Why does everyone on here keep mentioning using an MBC plus a tune? There is absolutely no reason to run an mbc if you are getting a tune. The only reason to run an mbc is if you are on a stock tune and want to make some extra power but can't afford a reflash. There are major driveability issues with MBCs though. An MBC doesn't allow the ecu to properly modulate part throttle boost via boost correction, which is why people with mbcs keep throwing P1235 codes (partial throttle overboost codes).

MBCs are junk in my opinion, but either way, you people have got ot get it out of your head that an MBC + a tune will make more power than a tune by itself. That's simply not the case. Whether the boost is raised in the ecu or by an MBC, it can only be raised to a certain level and an MBC can't magically make more boost, nor will it provide a better taper. Compressor efficiency, knock threshold, etc don't care what's controlling the boost, the limits are always the same no matter what and your engine isn't going to say, "oh, well I was knocking at 25 lbs of boost, but since you put an mbc on I'll make 30 just for you." Sorry, doesn't work that way.

 

I just installed the Forge actuator on my X and I'm having boost spike issues. I am running a stock boost controler and I have the rod adjusted just tight enough to hold the wastegate shut, no extra turns to keep it tighter.

I have the AMS mail-in flash and after getting it back I registered a peak of 25 psi on my Defi gauge. After installing the Forge unit I am seeing 27 and 28 psi around 4-5k rpm.

I had heard somone before say there is a restrictor somewhere in the vac lines between the turbo outlet>boost controler>wastegate control. Is there any truth to this and if so would this be keeping the forge unit from opening enough to get things back to 25 psi?

 

^You need to get remapped to run that forge actuator safely. Your tune from AMS is using wastegate duty cycle values that are meant for a softer sprung wastegate and you are going to get overboost issues no matter what you do at this point short of getting remapped. Not to be a jerk, but do you know anythng about tuning? Do you understand how the ecu values for WGDC control the solenoids and how those solenoids in turn control the boost?

Do you know that when boost is too high, especially when timing values are also high, that you could get a bad detonation and crack a piston or worse? I would take this off until you are ready for a re-tune, and you should really get a custom tune with your car actually on the dyno because a mail in for something like this will be purely based on guestimated values when it comes to boost control.

 

I really don't think you need to be worried about any detrimental harm to your engine at all at this point, but you don need to reevaluate what sort of secondary boost control you are using with the actuator, and the tuning as well.

The simple fact that you're aware of the overboosting issue is clearly indicative of your cautiousness about the situation, and you would only have a problem if you continued to "beat" on the car and push the engine further and further without correcting the overboosting problem. If you stop boosting as soon as you notice the issue, any concerns about doing damage are overexagerated.

With that said, the factory lines for the boost reference to the solenoid and back to the actuator do, indeed, have restrictor pills in them, and they can often times dramatically affect the pressure signal to the actuator, so I would recommend removing them and using standard line at a minimum.

Additionally, as was mentioned, the factory boost control solenoid is operating under the assumption that a lower sprung actuator is in place, so it is trying to acheive a target boost level based on a lower spring tension. Having a higher base spring, but still utilizing the same programming for the solenoid, the boost will subsequently go up.

My recommendation would be to bypass the solenoid altogether and use a standalone boost controller (either mechanical or electronic) set to a target boost level that is within a safe level for the specific tuning of your partcular car. This will give you more control over the boost your car will be making, and the ability to make adjustments based on the specific level of pre-load you have used on your actuator.

Regarding the earlier question about horsepower figures, as I have mentioned already, we have no yet done a dyno bolting this part onto a more or less stock Evo, but we are working on arranging doing just that and we hope to have the dynos available soon. The resulting power gains, however, will vary WIDELY based on which of the available base springs is built into the unit, how much preload it is adjusted to, what sort of secondary boost control is used, and what the target boost level is. The other modifications on the vehicle will greatly affect this as well.

