My personal car was one that gained almost 40 HP just by holding more boost at redline with a 3 port. Yes I had to lower timing, still makes more power.

As far as changing boost with air temp with the MBC, if ecu controlled boost is tuned correctly it will always be spot on in any temp.

 

PROs of ECU controlled boost:
Part throttle TPS boost reduction to avoid full boost at part throttle
RPM based boost control to allow you to increase boost as VE falls off to keep torque constant (works great for low octane setups with adaquate turbo size)
Gear based boost control for traction limited setup

PROs of MBC or very simple EBC:
Consistent and easy to setup
Great boost response with minimal effort
Turbo will self limit on EBP



MBCs are VERY consistent if you use the UICP for your boost reference. The problem with this though is that if you have an internal wastegate, you'll often get boost spiking from the time delay caused by the airflow in the LICP and intercooler.

 

subscribed! was actually looking into getting a Perrin EBCS over my Forge UNOS MBC. not fully convinced yet. great thread guys!

 

It's good to see some evo owners looking in to this controller. My next upgrade will be the ams-500. Built in map sensor, compatible with c02, and applies target pressure to the top of the gate. I can't wait to try it out!

 

I went with a GM 3-port/4-bar omni setup, and am very happy with it. Regardless of the pros/cons, I did want to say that the reason I didn't get a Mellon tune was because I heard he didn't do ECU based tuning. Apparently he has, so I might consider him for my next. While I definitely understand a tuner will have preferences and I would expect him to make recommendations, at the end of the day, my setup is what I wanted and what is right for me.

 

im a fan of the turbo XS dual stage. there is alot of talk about them not working well, droping boost at high rpm, boost spikes,ect..... i found it only has that problem when you plumb the reference into the turbo (lower ic pipe). connected to the intake manifold 90% of the issues goes away. after that its all in tuning the ball & spring and bleeder together. i get nice boost curves at fairly high boost levels (35psi). PLUS i trigger my second bleeder valve with my AEM ecu to raise the boost after 1st gear. things i like about this MBC.........

1- fast spool!
2- still has 2 boost settings
3-easy to adjust (knob)
4- old skool mechinical. it just works!

 

A MBC can eliminate taper just as well as ECU boost. You just have to "tune" your WGA.

 

But are you willing to pay for it? A Mellon e-Tune is $350. Let's say it takes three times the tuner's effort/time to do an email tune that includes ECU boost control. Are you willing to pay $1,050 for that tune?

One of the many reasons I prefer the MBC is that it greatly simplifies the tuning process thereby making email tuning even more highly desirable.

 

With ecu boost control you can keep torque in check and increase boost up top to make more HP. This can come in handy for guys running stock rods, or an sst transmission.

 

No I wouldn't be willing to pay $1050 for a tune from anybody for my car. Paying a little extra is not out of the question but that is just insane. There are plenty of other tuners who tune with ecu based boost control, and they all seem to manage to do it in a timely fashion and make money without charging $1k.

I understand mellons preference for a mbc. I just think if he were able/willing to tune both(for a reasonable price), his business would be open to more customers.

Sorry for getting off topic.

 

I can see the benefits of all of the different systems ... here is a brief explanation of how I see it, which coincides with much of what has already been said.

For the "common," daily driven In/Ex/Tu Evo, I'd say an MBC is a great choice. It's simply and inexpensive. A good controller (like the Hallman) holds boost well and doesn't taper badly. Like Mellon said, it's easy to adjust if needed.

Once you start to talk about specific disciplines, then the benefits of ECU controlled boost begin to show.

I generally shy away from tuning the stock solenoid. I've done it on my car and a few others in the past, but with the price of the Ingersol Rand being basically nothing, I generally suggest that option. The stock solenoid is a bit laggy and requires modification to the lines, which is just a hassle for install and tuning.

But, once you switch to the 3-port, you have amazing control over the boost response and curve. You can put the boost on heavy and early for more TQ, for say an autocrosser, or shift the boost curve to the right a little for heat management for a track/drag car. As mentioned, with the new Tephra mods you can also run gear-based control, which is helpful for fine tuning response for many disciplines.

As for a solenoid holding boost better than an MBC, those gains are minimal. For one, an MBC has dynamic response by nature (assuming it's a ball/spring style). When boost pressure drops, the spring essentially increases duty cycle of the controller by closing the bypass. So, it works the same, but with a linear response curve based on the spring rate. For someone that wants/needs more control over the response curve, ECU control is a better option, but doesn't necessarily make more power ... it just gives you the extra control.

But, basically, I don't push hard for ECU controlled boost for customers unless they simply need more out of their setup, or if they are running map switching. ECU control can be a pain, but it can be a great tool when used correctly and not just for "pizzaz" or whatever. I've actually talked people out of ECU control before because the just wanted it for no reason.

 

I have to agree with most of the points here than boost control really is dependent on application more than anything.

I made the switch to 3 port because I do multiple fuels e85 and regular pump and I needed a safety switch to disable high boost when I'm not using the good fuel. The 3 port provided me an excellent solution to that as well as other certain failsafe's for dialing back boost when it gets too high.

As for tuning the boost curve I think one of the easier ways is to simply let the computer do it. Set your desired boost curve and use a boost error control map to let the computer adjust it to the right spot. Combine that with a WGDC map which should be close but not spot on maybe even a little too much boost for example and you can just follow the WDC path the log takes and apply it to the next tune. Within 3 trials you should be spot on.

 

This is the part that many people miss. The MBC really does have infinitely variable proportional control built into it's mechanism. I feel like the poor little spring is sorely misunderstood!!

 

Oh, the MBC is a quite wonderful design. It's just limited by air density variations and lack of boost curve manipulation. Those are the only two big differences between it and EBC. You can even get electronically switchable dual MBC's so the EBC can't win that argument either. Some guys made some GREAT points in here on the benefits of both systems.

 

I was quite impressed with how well the ball and spring MBC performed on Jeff Denmeads Evo8 at Pikes Peak.
This unit, as sold by Road Race Engineering, was still holding 19-20 psi at the top - 14110 feet. Good unit there for big altitude change applications.