Ebay in-cockpit MBC review
 

Figured I'd share my experience with this product, to better inform/warn any future purchasers.

I knew I'd adjust my boost level and leave it, although being able to turn down the boost to wastegate pressure sounded like a nice feature. There wasn't really any packaging, just the parts in a padded envelope. It included the in-cockpit valve, t-junction, ~3' of vacuum line, 3 little worm clamps, and two screws/mounting plates. Total came to $12.99. Not sure why there's two mounting plates, you only need one. I didn't get that large bundle of vacuum line, only the little piece.
http://a71.ac-images.myspacecdn.com/...8e50cdc026.jpg

For starters, it didn't come with any instructions, so along with some helpful forum instructions (below) and using Turbosmart's instructions, I managed to get it hooked up in what I thought was the correct orientation. Go ahead and ignore the arrows that supposedly point towards the wastegate, they were incorrect for me.
http://forums.nicoclub.com/generic-e...t-t346138.html
I couldn't figure out the mounting plate at first, but then I realized you have to poke the screw through the sticker.

This resulted in hitting my 14psi boost limiter, and any configuration of the t-valve wasn't helping. Eventually I took the t-valve apart and did some measuring. Between the ball, spring, and very shallow hose barb, The spring was completely compressed and acting as a spacer, stopping the ball from moving at all. Cutting the spring down to the below length allowed me to adjust between 9psi (wastegate pressure) with the valve all the way closed, and 12psi. The next click would hit my 14psi boost limiter.
http://i228.photobucket.com/albums/e...1/a0f8230d.jpg
That spring started about being about .5" long. I cut it down to the three coils shown, then stretched it out a bit. I'm going to play with it some more, including drilling out the hose barb to allow more spring travel, but I'm fairly certain I'm going to follow everyone's precautions and go with a simple engine bay mounted ball and spring device. Now if only I can find a cheap one that isn't Lightning Blue or Crimson Red.

I have used many ebay boost controllers and have had good luck. I am not shore about the whole t-valve I have always just used the adjustable valve by itself and it seems to work fine. I hope you have better luck with it.

I had great luck with my FM valve, it was just annoying to unhook the vacuum line and use two big wrenches to adjust. I just bought a ebay MBC with a finger knob. $9.45 shipped.

i have the turbosmart one in my festiva but i have it closed due to the stock computer cant handle anything past 9psi. i have yet to test mine so i hope i dont need to modify my spring either

Hopefully the real one is much better.

14 psi with the valve all the way "loose"?

With the little spring pictured above, and the valve screwed all the way in, it runs off the waste gate, 9psi. If I unscrew the valve to the first click, it's a little under 12psi. one more click makes it hit my 14psi limiter, no idea how high it actually is.

Which version?

Does the length of the vacuum line make any significant difference in spool/boost? I like the idea of an in-cabin MBC.

Supposedly it does. Problem is this MBC is a bleeder valve type, not a true ball and spring. The benefit of a true ball and spring design is that it keeps most of the pressure from going to the wastegate until the target boost pressure is reached. This helps spool, since the wastegate isn't slowly opening the entire time you're trying to hit your target boost. AKA: better spool.

This bleeder valve type lets pressure by constantly. All you're doing is bleeding the appropriate amount of air out before it hits the T-valve. That's also the problem of the T-valve, is that you're trying to "float" the ball between pressure and the spring.

With the valve all the way closed, it takes 9psi (just my setup, yours may differ) for the boost pressure to push the ball away from the spring, go around, and open the wastegate. So assuming there's some crazy 1:1 ratio in this thing, the first click of the valve is letting 3psi VTA before going around the ball, and the next one would supposedly hit 15psi (another 3psi VTA), but instead hits my boost limit of 14.

So you need to find a weak enough spring in the T-valve so your wastegate pressure alone opens it. I found this was about the same time I could manually blow the ball around with my mouth. AKA, I can give a 9psi blow job.

It's all a little complicated to think about and especially write done, so forgive me for any mistakes.

Edit: I realized I never related all this to my original point: I'm used to the superior ball and spring design. So yes, the spool is worse. How much of that is due to the extended vacuum line, who knows. Although the path is technically still very short, I'm only bleeding some off half way to the wastegate.

This one:
http://cgi.ebay.com/ebaymotors/High-...95530301218916

I've been running the turbo smart version for about 6 years or so. no issues with anything. my waste gate actuator is a 4 pounder off of a saab. so I can back it down to 4 and then every click is worth about .5lb of boost. spool is noticeably quicker even at 4 lbs than just running off the can. 4th gear wtfo pull from 2000rpm will show 10lbs by 2500rpm and 14lbs(max) by 3k. very little overshoot if none at all. the higher you turn it up the more it overshoots, but it's very minimal (maybe) 1lb at the most. makes it real easy to tune in your boost cells. I tune full throttle boost one click at a time until I reach full boost. any way; long story short, been using it for a long time and couldn't be happier with it.

I know it's kinda pricy, but Hallman has it "the right way" where the actual boost controller sits in the engine bay and the remote portion is a cable that runs into the cabin to adjust load on the MBC. The shorter your signal lines are the better...longer reduces precision. Running vacuum lines into the cabin is "meh" at best.

http://www.boostcontroller.com/products/evoredbig.jpg


I tried one of those Turbosmart or XSTurbo MBCs once and boost was about as predictable as a paper plane in a hurricane.

No offense, but the mbc you bought is garbage, I've thrown a couple of those away. If you want a ball and spring design that is dirt cheap, I've had good luck with these- http://cgi.ebay.com/ebaymotors/High-...Q5fAccessories

edit: just saw that you already linked to this controller, so I guess this is just a +1 vote for it

Yeah, it's installed and needs to be tuned now. The new one that is.

Dopple, I thought about using that wilwood cable that splittime integrated into his brake bias adjuster. Cheap, and this new eBay mbc has a big enough thread size on the adjustment bolt, it just might work.