2018 Mustang Manual vs. Auto--MotorTrend

[Angry50]

just interesting thing i found about engine braking..

First of all, to dispel the myth – engine braking does not harm your engine at all. Engines are designed to run at thousands of revs per minute for hours at a time. Changing down, whilst may be a bit jerky at times, doesn’t inflict any damage.

It’s also good for the engine because it was designed to be driven that way. Whilst brakes have moved on from drum brakes (which is why engine braking was relied upon a few decades ago), the core of an engine is essentially the same.

It’s better for an engine to gradually shift down (or up) through gears rather than going from 5th to 2nd.

It’s also far more fuel efficient for the same reason. Engine braking shuts off fuel consumption, as opposed to just braking or putting the car in neutral.

You’ll also use less fuel when pulling away in a lower gear than pulling away at low speeds in high gear.

All this adds up to a safer, more economical drive on brakes that will last longer.

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[Ebm]

just interesting thing i found about engine braking..

First of all, to dispel the myth – engine braking does not harm your engine at all. Engines are designed to run at thousands of revs per minute for hours at a time. Changing down, whilst may be a bit jerky at times, doesn’t inflict any damage.

It’s also good for the engine because it was designed to be driven that way. Whilst brakes have moved on from drum brakes (which is why engine braking was relied upon a few decades ago), the core of an engine is essentially the same.

It’s better for an engine to gradually shift down (or up) through gears rather than going from 5th to 2nd.

It’s also far more fuel efficient for the same reason. Engine braking shuts off fuel consumption, as opposed to just braking or putting the car in neutral.

You’ll also use less fuel when pulling away in a lower gear than pulling away at low speeds in high gear.

All this adds up to a safer, more economical drive on brakes that will last longer.

Yet the A10 skips gears all the time. I have 4.10 gears in my M6 and skip shift all the time. No harm, no foul.

 

[Angry50]

Yet the A10 skips gears all the time. I have 4.10 gears in my M6 and skip shift all the time. No harm, no foul.

i think this was in reference to probably more standard 5 or 6 speed transmission with wider ratios. going for 1-3-5 is probably still closer than your standard 5 speed 4-2 shift. i am thinking its more based on a sudden drastic change in rpm. even thought i have dropped from top gear to 2nd many times. if rev matched not sure how much damage or issues could be encountered

 

[Norm Peterson]

No, you're absolutely NOT increasing your braking distance being in neutral.

I'll give you "not normally" here, while hoping that people don't ever have to go much past 'normal'.

It's too difficult to establish whether the presence of engine braking helps or hurts when you don't know if engine speed is trying to slow down slower than, faster than, or at the same speed as the drop in road speed requires it to. Nor do we know what any engine braking effect would have on brake balance or ABS intervention, both of which directly affect stopping distances.

Most times, it's probably better to leave the transmission in some gear and declutch in the last few feet before a full stop, somewhat before the engine starts to lug (an indication that some of your brake activity is being wasted slowing the engine and hence affecting brake balance).


Norm

 

[NoVaGT]

I'll give you "not normally" here, while hoping that people don't ever have to go much past 'normal'.

It's too difficult to establish whether the presence of engine braking helps or hurts when you don't know if engine speed is trying to slow down slower than, faster than, or at the same speed as the drop in road speed requires it to. Nor do we know what any engine braking effect would have on brake balance or ABS intervention, both of which directly affect stopping distances.

Most times, it's probably better to leave the transmission in some gear and declutch in the last few feet before a full stop, somewhat before the engine starts to lug (an indication that some of your brake activity is being wasted slowing the engine and hence affecting brake balance).


Norm

We've been talking about max, emergency braking, not trail-braking or anything of such nature.

Emergency braking, especially in a modern, ABS equipped car, is down to one thing; mechanical grip to the road, I.E. tires.

A Mustang's braking distance (when the brakes aren't over-heated) is up to the tires. Engine braking has 0 to do with it. The brakes provide massively more whoa than any engine braking, completely over riding it. In fact, if the car is in gear when you start engine braking in an emergency situation, the brakes have to fight the intertia and friction of the engine and drive-train too.

Once you stomp in the STOP pedal, it's all about your tires. Well....tires, and the sophistication of your ABS.

 

[Jdenkevitz]

It’s also far more fuel efficient for the same reason. Engine braking shuts off fuel consumption, as opposed to just braking or putting the car in neutral.

.

I am not sure if this is true in a practical sense. Let me explain.

I understand how the injectors are shut off when you release your foot from the gas, and that the cars forward velocity maintains engine rpm through the drivetrain engagement.

My question is whether putting the transmission in neutral is actually more efficient in terms of distance traveled against fuel used.

When engine braking, you slow down significantly faster than when coasting (obviously). So even though when Engine Braking you are using no fuel (and you are cooling your engine off due to no explosions in the cylinders- an added benefit), coasting only uses a small amount of fuel to maintain engine rpm, but is considerably more efficient as there is no braking force slowing the car down.


