motlagh

What are your thoughts on the re-introduction of VCM in this model? Apparently VCM was the cause of eventual spark plug fouling and engine mount problems in some prior Honda V6 models. I haven't seen this discussed much, but if I read the press correctly, it seems like one of Acura's goals with the Type S was to re-introduce a V6 with VCM. Any thoughts or experiences here? One observation I have is that there is some disagreement on whether the car experiences turbo lag, especially when not in sport mode (I didn't feel it in my test drive, which was admittedly mostly in sport+). Could this just be the VCM? Current owners who have had the benefit of more than a test drive, do you notice the VCM? Do you intend to muzzle the VCM? More generally, any concern on how possible VCM can combine with fouling from DI long-term? For reference, I've include Acura's discussion of VCM below. Thanks!

Variable Cylinder Management™
A primary goal of the new Type S Turbo V6 was to implement Variable Cylinder Management™ (VCM™) to improve fuel efficiency and reduce emissions. Simultaneously achieving this goal with the twin-cam, low-profile heads and turbocharged engine presented unique challenges, resulting in an all-new mechanism.

VCM™ operates the engine with three cylinders in a wide range of situations to maximize fuel efficiency and lower emissions, switching seamlessly to six-cylinder operation when more power is needed. In order to prevent pumping losses, the engine computer closes the valves on the inactive cylinders. On the SOHC 3.5-liter engine, this is accomplished by using VTEC®, which locks the rocker arms activating the valves together to prevent the valves from opening when VCM™ is active.

Due to the low-profile of the new DOHC cylinder heads, this arrangement has been replaced with a more compact rocker arm and hydraulic lash adjuster design. When all six cylinders are in use, a pin in the valve lifter assembly is held in place with oil pressure. When VCM™ is activated under light cruise and when off-boost, the engine’s Electronic Control Unit (ECU) drops the oil pressure, allowing the pin to slide out of the lifter, creating a gap that prevents the valve from opening. When the ECU determines all six cylinders are needed, the system re-pressurizes the oil, sliding the pin back in place and reactivating the valves for full power, all before the turbo can create boost.

Active Vibration Control
To maintain smooth operation when Variable Cylinder Management™ is engaged, new engine mounts and Active Vibration Control are used. Unique to the Type S Turbo V6, AVC uses sensors to detect and cancel out vibrations from the engine, and for the first time also help to cancel out vibration from the chassis as well, making use of VCM™ nearly imperceptible by the vehicle’s occupants. In addition, careful tuning of the AVC is used in the different Integrated Dynamic Modes to create a quieter or sportier engine sound.

fiatlux

I'd be curious why the car has VCM and still has worse highway MPGs than the competition.

someguy11

This is news to me if it’s true about the Type S. I’m not as tech savvy as some others here, but I can tell you that VCM can cause damage. Honda even admits it. Google “VCM misfire” for more info. The gaskets on the cylinders that deactivate have a tendency to seep and leak oil, which doesn’t get burned off (because deactivation), causing plug fouling, misfires, dash idiot light and engine rebuilds.

It doesn’t happen to all engines. There is no rhyme or reason to say which engines will experience it. The only way to guarantee it doesn’t happen is to deactivate it with a muzzler or s-vcm.

Decent concept. Terrible technology in real life. Plus it saps performance because those cylinders take time to reactivate. Like fiatlux said, if it doesn’t even save gas, why is Honda sticking with this really bad idea??

fiatlux

Well, it could save gas compared to no VCM, but the question still stands: why are the competitor's able to provide better MPGs? I suppose that's a bit of a rhetorical question, since we all know that the Type S is considerably heavier.

someguy11

True. I should have said the 1, 2, 3 or 4 mpg it saves, if it does save gas at all, isn’t worth the risk to the engine. Not to me anyway. Especially out of warranty which will crush whatever you save at the pump.

mike03a3

It's not about you saving $$$ at the pump, it's undoubtably about Honda meeting mandatory fleet fuel economy rules. The ever increasing percentage of SUVs and Trucks are making that very hard for the manufacturers.

motlagh

It's not clear to me whether the VCM is designed to primarily increase fuel economy or reduce emissions, but presumably it's both, as the press release suggests (and it's hard to see how they wouldn't be related here). I'll also highlight the parts of the news release that suggest they've made improvements to the prior VCM, but I don't know how these actually play out.

"To prevent pumping losses, the engine’s Electronic Control Unit (ECU) closes the valves on the inactive cylinders."

"To maintain smooth operation when Variable Cylinder Management™ is engaged, new engine mounts and Active Vibration Control are used. Unique to the Type S Turbo V6, AVC . . . "

ELIN

If I was in the market for a Type S, this is definitely something that would cause concern. All the folks that are banking on "Acura reliability" may have to see how this plays out.

