FAQ - ECU Controlled Boost

[TouringBubble]

Controlling boost with the ECU is a great option for many Evo owners. ECU controlled boost allows for very specific control of boost levels and also allows automatic switching of boost levels if you have multiple ECU maps.

I hate myself for doing this, but I'm going to list the ECU boost setups in "stages."

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Stage 1

Stock boost control solenoid
Modified wastegate "pill"
Modified ECU ROM

Pros
Cost
ease of install

Cons
slow response
a little more difficult to tune due to slow response

The stage 1 setup is very simple. You use the stock system, but replace the "pill" in the wastegate vacuum line with a custom one with a smaller orifice. This allows for the stock system to hold more boost than stock, but still responds somewhat slowly.

Stage 2

3-port boost control solenoid (Perrin, GM, Ingersol Rand, or similar)
Modified ECU ROM

Pros
More precise control
Faster Response

Cons
none specifically. Middle of the road.

The stage 2 setup allows for more precise control and faster response time from the solenoid. This setup retains the stock ROM's "load-based" boost targets. Load is based on the MAF/temp/baro reading, so when these change, boost changes as well. This setup replaces the stock solenoid.

Stage 3

3-port boost control solenoid (Perrin, GM, Ingersol Rand, or similar)
MAP sensor (JDM/Evo X 3 bar, OMNI 3/4 bar, or similar)
Modified ECU ROM

Pros
More precise control
Faster Response
No variation in boost level with different temps
PSI-based boost targets

Cons
Cost

This is by far the best setup for the Evo. Once dialed in, you will have rock-solid boost levels in all conditions, save for drastic barometric pressure changes. The cost is the only drawback. The solenoid runs from $30 to $120 and the MAP sensor is $60 - $130 or so.

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All of these setups will work with Tephra's mods for map switching and boost control, and all are better than the stock setup which has a low max boost level and delayed response time.

I've personally run all 3 setups on my car, so please ask if you have questions.

[VIIIrs]

this is exactly what i was looking for.....thanks for your time man

[VIIIrs]

my only question is what is a "pill"

[TouringBubble]

A vacuum "pill" is just like a nitrous "pill." It's a small piece of metal/plastic in the vacuum line that limits the flow to a certain amount. You want to limit the flow further to increase boost, so you replace this with a smaller "pill." You can make a "pill" for the stock system with a small piece of aluminum rod and a drill with a tiny bit.

[blkonblk2red]

already have the jdm sensor ordered :) loved it on the last car... just waiting for injectors :) and e85 switch :-D

[VIIIrs]

A vacuum "pill" is just like a nitrous "pill." It's a small piece of metal/plastic in the vacuum line that limits the flow to a certain amount. You want to limit the flow further to increase boost, so you replace this with a smaller "pill." You can make a "pill" for the stock system with a small piece of aluminum rod and a drill with a tiny bit.

gotcha boss man....so it's kinda like a non adjustable boost controller...unless u take it out and redrill it

[VIIIrs]

has anyone had problems with the omnipower map sensor not fitting properly?

[mike@sargentpower]

A vacuum "pill" is just like a nitrous "pill." It's a small piece of metal/plastic in the vacuum line that limits the flow to a certain amount. You want to limit the flow further to increase boost, so you replace this with a smaller "pill." You can make a "pill" for the stock system with a small piece of aluminum rod and a drill with a tiny bit.

Or just replace the boost controller with another and say #$%@ the pill. Seriously, why mess with this nonsense. The GM boost controller is much better than most stock (interrupt style) for CHEAP! I am sure you could adapt it to the evos.

[TouringBubble]

Or just replace the boost controller with another and say #$%@ the pill. Seriously, why mess with this nonsense. The GM boost controller is much better than most stock (interrupt style) for CHEAP! I am sure you could adapt it to the evos.

Yes, as noted in the write up, you can use the GM solenoid, but you have to solder in a resistor. Not difficult. I generally recommend the Ingersol Rand option as it requires no resistor and is much sturdier, and only about $10 more after buying the vacuum nipples for it.

