flounder

Picked up another piece of the puzzle today. I love how it says 'high performance' on it

Is everyone on here tapping into the cold side now?

curly

iTrader: (25)

Junk it.

https://www.miataturbo.net/diy-turbo-discussion-14/ebay-cockpit-mbc-review-55177/

18psi

iTrader: (76)

yup that thing is a piece of ****.
get the nxs one. proven to work.

flounder

Damnit. lol

I was trying to figure out what the tee was for. Can't I just use the controller by itself between the turbo and actuator?

curly

iTrader: (25)

It won't be very finite. There's no spring and ball in there, it's just a bleeder valve. It might end up being "all of it" and wastegate pressure with one click.

Fireindc

iTrader: (13)

I had the SAME mbc at one point. DOES. NOT. WORK.

Pen2_the_penguin

iTrader: (4)

Thats because you guys used their non-intelligent instructions... ignore them all.

This is what I did and it works great.

wittyworks

iTrader: (6)

That makes no sense. In that picture nothing is restricting flow to the wastegate.

Nevermind I see that it is basically a bleed valve in that system. Does that work well for you?

Pen2_the_penguin

iTrader: (4)

The "bleeding" makes a "boost leak" for the wastegate. Say the average wastegate is set at 7psi. When usual stock turbos come with a vacuum line direct from the compressor housing to the wastegate, the car either receives boost sag or not the correct boost pressure since the wastegate is opening at compressor pressure and not manifold pressure. Well this is like that in reverse. "The leak" makes the turbo put out more psi to fill the loss of pressure to bleed out in order to open the wastegate. When the boost controller is closed as tight as possible, the wastegate will open at the stock psi, but when you turn it a couple of clicks, it gradually opens to the outside atmosphere for those that dont know.

yes, it works pretty good, its not accurate to measure by, but for my t25 it is one click for 1-3psi increase.

edit: it takes 4 clicks to raise MY pressure from 8psi to 11psi,

curly

iTrader: (25)

Never tried it with a check valve. Works as Pen said. Normal ball and spring MBC work by adjusting the stiffness of the spring. These work by adjusting the amount of air going to the ball and spring.

Pen2_the_penguin

iTrader: (4)

I just did the check valve so the potential vacuum leak doesnt become an idling issue, thats all.

flounder

Now we're getting somewhere! I'll be installing it later tonight per the penguins wonderful artwork and will post my results.

Wish me luck, i'm goin in!

flounder

Ok, installed like pens diagram.

I have a 7psi actuator and I loosened it to basically just enough to keep the wg closed with slight pull. With two clicks from minimum setting I spiked to almost 13 psi but I quickly got off the gas. I pulled over and turned it down a click. This time I spiked to 10psi but it dropped down to 8 psi within a second and a half and stayed there. I was seeing 8 psi before the install.

Once again I stopped and turned it down one more click (off basically) and this time it peaked at 7 psi but quickly tapered off to 4-5 psi which I figure is what I had the actuator set to.

Here is a screen shot of the last run with it on the lowest setting.

flounder

/\This was with the boost line run off the turbo. I may try tapping the cold side tb pipe as Joe Perez suggests to stop the drop off but before I installed the mbc, I had no problem with drop off at all using just the actuator.

Is this just the nature of bleed off mbc's or what? I'm kinda pissed because the ebay ad said this was a ball and spring type mbc. Whatever, it was $15 delivered.

Edit-I think I just figured it out. Originally, I had to wind up the actuator after the IC install to hit my target of 8 psi due to the drop off from the new IC. I'm now experiencing the same thing with the mbc since it's attached to the same compressor nipple.

So...If I take Joes advice and run my hose post IC I can maintain 10psi with the mbc out one click yes?

Pen2_the_penguin

iTrader: (4)

Yeah, I would run the mbc from a source after the IC. I never ran mine off the turbo, it is too raw of boost to run the mbc on, and causes what you just experienced.

To get the best idea on how your mbc is built, (if you're not afraid of china germs) stick your mouth on the input nipple on the mbc and start blowing. While blowing, start turning the ****; this will give you the best idea on how that china pos works.

Pen2_the_penguin

iTrader: (4)

DO NOT USE THEIR T FITTING!


Thats the part where they get to claim its a ball w/ spring... it will also cause boost spikes.

curly

iTrader: (25)

When I opened my t-fitting, the spring was so long that it completely compressed the ball, and wouldn't let ANY boost by. By trimming the spring down, I was able to manually blow on ball side and I could hear it bouncing between the other side and the bleed port. I found that if I couldn't manually blow the ball around with my mouth, the car couldn't move it either and it'd just spike above 15psi, with my goal to be around 12.

+1 for changing to a directly pre-throttle body boost source.

flounder

@curly- So do you suggest I do the same with my T?

kenzo42

iTrader: (6)

=)

flounder

manually!