Standard Braking vs. Engine Braking

Brakes definitely handle long steep grades. I’ve never used down shifting to handle a steep grade.

Modern vehicles handle all the “engine braking” normally. If you are are going to fast, then feel like you need to shift down your transmission to handle the speed, then it was a driver issue, not a need to manually shift down.

There is case to be made for a manual shift transmission, but who drives those unless you’re running a quarter mile using a trans break.

And they used to tell you to use your parking break to slow down too. Now in Colorado, of course they do everything backwards!! In part, no doubt, due to certain laws using certain psychoactives. :laughing:

I think you’re doing this “driving” thing wrong…

There’s the confirmation. :slight_smile:

In all sincerity, I must disagree with you, but I don’t expect to change your mind. I hope you never discover your brakes and automatic transmission magic aren’t what you think they are.

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That’s what’s great about America, we can agree to disagree! You couldn’t change my mind nor I you, and I wouldn’t even want to try too.

My opinion is based on experience having done a lot of driving on steep grades. Perspectives is in the eyes of the beholder. If you believe engine breaking helps you, then it does. If I believe braking is all you need, then it’s all I need.

It’s all good brother.

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Some cars with automatic transmissions have a single pushbutton to turn off overdrive. For many situations, that is enough of a downshift to be a useful engine brake.

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Both my F-150 and Acadia SVU automatically use engine braking when in tow mode. As i apply the brakes the transmission will downshift to help slow the vehicle. This works perfectly with my surge brake trailer. As the engine brakes the gentle slowing pressure engages the surge brakes. So at least Ford and GM do not seem to think it is inherently bad.

I think there might be a misunderstanding in this thread about the physics of engine braking. The energy is not dissipated by friction in the drivetrain (wearing the drivetrain like a brake pad) but rather it is dissipated by the compression of air in the cylinders. That compression generates heat which is then removed by the engine coolant. This heat is significantly less heat than what the same compression and subsequent burning of fuel would generate during combustion on acceleration or even steady driving at the same RPM.

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For what it’s worth, there are signs in some of the more mountainous parts of Big Bend State Park and Big Bend National Park that read “Warning: Steep Grade, Use Engine Braking”. I guess the Coloradans aren’t the only ones on “psychoactives”. :joy:

Y’all should check out this video: https://www.youtube.com/watch?v=o8Cta2cC2Co

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That’s for the diesel rigs only, nobody should be down shifting engine breaking in their Lexus. :wink:

But then. Who knows that area of Tejas is very remote. There may be a need for “medical” psychoactive! :sunglasses::laughing:

I can say that I have used engine braking on a fully loaded Chevy 3500HD. It works pretty well with the variable geometry turbocharger to slow a heavy load.

That being said, engine braking plays hell with your tires. (This is why you have to rotate your tires more often on an electric car.)

For a fully loaded vehicle, yes it is a good practice. For every day, not so good.

Here is the thing. Hydraulic brakes work just fine until they don’t. And usually there is no forgiveness. Maybe if you are lucky, you start outgassing the brake linings first, which puts the gasses between the linings and rotors/drums, just significantly reducing the braking ability. (And seriously damaging the linings and their life) But if you get the fluid in the pistons hot enough to boil, your done. It doesn’t happen often, but sadly most people who do it once on long mountain descents don’t get a second chance to do it differently.

And generally a lightly loaded passenger vehicle is fine. But a loaded pickup truck or tow vehicle is at risk. A passenger car in Texas isn’t going to make any meaningful difference at all. But when it counts, it counts.

You can add Idaho and Washington to the states that post signs on decent asking you to engine brake, and train engine braking for hill decent in drivers ed. There is one stretch of interstate in Idaho that is 6% grade for so long that they have 3 runaway vehicle ramps on the way down. (It seems like several miles, and the runaway ramps don’t look like they are remotely often enough) Even in a passenger car with a 3 speed auto, I usually shifted to second at the top, and comfortably stayed around 60 on the way down with reasonable engine RPM and occasionally applying the brakes.

You can also add GMC 2500 pickups to the list of vehicles that aggressively engine brake through the automatic transmission, entirely on their own, when in tow mode.

And you can add high performance driving to the list of things that will overheat brakes in Texas. I have an Audi TT, and there are many reports that if you take them to a track day with factory brake pads, expect to limp back to the pits before the day is over, usually from severe brake fade, or flat out wearing them out in one day. Unless you have one oafish clutch manner, you won’t wear out the clutch, transmission or engine in many days of track driving, much less one day.

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Have any of you ever seen a big rig take a runaway ramp? I have once and it is something I will never forget.

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The reason for using engine braking for a mountain descent is twofold: brakes are designed to operate in relatively short intervals rather than constantly over half an hour or more and if your engine were to fail at any point (it likely won’t it’s designed with engine braking in mind), you still have brakes to prevent you from driving into another vehicle or off the side of the mountain.
It should also be noted that engine braking works by allowing the load of running the engine to slow the vehicle. The loads applied are the similar to letting the engine idle and are less than propelling the car to similar RPM. The drivetrain is loaded in the opposite direction, but it rotates in the same direction. Clutches are designed to hold one surface against another, they don’t care which direction they are loaded. There may be more noise and slightly more wear to the differential, as it is designed to operate better when loaded in a particular direction, but it is designed to be loaded in both directions, nonetheless.

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Scanned thru all and a had few chuckles. No one mentioned “drive by throttle”. Novices…

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@kbraby

  1. Great to know about GMC 2500s, as I have one of those suburbans.
  2. An Audi TT?? Let’s go ingress!!

I’ll add engine braking is a lot more fun and easier to control speed on a mountain grade than riding the brakes.

Cities that ban engine braking do so for noise related reasons, not efficiency of deceleration.

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The signs you see banning engine brakes is talking about a system typically installed on big diesel rigs: https://en.m.wikipedia.org/wiki/Compression_release_engine_brake

It’s essentially sounds like a really loud diesel fart.

Very different than downshifting and coming off the throttle, which sounds like an engine revving a little.

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Engine break on long downhills or you may wear down your pads/rotors very quickly by overheating them if the pedal is held down continuously.

Also engine break by shifting through gears in slick conditions like snow. The car is much more stable compared to regular breaking especially if you try to stop quickly and clutch in.

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