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-   -   Do I need a MBC? (https://www.miataturbo.net/diy-turbo-discussion-14/do-i-need-mbc-30221/)

IcantDo55 01-12-2009 04:35 PM

Do I need a MBC?
 
I got the new turbo in and it included a WG actuator that can hold 14PSI. I know the EBC would have benifits but I'm was using a MBC. Is there a point to put on the MBC on the car when the WG actuator itself can hold the 14 PSI I want?

Braineack 01-12-2009 04:37 PM

even set to 14psi, you'll see better spool with a MBC inline.

18psi 01-12-2009 05:06 PM

WAY better spool lol....
on wga you will see the 14psi whenever the turbo feels like it, with an mbc set to 14psi you will see 14psi AS SOON as the turbo can possibly make that.

Stein 01-12-2009 05:14 PM


Originally Posted by 18psi (Post 352505)
WAY better spool lol....
on wga you will see the 14psi whenever the turbo feels like it, with an mbc set to 14psi you will see 14psi AS SOON as the turbo can possibly make that.

Same hold true for my (planned) 8PSI or is it less critical? I was thinking still critical. Even if the WG starts creeping open even 2-3 psi early, that is 25-40% of my total pressure.

18psi 01-12-2009 05:21 PM


Originally Posted by Stein (Post 352508)
Same hold true for my (planned) 8PSI or is it less critical? I was thinking still critical. Even if the WG starts creeping open even 2-3 psi early, that is 25-40% of my total pressure.

you are absolutely right....that is why I will be running my hallman es mbc even on the measly 8psi that I am planning to run as well:)

IcantDo55 01-12-2009 05:29 PM

Ok answer accepted. Thanks!

Now why? If the MBC only restricts the flow to the actuator what would be the difference? I understand the EBC can hold flow until desired boost is reached and then let go but the MBC is just a spring, won't that just bleed a little more and more like like the actuator?

Another Q, when I use the MBC what do I adjust the actuator rod to? Leave it where it was from the factory or make it tighter or looser?

Braineack 01-12-2009 05:38 PM

the MBC limits any boost from entering the wastegate actuator. Any boost, be it say 5psi as the turbo builds, will slowly cause the actuator to push the rod out and open the wastegate. A 14psi wastegate actuator means 14psi peak boost. Since the MBC uses a ball and spring, you can severely limit the flow of boost entering the actuator can. Then it's like the turbo doesn't "think" it's making any boost and the wastegate stays shut during spool. Once the preload of the MBC spring is achieved, then and only then will boost enter the can at a full set amount...14psi in your case.

Since you're holding the wastegate closed longer, it will spool faster; no exhaust is being diverted around the turbine and directly into the exhaust.

The tighter the rod the faster the spool, it may increase the lowest boost possible if it prevent the wastegate from opening enough to bleed enough exhaust around the turbine to maintain a specific boost level.

patsmx5 01-12-2009 05:45 PM

MBC helped my spool. MBC FTW.

18psi 01-12-2009 05:51 PM


Originally Posted by Braineack (Post 352522)
the MBC limits any boost from entering the wastegate actuator. Any boost be it say 5psi as the turbo build will slowl cause the actuator to push the rod out and open the wastegate. a 14psi wastegate actuator means 14psi peak boost. Since the MBC uses a ball and spring, you can severely limit the flow of boost entering the actuator can. There it's like the turbo doesn't "think" it's making any boost and the wastegate stays shut during spool. Once the preload of the MBC spring is achieved, then and only then will boost enter the can at a full set amount...14psi in your case.

Since you're holding the wastegate closed longer, it will spool faster; no exhaust is being diverted around the turbine and directly into the exhaust.

The tighter the rod the faster the spool, it may increase the lowest boost possible if it prevent the wastegate from opening enough to bleed enough exhaust around the turbine to maintain a specific boost level.

couldnt have worded it better if I tried;)

Originally Posted by IcantDo55 (Post 352518)
Ok answer accepted. Thanks!

Now why? If the MBC only restricts the flow to the actuator what would be the difference? I understand the EBC can hold flow until desired boost is reached and then let go but the MBC is just a spring, won't that just bleed a little more and more like like the actuator?

Another Q, when I use the MBC what do I adjust the actuator rod to? Leave it where it was from the factory or make it tighter or looser?

Be very careful when adjusting the mbc. they are touchy little fuckers. you want to have it loose, or set as low as possible, and start from there. after a while you get the hang of it and can guestimate how many turns = how many psi increase.

Braineack 01-12-2009 06:04 PM


Originally Posted by 18psi (Post 352531)
couldnt have worded it better if I tried;)


yes, it could of had better grammar.

SloS13 01-12-2009 09:10 PM


Originally Posted by Braineack (Post 352539)
yes, it could of had better grammar.

could have had :):fawk::giggle:

miatamania 01-12-2009 09:19 PM

This is good to know.

Mike, how does yours feel? I haven't posted videos/response because I've been fighting with MS/Injectors for the past few days. 10:1 + Boost = bog and spitting :(

hustler 01-12-2009 09:54 PM


Originally Posted by SloS13 (Post 352601)
could have had :):fawk::giggle:

passive voice ftl.

IcantDo55 01-13-2009 03:05 AM

Tough to say so far. With out MBC the WG gives me a SOLID 10 PSI but I was running 14 on the old setup. I have not got a change to tune it yet but I have been watching the WB closely and it seems to only be a point higher. Leanest I have seen it so far is 10.9 After some data loging and makeing sure I don't kill it I will up the boost, maybe tomorrow.


Originally Posted by miatamania (Post 352607)
This is good to know.

Mike, how does yours feel? I haven't posted videos/response because I've been fighting with MS/Injectors for the past few days. 10:1 + Boost = bog and spitting :(


Savington 01-13-2009 03:19 AM

FAR better spool. After I pulled my clogged cat and ported the WG I had to retune my EBC map and I messed up the scales at first, and the car felt AWFUL. I seriously thought it was broken. Adjusted the scale so the EBC was actually on at 20% throttle at 3000rpm, and it was back to normal.

Hell, I would run the MS EBC. Run it at the max DC you can before it starts to affect the boost. It will make a big difference in response.

Braineack 01-13-2009 09:03 AM


Originally Posted by SloS13 (Post 352601)
could have had :):fawk::giggle:

see. i fail. I have yet to learn the correct usage of have vs of. I blame my ADHD.

luiml73 04-20-2010 03:39 PM

If I add the Hallman Mbc to my car and leave it at the same 8lbs I'm running now without it, will I still need to retune the Link ecu since it will spool faster?

Braineack 04-20-2010 04:16 PM

possibly/probably

hustler 04-20-2010 04:18 PM

I wonder if an MBC would make my TiAL MV-S function better?


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