If I am at 60mph in 5th gear and release the gas, I travel X distance before stopping/stalling.
If I am at 60mph in 5th gear, place the car into neutral and release the gas, I travel considerably farther.

The question is does the fuel used to keep the engine running in neutral offset the additional distance traveled?

 

[Norm Peterson]

Yet the A10 skips gears all the time. I have 4.10 gears in my M6 and skip shift all the time. No harm, no foul.

Skipping gears is far more reasonable when they are 20% apart or tighter instead of 30% or more. Some pairs of upshifts in the 10R80 are closer together than a single upshift in the MT82-D4. Highlighted by the oval, note that the spread from 3rd to 5th in the 10R80 (red traces) is always within the spread from 2nd to 3rd in the MT82-D4 (black traces), and that this applies over the same range of road speed.

Norm

 

[NoVaGT]

just interesting thing i found about engine braking..

First of all, to dispel the myth – engine braking does not harm your engine at all. Engines are designed to run at thousands of revs per minute for hours at a time. Changing down, whilst may be a bit jerky at times, doesn’t inflict any damage.

It’s also good for the engine because it was designed to be driven that way. Whilst brakes have moved on from drum brakes (which is why engine braking was relied upon a few decades ago), the core of an engine is essentially the same.

It’s better for an engine to gradually shift down (or up) through gears rather than going from 5th to 2nd.

It’s also far more fuel efficient for the same reason. Engine braking shuts off fuel consumption, as opposed to just braking or putting the car in neutral.

You’ll also use less fuel when pulling away in a lower gear than pulling away at low speeds in high gear.

All this adds up to a safer, more economical drive on brakes that will last longer.

It's not a myth. Engine braking adds stress to your engine, transmission, diff, etc. Logic dictates this. Yes, the drive-train can take it, but the less you ask your drive-train to take, the longer it lasts.

I agree on saving gas.

No one said anything about pulling away in a gear not suited to pulling away.

Lastly, brakes are a wear item, they're designed and meant to wear. If you shorten the life of your engine, trans and diff, that's in no way more economical than changing brake pads.

Brakes are engineered, designing and built to slow and stop your car. Engines, trans and diffs were not.

 

[Norm Peterson]

If I am at 60mph in 5th gear and release the gas, I travel X distance before stopping/stalling.
If I am at 60mph in 5th gear, place the car into neutral and release the gas, I travel considerably farther.

The question is does the fuel used to keep the engine running in neutral offset the additional distance traveled?

Mr. Apple, meet Mr. Orange :lol:


Norm

 

[Angry50]

I am not sure if this is true in a practical sense. Let me explain.

I understand how the injectors are shut off when you release your foot from the gas, and that the cars forward velocity maintains engine rpm through the drivetrain engagement.

My question is whether putting the transmission in neutral is actually more efficient in terms of distance traveled against fuel used.

When engine braking, you slow down significantly faster than when coasting (obviously). So even though when Engine Braking you are using no fuel (and you are cooling your engine off due to no explosions in the cylinders- an added benefit), coasting only uses a small amount of fuel to maintain engine rpm, but is considerably more efficient as there is no braking force slowing the car down.


If I am at 60mph in 5th gear and release the gas, I travel X distance before stopping/stalling.
If I am at 60mph in 5th gear, place the car into neutral and release the gas, I travel considerably farther.

The question is does the fuel used to keep the engine running in neutral offset the additional distance traveled?

other question would be how soon do you want to stop. not how far can you go.. if you have 300ft till you must be stopped and youre going 60 mph. and coasting would go too far what is most efficient to stop in that 300 ft.

It's not a myth. Engine braking adds stress to your engine, transmission, diff, etc. Logic dictates this. Yes, the drive-train can take it, but the less you ask your drive-train to take, the longer it lasts.

I agree on saving gas.

No one said anything about pulling away in a gear not suited to pulling away.

Lastly, brakes are a wear item, they're designed and meant to wear. If you shorten the life of your engine, trans and diff, that's in no way more economical than changing brake pads.

Brakes are engineered, designing and built to slow and stop your car. Engines, trans and diffs were not.

https://www.matfoundrygroup.com/News and Blog/What_is_Engine_Braking_and_Why_you_Should_do_it

i should have put the link.. i didnt come up witht his stuff so i cant make any arguments with out more research. i just did a quick search to see what are all the listed "benefits" or "drawbacks"

i dont believe engine braking is any more stressful on the car than the aggressiveness of the shift and the rpms used.

 

[NoVaGT]

url]https://www.matfoundrygroup.com/News%20and%20Blog/What_is_Engine_Braking_and_Why_you_Should_do_it[/url]

i should have put the link.. i didnt come up witht his stuff so i cant make any arguments with out more research. i just did a quick search to see what are all the listed "benefits" or "drawbacks"

i dont believe engine braking is any more stressful on the car than the aggressiveness of the shift and the rpms used.

