MBC users thoughts?

[jxs1984]

used to have ebc (hks evc v) for 3 years and after switching to a mbc i definitely noticed a quicker boost response

[awd2gen]

MBC ftw. ebc doesnt respond as well, cost more, and usually cant hold as high of a peak boost as a mbc.

[Evoryder]

3 port > mbc = holding boost / spool
mbc > 3 port = Tuning

I had a 3 port which did spool quicker on the butt dyno and logs also. It held about 2psi more than my mbc.
The reason I am back to my FORGE mbc is due to inconsistencies, my particular rom with the ecu would freeze settings and not correct or change maps. Also Tuning was a pain in the arse with load, but i got it where i wanted. I am willing to the give the 3 port ebc another try, this time with direct boost control.

[Evo_Kid]

Ill chime in.

(just for the people who dont know, I am the one who wrote the HOW-TO on controlling boost with the stock solenoid and upgraded pill. And I also wrote the HOW-TO on the GM 3 port solenoid.)

I have been back and forth between a MBC and ECU boost (load based and PSI based). There is pros and cons to each one.

MBC
PROS - super easy setup, very consistent, easily adjustable for the end user (ie if they need to lower boost)

CONS - boost curve is not customizable, may taper to much (theres tricks to fix that though). Also MBC is not as stealth as stock solenoid/3 port (Mostly only a care to CA evo owners)

ECU boost
PROS - customizable boost curve, can basically eliminate taper, stealthness, techness (some people like tech stuff ie electronics)

CONS - takes more time to set-up, some people (a good amount) get inconsistencies due to incorrect tuning, hard to adjust for the end user (ie if they need to lower boost)

BOTH the 3-port and the MBC will spool very quickly, as BOTH hold the wastegate closed till the desired boost (MBC this in just the way it works, and ECU control boost can be tuned to do it)


I think something some people over look when deciding between a MBC or ECU boost is future plans/goals.

If your gonna add more mods all the time, then a MBC might be better, since you will not have to take the time to retune the boost tables every time you add mods. (may have to adjust MBC but that takes 3 seconds.)

But if your just gonna do a couple basic mods and stop, then you would only have to tune ECU boost once, and be done with it. This gets rid of the CON of being timing consuming to tune every time.


Also, it depends on what type of person you are.

If you are techie and like to tweak and make changes, like to have fun lil electronic gadgets, then ECU boost control may be for you.

If you just wanna set your boost, tune your car and be done with it, then a MBC might be a better route.


One lil thing I would like to add is boost isnt everything. Its only one pat of the power equation (optimal boost+optimal AFRs+optimal timing=best power). Holding a extra lb or two of boost at redline, may or may not be beneficial (depending on car, mods, condition, etc).

And last,on both the road course and the drag strip, there are fast cars running MBCs and there are fast cars running ECU boost control.

[Evo_Kid]

To everyone saying that the 3port (or ECU boost) spools faster, just check the post #28 in this thread and look at the logs.

On the 3-port vs MBC log, the 3port only has a very slight advantage in spool before 14psi, which I believe is due to going WOT with the 3port very slightly before going WOT with the MBC, in those set of logs. Even then, after 14psi, the MBC has better spool

In the stock solenoid vs MBC log, the runs look to go WOT at the same time/rpm (2601 vs 2608), with the MBC having slightly faster spool.

Also, I believe those logs were with a hallman boost control. I believe a FORGE UNOS would have slightly better boost control, with less taper (but dont wanna debate that here and now, so dont attack me.)

[sparky]

Kid: Do you like to reference off the IM/DV line or the comp discharge tube nipple when using an MBC?

[scheides]

Both have their advantages/disadvantages. Ultimately if you want to keep it simple, the MBC is the way to go. If you want to spend some time tweaking maps to get your car to hold more boost towards redline the GM BCS is the way to go. Getting it to perform consistently is the trick, and like Kracka said, it didn't work for him. I think there are enough supporting ECU mods now in tephra v7 with mrfred's direct boost control mod to make ecu-controlled boost perform just as consistent as a MBC in any gear year round. My setup has performed flawlessly all summer and through the fall season. I'll have some logs once it gets colder here in MN to support this.

