Anyone else tried "downshifting" with the CVT when coming to a stop w/o touching the brakes?

Amazing how much speed it drops when your able to get it into "first gear".

Saving gas and brake pads every chance I get!

 

A broken tranny will run you a lot more than brake pads and gas. Just saying.

 

In engine braking, you're just downshifting to lower the speed of your car. There shouldn't be any undue wear and tear in a modern engine/auto transmission design unless you are doing something that creates excessive load on the engine....

 

I have been down shifting my 09 ge fit since I bought it. Now 90k miles
Later still works like new. Saves me gas and brakes. I haven't changed my brakes yet.

 

downshifting wont hurt the transmission if its not done crudely

just saying....

 

Are you sure engine braking saves gas ? I thought that the gas connection remained partially open, as it would for idle, and the high rpm engine is actually pulling more gas than a lower rpm would.

 

If the car was designed properly, it will let the wheels drive the engine and only inject fuel once the car's RPMs get low enough to where it needs it to keep it alive.

 

OP's using the transmission to do the job of brakes, he's not using his brakes at all to stop. Transmissions weren't designed to replace your brakes. A CVT is a tranny I'd be even more worried abusing, they're more prone to failure over time vs. conventional automatics. Once that belt gives way...

 

He never claimed that he never uses the brakes. That would be a foolish thing to believe.

I engine brake all the time, but I still apply brake pedal pressure. What do I have to show for it? nearly 40k miles of daily driving abuse, and still have great pad thickness and good looking rotors. While engine braking, I wager I am using less then half of the pedal pressure I would be using if engine braking was not being performed.


A CVT transmission relies WAY more on its fluid quality then anything else. So more frequent fluid changes will be required.

And when the CVT tranny starts slipping, Hondas posted method is to partially apply the brakes, and go heavy on the throttle in short bursts. Inside, the belts get like your typical serpentine belts for accessories; glazed over and dirty. Roast them with brakes and throttle in short bursts, go to the dealership and purchase some fresh fluid.

Please note, this above method is ONLY for Hondas as far as I have read in technical books. Subaru treats their CVT different, as does Toyota, Mazda, and others.

 

Ever notice how people who are "just saying" aren't really "just saying?"

On old carburated engines there was a valve that actually allowed a bit more air in at low manifold pressure to assure combustion on deceleration in order to reduce HC emissions.

On EFI engines the injectors can cut off completely when the manifold pressure is low enough to indicate deceleration at higher than idle RPMs.

For my 2 cents, I can replace brake pads easier than I can rebuild engines and transmissions. Modern cars are built with excellent brakes and there is no reason to use stopgap systems of braking such as engine friction. There just isn't any advantage to doing so.

 

I do the same on my 09 some of the time. I like using it went taking off ramps . In town I usually just leave it in 3rd. I do not try and save brakes.

I like to try and match the engine speed with car speed when I downshift by adding a bit more throttle. More or less like down shifting an old manual without synchro.

 

Started doing this about a week ago. Until then, I hadn't planned on using the paddle shifters...ever. Works quite nicely in place of light to moderate braking, and if using entering a turn, leaves the ratios primed for nice acceleration should the desire arise.

 

FWIW, I don't plan to use the paddle shifters at all, and not because I'm scared of screwing up the transmission because everything is drive by wire and the software is not going to let you load the engine or clomp around the gears in an unsafe manner. I just don't feel compelled to use it. I'll probably just keep the Eco button on and drive conservatively like I usually do lol.

 

Doesn't the CVT engine brake on it's own when you aren't using the paddle shifters and you release the accelerator? How is what he's doing different than what the computer does for you?

The benefit to enginge braking would generally be less waste, higher MPGs. But I don't know if that's still true on a CVT. I didn't think the goal was to save your brakes.

From what has been posted in this thread, I don't understand how I'm harming my engine/transmission if I coast to a stop with light braking over a longer distance as opposed to maintaining speed and then using heavier braking later in a shorter distance? What exactly did I save my engine/transmission from by using additional braking force?

Genuinely curious, not trying to be an ass or anything. I don't know much if anything about cars. This could help me fine tune my driving technique in this car. So far I've been content to let the car do most of the slowing down on it's own. The car has no sense of momentum, at least compared to my previous vehicles. Not sure if that's the light weight or the CVT. But for the most part I don't need to use brakes when exiting the interstate. I thought I was helping my overall driving efficiency, please correct me if I'm wrong or what I'm doing may affect the reliability of this car. Thanks!

 

You're exactly right

 

The short answer is, you're not harming your engine or transmission at all. The only time you would risk damaging anything is if you're doing stuff outside of the engine spec. But really, the car's microprocessors and tuning will not let you do that. If it was that easy to mess up your trans, they wouldn't even put the paddle shifters in--it'd be no point at all. You should always drive safely and defensively and that would mean keeping speeds down, braking and planning your maneuvers well in advance, etc.. It's those kinds of things that save wear and tear on your car, as well as regular maintenance. Even if you're kind of hard on your driving and/or drive a lot, regular maintenance should keep you going and extend the life of your vehicle regardless.

 

No, to improve MPGs you want to minimize braking of all kinds. Braking, whether using the friction of the brake pads or the engine, turns your car's kinetic energy to heat. You have to burn more gas to regain that kinetic energy. Hypermilers avoid the brake pedal like the plague, but they also avoid driving with their foot off of the accelerator and the car in gear. Both cause energy to be wasted. If you want to slow down most efficiently you plan ahead, put the car in neutral, and coast to a stop without braking. Better yet, time your braking so you won't have to stop at all if you can.

Now, some say that coasting in neutral is dangerous and it might well be. What is most efficient isn't necessarily safest.

 

I know in the last few generation VWs when you are going above 40 MPH and let off the gas pedal the car will coast using zero gas. The injectors (measured with a dwell gauge) are actually shut off, and the car engine brakes (not a lot though). I would assume then leaving the vehicle in gear (in this case) will achieve optimal MPG results (neutral would need gas to keep the engine at idle speed). The engine braking was so minimal that you really coasted about as far in gear or in neutral anyways.

Course that only works if you are going 40+. After that the engine kicks in whether in neutral or not, to provide faster power if you need it.

 

You get some deceleration from releasing the accelerator. You get a bit more deceleration from releasing the accelerator and downshifting with the paddle.

 

Putting it in neutral uses more gas.

Engine braking - Wheels are driving the engine. All fuel is cut off because the driving of the wheels is enough to keep the engine alive.

Neutral Coasting - Wheels aren't driving the engine, fuel is needed to keep the engine alive.