If "heavy" is the future of Acura sedans, they may as well scrap the lineup.

jhb31

Perhaps the muzzler that was very effective on the Gen1 V6 TLX is plug and play on the type S as well? The only regret I had about it was not buying it on day 1. Difference in mpg was near nothing that I could tell and always kept it running on all cylinders. Particularly good in the less aggressive drive modes where the vcm can take out some of the cylinders and create some lag. I imagine if they didn't change the connector (which is likely) it will plug right in. Didn't generate any CEL errors either. I imagine the few people that are selling them already know if it will plug into the type S connector or not.

The stop start feature was another issue and nobody that I found was able to defeat it like on most other cars. I assume the Type S is equipped with that awful feature that can't be turned off permanently.

motlagh

I'm open to the VCM having been improved, but it seems like the TLX Type S is a first run for whatever new version Honda is introducing, which I expect we'll see in all Type S models going forward (MDX, etc.). That said, I agree, it looks pretty cheap and easy to neuter if it's just the same muzzler fix. Auto idle needs to be turned off with each start but is also automatically deactivated in Sport and Sport+ modes. The button for manual turnoff is pretty convenient too, although I get it'd be nice to have the option to turn it off always. Livable in both cases, but it is the car working against you. That's the future of cars, so it's probably barking at the wind.

motlagh

Actually, I'm not certain the muzzler would work on the Type S, since the battery is in the back.

jhb31

Battery location has no bearing on installing the muzzler. I would guess if the upper temp sensor connector is the same it would be a simple 2 to 3 minute install and easily removed it you make that choice. There is no cutting of wires or anything to connect it. Just plugs into existing connectors. I sold mine on here after I took it off when trading the car in.

Ghostof TypeS Past

What’s the solution? Sport mode? I will say my master tech buddy has about 400 piston rings he’s saved up from Odyssey, Pilot and Ridgeline..

motlagh

Thanks for the clarification. I watched a video of the muzzler install on a V6 TLX and it seemed to connect to the battery, but sounds like you've done it. Good news if it might still work.

motlagh

I couldn't tell if a drive mode would deactivate the VCM, but it'd make sense. Any chance there's something about it in the owner's manual?

leomio2.0

You can get an IdleStopper that will disable the Auto Stop/Start, but the light on the dash still appears. That was my biggest annoyance with it. Now, it's basically my start-up routine. Get in, start the engine, buckle my seat belt & turn off the auto stop/start and crash mitigation system. Thankfully, Honda/Acura make it very easy to turn the system off.

DubPK

There are hundreds of thousands of Honda's still on the road with high mileage and VCM that have had absolutely no issues but like anything it had growing pains. Honda faced a class action over VCM issues and it was a highly reported problem in the J35Z engines, in 2013 models started coming out using the J35Y engines and I don't think I've personally heard of VCM problems on those and many are easily into high mileage phases of life by now.

People still turn it off out of paranoia since you don't really lose anything but I think the tech is fine now overall. What would concern me more on the TLX is not the VCM but the first application of VCM with a turbo I believe and any 'first' is very unproven tech as demonstrated by the first cars with VCM in general.

loki

Sports car with VCM and auto start stop 😂

DubPK

I mean nearly all of them have it these days so you can't really hold it against Acura anymore than anyone else.. even the V10's in a Lambo Huracan have cylinder deactivation.

BEAR-AvHistory

Expect its to get them through the stricter Euro version of the EPA + our EPA requirements. Most likely one of the first things that gets shut off on delivery.

someguy11

Anyone reading this should be careful how you interpret it. Yes, Honda has a lot of engines (hundreds of thousands) with VCM on the road. No one except HMC knows exactly how many recall repairs they have performed for the ring/fouling/misfire, which run to the tune of $3,000, for yes, the class action lawsuit they lost. Just the fact they lost that case suggests they know of it and cannot disprove it's an extremely real problem. I've read people with as low as 30k miles to up to 120k miles throwing the misfire code for the first time. Some people have thrown the misfire code AFTER their plugs and rings have been replace, which indicate VCM going unmitigated could continue to cause this damage. I think I read something online that Honda won't cover the second ring replacement (I can't verify this with 100% certainty, so you should ask a dealership or do your own research online). I also believe HMC only extended warranty coverage for this recall for eight years (again, not positive on that), meaning these 2011-2014 do or soon will cost $3,000 out of pocket. Pick your site, DriveAccord, Piloteers, OdyClub, all sorts of people who aren't gearheads talking about this exact issue. You will be pissed off it it happens to you after you believed the downplaying you read above.

I typically agree with a lot of what you say on this forum, but this particular commentary and suggesting S-VCM, VCMuzzlers and VCMTuner exist and are installed because people are paranoid sounds stooge-y. You're right that the current gen of VCM-2 (like 2015+) is the exact same tech and haven't displayed issues, but they also haven't really reached the high mileages yet.

someguy11

PS - here's a better analogy on VCM than calling people paranoid:

Do you drive with insurance? Probably, since most of us are smart. Does driving with insurance mean you will crash? Of course not. But if you do crash, you will be glad you have insurance.

