Just wondering where everyone is getting their boost source from on their MBC installation....I bought an AMS boost controller this past weekend and put it in today, nice piece, but not sure if its my install or something else but the boost spikes up to about 23 psi then will drop to about 20 psi (which is what i want) and then will bounce back up and down between 18-21 psi. I got my boost source tapped into the BOV line connectin to the intake manifold. Something I installed wrong? Or is this normal on an evo? The AMS piece looks great and dont think its the prob but I had a hallman on my eclipse and it held rock steady.

 

When I had my hallman MBC connected to the BOV line, the boost tended to spike to 21psi and then drop very quickly to 19psi BEFORE redline. When I connected it to the turbo nipple, it spiked to 21psi and tapered very slowly to 19psi AT redline. I decided to use the turbo nipple instead.

After I installed my full 3" exhaust, the boost now goes to 21psi and holds rock solid.

 

Tap the line running across the valve cover, which eventually runs to the bov. No spiking with the hallman pro

 

hmmm...where did you then mount the boost controller? mine is mounted on the radiator screw hole on the top....seems like it would take a loong vaccum line to get all the way there unless i move the actual controller

 

I mounted it on the radiator bolt as well. The line isn't that long. I haven't noticed any problems. Boost holds 20-21 psi, absolutely no taper.

 

I mounted on the radiator screw on the top I also got AMS MBC one of the hoses is longer so use the longer one and short one for VAC (bov line)

btw, where do you live? if you live closer i can stop by and take a closer look if you want. PM me.

 

I tapped the BOV line, holds 21PSI like a rock

 

generally - its best to stay away from the bov line to socure your MBC b/c the activaton of the MBC can sometimes cause the bov to leak open as the mbc opens. The turbo discharge nipple is prefered.

If your boost is jumping up and down up top - it could be a sign of timing pulling and knock.