your 2 cents on mbc's

[lowridin2g]

just wanted to make a thread on mbc's. who has them how u like it and y. i also wanted to bring up the issue of the bleeder holes in the actual t fitting of the mbc. u do leak boost out of that pretty badly. what is your thoughts on that hole, and how much better is ebc than mbc? im about to take mine out because of that fact. i dont like the fact it leaks out that hole but i know it has to be there for the mbc to function properly. post your 2 cents

o and another thing who thinks i or anybody else would be better off just by doing the boost restrictor mod than an mbc? at least that way u wouldnt leak. im talking with stock turbo, but aftermarket intercooler piping,upper and lower, intake and catback.

 

[Streetbeat]

i havent had any complaints with my mbc...joe p..cheap...useful...ill build my car up then get a ebc, i see it as more of a comfort then something i just gotta have

 

[lowridin2g]

do u have the joe p mbc or are u saying it is just cheap in general?

 

[swordfish]

I have a Hallman MBC and it has always worked great for me. Plus its only $45. We have a HKS EVC EZ on the 92 Laser project car and its great too.

jeff

 

[jmc94gsx]

Bleeder holes are very important, I would not use ones without it. They can be in several locations depending on who made them. The Hallman (old style ~1997) has a hole in the T-fitting as described, although some have a purge hole in the brass fitting that is right before the vac line to the wastegate such as the FFWD connection.
The bottom line is that the bleeder hole is important and the will indicate a well designed boost controller. This will not cause an ineffective signal.
The function however is very important. The reason is for example after you lay off the throttle and boost pressure subsequently decreases, the purge hole will relieve any pressure in the boostcontroller to wastegate vac line. This is important for boost response. How? Once the ball moves back when there is less or no boost after you lift to shift, the purge hole will vent the extra pressure in that vac line. Without this purge hole there will still be pressure in the line, causing the wastegate to stay open longer than is needed. The result will be a laggier turbo response between shifts. The bottom line it is there for a very important reason, so keep it there.

Secondly the hole is too small to cause a boost leak, think about it, it must first go through several feet of small diameter line and go out a very small purge hole, not likely.

I've never had a problem with either these two boost controllers mentioned above and will not change from a MBC to EBC anytime soon. They work and have adequately controlled boost at 24 psi for me.

I hope this has cleared some things up, if not then let me know.

 

[lowridin2g]

thanks for your explanation man i appreciate it. i wasnt planning on pluggin the hole anyway. y does it leak air out the bleeder hole when u do a leak test then? are u saying the ball moves and allows the air to only escape in between shifts? or when the wastegate closes?

 

[jmc94gsx]

Originally posted by lowridin2g
thanks for your explanation man i appreciate it. i wasnt planning on pluggin the hole anyway. y does it leak air out the bleeder hole when u do a leak test then? are u saying the ball moves and allows the air to only escape in between shifts? or when the wastegate closes?

When doing a leak test I thought the same thing, but I also noticed it's a very small, slow leak and will not make too much difference in manifold boost pressure. With no boost the spring will push the ball back, closing off the line from the controller to the wastegate.

 

[lowridin2g]

hmm thats wierd cause with 5 psi into my system, it leaks out at a good rate. i have the joe p. by the way

 

[kpt4321]

The Hallman MBC is the best boost controller for a DSM, or most other cars, bar none.

That boost leak is minute. If someone wanted to hook a MBC up to a volume of a known size and then measure the pressure every second or so, you could easily figure out the size of the leak. It is tiny though.

Technicially, it is not a bleeder hole, but a vent.


....Kyle T.

 

[lowridin2g]

thats funny cause about a year ago the joe p mbc got better ratings than the hallman. in fact it was on the top of the list for best mbc. is where its at

 

[Defiant]

Originally posted by kpt4321
The Hallman MBC is the best boost controller for a DSM, or most other cars, bar none.

It may well be the best-looking and/or best made, but does it work better enough to justify its cost? Is it that much better than a Gus valve, or a Home Depot?

 

[kpt4321]

Yeah, but where was the Joe P. rated? By whom? Where did the Hallman place? You can't trust a "survey" if you don't know who is doing it, or who they are polling.

A homemade ball-and-spring boost controller can be just as good as a hallman. However, that depends on your skills, and what parts you use, and as such it's not a safe comparison.

A Hallman is always better than a bleeder valve.


....Kyle T.

 

[Defiant]

Is anyone using a regular old compressor regulator? It was The Trick Way, long, long ago.

 

[EuroGSTSpyder]

I have the dual style Dejon MBC with switch in the cockpit...Works like a charm and I like the fact that I can frive around on stock boost and if I wanna race I just flip the switch and get alittle more power ;-)

 

[jbillakdsm]

I took an existing design and doubled the pleasure. Basically got a SBR MBC and doubled it on a single piece of aluminum. Got myself some SS springs and ball bearings and a electronic "Y" splitter from a local hydraulics company and ran the switch into the cockpit under my seat. I also made a mount for it so it hides right underneath the lip by my passenger side headlight (can't see it at first glance). Now I run 15 on the street and with the flick of a switch, I run 19 when it's needed.