I'm hoping for some feedback from individuals running manual boost controllers on the stock twins above factory boost levels. From what I've read, the inherent flaw with a MBC occurs during attempts to achieve levels of boost above the factory wastegate setting. In which they have the tendency to hit full boost then taper off till redline.

I was wondering, does anyone have any experiences with a MBC above factory levels (13-15psi for example) that holds boost constantly to redline without tapering. And if so, what boost controller are you using.

 

I'm converted to non-seq. and use a mbc needle valve at the wastegate actuator. I used the write up on rob robinette's site as reference to installation. My PFC shows .85 bar constant till redline. Well sometimes its goes... .85/.86 .85/.86 .85/.86 but you get what I mean .

Jeremy

 

I have non-seq twins and a turbosmart mbc locked into 15 psi. I hold a strong 14-15psi all the way to redline. Honestly it waivers a little but nothing major, always at or above 14 psi.

 

IMO, if your boost is tapering off approaching redline, this is a sign of a lack of capacity of something other than poor function of the boost controller (restriction in air intake and/or exhaust, or weak turbos).

BTW, the above applies only to ball-spring controllers. Needle-valve controllers are just an adjustable "pill," and still rely on the stock PC & WG solenoids to control boost, and, therefore, will not control as well.

Any boost controller may not sufficiently limit boost (boost creep) if the WG is not capable of enough flow.

 

I run 13 psi on a needle valve boost controller. It holds strong to red line. Those who have tapering off, will have it regardless of boost controller.

http://www.robrobinette.com/boost_controller.htm

 

16 psi here, non-seq. on a home cheapo needle valve, till redline... Will see how the el'cheapo BC valve will work w/my new rx6b setup...

 

I am running dual Hallman Pro-RX's and my boost holds perfectly until redline. Adding an MBC shouldn't cause a loss of boost as redline approaches.

 

IM using a DAWES DEVICE Boost controler (ball & spring) along with a Power FC.

I run 1 bar (14.7psi) & haven't notice any boost creep or high rpm drop off.

Granted, I don't just focus on my boost gauge while going WOT on the street/track, but on the dyno it stayed steady.

 

1 bar = 14.5037738 psi

 

I was approximating............my bad

IM using a Auto Meter Sport comp gauge, but thanks for being an ******* & straightening me out. I know alot of engineer's lost sleep over that 0.2 psi misquote.

 

I'm not being an ***.. sorry. That size font was just off googles website.

And yeah I lost .2 hours of sleepies Sorry for trying to help.