VCM Vibration
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530 Posts
Can you give a bit more description on the circumstances? I'm curious what led you to believe it's the VCM system. Thanks!
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153 Posts
I can tell when it engages, but only if the radio and a/c is off and I'm listening really hard for it. I have noticed that when it does comes on, which isn't very often, it doesn't stay on for more than 20 seconds or so before it kicks back out. One thing I've noticed that seems counterintuitive though is that the fuel economy rings turn white when VCM engages. If green means good economy and white means poor economy it doesn't make sense to me that the lights turn white when VCM engages.
I think it was Zroger who came up with an explanation for that phenomenon. When the engine drops from six cylinders to three cylinders, it has to work harder (twice as hard?) to make the same power to move the truck along. Therefore, it is using more fuel per cylinder, but less overall than six cylinders would use.
I remember an engine engineer once saying that the only real difference more cylinders gives you is more friction, and that's what makes a V8 less efficient than a V6. If friction were the same in each engine, you would probably not see an appreciable difference in fuel economy, all else being equal.
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7,342 Posts
If your true long term goal is engine longevity I recommend a VCM Muzzler. The inside name for VCM at Honda is Voluminous Consumption of Motor oil. That's why they increased the oil capacity considerably.
VCM is a PC correct issue only... not good for the vehicle or the owner, just the environment. Each has to make their decision on what's more important (and no I don't care about the save the planet debate).
I sat around and heard joke after joke about VCM. None of them good.
VCM is a PC correct issue only... not good for the vehicle or the owner, just the environment. Each has to make their decision on what's more important (and no I don't care about the save the planet debate).
I sat around and heard joke after joke about VCM. None of them good.
I will be putting in my order for the Muzzler tomorrow. My truck already sounds like a freight train when traveling around 35-45 mph.
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3,009 Posts
There's the reason for increased oil capacity.
Save the planet, save the planet, save the planet. Building & selling a truck shows saving the planet isn't priority one. I hope Honda doesn't think I'm buying that crap of goods.
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479 Posts
Joe, some time back I was on a long highway trip driving behind a new Accord V6 and I noticed that frequently it would emit quick twin puffs of smoke from the exhausts, which I believe correlated to changes in the road that might have made it shift in and out of VCM (hills, accelerating etc). Is behavior like that something that is actually known to happen with VCM, or an aberration? It would be very interesting to set up an experiment to follow behind a Gen 2 to see if similar puffs were emitted on hills etc.
The puffs it emitted were very noticeable but very quick, at highway speeds they looked like streams maybe 6" long - quick little "dashes" of smoke followed instantly by clear air. I had not seen a car do that before, and it persisted over many miles of driving on West Texas interstate.
The puffs it emitted were very noticeable but very quick, at highway speeds they looked like streams maybe 6" long - quick little "dashes" of smoke followed instantly by clear air. I had not seen a car do that before, and it persisted over many miles of driving on West Texas interstate.
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784 Posts
So for you guys who have disabled the VCM... You have a nice extra large oil capacity that you don't really need anymore.
So if you own a G2, and are using VCM muzzler, will you be willing to run that maintenance minder down to 0% oil life? I think I would be willing to push it more knowing how much larger-than-necessary the oil capacity is.
Here I'm assuming that the MM algorithm will not know about the disabled VCM, but that might be an incorrect assumption? If it does factor lack of VCM activation into it's calculation, I wonder how much more oil life you are then getting?
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My guess is that it is so you can burn a quart of oil between oil changes and suffer fewer repercussions, and possibly not even notice it. You might get some extra oil life, but i don't know how significant it would be. And given that cylinder wear and oil burning can vary significantly from vehicle to vehicle, I don't know if (or even how) the MM algorithm can take that into account. And what if you did add half a quart? Would the MM compensate? Only the algorithm engineers know the answer, and nobody's talkin'!
I postulated last summer that the extra oil capacity was mitigation for the VCM, but I don't think anybody took me seriously.
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I thought that has been an acknowledged fact for quite a while?..
