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by xyzzyz 1408 days ago
One can occasionally do engine braking in an ICE car, but it is simply not feasible to use it for most, or even significant fraction of one’s braking needs: try driving through a city without touching brake pedal (actually please dont, it’s dangerous). On the other hand, in an electric vehicle/hybrid, you can use regenerative braking for a huge chunk of braking situations. If you use it half of the time, that extends life of brake pads by 100%, which is huge.
3 comments

I drive a stick shift and I would bet that at least half of my braking is engine braking. It's pretty much my default behavior if I want to slightly slow down to downshift and then immediately shift back.

With an ICE, I have no idea whether the wear and tear you avoid on the brakes is offset by the strain you put on the engine or if it saves or wastes gas. Don't know don't care. I just do it because I am Walter Mitty.

I’m convinced most automatic cars disconnect the engine and drive wheels when you step off the throttle, thus keeping a small amount of fuel running to the engine and putting more wear and tear on your brakes for the braking. With the exception of the 2014 Hyundai I was driving.

One could shift the automatic gear selector to 3 or 2 (or whatever you have) to engine brake in most autos. This is taught as a thing to do if your brakes fail.

But on my manual, I can take a freeway exit and do most of my braking from 120km/h to about 15km/h through the engine. And similar if the light ahead turns red.

This is actually what you’re supposed to do in a manual: be in gear at all times so you can accelerate if you have to.

My brakes will probably last 3-4x longer than an automatic’s.

My experience in my vehicle (mazda cx5) is that foot off both pedals seems less drag than engine braking from a downshift in a manual, but also more drag than neutral/clutch disengage in a manual.

Letting the drag slow the vehicle in an automatic is still a win -- your instantaneous MPG goes to >99 and you save wear and tear on multiple parts of the vehicle. It's a really big win, and with people so antsy about the price of fuel (aka the cost of driving) I'm shocked to observe how many people are still driving in very expensive manners (fast starts, hard braking)

> even significant fraction of one’s braking needs It's easily practical if you drive in a non-aggressive way. (Its not a race )

I frequently coast up to red lights and stop signs, shedding 25-50% of my miles per hour, but brake wear is greater under heavier loads so doing 25% less breaking is a lot more than 25% savings on wear & tear.

I'm not sure what % is a "significant" threshold for you, but >25% is definitely significant to me.