I think it's almost universally accepted that in theory, a computer controlled boost control solenoid has the potential to be a far superior solution than a simplistic manual controlled bleeder valve (aka MBC) in terms of boost control.

A computer controlled BCS can:

- learn to control initial boost spike
- hold more boost to redline by increasing solenoid duty cycle as RPMs increase to meet desired boost targets
- hold the same boost in all gears (assuming enough load) instead of creeping higher in the higher gears (which makes it harder to set desired peak boost in all gears)
- adjust to changing atmospheric and load conditions
- implement failsafe mechanisms to lower boost depending on certain conditions

However, in most factory boost control systems, the key limiting factor I believe is the stock boost control solenoid and it's ability to bypass enough air to achieve the higher boost targets.

Which leads to my question.

Have any open-minded tuners out there tried to use any of the aftermarket boost control solenoids in conjunction with the stock ECU and a flash (EcuTek or Techtom or whatever) or other EMS (AEM, UTEC, etc.) for a superior boost control solution then the beloved MBC?

I think I saw a post from Dave Buschur about using a GM solenoid and AEM in which he was thrilled with the performance? I'm also thinking about the Prodrive or Perrin units.

 

From what I have seen the stock ecu even with one of the solenoids isn't as good as a mbc or a ebc, I could be wrong though

 

The thing is, the stock ECU as well as AEM, UTEC, XEDE, etc. etc. are EBCs as one of their designed functions, right? The only difference with the common EBCs (AVCR, EVC, Profec, etc.) is that they only perform boost control (plus some other stuff I guess, but not engine control) and they all come with replacement boost control solenoids! Which leads me to believe that the better BCS is the critical piece.

 

OK, I was finally able to find DBs post regarding using an aftermarket BCS (NOT GM I guess) with EMS controlled boost.

Obviously, I have the highest respect for Mr. Buschur, so I think his thoughts are worth contemplating here:

link to thread

and I quote:

 

I believe that was a GM solenoid that was used.

 

I believe that the Works P2 and at least some of the Ecutek flashes do NOT require a separate mbc/ebc. They simply replace the stock boost control solenoid for a jdm-like (think it's actually from Japan honestly) host that do NOT contain the pill.

I know I had the P2 with the upgraded hose and it held boost like a bandit - no fading whatsover, and no need to trick out the ecu to push 22psi in order to have 19psi at redln. I believe the Ecutek has similar results -- I'll know in a few months after I'm tuned!

A word of warning; don't replace that stock boost line if you don't have something aftermarket controlling boost - you'll see upwards of 30psi pretty fast since there's no pill to stop it.

Dunno if that answers your question or helps.

 

The works P2 comes with a new hose with larger restrictor pill (mainly to save you the hassel of removing replacing the pill inside the tube).

Most of the MBC only types eventually come over...

The stock boost solenoid is as JDM as the rest of the Evo. Does Works physically replace the solenoid now?

Malibu Jack has a lot of great posts about replacing the stock Evo solenoid with a GM model. I have also heard of people using the greddy solenoid without the rest of the EBC.

 

Thanks guys. Yeah, I didn't think Works replaced the solenoid, just the vacuum lines ...

The problem there is that you're still running at the very limit of the duty cycle of the stock solenoid I believe. And when you're at or near 100% duty cycle, I don't think the solenoid works as well as it does in it's normal operating range, and you also can't raise boost as high as you might want. Hence the need for the modified solenoid for best performance, giving you more headroom with respect to the duty cycle.

A few reasons for my post:

1. I've been very frustrated with the MBCs I've used on my car and disappointed in the performance as compared to my previous car with EcuTek controlled boost. This may be a unique experience for me, but I've seen plenty of posts on here with people complaining about some aspect of MBC performance.

2. I really wanted to hear from people/tuners that have tried other boost control solenoids and could report their experience.

3. There seems to be this prevailing overbearing attitude that MBCs are the greatest thing ever and the only way to go. They are certainly cheap and mostly effective, but are crude and have many limitations, as mentioned in my first post. I guess a lot of folks here come from the DSM world for many years back, and the MBC was always the device of choice I guess. Similar to the whole 20G thing Not that they are bad or don't work, just that there are better solutions out there. I was trying to get people thinking about those better solutions ...