when i go for boost runs i start in 3rd great at about 2500RPMs i will only boost about 18 spike and 16 hold. but if i get on it from 2nd, then go to 3rd it will spike a fast 21 and hold 18. what do i need to do? up the boost from the MBC?

 

That's exactly opposite of how it should work. It should see its highest spike when rolling into boost from low rpm. When you shift from a lower gear to a higher gear while going fast, you see LESS peak boost, because you're at a higher rpm in the next gear where the boost is already at a taper point.

What MBC are you running? It should not be behaving like this.

 

its a Dejon tool. it was like $50. one line is T'ed into my BOV and the other is going to the actuator. and the Nipple that is on the turbo outlet pipe(that goes to the LICP) is caped off.

 

Is the Dejon BOV a bleeder type? T'ing off the BOV line might not be such a hot idea.

 

i read the instructions posed on some other Evo sight and he said to tap the mani pressure side of the MBC on that vaccume line. where should it be?

 

Try the turbo nipple, which is the preferred method. This behavior you're seeing is not normal at all.

 

i had the dejon tool mbc for a while, and it had less boost spike than the forge mbc i have now. put the mbc between the turbo oulet pipe nipple and turbo wastegate nipple.

 

alright ill try that.

http://www.evotuners.net/forums/showthread.php?t=335

this is the instructions that i followed when i installed it. is it incorecct?

 

bump

 

did i install it wrong?

 

sorry but thats wrong.

when you shift from a lower gear into a higher gear your boost will INCREASE not decrease. First off your putting more load on the engine in a higher gear. And secondly when you shift @ 7k in 3rd gear your tapper is down to 20psi, you will drop to 5400 RPM in the next gear where your boost will be back up to 23psi, and then tapper back down.

 

I think your problem is the MBC your using. if you have another one available I would try that and see if you still have the same problem.

I'm guessing your RPM in 2nd gear is moving very fast and I suspect your not making enough load long enough to open the WG fully. Its kind of like boost creep, but not really. In third the MBC has enough load and time to vent off the pressure and the WG respons like it should.