i get the 5 psi with the boost controller? Or can i even get a lower than "stock" boost pressure with an electronic controller? is the controller limited to the lowest psi that the wastegate will open at?

when im done with my rebuild i dont want to boost for a while till the motor is broke in. can i control that with the electronic controller, or willi have to use the "light foot" boost controller? :)
thanks

to get 5 psi you will need to adjust the wastegate actuator arm down to 5 psi. After that your boost controller will modify the signal to your wastegate to raise the boost. I think electronic boost controllers work better with higher wastegate setting because the adjustment spectrum is larger.

Be careful with that light foot deal, make sure you watch your egt's. The stock ecu will advance the timing a lot. By the way, I started boosting at 200 miles with my block from VT, it loves the boost. :7

so you are saying that you should set your wastegate at like 10psi and then use the controller to put it at 5? just want to make sure i understand. a boost controller and gauge and etc are some of my next mods.

Like said above, you can't go lower than what the wastegate actuator is set at. To prevent boosting durring breakin, the best thing to do is to pop off the wastegate arm. It will let the wastegate stay open all the time.

^^^you sir, are a genious!!!!! thank you.

But if it was open all the time you wouldnt get any boost would you ... there would be no pressure building up it would just go right out.

BINGO! that what i want while in break-in period on fresh rebuild. so after break-in i can set low boost to 9 and hi to 15 or 16! groovey!
thanks

Isn't the wastegate normally closed? If you disconnect it you would build too much boost.

If you disconnect the actuator arm from the flapper, the flapper will be free to swing open with no resistance. Unless you bring it to redline you won't see any boost.

Originally posted by etx
Isn't the wastegate normally closed? If you disconnect it you would build too much boost.

You would not build any boost b/c when your turbo spools it creates pressure and the excess pressure goes out of the wastegate . The wastegate is told when to open and close. If the arm is disconnected then it can not open and close the wastegate. Then the wastegate will be always open by the boost being generated by the turbo, B/C that arm is not there to keep it closed until it is told to open . So you would be generating about this much boost -------> 0 .

Originally posted by etx
Isn't the wastegate normally closed? If you disconnect it you would build too much boost.

You would not build any boost b/c when your turbo spools it creates pressure and the excess pressure goes out of the wastegate . The wastegate is told when to open and close. If the arm is disconnected then it can not open and close the wastegate. Then the wastegate will be always open by the boost being generated by the turbo, B/C that arm is not there to keep it closed until it is told to open . So you would be generating about this much boost -------> 0 .

srry dbbl post.

mr mike is right.. though yall have internal wgs, external works the same.. just have to keep it open all the time

etx is right when he said you cant go lower then the wg.. like forme its set at .45 bar, aka 6.5 lbs i cant go lower only higher..

tim be careful though, not sure how you guys have it set up..g ranted you prob wont be getting the car too hot but all them exhaust gases are now pouring out more then before.. my radiator is starting to melt already.. but keep in mine its a 35mm tial and its right near the ac linea nd radiator

used some more heat tape and about to buy a metal one and nice slim fans

but if i had it open all the time not just in boost oh lord

plus im not sure how and where internal ones dump

even with a dumptube i will still prob melt my radiator