47 replies to this topic

[RZT5]

as much as I've bashed on MBC's I'm going to try using one in parallel with the TCV to control my boost spikes. I think I've narrowed it down to the Forge UNOS boost controller and the Turbosmart Boost Tee. Anyone have any experience with either or any reason to go with one over the other? Or any other MBC I should consider for that matter?

[AverageVolvo]

Hallman Pro Ideally with In-cabin Control.

For manual cars I ditch the Bcs/Tcv and only use the Mbc, This requires a boost gauge and not being a complete idiot and flooring it in low rpms.

Flame all you want. I run a 19t and Mbc from Compressor to a Garrett 11 psi Wastegate. Never had a single boost spike


A top notch Mbc like Hallman Pro with ceramic ball will respond faster than any Greddy Profec Spec B Ebc. Less spikes too
And no electronics to fail

[ozzimark]

Kinda like this?
http://forums.nasioc...ad.php?t=602674

Good way to go, gives you the good spike control and quick spool when WOT from the MBC, and good boost control with pedal movement from the EBC.

[magicaljake]

Hallman Pro Ideally with In-cabin Control.

For manual cars I ditch the Bcs/Tcv and only use the Mbc, This requires a boost gauge and not being a complete idiot and flooring it in low rpms.

Flame all you want. I run a 19t and Mbc from Compressor to a Garrett 11 psi Wastegate. Never had a single boost spike


A top notch Mbc like Hallman Pro with ceramic ball will respond faster than any Greddy Profec Spec B Ebc. Less spikes too
And no electronics to fail

+1 to infinity

[the commissar!]

Kinda like this?
http://forums.nasioc...ad.php?t=602674

Good way to go, gives you the good spike control and quick spool when WOT from the MBC, and good boost control with pedal movement from the EBC.

So to use this where do you plumb the MBC in relation to the TCV? I would think they would be run in series, TCV then MBC but that guy has them run in parallel. That would seem to bypass the TCV in favor of the MBC. Perhaps I don't understand how they work...

Ready to be schooled...

[Pops Racer]

Parallel allows the ecu to control the onset of boost, and the MBC is set to max boost, controlling spikes and quickly controlling heavy throttle foot.


Bypassing the TCV/BCS, I suspect you are limiting its ability to control fuel trim, timing, and other desirable attributes of a good tune. Parallel allows the TCV/ECU to do what you paid for it to do.

To me, an MBC is like a bandaid. But you guys are happy with it, and thats what a car hobby is all about.

I actually have an MBC on my R (Hallman), its not tuned and we are running a 19T and other air flow up grades, so I'm using it to keep my kid from wrecking shit.

If I recall member JAXX is a big proponent of parallel MBC.

[RZT5]

Parallel allows the TCV/ECU to do what you paid for it to do. To me, an MBC is like a bandaid.

I agree with this 100%, but a spike to 24 psi is very capable of bending a rod and my setup seems just too eager to do this. This is why I want one in parallel that just stays out of the picture unless I go over max boost.

[ozzimark]

So run an MBC in parallel with the solenoid, it'll only crack open to limit boost when it reaches the preset pressure, and won't let it go higher.

[adamjjohn203]

I came up with this little diagram a while ago.....I'm still planning on trying this to control boost spikes...

Edited by adamjjohn203, 08 September 2010 - 06:50 PM.

[RZT5]

thats exactly how i'm going to do mine adam

[adamjjohn203]

In theory it should work great....you won't have to worry about getting into boost too quickly because the TCV/BCS will work as normal until TOP boost pressure is hit then it should divert through the MBC and quell the spikes.

[RZT5]

In theory it should work great....you won't have to worry about getting into boost too quickly because the TCV/BCS will work as normal until TOP boost pressure is hit then it should divert through the MBC and quell the spikes.

Thats exactly what I'm thinking. Gonna go pick up an MBC today hopefully and try it out.

[adamjjohn203]

Thats exactly what I'm thinking. Gonna go pick up an MBC today hopefully and try it out.

Please let me know the outcome!

[Keep Calm Chive On]

haha i posted this a while ago & your sketch looks just like mine thanks hommie now if only a MBC would fall outa the sky

[adamjjohn203]

haha i posted this a while ago & your sketch looks just like mine thanks hommie now if only a MBC would fall outa the sky

I need one to appear in my hands as well! Trying to fix my exhaust right now so this will have to wait!

[RZT5]

So even though HPF (located in portland) has the MBC I want listed on their website, it ships from florida so i wasnt able to get one today. guess i'll have to wait for shipping

[adamjjohn203]

Yeah I just ordered a Magnaflow muffler from a place that says they have a warehouse in Cali and a few other places.....where did it ship from.....the east coast, figures.

[Volvowith18psi]

You think this idea would still apply to the earlier BCS versions, like what came on a 95 t5r?

[RZT5]

I dont see why it wouldnt. The idea behind setting it up the way adam described is that the MBC will completely bypass the stock boost control system (regardless of what type it is or how it works) when boost goes above a certain point and open the wastegate.

[Keep Calm Chive On]

it basically "helps" control overboost that the TCV / BCS cant control fast enough. I have wanted to do this for over 4 months now but have yet to get a MBC ive tried to do other things to solve the issue such as wastegate adjustments via hand pump, shortening vac lines to TCV, etc. & the point came across to me that i only have a 30hg/20psi gauge. past 15psi the gauge becomes inaccurate so i might not be spiking as much as it says i am. Boost hits hard to the initial WHAMMY to the spring within the gauge might bounce & toward the upper limits of the gauge it becomes less accurate. I will prolly get a 30hg/30psi gauge to see if anything i have done has made an improvement. If not I will use the MBC. I just dont want to go through all of this to find out that its simply testing the upper limits of a spring that measures boost. Its similar to injector DOOOOOTTTTYYYY cycle & how at the upper limits it gives chance for more error. Ill have to find someone with a 30/30 gauge because i liked mine but had to special order it & it was like 60 bucks soo maybe i can barrow one & see. But please do keep both the forum & myself posted because when all else fails this has been my plan for quite some time just have to stop buyin pointless crap & get a MBC (even though i hate them)