Leave MT car in gear when braking, or go to neutral?

[Ferzerp]

The fuel injection system of any modern car will cut fuel completely while in gear during engine braking. In neutral at idle fuel is necessary to keep the engine running.

And if you have a car with an integrated wideband (not sure how accurate mine is) you can see as the A/F ratio skyrockets when you put it in this state as proof.

 

[mafia]

The use of engine braking in normal day to day driving isn't going to cause wear and tear on a drivetrain.

This. Isn't that what they are built for anyway? Might as well not drive the car at all if you don't want to cause wear and tear.

 

[KrAzYaZnFLiP808]

Air fuel ratio, and injection duty is 2 different things. You need fuel to keep engine at idle, while you downshift, no fuel is used, while using engine as breaking force. Injection duty of injectors should be 0 percent. I know because I run stand alone ECU.

 

[exdeath]

And if you have a car with an integrated wideband (not sure how accurate mine is) you can see as the A/F ratio skyrockets when you put it in this state as proof.

Confirmed this with solid proof for ATG long ago with a datalog posted showing injector duty cycle going to zero and AFR pegging lean when TPS went zero and RPM was above idle target.

But we still have this argument at least twice a month.

 

[Zap]

Shift cable broke on me Friday (unknown aftermarket should have known better), had to drive home without a clutch pedal. Fun times.

Transmission broke in my 1986 Mustang GT twice (after it was a decade old). First time I had 4th gear only. Managed to limp it through town into the nearest dealer. Hooray for torque! Second time I was going a steady speed on the freeway and there was a loud noise and lurch, and then nothing in any gear. It was towed to a different dealer. They said it was fixed improperly the first time, causing the second break. They fixed it at no cost, stating that it had a 1 year warranty from any Ford dealer from the previous fix (around 10 months passed from first time).

3) Shifting into neutral, particularly going down a hill is less safe than being in gear for the extremely rare case where brakes fail, or the more common case where you've got wet brakes and need to dry them off with a few pumps (happened to me last week)

Heh, something similar happened twice last week. Long freeway drives in snowy weather, when braking for exit... WTF? So pumped brakes while downshifting. No problem.

I think were all missing the big picture here. Lets give a golf clap to the OP for actully taking the time to buy and learn to drive a standard transmission! big credit to you sir. either way isnt wrong! welcome to the minority who can drive a manual transmission!

*CLAP CLAP*

Am I the only one who can't heel toe? I don't have the dexterity in my heel to do it

Most of my cars have had too much height difference between the pedals, with the accelerator pedal much closer to the floor than the brake pedal. My Mazdaspeed 6 is actually pretty close compared to my previous vehicles and I've tried it a few times. Usually my heel gets stuck though. I'll keep poking at it on occasion, in case I eventually get the feel for it.

Along the lines of "feeling" the shift, I have recently been trying to learn to shift without using the clutch.

Easy! Been doing it for decades. :whiste:

 

[camoxiong]

when you are rolling slow like 5 - 10 mph, just 2nd gear and when you complete stop just put it in neutral

 

[Ferzerp]

Air fuel ratio, and injection duty is 2 different things. You need fuel to keep engine at idle, while you downshift, no fuel is used, while using engine as breaking force. Injection duty of injectors should be 0 percent. I know because I run stand alone ECU.

Never said they were the same, but not many cars have an integrated display telling you that

 

[skyking]

Most of my cars have had too much height difference between the pedals, with the accelerator pedal much closer to the floor than the brake pedal. My Mazdaspeed 6 is actually pretty close compared to my previous vehicles and I've tried it a few times. Usually my heel gets stuck though. I'll keep poking at it on occasion, in case I eventually get the feel for it.

Cars that are really built for it have adjustable pedals. The rest of us grunts make do; I have big feet and that helped

 

[EagleKeeper]

DFCO

???

 

[EagleKeeper]

The fuel injection system of any modern car will cut fuel completely while in gear during engine braking. In neutral at idle fuel is necessary to keep the engine running.

Thanks. Showing my age
Grew up on manuals; fuel injection were for transfers only at that time

 

[phucheneh]

???

Deceleration fuel cutoff. As in, the wheels are spinning the engine and there's no throttle input. The PCM will stop fueling entirely, as the small amount needed to simply keep a 'disconnected' (neutral or clutch in) engine spinning is not needed and would be counterproductive to braking.

edit: I'm a bit late, apparently.

