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Discussion Starter · #1 ·
I remember someone mentioned VCM may damage torque converter. Somehow I can't find the link. Could anyone enlighten me how VCM can harm torque converter?

Also, "with" VCM disabler, TC will not lockup due to artificial lower temperature. If TC doesn't lockup, higher transmission temperature will reduce the life of transmission. So, disabling VCM may actually do more harm than good? I'm so confused o_O o_O o_O
 

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Disabling the VCM made this TSB unnecessary for me.
 

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VCM disabling device work by tricking the ECU into believing a lower operating temperature. The VCM will not activate at this lower temperature. Thus, no TC issues.
 

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Discussion Starter · #4 ·
Disabling the VCM made this TSB unnecessary for me.
VCM disabling device work by tricking the ECU into believing a lower operating temperature. The VCM will not activate at this lower temperature. Thus, no TC issues.
Yes, that I understand. VCM disabler makes the ECU think temp is lower (so VCM won't engage). Without VCM disabler, how does VCM damage TC?
 

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Yes, that I understand. VCM disabler makes the ECU think temp is lower (so VCM won't engage). Without VCM disabler, how does VCM damage TC?
When coasting, cruise control on, or just maintaining a steady speed, the VCM deactivates 3 cylinders. This creates tremendous vibrations, causing the Torque Converter Clutch Lock issue.
 
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Discussion Starter · #6 ·
When coasting, cruise control on, or just maintaining a steady speed, the VCM deactivates 3 cylinders. This creates tremendous vibrations, causing the Torque Converter Clutch Lock issue.
I see. ACM can't fully counter vibration of 3 cylinders. This vibration damages TC. Correct?

Another questions here. With S-VCM, ECU thinks temp is lower. If ECU sees temp is low, TC will not lockup. If TC doesn't lockup, transmission will be running at higher temperature. High temp shorten the life of transmission. So, S-VCM has the potential to harm transmission? Am I correct?
 

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I see. ACM can't fully counter vibration of 3 cylinders. This vibration damages TC. Correct?
The engine mounts may prevent you from feeling the vibrations, but that's not going to prevent the vibrations from the engine from traveling into the transmission. The TSB I posted comes with a software update that effects how the transmission operates under this condition.
Another questions here. With S-VCM, ECU thinks temp is lower. If ECU sees temp is low, TC will not lockup. If TC doesn't lockup, transmission will be running at higher temperature. High temp shorten the life of transmission. So, S-VCM has the potential to harm transmission? Am I correct?
I'm unaware of any harmful effect that S-VCM or any other VCM disabling device could possibly cause to the transmission. It's saving mine.
My torque converter clutch lock issue is no more, and nor do I have any transmission temp issues after S-VCM installation.
I don't believe the lower temp the ECU reads has any effect as you have described in your question.
 

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Discussion Starter · #8 ·
The engine mounts may prevent you from feeling the vibrations, but that's not going to prevent the vibrations from the engine from traveling into the transmission. The TSB I posted comes with a software update that effects how the transmission operates under this condition.
Got it. Thank you. I didn't know the active engine mount doesn't mute the vibration from engine to transmission.
 

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I see. ACM can't fully counter vibration of 3 cylinders. This vibration damages TC. Correct?

Another questions here. With S-VCM, ECU thinks temp is lower. If ECU sees temp is low, TC will not lockup. If TC doesn't lockup, transmission will be running at higher temperature. High temp shorten the life of transmission. So, S-VCM has the potential to harm transmission? Am I correct?
Actually when the VCM is active, the torque converter slips a bit more to dampen the vibrations in the driveline. This causes extra wear on the torque converter clutch and causes the fluid to break down faster, especially the OEM non synthetic DW1 fluid. The SVCM temp signal to the PCM is not low enough to prevent the transmission from going into overdrive and TC lockup. The end result is less stress on your transmission.
 

