well i made 2 of these http://www.geocities.com/chmwatson/FAQs/mbc.html they do raise boost but they also loose alot of spool up time and in general the car feels slower when i use one of these even if the boost is higher ? why ? ive ended up using just a little "bleed" valve boost controller and it works great but why does the other one suck?

 

a ball and spring type mbc should make it spool up faster

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lightcrx &raquo;</TD></TR><TR><TD CLASS="quote">a ball and spring type mbc should make it spool up faster</TD></TR></TABLE>

That's the kind he used.

 

maybe it feels slower cause it was put together with air tool parts

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 97grnrs &raquo;</TD></TR><TR><TD CLASS="quote">well i made 2 of these http://www.geocities.com/chmwatson/FAQs/mbc.html they do raise boost but they also loose alot of spool up time and in general the car feels slower when i use one of these even if the boost is higher ? why ? ive ended up using just a little "bleed" valve boost controller and it works great but why does the other one suck? </TD></TR></TABLE>

How much did you raise the boost? If you went from 5psi to 15psi, you're obviously going to have a longer spool time. However if your datalogs actually show that you're hitting the previous psi level at a later RPM when the mbc is on, then you may just have leaks in it.

The deal behind these raising max boost is easy to see - delay the application of boost pressure to the wastegate until you reach that higher boost level, and then allow only enough flow to keep the actuator open just enough. It should also decrease spool time (at least to reach the actuator's stock boost setting) because typical wastegate actuators will start opening slightly before max boost. The MBC keeps it completely shut until the exact desired boost pressure.

With that in mind, maybe your MBC just doesn't seal well enough at the bearing, or the spring sucks. The free MBC I got looks exactly like that, but it quickens spool just a bit but could probably be set to 30+ psi. I had to cut the spring a lot just to get down to 10psi. The actuator I used was ~6psi.

 

you need a 1/8 brass tee, 2 1/8 hose barbs, 1 small ball bearing, 1 small spring, and a bolt that has the same threads as the "T" and jamnut, you can figure out the rest. i tap the "T" on one side so i can swrew te bolt in more than 3 threads. also dont forget the vent hole

hope this helps
-joseph

 

well i use just a little valve that i t off in the wastegate line and the more i open it the more is raises boost but that just seems to me like it kinda defeats the purpose because its creating a boost leak which i would think would lose power but maybe im wrong .. but every time a made one with a ball and spring i noticed a considerable power loss?

 

i also am running 16 psi on the T25 300 zx turbo. it takes off like a rocket then around 4-5K rpms i feel a slight drop in power and then around 6 it comes back.. could this be caused by the type of boost control im using?

 

courius are u using factory waste gate or external waste gate.

unless u have solved problem already?

 

ya problem is fixed along with the blown motor. but now i run turbo sohc . internal oem wastegate