Cylinder Deactvation

It is frustrating. Knowing what I now now I do get on the gas a little earlier and firmer when I need to move.

This is my first drive by wire throttle and there seems to be a 2 stage response based upon throttle position. Light throttle pressure and economy is emphasized. To get fuller throttle and burn more gas as intended one must get past around the mid way point of the pedal and stay on it.

Around town with a somewhat more aggressive pedal acceleration is just fine especially over 30 mph, even w/o sport mode. I live at 5000 feet and the car does OK here. Going up in the Sierra Nevada Mts. does become more challenging and using the auto stick and not the cruise control is key.
 
I have found the same..but then its been same with other cars I had. like you said eco mode and sport :)
also bear in mind in that rpm range which is low there isnt much torque.
its NA engine, need to be in the power curve rpms. plus the electronic throtle also plays a role probably.
 
I infer from the chart that they don't use CDA below 1000 RPM because it will shake and make noise, not for efficiency or engine longevity reasons. They don't use it when the torque demand is over the blue line because it would be less fuel efficient than using all 4 cylinders. They don't use it above 3600 RPM because it would shorten the engine life or risk damaging the engine.

I think the guidelines about speeds and such are just a way to translate these things into something people can generally understand. It's a level of nuance that is difficult to communicate well to a broad audience.
 
I infer from the chart that they don't use CDA below 1000 RPM because it will shake and make noise, not for efficiency or engine longevity reasons. They don't use it when the torque demand is over the blue line because it would be less fuel efficient than using all 4 cylinders. They don't use it above 3600 RPM because it would shorten the engine life or risk damaging the engine.

I think the guidelines about speeds and such are just a way to translate these things into something people can generally understand. It's a level of nuance that is difficult to communicate well to a broad audience.

While I can see from the graph that there is NVH below 1000rpm it would have been an even greater engineering feat for Mazda to design this engine so that it would have 2 cylinders deactivate while idling, or maybe there isn't enough fuel saving at idle on 2 vs 4 cylinders. In addition, that "Fuel Consumption Breakeven Line" on the graph has got me stumped.
 
Last edited:
My understanding is that the throttle response is not only based on how far you depress the pedal but how fast you depress it. The computer recognizes a quick stab at the throttle versus a slow acceleration style.
 
There is supposed to be a switch behind the gas/throttle pedal. If you press too much it activates the switch.
 
My understanding is that the throttle response is not only based on how far you depress the pedal but how fast you depress it. The computer recognizes a quick stab at the throttle versus a slow acceleration style.

I wonder if we think that because the CX-5 is so quick to upshift out of first. If you don't stomp on it and keep it on the floor, it'll be in second before you can say "where'd the power go?".

Does anyone have any documentation regarding throttle response?
 
I agree that it helps to be more "assertive" with the throttle (as opposed to "aggressive"). It's been hard for me to get used to since I have been driving cars with V6 engines and 3-speed transmissions for 20+ years. Just touch the throttle and they go.
 
Last edited:
Seems to me the car does show when cylinder deactivation takes place. Just watch the MPG gauge at the top of Trip Meter A or B. It can jump to the top of the scale even though speed and grade are constant. Cruising along on a flat road at 30 mph and it suddenly goes from mid range to 80 mpg. Does that happen with cars that don't have deactivation? I also see big jumps on the gauge when going downhill but that just be gravity doing its thing.

From what I've read, this system improves economy about 20% at 25 mph and just 5% at 50 mph. Doesn't kick in at all outside of that range so mostly a green-washing gadget for commuters in big cities. Limited real-world value.
 
Seems to me the car does show when cylinder deactivation takes place. Just watch the MPG gauge at the top of Trip Meter A or B. It can jump to the top of the scale even though speed and grade are constant. Cruising along on a flat road at 30 mph and it suddenly goes from mid range to 80 mpg. Does that happen with cars that don't have deactivation? I also see big jumps on the gauge when going downhill but that just be gravity doing its thing.

From what I've read, this system improves economy about 20% at 25 mph and just 5% at 50 mph. Doesn't kick in at all outside of that range so mostly a green-washing gadget for commuters in big cities. Limited real-world value.

Interesting... I had forgotten about that gauge because I never use the trip meters. I wish the mpg gauge was on the main screen instead of the temp gauge.

I tried it out on the way to work this morning. For me, the only time the mpg gauge maxes out at 80 mpg is when I am coasting, i.e. no throttle at all. However, there are times when I'm applying only a little throttle that it hovers around 60 mpg, and much of the time it's around 40 mpg.

If the relationship between the mpg gauge and cylinder deactivation is accurate, then cylinder deactivation is occurring far more than I realized. I will keep an eye on it and see if I notice any other patterns.
 
I wish Mazda would offer the choice of a software change that would eliminate CD. As a 2018 owner I feel I am testing this for them, and I'd rather not.
 
Back