The modification of the stock system via pill isn't the best option, but it works fine. It's the least expensive way to get the control and boost levels you want from the system.

VIII, i have not heard of issues with fitment on the OMNI sensors. I've not used them personally, but tuned a few. No one has specifically complained to me about fitment.

[VIIIrs]

ok thanks cuz i bought the grimmspeed and omni 3bar

[mike@sargentpower]

Grimspeed is also an interrupt style. But you will HAVE to tune for it. The WGDC go way down with these over bleed style controllers.

[TouringBubble]

Yes. Any modification to the system listed above must be performed with a flash or you'll see massive overboost.

[Apex i ITR]

So Matt when you and I talked about this before you didn't seem like you were too keen on me getting rid of my boost controller to do ECU controlled boost, is that still your stance? I was thinking of going this way because honestly my boost controller is way too fancy fancy for me and I think after selling it used and going with stage/option 3 ECU controlled boost I'll still have some cash left over.

[Evolvedgti]

I am even thinking about this. Last night, while cruising with Joe in Columbus I hit it in fifth and hit 35.5 psi. i'm tuned for 30psi. The weather is too cold. Off course I hit over boost.

Side question for anyone. if I am tuned for 30psi in third, and every gear has a higher load(high bost) how does that work so I dont hit overboost. I assume by the definitions in this thread, that ecu controlled boost is the way to go for the weather corrections.

[TouringBubble]

Hurell, your EBC is a good controller, and there was just no reason to spend the extra money for ECU controlled boost. The EBC you have works in almost the same way, just not through the computer. Switching to ECU controlled boost would only really benefit you by automatically switching boost levels rather than having to switch boost levels on the EBC.

Evolved, you don't really hit higher load values in each gear. 1st and second spike and fall off quickly, but 3-5 (or 6) hold the same load for the most part. Load is a calculation of airflow, and the turbo can't flow more air just because you're in a higher gear. Spikes and spool time do change, but not airflow.

ECU controlled boost and Tephra V7 can help with your issue. With V7 you can tune different boost targets based on your gear, which can help with overboost on spool up or spikes. Otherwise, ECU boost with the psi target (stage 3) automatically corrects for pressure/temp changes as it uses psia (boost + atmosphere) as the boost target, and psia changes with temp and elevation. You can't really get tuned in Denver and try to run in Miami (much higher baro pressure), but it will keep the boost on point in most every other situation.

[Evolvedgti]

Thanks for the explanation. I was road tuned in Memphis which isnt too far from here. I am now home able to drive the thing, so its getting boosted more. so I should still try to spike the 30psi in 3rd? Joe explained to me, that since I was in Fifth at around 4krpm that could have been the cause of the over boost condition.

[TouringBubble]

Yeah, the boost limit table is RPM based, so if you are holding more boost at higher RPM for some reason (really cold in 5th) then you could trigger the limiter. Also, there is a timer on the limiter that allows you to overboost for X milliseconds before triggering the limiter. In 5th, RPMs will climb slower, so you might be overboosting in 3rd and 4th too, but not for long enough to trigger the limter.

I hope that makes sense.

[Evolvedgti]

TB, by saying
" This is by far the best setup for the Evo. Once dialed in, you will have rock-solid boost levels in all conditions, save for drastic barometric pressure changes. "

are you referring to say going from here to colorado ( elevation changes)?

[VIIIrs]

yeah that's exactly what he's sayin...

[TouringBubble]

Yes, exactly. The boost level is based on PSIA (absolute, including atmosphere) and not PSIG (gauge). This means when barometric pressure changes, so does your boost. Since most people don't travel thousands of feet vertically on a regular basis, this is acceptable. A MBC/EBC will do the same thing as it has no baro reference for compensation either, only manifold pressure which is technically PSIA as well.

[Evolvedgti]

Thanks!

[VIIIrs]

Bam!!

[Evolvedgti]

BAM back at cha! ;)