I bought NXS ones. Regular price is $20 shipped. I ordered 8 total for a bunch of these jersey fuckers and got em for $14.75 each. And Phil threw in a 9th one free. So $13.11 each shipped. From the DIY MBC sites it looks like you'll spend $12 in parts to make your own plus an hour or so in labor. For the few extra bucks it's worth it to me.

NXS Motorsports

ive built one before, cant find it, dont feel like doing it again.

im going to give this a shot, i like you, have got tired of random boost levels with temperature changes.

I was a lil weary about this one. eBay Motors: High Quality Manual Boost Controller Toyota Subaru Audi (item 320355035550 end time Apr-01-09 18:53:11 PDT)

Just wanted to update and say I installed the ebc+mbc as in my updated configuration diagram and it is working as planned.

http://www.miatamx5.com/ebc+mbc.jpg

Just for the hell of it I set my boost duty target table all to 100% to see how the Machine would respond if I didn't run this setup and only ran a simple MBC setup. Well it hits boost target which I happened to have set at 17psi with only 49% throttle so fuck that. That's the exact reason I use an EBC to begin with, so I don't build boost too violently at low throttle.

Eh, I bought one of those cheapy ones. It's such a simple mechanism, what is there to be wary about? (seriously, tell me if something horrible is going to happen)

You are probably right that it will be fine but if it does vibrate and fall apart, like that knob end comes out you will not be telling your wastegate to open and you will overboost. if you have boost cut set you should be fine.

Yeah, that's what I figured. The worst that can happen is hitting the boost cut.

Do you guys ever experience different boost levels with the MBC based on the temperature of the spring inside it? Isn't the spring stiffer when it's cold, effectively raising the boost limit? One thing I experienced soon after putting the MBC in (i just did it this week, and was going to setup the EBC with it this weekend) was that I hit the overboost cut once (the first time i floored it), but then never again. I had my overboost set to 187kPa, and every subsequent pull was topping out at 170kPa. So I can't explain why I would hit overboost that one time... except with spring temp or something like that.

edit: after some more driving and reading, I realized there are a lot more variables involved and this is a simpler issue relating to the common MBC issues of spiking, creep, etc... I'll have to experiment with this MBC and my overboost settings.

Since when??? I'm in search of a new bottom end now cause of it.

Well thats because you didn't set it right, no fault of the equipment. User error on DIY stuff is far more likely than an honest-to-god screwup on the manufacturers part, especially with such widespread use and effective dissemination of good information.

Overboost fuel/spark cut worked fine for me on my MS and also works fine on the Adaptronic.

Artie's boost cut was set for like 225 to get it out of the way when he wanted to run 17psi. He refused to re-tune his eBC when the weather got colder and he was hitting 20psi

I finally jumped on board. Dealing with a lot of boost loss due to ambient temps that I've never really dealt with before. The last two mornings were 65*F out and at lunch it had hit over 80*F. Would go from 13-14psi down to 10psi once it got hot out.

My initial results are good. I need to tune it a little better, as I have to bleed boost with the EBC since I get bad boost creep, but so far so good. But from 5K to 7K I've never seen it so flat.

Here's my plumbing using the ARO solenoid:

http://boostedmiata.com/technical/ebc_mbc.jpg

I'm about to go back out and see now that it's about 10*F warmer out if I'm still making the same boost.

blah. it's performing good, but the problem is my boost creep.

If i tune it in the morning to get flat boost, it's bleeding too much when it's hot out. likewise, when i tuned it in the afternoon when it was warm, I had too much boost past 5.6K in the morning.

I'm thinking maybe I need a pressure regulator after the MBC to prevent any more boost to push the wastegate open after the MBC has been overcome....because all the way up to 5.6K the boost is perfect and I want to continue using the MBC...


thoughts?

Let me get this straight, your boost control issues change with ambient air temp, right? Mine is doing a similar thing but i'm boosting fine when cold but as underhood temps rise and my spring heats up i'm back to stock WG pressure presumably because the spring is getting softer as it warms up. If I adjust for my target boost when everything is as hot as its going to get, I hit overboost in the morning when everything is cold.

I have reported this to Rick as being racist. Thanks for a link to an overpriced MBC that will not do me any good.

That was my issue with EBC only. I was hoping that when I went to this mbc/ebc combo I could bleed boost with my solenoid and since the MBC was the main controller, it wouldn't be effected by the temperature change. It doesn't seem to be the case, so when I bleed off boost, it's still temperature dependent how much I bleed off.

So I guess i really just need to port my wastegate more, because now that i think about it I don't think a regulator will work, because I need the wastegate to open more with higher revs, not keep it at the same level.

Keep in mind I've only had it installed a day, so i might need to play with it more, but right now I see a perfectly flat 12.5psi from 3800-5600RPM. In the morning, at 5600RPM it would rise to 14psi, with my solenoid bleeding from 100% to 65% Duty cycle. When I drove home and it was around 82* out, I made 12.5psi till 5600, and then it dropped down to 11psi at redline with the same solenoid settings. So it seems it's still effected by temps...

Did you try locking the EBC at 100% and tuning the MBC? I had some boost creep wierdness, even with the EBC at 0% until I tuned the MBC, then it was fine.

It's cockpit adjustable. You're going to have problems with creep when temperatures change; the ease of adjustment on this one is why I suggested it.

yeah. Here's how I have it setup, this morning it was pretty much perfect.

http://boostedmiata.com/MS/duty_targets_mbc.jpg

deliverator, that wont help me, I'm not going to sit there twiddling a knob once i starting overboosting due to creep....

If anything I'll go back to just the EBC, Once I tuned for summer afternoons, it will be perfect until the weather gets cold again where I'll have to lower the numbers in the table a little. I've run this thing for 2 years now, I never remember it being so bad due to temps, but i dont really boost all the much driving to and from work.