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The engine mounts may prevent you from feeling the vibrations, but that's not going to prevent the vibrations from the engine from traveling into the transmission.
I guess the question is: do newer versions of VCM deactivate all cylinders randomly when it makes sense to do so in the firing order to minimize stress and vibration or does it still deactivate the same cylinders every time? I'd feel better about it if the system "shared the love" evenly with all cylinders with regard to oil pumping and minimized vibration naturally by jumping around randomly in the firing order in a logical manner.
 

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I guess the question is: do newer versions of VCM deactivate all cylinders randomly when it makes sense to do so in the firing order to minimize stress and vibration or does it still deactivate the same cylinders every time? I'd feel better about it if the system "shared the love" evenly with all cylinders with regard to oil pumping and minimized vibration naturally by jumping around randomly in the firing order in a logical manner.
It's not shared equally, nor would it make me feel better if it did. Even if just 1 cylinder isn't firing, it causes vibration. The VCM on 3rd gen Pilots turns your V6 into an I3.
 

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I don't believe the lower temp the ECU reads has any effect as you have described in your question.
I don't know how much a VCM muzzler cheats the ECU, but it can't be much. 5% maybe. Any more than this and the ECU (PCM) will think there's a problem with the thermostat and that the engine is "cold too long" which affects emissions and fuel economy. The ECU expects an engine to reach full target temperature within a certain time period no matter how cold the ambient outside temp is.

Whatever temperature value these muzzlers are feeding the ECU, it must be within the error window of the ECU and it ignores it. TECHNICALLY, if you are BS-ing your ECU into believing that your engine is colder, you are using more fuel, but only a little and the benefits of muzzling probably way outweigh this.
 
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Just get the svcm. Don’t make it complicated, lol. All kidding aside I feel smoother shifts throughout. I’ve got a factory transmission cooler waiting to go in. Just been lazy putting it in. I also did one drain and fill with Amsoil SS atf. Currently at 20K. Probably do another one soon.
 

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I don't know how much a VCM muzzler cheats the ECU, but it can't be much. 5% maybe. Any more than this and the ECU (PCM) will think there's a problem with the thermostat and that the engine is "cold too long" which affects emissions and fuel economy. The ECU expects an engine to reach full target temperature within a certain time period no matter how cold the ambient outside temp is.

Whatever temperature value these muzzlers are feeding the ECU, it must be within the error window of the ECU and it ignores it. TECHNICALLY, if you are BS-ing your ECU into believing that your engine is colder, you are using more fuel, but only a little and the benefits of muzzling probably way outweigh this.
I had similar concerns prior to biting the bullet and installing a S-VCM. That was several months ago and all I can say now is that I should have done it sooner as the car now runs like it should and the 1mpg that I lost is worth all the benefits.
 

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I had similar concerns prior to biting the bullet and installing a S-VCM.
Thanks for the recomendaion. I like how easily reversible this is in case a person's vehicle comes into contact with a dealer while under warranty.
 

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Discussion Starter · #16 ·
It's not shared equally, nor would it make me feel better if it did. Even if just 1 cylinder isn't firing, it causes vibration. The VCM on 3rd gen Pilots turns your V6 into an I3.
My concern is the "tilted" I-3. Sorry, I'm not sure the technical terms. My understanding is that a regular I-3 is placed perpendicular to the ground. All the vibration / shaking is simply up and down. Assuming Pilot's V6 is 60 degree. When turning to I-3, these active 3 cylinders (on the same bank) are 30 degree off center and makes the shaking less manageable (more damaging to mounts).
 

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My concern is the "tilted" I-3. Sorry, I'm not sure the technical terms. My understanding is that a regular I-3 is placed perpendicular to the ground. All the vibration / shaking is simply up and down. Assuming Pilot's V6 is 60 degree. When turning to I-3, these active 3 cylinders (on the same bank) are 30 degree off center and makes the shaking less manageable (more damaging to mounts).
VCM on the 3rd gen deactivates bank1 and as a result you have an out of balance 3cyl firing only bank2 cylinders 456. The intake and exhaust valves remain closed on the deactivated cylinders and the fuel injectors shut off fuel but the sparkplugs continue to fire. I am thinking that having the valves closed, is what causes the excessive engine braking and harsh downshifts when coasting.
 

