desmond

i recently installed a catback on my car. now it has a dp, high flow cat, catback, intake and reprogrammed ecu. i also have a home depot type mbc. my problem is that the car is boosting 12-14 psi from 3K- transition, it holds about 11 at the transition and after the transitions it goes anywhere from 14-19 psi. i have the mbc almost closed completely so im wondering why it is making so much boost. and when it was closed completely it was making like 13psi and creeping to 17 up top
i guess it is boost creep. anyway should i get electronic boost controller or try a different mbc.
or maybe i should check vac hoses, but wouldnt that cause a link and make less than stock boost.
before the catback i was getting 10.5-9-10.5 boost pattern

adam c

iTrader: (2)

Closing a MBC will increase your boost. Open it up to reduce boost

desmond

i thought closing it would allow less pressure. so if i turn it counterclockwise, opening it up more, it will lessen boost pressure?
the contoller im using is like the one here: http://robrobinette.com/boost_controller.htm
on that page he closed it fully and got 8 psi and when he backed it out, turning it counterclockwise, he got 13 psi

desmond

or do i have that wrong?
so i need to close it fully to the right, then back it out a couple of turns, the close it slowly till i get the desired boost i want?

desmond

i played around with it a little and now i get 10-8-8, so i guess that would be almost closed. so if i turn it the other way and fiddle for a bit i should get it right

adam c

iTrader: (2)

Manual boost controllers take a bit to get them adjusted right. Clockwise (closing) gets you more boost. Counterclockwise (opening) lowers your boost. Do not install the prespool controller. It will make adjustments nearly impossible.

desmond

i turned it all the way down and i get a 10-8-8 pattern. ive tried different number of clockwise turns to allow more boost but i only get 11-8-8. any ideas why? or should i just keep fiddling with it?

A.W.O.L

could it be possible that your second turbo is on its way out?

birdy01

may b different depending on how u hooked up the mbc

desmond

its hookup up exactly like the one on rob robinettes page. ill try turning the mbc some more today

riptor

question...my buddy..just bought the turbo xs boost controller. i saw the hook up on rob's site, my question will there be a problem if he leaves the stock pill for the prespool, or does he need to get a controller or tee the line..i was thinking that it will control primary, but at transition it would spike, his mods r,
gerddy intake
(dont know brand) downpipe
apexi N1 exhaust.
greddy polished elbow kit, had the lower ic pipe on just not the inake elbow yet. got the one with injector bosses.

`sl!mXP

the mbc can also go bad, my homedepot type boost controller lasted for about 2 months until it couldnt hold anything above 10psi, but what do you expect for $5 :\

DaveW

I saw your other post on getting an electronic boost controller. Before you buy one, consider these points:

1. If it is boost creep, no boost controller will control the boost level. You will need to port your WG.
2. Needle-valve boost controllers still use the stock duty-controlled solenoids to actually "control" the boost, and are not as effective as EITHER ball-spring MBC's or electronic controllers with the actuator exits (to the solenoids) plugged.