HERE'S THE CATCH: some setups won't benefit to holding more boost in the upper rpm range. Kracka's car (again) is the prime example. Tweaked to hold more boost to redline, his GM BCS setup couldn't run as much timing as it could when it was setup to taper (as a MBC would) and on the dyno we saw nearly identical power on both setups. IIRC this was stock IX turbo on stock FMIC. By the time he upgraded his FMIC he was having mega inconsistency problems and kicked the GM BCS to the curb.

There's lots of factors to weigh here--we now have 93 octane and only had 92 available before, weather differences could come into play long-term, etc. If all this makes your head spin and you don't want to deal with it, guess what, MBC is for you

[Evo_Kid]

Originally Posted by sparky

Kid: Do you like to reference off the IM/DV line or the comp discharge tube nipple when using an MBC?

I always use the turbo/j-pipe for boost signal when hooking up a MBC, EBC or any form of ECU boost control.

[MOREPSiTEHBETT4]

use both in conjunction ftw

[sparky]

Originally Posted by scheides

Both have their advantages/disadvantages. Ultimately if you want to keep it simple, the MBC is the way to go. If you want to spend some time tweaking maps to get your car to hold more boost towards redline the GM BCS is the way to go.... I think there are enough supporting ECU mods now in tephra v7 with mrfred's direct boost control mod to make ecu-controlled boost perform just as consistent as a MBC in any gear year round. My setup has performed flawlessly all summer and through the fall season.

HERE'S THE CATCH: some setups won't benefit to holding more boost in the upper rpm range. Kracka's car (again) is the prime example. Tweaked to hold more boost to redline, his GM BCS setup couldn't run as much timing as it could when it was setup to taper (as a MBC would)...There's lots of factors to weigh here--we now have 93 octane and only had 92 available before, weather differences could come into play long-term, etc. If all this makes your head spin and you don't want to deal with it, guess what, MBC is for you

Good post Scheides! Like you, I agree that ECU-controlled boost would probably be more consistent than an MBC across all the gears.

[PlanoEvo]

Originally Posted by sparky

Good post Scheides! Like you, I agree that ECU-controlled boost would probably be more consistent than an MBC across all the gears.

Close but no cigar....he said with the tephra changes the ECU-controlled could be as consistent as a mbc year round

[sparky]

I have never tried ECU-controlled boost myself and admittedly know nothing about it. I was hoping that in 1st and 2nd gears it might allow better boost control than my El Cheapo MBC seems to.

I use an MBC but experience no taper/creep issues. I set boost in 5th. I think that the way it is currently setup I am probably not reaching peakboost in 1st and 2nd gears.

I was thinking that with ECU-controlled boost, or an EBC I could see better boost control in 1st and 2nd. Probably it is just wishful thinking on my part though.

[scheides]

If you aren't seeing the same performance in 1st and 2nd gear as you are in higher gears, your MBC is suspect. It will be slightly different due to the nature of 1st gear being a bit laggy in general (just not enough time to build boost!) but in this case, yea, you can crank up the WGDC in first gear and get earlier spool (or later, or progressive to reduce wheelspin...whatever you want!). Then again you can just set your MBC in a lower gear and probably see similar results.

[up]

Personally, I think it depends on whatever your tuner prefers. I switched from an MBC to a 3 port when I switched tuners.. makes everything easier that way imo.

[nightwalker]

I was one of the first Evo's to be tuned on a GM 3 port in Norcal. My 3 port failed on me while I was climbing up the Sierra Nevada mountains. That was at 40,000 miles. Maybe it was the unusual loads and high altitude, but I lost boost control. That made the drive horrible. Then it came back on when I went down into sea level.

After the 30 psi spike scare, I bought a Hallman and have never looked back. 144,000 miles now and still boosting strong!