Lalin

Does anyone know at what speed and/or RPM the cylinders deactivate and then reactivate?
In my RDX I cannot tell when this happens.
I am getting around 30 mpg in highway driving at 70 mph so the feature is probably working well.

emry

The control unit will monitor your driving habit and makes its own calculations. Based on the load/weight and speed it deactivates some of the cylinders to save gas.
On a steady cruise at 70 MPH in highway I get easily get 32 MPG.

Doobiewah

+1.

@emry is correct. It is not a specific speed or RPM at all. Honda/Acura programmed a matrix into the system that turns the VCM on under a variety of situations where the engine and vehicle can function well without the additional cylinders active under a lighter load. They've actually updated the original VCM system to prevent what was some excess oil burning on some earlier Pilots and the Odyssey by changing the sequence as to how it turns cylinders off and on. There is a good FAQ about VCM over at ridgelineownersclub.com and on piloteers by a poster named verbatim, who is out of Canada and created a device called a VC Muzzler to turn the VCM off for people who don't like or are wary of the technology. You can read several articles both praising VCM and excoriating it throughout the net. My personal judgement is that Honda got the re-programming right. Earlier Pilots and Odyssey's used to have a light that came on that told you when VCM was active. They have gotten rid of it on the Honda side. Can't speak for the Acura side as to whether it had that at some point or not; although, I can tell our '17 RDX does not have one.

Rolf65

2016 RDX Advance: also getting 30-31 mpg on highway but at speeds between 75 and 85 mph.

snorf

Around town I notice the VCM going off/on around 38 mph. It is consistent. I have felt it on the highway, but usually don't pay any attention to it as I'm focused on the traffic. I drive 72 mph with cruise on and only checked the mileage once. I got between 27 and 28 mpg (math done with a calculator).

BLEXV6

Funny, I have 2 second generation RDXs and never notice the VCM shutting down the cylinders or starting them back up.

snorf

My daughter-in-law has a 6 cyl accord and neither she nor her husband can feel anything. I've driven their accord and had not trouble telling when the cylinders were turning on/off.

Lalin

What do you feel/hear when the cylinders deactivate?
I don't feel any different sound or vibration at all.

snorf

It feels like a small jolt - like you might feel in a downshift, but not as strong. I've never looked at the tach to see if there's a change there, but I would assume there would be.

emry

There is indeed a jolt during the activation. It is unfortunate that Acura's engineering and quality control have not noticed it. Or may be they have noticed it but they closed their eyes.
It is literally impossible to find any vehicle that doesn't have something wrong. So be it and we just move on and try to focus on the positive sides of RDX.

Doobiewah

I can't feel the activation on either my '17 Ridgeline or on my '17 RDX. There are some on RidgelineOwnersClub who claim to be able to notice when it kicks in or out on their Ridglelines and others over at Piloteers who state the same. I don't doubt they feel it. I just don't or can't tell.

Certainly won't be an issue if the '18 or '19 redesign calls for a small high output turbo....

Comfy

I think one way to see when the cyclinders deactivate is to check the mpg on the instrument cluster. When driving you will suddenly see the instant mpg going up or down based on 3,4 or 6 cylinder modes (in 13-15 RDX).

emry

Putting back the turbo means going back to 4 cylinders again. Turbos are sensitive to oil film and if proper oil is not used then they can be damaged over time. Besides turbo by itself could go bad causing a major repair expense.
I like the idea of turboless 6-cylinders in the current gen. You have direct access to full engine power without begging for any side aid from turbo and of course no question about turbo repair expenses.

Doobiewah

I agree....when I read rumors that '17 might be the last year with the nice, smooth, powerful V6, it definitely played a part in our decision to buy. Checked out the Lexus NX with the turbo...didn't like the power delivery at all....

SkylineEX-S

That was one of the deciding factors in us buying the 17. NA V6 power and a 6sp auto. No turbos and dual clutch or CVT transmission. I least I can do some of the maintenance myself.

Jpbecker2112

2016 TLX with only 1500 miles. The VCM drove me crazy as most my driving is 35-40mph. Had to use sport+ mode but the downshift lunge was even worse than the vcm vibration. Got the vzmuzzler - wow what a difference. Recommend to all vcm enabled Honda / Acura cars

rdxottawa

Does anyone know why the RDX or honda/acura in general did away with the ECO light?

I liked knowing when I was in ECO mode or not.

colt427

I don't feel anything in both the RDX and Accord with the VCM..
I do feel a trans downshift when slowing down to around 25-30 MPH from highway speeds in the Accord.

Skidoor

Just reading thru the earlier posts in this tread, I don't understand how people can be getting 31 MPG at 70+ MPH...are these imperial gallons or US gallons ?? What grade of fuel??? I only get that kind of mileage with a good tailwind, 91 octane and the A/C needs to be off. I wish there was more context when people post their mileage.....

colt427

31?
I can get 25.

RDX-Rick

The very best I ever had in 2 years (and 99 fill-ups) was 28.8.US MPG The average of my 5 best tanks was 27.5 US MPG. These would have all been 100% highway travelling.

My worst was 15.1 US MPG, which of course was city driving in December 2015 in Ontario. The average of my 5 worst tanks was 15.7. These are all 100% city driving.

Lalin

In my case US gallons with regular gasoline. Probably with the AC on. Sometimes I get better than 31 mpg. For refence, my 2013 MDX with the same engine but no cylinder deactivation dies. To get more than 22 mpg under the same conditions.
In NYC driving, the RDX is as bad as the MDX with 11-12 mpg average.

Skidoor

well sorry to take this thread off topic...on the highway I normally go about 70-75. I watch the mileage indicator very closely and can tell when the cylinders de-activate. It's almost never ...sure, if I start to slow down or start going down a big long slope, it will happen...and if I reduce my speed to 65, it kicks in more frequently. I seriously think that in order to get 31 MPG, one would have to consistently keep speed below 65. Anyway, bottom line is, I very much enjoy getting the mileage that I do with the RDX, most of my driving is highway.

FreddyBeach

Skidoor, my mileage is online with yours. It is sometimes hard to drive at 60 - 65 mph though when everyone else is passing you at 70 -75. Although I have only 8400 miles on my 2016 Tech, I plan on doing more road trips this summer so I am going to see if I can best my 31mpg which is the most I have gotten so far. I only wish the gas tank in the RDX was just a few gallons bigger.

Doobiewah

[QUOTE=FreddyBeach;16047418 I only wish the gas tank in the RDX was just a few gallons bigger.[/QUOTE]

Agreed!