Cylinder Deactvation

[kdaug]

I have yet to see it anything on the instrument cluster so I assume that 2018 or 2019 CX-5's have no display of any kind to indicate when the 2 outside cylinders deactivate between 40-80 km/hr. I have read on other websites that some can feel/hear the difference. Exactly what should I be looking/listening for? (drive)

 

[dougal]

There is nothing. I would be surprised if anyone feels it. It only comes on under specific driving conditions between the speeds you listed.

 

[madar]

I've driven a few with CDA. You won't notice anything.

 

[kdaug]

There is nothing. I would be surprised if anyone feels it. It only comes on under specific driving conditions between the speeds you listed.

If only I knew when I was mimicking those spscific driving conditions I would then know I was getting better gas mileage, as Mazda claims to offer under cylinder deactivation.

 

[dougal]

If only I knew when I was mimicking those spscific driving conditions I would then know I was getting better gas mileage, as Mazda claims to offer under cylinder deactivation.

So basically, they say the CD works under light engine loads at those speeds (30-50 MPH).

 

[flyingpylon]

I don't claim to be an expert on any of this, but...

My daily commute involves fairly long stretches of flat 40 mph roads and I swear I feel something occasionally. It's just a split-second blip and a barely-perceptible gap or change in the engine sound. It's more "did something just happen?" than "yep, there it is". I will totally acknowledge that I could also be imagining things.

I do suspect that I benefit from the improved gas mileage. About 1/2 of my 23-mile commute is 30-50 mph and the other 1/2 is freeway at roughly 60-70 mph. The mileage that comes up on the display when I turn the car off is typically 31-33 mpg and I've seen it as high as 34.5 mpg.

I can't say that I notice anything when the cylinders are reactivated. I have other issues with a lack of initial response under acceleration but I don't believe they are related to cylinder deactivation because it happens below 30 mph. I think it's just the way the car is designed and I would prefer it to be different.

 

[cz5gt]

seems to be based on RPMs and Torque.

 

[VQ35DE]

Interesting graph.

 

[dougal]

Interesting graph.

But what the heck is it trying to show?

 

[VQ35DE]

I agree we need more details.

 

[cz5gt]

This was the only more technical info I could find from a japanese page apart from the generic info on blogs and news pages.
Unfortunately they have not listed the torque values on the graph.
I am asuming CDA kicks in the 50-120 torque range. i.e partial engine load (steady speed, not climbing) and between the rpms referenced.
It is for the NA engine. not turbo.

They also do all kind of tech.magic to eliminate vibrations, resonance, etc during CDA on,off...there is also a resonator air box (if you look before the air filter) which plays a role too.....so I appears very hard to notice it in the real world.
There

 

[kdaug]

seems to be based on RPMs and Torque.

If it's based on RPM's and Torque as the graph suggests why do all the Mazda sites I've seen only make reference to CDA occurring between certain speed ranges? And what doe Engine Reliability and NVH have to do with this?

 

[dougal]

Also, the bottom text when translated say these are plans to make a robot version of Godzilla. Just saying...

 

[cz5gt]

トルクのつなぎ 気筒休止運転をする範囲をFig. 8 に示す。Fig. 3 の燃費特性を基に2気筒運転／4気筒運転の燃費の良い方で運転している。

Fig. 8 shows the range in which the torque is connected and the cylinder deactivation operation is performed. Based on the fuel consumption characteristics in Fig. 3, we are driving with better fuel economy for 2-cylinder operation / 4-cylinder operation

 

[cz5gt]

 

[cz5gt]

you wont see that on the marketing blogs and pages, because the usual consumer does not care. Especially the average american. As long as the car drives they dont care.

 

[kdaug]

you wont see that on the marketing blogs and pages, because the usual consumer does not care. Especially the average american. As long as the car drives they dont care.

And since all of us on this thread probably do care, I'd sure love to be able to identify the moment that CDA kicks in.

 

[Nevada CX5]

I do not feel CD activating. However when driving around with light throttle at 25mph with the automatic in 4th gear, there is a hesitation when I want to accelerate with light pedal input. The tranny needs to downshift a gear or 2 and the CD needs to disengage before the revs come up. This is frustrating and require a firm hit on the throttle to get moving. Has anybody else noticed this?

So no I do not feel activation engaging, but only in this scenario when it disengages and I need acceleration.

 

[cz5gt]

try the sport button.

 

[flyingpylon]

I do not feel CD activating. However when driving around with light throttle at 25mph with the automatic in 4th gear, there is a hesitation when I want to accelerate with light pedal input. The tranny needs to downshift a gear or 2 and the CD needs to disengage before the revs come up. This is frustrating and require a firm hit on the throttle to get moving. Has anybody else noticed this?

So no I do not feel activation engaging, but only in this scenario when it disengages and I need acceleration.

YES. This is what I mentioned in my previous post. Drives me nuts. But I don't think it's related to cylinder deactivation, I think the car is just in a gear that's too high. What I think is actually a little dangerous is that it encourages the driver to depress the accelerator too much in search of power, and then when it finally kicks in it can be sudden and way too much.

Sport mode is a partial solution, but it's too aggressive for normal driving. I used to switch between sport and normal mode when I needed it, but now I shift manually when necessary. That's fine, but I bought a car with an automatic transmission. The other thing I do is to start accelerating early, but that's not ideal either.

As I mentioned in another thread, it's like the CX-5 has a Sport mode and an Economy mode, but is missing a "Normal" mode. It's unfortunate, and one of my very few complaints about the car.