Let's use our logic;

When you max accelerate, the engine, transmission and diff are under tremendous stress. There's heat and pressure from combustion, massive changes in direction of the rotating mass, piston rings moving against the metal of the cylinder walls faster, creating even more heat, valves opening and closing creating stress on valves, cams, lifters......and the list goes on and on.

Yes, your engine is designed to do this, but it has a life span, with a downward curve in tolerances and efficiency, plus possible materials fatigue. So, an engine, transmission, and diff all have life-spans. In fact the entire car does. It's why people want cars with highway miles; such miles put very little stress on the drive-train.

When you engine brake, you are subjecting the engine to all of the same stresses and pressures, except minus the combustion heat and pressure. Other than that, engine braking puts the same stresses on the engine, diff, trans, etc., just in reverse. Not at the same level of stress, but still it's using up the life of the drive-train.....when it's not necessary.

When the car is in neutral, and the engine is idling, that's an almost 0 mechanical stress situation for the drive-train.

 

[Angry50]

Let's use our logic;

When you max accelerate, the engine, transmission and diff are under tremendous stress. There's heat and pressure from combustion, massive changes in direction of the rotating mass, piston rings moving against the metal of the cylinder walls faster, creating even more heat, valves opening and closing creating stress on valves, cams, lifters......and the list goes on and on.

Yes, your engine is designed to do this, but it has a life span, with a downward curve in tolerances and efficiency, plus possible materials fatigue. So, an engine, transmission, and diff all have life-spans. In fact the entire car does. It's why people want cars with highway miles; such miles put very little stress on the drive-train.

When you engine brake, you are subjecting the engine to all of the same stresses and pressures, except minus the combustion heat and pressure. Other than that, engine braking (and I'm guessing here), puts the same stresses on the engine, diff, trans, etc., just in reverse. Not at the same level of stress, but still it's using up the life of the drive-train.....when it's not necessary.

When the car is in neutral, and the engine is idling, that's an almost 0 mechanical stress situation for the drive-train.

https://mechanics.stackexchange.com/questions/3600/is-engine-braking-harmful

https://jalopnik.com/actually-engine-braking-is-fine-1818491096

https://www.roadandtrack.com/car-cu...myth-that-engine-braking-is-bad-for-your-car/

better let everyone know you figured it out.. not sure id really take the word of someone using a bama tune anyway lol

 

[Norm Peterson]

We've been talking about max, emergency braking, not trail-braking or anything of such nature.

So have I. If I meant trail braking I'd have said so. Though the concepts of what I posted still apply to less than limit braking, where you'd be stepping a little harder (or a little less hard) on the brake than you would in neutral to get the result you want. IOW, you're actually compensating for drivetrain torque either added or deducted. This affects what gets down to the rear tire contact patches.

Emergency braking, especially in a modern, ABS equipped car, is down to one thing; mechanical grip to the road, I.E. tires.

Not exactly. Brake balance matters, because tire grip is not proportional to the normal force pressing the contact patch to the pavement. The rear contribution of braking force is a function of net braking torque. Net being the torque at the rear brake rotors minus torque lost to decelerating the engine, or plus any torque added by engine braking if this is possible. You can't hand-wave the engine side contribution away here.

The brakes provide massively more whoa than any engine braking, completely over riding it. In fact, if the car is in gear when you start engine braking in an emergency situation, the brakes have to fight the intertia and friction of the engine and drive-train too.

You're part-way to understanding it. Sure, the brakes are overpowering the engine. But in this case it's taking away rear braking for the car to do this, making the effective brake balance slightly more front-biased.

So let's say Ford engineered the optimum brake balance to suit the case where the car was left in gear and the clutch fully engaged. Now it's going to be more rear-biased than optimum for the braking-in-neutral and braking-clutch-in cases. Pick one, can't have both. Not even with ABS either, because releasing a locked wheel increases stopping distances (albeit with greater directional control coming as an entirely separate advantage).


For this ↓↓↓, see this ↑↑↑

Once you stomp in the STOP pedal, it's all about your tires. Well....tires, and the sophistication of your ABS.

Norm

 

[bluebeastsrt]

Not bad. #309 posts already.

 

[NoVaGT]

https://mechanics.stackexchange.com/questions/3600/is-engine-braking-harmful

https://jalopnik.com/actually-engine-braking-is-fine-1818491096

https://www.roadandtrack.com/car-cu...myth-that-engine-braking-is-bad-for-your-car/

better let everyone know you figured it out.. not sure id really take the word of someone using a bama tune anyway lol

I'm sorry you can't figure this out for yourself, using logic. I've tried to help you, but logic doesn't seem to work for you. You're probably a youngin' who thinks everything he reads on the internet is true and correct.

Would you like me to find a few links talking about the harmful effects of engine-braking?

I would like to know why you think a Bama tune on my car means you're not going to accept any information I provide.

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