 

Mike, I am curious as to the ic inlet temps with the stock turbo being pushed so hard. I have a hard time believing that the stock turbo can hold 30 psi for much longer than a couple hundred rpms, let alone all the way to redline. My suspicion is only further reinforced by the fact that some guy in this thread has his set to 23 psi and it's still tapering to like 16 at redline just like the stock actuator. I just don't see how there's any way that this turbo is going to be cool and efficient at anything beyond 24 psi tapering to like 18/19 at redline, so I would tend to think that you are better off running less boost and more timing to make power just from an efficiency and EGT point of view.

Please don't take this as me bashing your product, as I think that forge products are very well made and I'm sure that this wastegate actuator is no different. I'm just not sure about pushing a little turbo like this to these kind of levels. I know that from what the compressor maps of the X's turbo would have to look like that it's pushing very hot air at such high boost levels and it seems like it might be doing more harm than good. Any ic temp data with this turbo being forced to run such high boost? If I am wrong then I would be very interested in purchasing one of these! Again, I mean no disrespect in any of this, I just want proof because I've seen bad things happen from pushing a tiny turbo too hard.

 

Leave the rest out of your post, i'm just saying what the "Mitsubishi academy 2008 evo X new model technology guide" CD 1 said in the video.
You don't like it, or you not agree with it . You have a right to call them and educate them over the turbo.
I'm not thinking anything about the IX or the X. I'm stating what the factory guide say's in there.
I personally didn't take a part any turbo and didn't investigate it. Or better designed it.
But i'm sure you had a big part of it since you know it better.
Check out a video first, and then state something. They clearly saying the X turbo moves more volume of air then the IX. Also they made it to handle a big boost too. Maybe is smaller some parts of it, but they change a lots of things on it , and this is what they come up with. As i told you i f you have a video or you can watch it , the turbo section starts from the 5 minutes 10 sec, in the first CD.
It is true ? I dont know.
But the Mitsubishi corporation saying that , for sure.
And sorry , but for me the mitsubishi is more reilable source then you.
thats all about the IX and X debate.

For more education get that 3 CD and learn about the new X. It is informative for sure.
I dont know the dealer can get you though. If you need copy i can send it to you. /if you pay the shipping/

Cheers Rob

 

We are not specifically recommending to anyone to push their turbo to 30+ PSI without considering every other aspect that will aid in safely running their car at whatever boost level they so choose. We are offering a functional component that affords everyone the opportunity to set their base actuator pressure to whatever level is right for their needs. They are not pre-set from us to a specific fixed level. It is up to the user to tune them properly (safely).

We offer the units preassembled with 19-24 PSI base spring pressures because we have found this spring rate to be the most suitable to keep the wastegate flapper closed properly. Based on it's placement directly in-line with the exhaust gas flow through the exhaust housing of the turbo, a lower spring rate will still allow for some premature opening of the wastegate flapper.

We offer lower spring rates that can be built into the units at no additional cost, unless of course the purchaser wants extra springs to swap in themselves at a later date.

Green - 5-10 PSI
Yellow - 10-15 PSI
Blue - 14-18 PSI
Red - 19-24 PSI

I will always recommend that people tune our products to operate within the appropriate efficiency range of their particular application, and we don't promise that the actuators allow for running an unrealistic boost level to redline. There will always be an element of tapering present, however, our units will affect the boost curve in such a way that those undesireable effects are minimized, but they cannot be overlooked when it comes to tuning.

Fuel octane, ignition timing, meth injection, upgraded intercoolers, etc. will all play a role in making sure that potentially too much boost pressure isn't going to cause damage to someone's engine, but it is the responsibility of the user and their tuner to make the necessary decisions regarding those other important aspects.

 

edit: duplicate

 

Everything that I cited about the differences in turbo design are completely based off of undisputable evidence of tear down reports from vendors who have examined the turbo, as well as the actual specs from mitsubishi. Ask any shop that has tuned both the evo 9 and X and they'll tell you the same. You seem to feel as though I've insulted you in some way, and for that I just shake my head at you because I've done no such thing. You tell me to educate myself about the X? I've watched every training video, read every tear down report from the vendors as well as the in depth reports from tomei, and I own one. I assure you that there is nothing you know that I don't. Just look at the boost curves of the tuned stock turbo X's compared to tuned stock turbo 9s and you'll find your answer. Good day.