Do you drive with VCM? Probably, since most of the hundreds of thousands of owners haven't muzzled. Does driving with VCM mean you will foul and throw a misfire? Nope. But if you do throw the code, you will wish you had muzzled. It's insurance to practically guarantee you will never throw the code.

dmski

I believe VCM gets shut off once you put it in Sport mode along with the auto shut off. This was put in to meet strict emissions but as usual some have to take cheap shots at the car.

ELIN

Is VCM responsible for the turbo lag in Normal/Comfort mode?

motlagh

I suggested this in my original post, but if VCM only kicks in at cruising speeds, it doesn't really add up.

DubPK

Don't get me wrong it was an extremely real problem and I'm not suggesting it wasn't. If you have a Honda with the J35Z* series especially go turn your VCM off to preserve the car, Honda extended the warranty but did nothing to fix the issue. I do believe we have evidence now that the revisions seems like they have worked, I believe all J35Y* series engines have the newer VCM and those were first seen in the 9th gen Accords in 2013 so its my belief that enough of those have reached high mileage now that we'd know if it was still an issue.

I could absolutely 100% be wrong but just calling it as I see it I stick by my comments, they don't apply if you drive a car that absolutely had the issue like anything with a J35Z, own an 8th gen Accord? Shut it off. Own a 2021 TLX-S? I don't believe there is enough evidence to warrant turning it off for reliability reasons but if you're really paranoid.. sure.

someguy11

Fair enough, I have to agree that newer gen hasn’t really experienced the fouling issue to the same degree, or at all. 2014 and earlier, I would shut off. After, like my 2015 TLX, I shut it off preventatively. Even though the concept is the same, hopefully technology and material quality has resolved this. Signs point to yes. I guess we won’t know until we know.

Still, on the Type S, I’m not sure why they would neuter the throttle response for negligible economy gain. They would be better off cutting weight.

ELIN

We all agree on this but steel is a lot cheaper than aluminum. We have to get away from premium and look towards luxury to get that.

motlagh

If we're going to see the same engine in the SUVs, maybe they went for every gain they could get.

Legend2TL

FWIW, there's a fair amount of aluminum components in the 2G TLX (hood, fenders, front bumper, front strut mounts).

ELIN

I'm actually glad there's none in the rear bumper as someone rear-ended me a few weeks ago. The damage appeared cosmetic but their insurance paid out more than $1400 for the fix.

Legend2TL

Ouch, sorry for your misfortune.

FWIW
https://acuranews.com/en-US/releases...-tlx-press-kit

Honda does use extruded aluminum bumper beam in the current CR-V's rear bumper.
​​​​​​​I removed it and replaced with a now much heavier steel combo bumper/trailer hitch which we use for hauling bicycles.

Furnace

In older models with VCM, there would be something to identify when VCM was active. Like "Eco" or "VCM" or something. I know my '08 Accord V6 had it and my 14' Odyssey does too. I haven't noticed anything at all in my Type S. There's no mention of it in the owners manual either. Are we sure the 21' TLX has it?

motlagh

I think we can be sure it's in the Type S. It's highlighted in Acura's press releases, most recently as of the day before launch: https://acuranews.com/en-US/releases...ype-s-turbo-v6. I missed it at first, but Savagegeese also quickly mentions the cylinder deactivation in his review (just that it exists).

Furnace

Makes sense. I assume both Canada and US vehicles are equipment with it. It's weird that this feature is listed on the Acura US website but not the Acura Canada website. I was used to feeling a slight change between 3-cylinder and 6-cylinder operation. I can't tell at all on this one.

someguy11

Me too. My ‘15 TLX had no indication, just the drone when it deactivated cylinders. Our ‘12 Odyssey had an ECO light that corresponded with the drone when it deactivated, but that rarely comes on anymore (only on the hottest summer days which is expected based on how the resistor works). For some reason, Acura forewent the VCM light.

jhb31

The main reason most people on the gen 1 TLX installed the muzzler was not to increase engine life but to eliminate lag in certain situations and some for vibration when the VCM kicked in. Made a difference for me with lag and pretty widely liked on the gen 1 forums. Had the car serviced multiple times and never heard a word about it being there but possible they didn't notice as it doesn't stand out at all.

ELIN

Since your car was muzzled, does that mean it also never reached the EPA fuel econ numbers?

jhb31

I think that car was rated 21/30. I could get 22/23/24 driving around, trips were always around 29 highway. I have a few pounds of lead in my foot though. I had the car without the muzzler for over a year so I can't say it was much different before as it was about the same. The loss may have been .5-1.0 mpg but overall near nothing. . The reduction in lag was more apparent since I had the car for well over a year before getting it and there was lag in that trans.

Edward'TLS

Is the 3G MDX using the same J-series 3.5L-V6 engine ? It seems that there is zero mentioning of any engine issue in the 3G MDX forum.