Are my habits harmful to this CVT?

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Just out of curiosity, when did car engine start using fuel cutoff during deceleration or going downhill to save gas? Was it when they started using fuel injectors? or only when they start using computer intensively?
 
Originally Posted By: PandaBear
Just out of curiosity, when did car engine start using fuel cutoff during deceleration or going downhill to save gas? Was it when they started using fuel injectors? or only when they start using computer intensively?


OBD2 iirc
 
Originally Posted By: 901Memphis
Originally Posted By: PandaBear
Just out of curiosity, when did car engine start using fuel cutoff during deceleration or going downhill to save gas? Was it when they started using fuel injectors? or only when they start using computer intensively?

OBD2 iirc

Well before that. My '91 Integra shut off the fuel on decel above something like 1,500 rpm.

The shutoff limit has been lowered over the years as engine computers have gotten faster and emissions regulations tighter. I think the newest cars shut off fuel on decel just above idle speed.

My understanding is that fuel-cutoff on decel wasn't practical before electronic injection.
 
i used to use neutral as much as possible on my Accord, after my tranny failure i decided to just put it at d4 and let it be.

I have not noticed any mpg gains or losses, engine will never rev down to below 500 rmp to your save basicly nothing.
 
You've made up your mind! Go for it.

Also take note when you put it back in drive it has to rev-match somehow, which is different than you doing so when stationary.

Originally Posted By: gr8gatzby
Quote:
a. The injectors shut off in many autos while engine-braking downhill;


Engine braking is not a factor when revving at idle speeds
 
Our old Mercedes four apeed automatics had instructions in the OMs for tow starting them.
You had to be going at a decent clip, though.
It isn't like push starting a stick.
 
Originally Posted By: gr8gatzby
I agree that it is dumb and unsafe. That is not my quandary.


It should be. You have a responsibility to your fellow motorists as well as your passengers to operate your vehicle in the safest possible manner. If, by your own admission it's both "dumb and unsafe" then the conversation ends there. Don't do it. There are a lot of people here telling you just how dumb and unsafe it is, but you're refusing to listen.
 
Slightly off topic...Though this only pertains to regular auto trannys(for those who want to know), IDK how this in particular relates to CVT's:

In a regular automatic tranny, by putting the gear selector in "N" while coasting as compared to keeping it in "D", the trannys torque converter is spinning at a higher speed and the engine is now at idle. Where as they(engine speed/tranny tq conv) should both be at the same speed while coasting/foot off the gas pedal at speeds.

I too have done this(gear selector in "N") on numerous occassions w/o issues but, it's probably not optimal!

Did I say all of this correctly?
 
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Originally Posted By: gr8gatzby
Quote:
a. The injectors shut off in many autos while engine-braking downhill;


Engine braking is not a factor when revving at idle speeds

Quote:
b. The engine is braking, so you don't need to use your actual brakes to maintain downhill speed;


Engine braking should only be used as a method of deceleration in emergencies. Engines are more expensive to replace than brake pads.

Quote:
c. If an emergency arises, you have the vehicle in gear to provide acceleration.


I agree, that's why I only shift into neutral on a downslope when not surrounded by traffic, and risk is at an absolute minimum.


I think it's already been established that you're not gaining anything to take it out of gear while coasting and if you think that you are going to wear an engine out coasting down some random hill at 2000 rpm, then you have some pretty serious misconceptions about engines. That engine will be completely fine and more than likely outlast the car, barring some fluke failure. Stop worrying and splitting hairs, life is too short for trivial things like this and it won't gain you anything that you be able to quantify anyway.
 
Originally Posted By: The_Eric

I think it's already been established that you're not gaining anything to take it out of gear while coasting and if you think that you are going to wear an engine out coasting down some random hill at 2000 rpm, then you have some pretty serious misconceptions about engines. That engine will be completely fine and more than likely outlast the car, barring some fluke failure. Stop worrying and splitting hairs, life is too short for trivial things like this and it won't gain you anything that you be able to quantify anyway.


A little engine breaking is actually good for the engine. It can help keep the rings free from sticking.
 
Unsafe to put it in neutral, actually. If you need to take evasive action, you don't want the car out of gear. Also puts unnecessary wear and tear on the trans.
 
Originally Posted By: gr8gatzby
Quote:
a. The injectors shut off in many autos while engine-braking downhill;


Engine braking is not a factor when revving at idle speeds

Quote:
b. The engine is braking, so you don't need to use your actual brakes to maintain downhill speed;


Engine braking should only be used as a method of deceleration in emergencies. Engines are more expensive to replace than brake pads.

Quote:
c. If an emergency arises, you have the vehicle in gear to provide acceleration.


I agree, that's why I only shift into neutral on a downslope when not surrounded by traffic, and risk is at an absolute minimum.


Did you say you were an engineer?

I know nobody that would do as you suggest or even consider it a sensible course of action

The vehicle was engineered to run as it does when coasting down a hill

That is why it does it.

Or are you saying the engineers involved don't know what they are doing?
 
DBW, right? In engine over-run it likely isn't injecting any fuel, and it's possible that it's not pulling air over a closed throttle plate either. If it feels like it coasts without dragging then I'm not sure I'd worry about it.
 
Originally Posted By: bigjl
Originally Posted By: gr8gatzby
Quote:
a. The injectors shut off in many autos while engine-braking downhill;


Engine braking is not a factor when revving at idle speeds

Quote:
b. The engine is braking, so you don't need to use your actual brakes to maintain downhill speed;


Engine braking should only be used as a method of deceleration in emergencies. Engines are more expensive to replace than brake pads.

Quote:
c. If an emergency arises, you have the vehicle in gear to provide acceleration.


I agree, that's why I only shift into neutral on a downslope when not surrounded by traffic, and risk is at an absolute minimum.


Did you say you were an engineer?

I know nobody that would do as you suggest or even consider it a sensible course of action

The vehicle was engineered to run as it does when coasting down a hill

That is why it does it.

Or are you saying the engineers involved don't know what they are doing?


I am saying the transmission is inherently flawed if it revs at 2k rpm when on a downward slope. As to whether the engineers know what they are doing is anyone's guess. I've seen this behavior in other CVTs, so I assume that it is an engineering obstacle inherent to the CVT design that has yet to be overcome.
 
Doesn't this put more wear on the transmission and possibly engine mounts?
 
Id figure there is no true benefit to it. If your foot is off the gas pedal, I doubt there is much difference whether its in neutral or drive. So why bother doing it?
 
Originally Posted By: gr8gatzby
Quote:
a. The injectors shut off in many autos while engine-braking downhill;


Engine braking is not a factor when revving at idle speeds

Quote:
b. The engine is braking, so you don't need to use your actual brakes to maintain downhill speed;


Engine braking should only be used as a method of deceleration in emergencies. Engines are more expensive to replace than brake pads.

Quote:
c. If an emergency arises, you have the vehicle in gear to provide acceleration.


I agree, that's why I only shift into neutral on a downslope when not surrounded by traffic, and risk is at an absolute minimum.


a. Exactly, so why idle at 0.3 gph fuel burn rate when you can engine-brake at 0.000000 gph? I don't get your logic.

b. Engine braking should be used as often as possible; it does no harm to your engine, and the high vacuum is usually seen as helpful during break-in.

c. See above comments
 
Originally Posted By: eljefino
You've made up your mind! Go for it.
why don't other participants here understand this simple concept? I believe I am the one who owns the patent on this though :)
 
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