michiganevox

I recently had EVO X MR tuned by a well known shop in the mid-west. He insisted that he get more power if I used his manual boost controller instead of the OEM solenoids. So I went for it. He set the controller for 25 psi and did a few pulls to tune the car. The car is definitely much more responsive; especially, in the low to mid rpm band. I only slight mods ( K&N cone intake and modified OEM muffle like Works sells but I did it myself). I am happy with the gains in power but have a couple of issues.

First, I believe the sport mode for the SST no longer works properly when in auto mode. After accelerating from a stop it will not up shift. Cruising with very little throttle at 45-50 mph it is still in 3rd gear. I don’t’ use sport mode much but I don’t recall it holding the high rpm at stead cruise. Can someone tell me if this is normal for a MR in sports mode? The tuner disconnected all vacuum lines from both solenoids. They just vent to atmosphere. I have read that the SST references the solenoids but I am not sure about this fact and what impact it would have on the SST function.

Second, during regular daily driving there is an annoying stumble at about 2000-2200 rpm when the SST shift into 4th or 5th gear after reach 40-50 and lifting off the throttle to maintain a constant speed. There is a weird choking or oscillation of the intake air and there is a brief loss of power when depressing the throttle. Does anyone have an idea as to what is going on? I want to contact the tuner about the issue but I would like to have a little knowledge about the potential problem/solution before I talk to him. This particular tuner was less than friendly when I brought my car to them for the tune.

jackygor

iTrader: (9)

take off the MBC and bring it to a tuner that is knowledgeable enough to tune your car. With a tune like this, it could potentially shorten the life span of your tranny. I would argue that the only reason your tuner advise you to use MBC is because he sucks.

kozmic27

MR's really hate manual boost controllers. It is possible to make the car tolerate it, but it honestly is more trouble than ECU controlled boost. Put a 3 port on the car, and tell your tuner to set the target loads high (this does not mean max them all out), and use the WGDC as if it were a manual boost controller to limit boost. This way if he can't figure out how to do load based boost, at least the car will tolerate it and work properly. Sort of.....

fostytou

iTrader: (15)

If the lines are all VTA at the solenoid (disconnected from the solenoid but still into the intake) then you could be leaking unmetered air which could contribute to some of the poor running. That would be strange for the tuner to do that.

MBC are much easier to "tune", however it may have just been a cost/time consideration for the tuner. With the MR it is good to limit the peak torque so you don't ruin the trans.

michiganevox

This is not the case. I cut and plugged the vacum line to the intake. The car runs great except for the stumble at 2000-2200 rpm. It does not occur under acceleration. It is a daily drive issue. It only happens when at partial ( low) throttle. Typically, when reaching the speed limit around town and when up shifting into 4 th or 5th gear at 2000-2200 rpm. I will contact the tuner about this issue soon but I am not optimistic about him doing anything for me based on his past behavior.


People are saying the MR don't like MBCs but nobody is supplying any real technical information as to why this is the case. My boost curve is smooth with no spike. It builds to 24.5 psi at about 3800rpm and tapers smoothly to about 16.5 psi at redline. What is the advantage of the 3 port solenoid for my car? It is not modified much; just muffler and intake.

Robevo RS

iTrader: (16)

do yourself a favor and for your Tranny. Get tuned with the Ecu controlled boost. Even if you pay attention on th eboost gauge and so , you still can miss one cold day in the future, and the SST wont tolerate that mistake well in a long run. The X controlls much better as i know the boost then the earlier evos, so the MBC is absolutely no neccesery. Fact is more of the problem then a solution .

Rob