Proof of concept: MBC + 3port BCS Hybrid

[scheides]

Caveat: I'm sure I'm not the first to ever try this. Full credit for this idea goes to Shane@DB Performance; he is always a bad influence :D

Theory: more boost = more power

Stock turbos taper. Aftermarket turbos taper. How do you try and cut down taper? A BCS seems to do the trick! However, they can be a tish inconsistent, and boost onset is not always as smooth or as early as a MBC. I tried the stock solenoids and they didn't work. So instead, I got a Pierburg 3-port BCS from CBRD (thanks chad! adapter fits PERFECT), ditched my stock solenoids, and mounted this on their little mount.

http://i.imgur.com/P8zbol.jpg

Here's JUST a MBC vs a MBC+Stock solenoid hybrid on my BBX. I tried both before the MBC and after it with pretty similar results. Maybe 1psi extra boost up top.
http://scheides.com/misc/pics/evox/evoX-mbc-vs-hybrid-boost-control.JPG


Now the 3-port. It is inline with the MBC, between the MBC outlet and the WGA, with the 3rd port 'venting' back to the intake. I'm only using 50% WGDC at 8000rpm so yea, there is some room to grow with this setup I think!
http://scheides.com/misc/pics/evox/BBX-MBC-Pierburg_3port-hybrid--boost.JPG

Note the kinda reverse taper, almost self-induced boost creep if you will. It will hold 28 flat or 26 flat or do this 26/27 going up to 28.5 thing pretty easily. This is like the perfect setup: the ease of adjustment of a MBC with the boost holding power of a BCS up top. Tunability is fantastic. I will have to report back on how consistent it is.

I just unplugged my secondary(passive) BCS and set all the tables to zero. No CEL yet.

[Halon]

Nice flatter line.

What happens when you bump it back up to 30psi like it was in the initial comparisons?

[mlomker]

It's no mystery that it worked...the question is what is going to happen when you fiddle with the MBC?

[scheides]

Nice flatter line.

What happens when you bump it back up to 30psi like it was in the initial comparisons?

I will let you know once I get this piss gas I got in duluth out of my car. It runs like crap, I'm surprised I got these logs!

It's no mystery that it worked...the question is what is going to happen when you fiddle with the MBC?

It's kinda cool actually. The BCS really only affects the top-end, because that is where I have any WGDC applied. From 0-5000rpm there is 0%WGDC applied. So, I upped the boost from 26/27 to 28 and it went from looking like I posted here to a more flat line (but would need just a bit more WGDC tuning to get flat again, there was a small spike to 29 at 6400rpm due to a spike in WGDC from 30-50).

I imagine once I turn the boost up to 30+ I will start to see diminishing gains and if I spike to 35 I'm sure it will still ultimately taper. For anything other than absolute max effort though, I think this setup has a lot of merit. As long as my FMIC can keep up there should be some decent gains to be had from an extra pound or two of boost up top!

[Rmondoh]

Subscribing over here too! I'm interested to see where this ultimately goes. Good work there Scheides!

[turbotalon1g]

Def. interested in this, as I'm looking into using the stock solenoid for my boost control.

Good work.