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My concern is the "tilted" I-3. Sorry, I'm not sure the technical terms. My understanding is that a regular I-3 is placed perpendicular to the ground. All the vibration / shaking is simply up and down. Assuming Pilot's V6 is 60 degree. When turning to I-3, these active 3 cylinders (on the same bank) are 30 degree off center and makes the shaking less manageable (more damaging to mounts).
The orientation of the cylinders doesn't really affect the mounts in the way you're looking at this.

All the moving hardware and their respective masses are "balanced" as a system all the time, whether VCM is engaged or not. The pistons in the cylinders that aren't firing are still moving up and down, so dynamically, the engine is in equilibrium. The imbalance is created by an inharmonic series of explosive forces, when some of the cylinders are not firing. Try dancing to music when every third beat and then every fifth beat and then two beats in a row are randomly removed from the song. Even though your arms and legs were still there and moving, you'd probably lose your balance and fall over because your muscles moving to the irregular beat are pushing your whole body in an inharmonic way causing imbalance, a.k.a. vibration to an engine.

Lockup of the torque converter is delayed or prevented due to VCM by design. it is done purposely by the onboard computer to help mask the irregular torque pulses due the inharmonic firing order from reaching the transmission and damaging it, albiet not always successfully. The mounts aren't designed to protect the transmission, but to mask the VCM caused engine pulses from the car inhabitants so they aren't screaming, "Oh my aching hemorhoids!"

So, despite the engineering attempts to mitigate the problems VCM creates for the car and its inhabitants, the obvious solution is to eliminate VCM, not mitigate its effects with expensive to replace sacrificial lambs.

So far, no one here that I'm aware of has declared any damage to their engines, transmissions, mounts or hemorrhoids caused by VCM disablers. Most people have testified to much smoother ride, better deceleration and engine braking and a clearing up of certain bottom end medical conditions.

Hope this helps ease your concerns. Sorry to the techies for taking so much poetic license in the over simplified explanations and bad analogies. I've removed all sense of reality for clarity.
 

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I remember someone mentioned VCM may damage torque converter. Somehow I can't find the link. Could anyone enlighten me how VCM can harm torque converter?

Also, "with" VCM disabler, TC will not lockup due to artificial lower temperature. If TC doesn't lockup, higher transmission temperature will reduce the life of transmission. So, disabling VCM may actually do more harm than good? I'm so confused o_O o_O o_O
Are you having any problems you think are related to VCM? I can’t detect VCM operation on my Pilot. I don’t think VCM operation is going to damage the TC. Not sure why disabling VCM would fix a TC problem. The TC routinely unlocks and locks independent of VCM operation based on engine load. I don’t know what effect these devices have on TC lockup operation. Most people don’t have any problems related to VCM. If you‘re not having any problems don’t worry about it.
 

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I remember someone mentioned VCM may damage torque converter. Somehow I can't find the link. Could anyone enlighten me how VCM can harm torque converter?
VCM allows the TC to slip in order to buffer the transmission from the engine. That creates heat and breaks down the ATF sooner.

Also, "with" VCM disabler, TC will not lockup due to artificial lower temperature. If TC doesn't lockup, higher transmission temperature will reduce the life of transmission. So, disabling VCM may actually do more harm than good? I'm so confused o_O o_O o_O
The engine coolant temperature and the transmission fluid temperature are two different things. The VCM disablers only deal with ECT1 sensor which signals the ECU to keep VCM disabled until normal engine operating temperature is reached. ECT1 has little to no effect on the fuel air ratio. That job is primarily handled by the computer and inputs from the throttle position sensor, the mass airflow sensor and the oxygen sensors. The TC is prevented from locking up until the transmission fluid, not the engine coolant, has reached a certain temperature. The VCM disablers have no effect on what the transmission fluid temperature sensor is telling the transmission module as far as TC lockup is concerned.
 
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