 

Agreed. What kind of taper characteristics does this provide on a stock turbo'd X with a reflash to help dial in the boost properly. Since the stock setup will allow for a taper of about 18psi at redline, what can we expect from the red spring, again assuming that WGDC has been optimized for the new spring. Also, can you do a test showing the ic inlet and outlet temps at these boost levels when compared to a tuned X on the stock actuator? Thanks.

 

We're still working on trying to get a mostly stock Evo X for before and after dynos. The taper characterics will vary with the settings the user adjusts their unit to, what sort of boost control is used, etc. I can't provide you with concrete figures that are based on variables beyond my control for any given car.

Beyond that, I won't get into any discussions regarding inlet temps due to the number of other factors involved.

 

Actually I use a dual MBC and it lets me run the flexibility to switch between 2 different boost levels that I set on each from inside the car. I have an ECUtek Tune now and plan on 26 PSI for the Drag strip on 100 unleaded, 24 PSI on the street, and 22 PSI for Track days for a little less wear and tear on the car. For me it just isn't very convenient to re-flash the ECU whenever I want to change the boost levels.

As for the person with the AMS tune, there is a restricter pill in the stock boost line from the turbo outlet. It has a spring clip on the outside of the line where it is and basically reduces the signal to the stock Wastegate solenoids to the range they normally need. If you need more signal to push the stronger spring on your Forge actuator, replacing that line may very well compensate enough to bring you back down to safe levels.

 

You are right that there are restrictor pills in the boost lines, but you are wrong about how they and the solenoids work. There are actually two restrictor pills, one in between the compressor side of the turbo and wastegate and one in the line that runs to the solenoid. The pill at the wastegate limits the amount of boost pressure that presses on the wastegate to prevent premature boost loss and the one near the solenoid limits how much pressure can escape out the vent port of the solenoid. But just to be clear, the solenoids are not based on "signals" from the turbo, they are based on programming from the ecu.

Also, you made the comment that the more pressure that is sent to the solenoids the better they will work since they "need more," and this will "help bring down the boost levels to more safe levels." This would achieve the complete opposite of that and cause uncontrollable boost spiking. To better understand how this works, let me explain how wastegate duty cycle tuning in the ecu works. Wastegate duty cycles tell the solenoid how long to open up the vent port, letting regulated amounts of pressure escape out of the vent port thus regulating the amount of pressure that is sent to the wastegate actuator.

When you raise WGDC by ecu tuning you are telling the solenoid to stay open for longer and thus more pressure is let out of the vent port, which means that less pressure is sent to the wastegate. When there is less pressure sent ot the wastegate it stays closed longer thus keeping exhaust gases pumping through the turbo to raise boost. What I think you were aiming for when trying to give advise to that guy who's having overboost issues is to remove the restrictor pill near the wastegate (NOT THE ONE NEAR THE SOLENOID) to allow the actuator to open easier and bring down the boost.

The problem with this is that when he's ready to get re-tuned this will need to be put back in or maintaining a good boost taper will be difficult. His best option is to just get the car re-tuned immediately or just put the stock actuator back on in the meantime. Hopefully this gives you a better understanding of how the system works.

 

Ah cool, wasn't sure if there was another pill in the lines leading up to the solenoids since I just put the stock setup on a T and had their outputs feed to each other to take them out of the loop. I'm pretty sure if you allow more boost to enter from the turbo source and leave the rest stock, that the boost will go down since it can't bleed all of that air off so the WG actuator sees a stronger signal and keeps boost lower/opens earlier. It may drop it too low if anything but swapping in a new line wouldn't be that hard, just save the one right off the turbo elbo in a safe place. You are right that the ECU just runs the solenoids to bleed off the air via duty cycles but if there is more air in the lines than it can get rid off, it will increase how much flows against the WG actuator.

Sounds like a Tune is his best bet or get a good controller if they want to change boost after the fact. Nice thing about the tune is it can remove the part throttle overboost CEL as well as fuel cut from high airflow which may not surface right away but the first cold/dense air night running at 25+ psi and you'll find that limit in a hurry!

 

Edit: nevermind.