I've been experiencing fluctuating boost after having installed my mbc, and i'd like to know how other people have installed theirs. I believe the write-up in the how-to section to be inaccurate, but no one responded to my post there.

So, where did you put the mbc, and did you disable your electronic boost controllers. If so, how did you disable them, and have you experienced any issues with CEL/SEL/Gimp modes.

 

I feel your pain. Doesn't seem to be too many knowledge being shared about the correct hookup of the mbc.
Heres my experience with my x so far:

first attempt, disconnected all the stock vac lines and just installed boost controller. works but CEL light remains on.

2nd try, t-ed in the original vac line from the stock valve and then installed the mbc after it. kinda worked but flucuated boost like you mentioned. so scrap that.

so I just unpluged mine for now, if you don't mind the CEL unplug the stock boost controllers. If you can find another boost source for it you may eliminate the CEL


hopefully the community can come up with a computer fix soon!

later,
kevin

 

I would call AMS and see how they hooked there's up. It something they recommend when you install there cold air intake. They should be able to help greatly.
-Dave

 

I installed mine and left the OEM one in place too, it made the boost curve even flatter than with the MBC by itself and does not trip the CEL (specially in Fith gear with high load and low RPM, so if anyone wants to know how I did it send me a PM.

 

What do you have on your X to produce 332whp?

 

When you say that you left the stock solenoids in place, but still used the MBC how does that work? Did you install the MBC between the wastegate and the T fitting that connects to the compressor housing and then leads back to the intake?

 

I installed my AEM tru boost without any problems. Just put it between the tubo outlet pipe and the wastegate and kept the hose from the intake pipe hooked up to oem boost solenoid. No CELs and peaks to 23.5 psi and is around 18.5 to 19 at redline.

 

Yes, but the MBC needs to be spring loaded like the Hallman's, and adjust the tension so that it starts to open later in the boost curve, that way it will make the boost curve flatter and have no peaks or problem in high gears with high load and low RPM.

 

I am free to share how I set up the MBC because I did it, but the mods that let the car handle more boost and lean the mixture are not mine, and I am not free to disclose it, this mods wont be needed once the ECU can be adjusted directly... Thanks againg to Colo and Javier Monroig...

 

Carrito, how would you adjust the mbc to open later? Almost all MBCs use a spring and ball design, and depending on how hard you crank down the spring it will open at a certain psi. So the problem is that there's no way to make the MBC stay mostly closed during peak boost and open up later in the rpm range when the boost pressure is less, they don't work like that.

If the MBC connected that way achieves those results than I am not sure if it's because of why you think it is. It is more likely that the factory mapping of the ecu runs higher wastegate duty cycle mapping at higher rpms to better maintain boost pressure (which is strange considering how the boost tapers so much in the X) and that it's limiting the amount of pressure that's being sent to the wastegate or in this case, your MBC.

This would make the most sense, but what's strange is that the boost tapers more with the factory solenoids on their own than when disconnected and a MBC is run independently. I know that you are running some kind of fuel controller or piggyback of some kind based on your comments earlier (it wasn't hard to figure out from what you said), and I almost wonder if that is having some interaction with the solenoids, altering how they are working in conjunction with the MBC.

I would like to try this MBC setup that you are using but I want to first understand how and why it is doing what it seems to be doing when connected like this. Can you explain in more detail, or if anyone else has ever tried this before can youcomment on this? Thanks.

 

OK, here we go.
Here is what you are going to remove:

It attaches in three places. The wastegate actuator, the boost source on the turbo, and the circled red part below.


Here is where it was located. This is under the positive plastic + terminal for battery jumping. You want the front set of hose that is closer to the front of the car, NOT the firewall side. The white circle is the line you want to pull. I just have it resting there for this pic. Its the same line you see in the pic above. You want to remove this and set it someplace safe.

The red circle is where it gets pulled from. Make sure you close off this line with a cap and a zip tie.



Here is the MBC. In this case, a Hallman PRO RX. Since you already capped off the line at the top, run the lines from the boost controller directly to the wastegate actuator line and boost source on the turbo from the 3 way hose you removed.


Here's the turbo and where the lines go. You can't see much in this pic. The one to the right of the brass colored water line from the turbo is the line from the MBC to the wastegate actuator.



Here's the difference in boost taper from stock and MBC. Red and green are stock boost, blue is MBC. As you can see, the peak value is nearly the same. This turned out to be a little much in higher gears, so I would recommend setting the MBC to about 21-22psi at peak boost in third.




I hope this is helpful. The person who owns this car has driven it 2000 miles with the MBC in this configuration with never throwing a code.

 

Fortunately for everyone, EcuTeK will hit the USA this coming week! I expect to see otherwise stock Evos well over 300whp on a Dynojet with just a tune.

 

 

Ok i have had much more success with a new setup:

I removed the boost pressure hose from where it attaches to the wastegate, plugged that into my mbc, and then plugged the mbc to the wastegate.

Since i didn't want to remove the electronic boost controllers, i disconnected the white-striped hose where it attaches to the intake, and plugged it (and the intake) with screws. This configuration leaves the electronic boost controllers hooked up and reading signals, but it does not allow them to adjust the boost since the hose is plugged.

I'm now peaking at 23psi in 3rd gear, and getting 17+ psi at redline. NO fluctuations at all so far.

 

There's no reason to cap off the intake portion of the solenoid. That will have no effect on anything. I would hook that back up so that the intake lines are providing suction pressure to the solenoids like they are supposed to. Either way, be it this way (which is almost identical to the way carrito has his) or noizes way (the more traditional way) is fine.