I postulated last summer that the extra oil capacity was mitigation for the VCM, but I don't think anybody took me seriously.
At any rate, you're probably right about the algorithm -- we may never know for sure whether it factors VCM activation or not. But if the owners using Muzzler technology all start reporting longer oil change intervals, then we might be on to something...
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2,017 Posts
I'm glad you're back, even if it is just temporarily. I installed my muzzler months ago. Just how much fuel savings does VCM provide anyway? I don't really notice much of a mileage difference in everyday driving with or without VCM. I also see lots of torn down Pilot motors in the Honda service departments. I think the muzzler is a wise investment. When you have "free-wheeling" pistons operating with no combustion, the rings will become clogged with oil no matter what new design Honda says they have implemented. Maybe the Trump Administration will trash the CAFE standards along with many other disasters forced upon the public in the name of Gaia worship.
VCM is a perfect example of a business decision made by Honda vs. an engineering quality decision. VCM is designed to give Honda that little extra MPG so they can avoid paying CAFE penalties to the tune of millions of dollars here is the US. A purely engineering decision would be to avoid adding complexity where not required - and VCM is NOT required from an engineering perspective or engine performance perspective. Additionally, Honda over-engineered the engine mounts as they are now active engine mounts to dampen the vibration when running on 3 cylinders - just something else to wear and replace.
Personally, nothing good can come from shutting down 3 of 6 cylinders, plus the extra control software and hardware is something extra to wear, break or exhibit an "unforeseen" problem. I bought a 6 Cylinder; therefore, I want a 6 cylinder.
I think if you do the research you'll find that NOTHING mechanically has changed with VCM since the original design other than some tweaks in the code that controls when it kicks on or off. Of course Honda will tell you it's the best thing since sliced bread but only because it helps them to avoid paying penalties for missing MPG goals - pure business.......
Personally, nothing good can come from shutting down 3 of 6 cylinders, plus the extra control software and hardware is something extra to wear, break or exhibit an "unforeseen" problem. I bought a 6 Cylinder; therefore, I want a 6 cylinder.
I think if you do the research you'll find that NOTHING mechanically has changed with VCM since the original design other than some tweaks in the code that controls when it kicks on or off. Of course Honda will tell you it's the best thing since sliced bread but only because it helps them to avoid paying penalties for missing MPG goals - pure business.......
I just removed the VCMuzzler II when I took the RL in for the safety recall (thankfully Procedure A). I left if off for a while as I've had it on since 1000 miles on the odometer (now at 5100). Without the VCMuzzler on a longer trip on the highway you can definitely feel when the cylinders are shut down - as I'm cruising at 70 or 75 I can feel a subtle vibration for a short period of time - almost like a wheel is out of balance (which I know is not the case), then I think the active engine mounts dampen the vibration and all feels normal. I do get 1 to 1.5 MPG better without the VCMuzzler BUT, since I bought a 6 cylinder engine I want a 6 cylinder engine - it's back on now.
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If you are talking about the VCM and the Pilot lawsuit, there were some mechanical changes made for the Earth Dreams V6. I've been trying to find a source post in Honda news and views back when the 9th generation Accord came out. There were apparently some new type of ring or ring coating and some piston coating or something like that as well as going to a 6-3 setup. Compared to the Accord VCM is a non event in the RL for me. In the Accord I can feel it more in the cold but the torque converter locking and unlocking is what I feel the most at speeds below 45. There is definitely black smoke when I floor it, I can see it in the mirror but never have noticed a decrease of oil on the stick. In the RL, maybe a slight buzz in the gas pedal which I think is torque converter related but it's pretty much non existent. Hopefully, it stays that way. Long term who knows but I suspect that in a beast like the RL, it's not going to activated for very long. I had an 08 Odyssey non VCM LX model and the MPG's compared to the RL are about 20 vs 23. I'd rather not have it though. It seems like oil is a big part of VCM operation so I'm less inclined to run the MM down to 15%. I'm a lower mileage driver so I usually change between 5 and 6k if that happens before the year is up.
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