 

[Rifter]

I would think that neutral/clutch in accomplish the same thing - allow the engine RPMs to freewheel down to min sustainable levels.
With the clutch engages and in gear you are using more fuels.

No, Most car computers will cut off all fuel while in gear and not at slow speeds with foot completly off the gas, to maxamize downshifting force and save fuel. If you vehicle is carburated obviously this wont matter.

 

[slashbinslashbash]

Easy! Been doing it for decades. :whiste:

I know, those "in the know" know about it, but it's not really talked about much, and I pretty much had to figure it out on my own and pull little bits and pieces from various forums and Google searches. Every discussion of "how to drive a car with a manual transmission" talks pretty much exclusively about clutch technique and excludes the fact that it's possible to shift without the clutch, or how to do so, or that it is actually fairly easy if you just try it, and you don't have to do a lot of mental RPM math.

 

[Ferzerp]

I could do it on my Festiva when I was 18. I don't even try on the current car.

 

[KrAzYaZnFLiP808]

why are you going to try shift without the clutch, other then you have too, hydraulic fluid, and cable is broken. If you didn't need the clutch, then why have it. Its a manual torque converter. You can try force it out of gear, and or force it in gear, depending on speed, and rpm. Theirs a sweet spot, and its really not hard to do. You try slip it into first gear without using clutch.

What you can do is from dead stop. You can try to shift into first without clutch. your car will slowly inch forward, then go into gear at around 5 mph. Then you can you press gas. release gas alittle, and see if you can pull it out of gear and go into 2nd, and it just might go into gear

Honestly, dont WASTE YOUR SHIFTING WITHOUT CLUTCH! PERIOD! Only do it if your cable, or hydraulic system is bad, and straight home.

 

[lakedude]

This has all been very interesting.

I thought I was a good/decent driver till I went to the SCAA races. Had lots of fun and it felt like I was going really fast but the clock don't lie. Then again I'm not sure that lap time is the same thing as being safe. A driver with a good lap time who drives near their limit is going to be more dangerous than a driver with a slow lap time who drives within their skill level.

I've looked into the legality of neutral coasting and it is in fact not legal in many states. The main reason is really a legacy from before we had EFI when cars might stall out if put in "N". This does not really happen anymore so the law is a bit silly and all but impossible to prove.

Hypermilers coast in "N" all the time and it is in fact an excellent thing to do under the right circumstances such as speed maintaining downhills. Really steep grades will need engine braking or "re-gen" if you have a hybrid but shallow hills can be coasted down in neutral and no gas will be used if you use the controversial FAS technique. Because of re-gen I typically leave the car in gear or downshift when coming to a stop but below a certain speed the vehicle is designed to shut off automatically. This requires the shifter be in neutral. The car will start up instantly when put back in gear. Clearly my vehicle was designed to be in "N" when coming to a stop so that is how I drive. Also leaving the clutch pedal depressed any longer than needed is something I was taught not to do...

 

[pandemonium]

I've been driving manual as long as I've been driving, but my last 2 vehicles that I've driven exclusively for commuting and as my primary vehicle (my current is my only vehicle and is manual).

1. You can downshift and - be able to decelerate faster; be able to quickly accelerate; wear more on the engine, transmission, clutch, engine mounts, suspension, your foot, ankle, leg; wear less on your brake pads and rotors; use more gas
2. You can go into neutral and - use less gas; wear less on the engine, transmission, clutch, engine mounts, suspension, your foot, ankle, leg; rely more on your brake pads and rotors; be slower in response to accelerate again

With above said, it depends on the situation. If I'm slowing to a stop-light and know I won't be going again until I've completely stopped or longer (I look at the adjacent light for changes or some lights I just know how long they take to change), I'll go into neutral and decelerate using my brakes only (there's absolutely no need to brake very hard and engine brake hard). The biggest thing is to anticipate and plan way ahead of what most drivers with automatics do.

Crazy story...when I replaced my clutch and was in the break-in phase, I got 38.8mpg since I was being gentle on it; allowing the flywheel to mate evenly with the pressure plate. Needless to say, I was very easy on the gas, never rode the clutch, and didn't decelerate much and the result was incredible mileage. My normal highway mileage is around 32mpg. So driving style makes a very large impact on your mileage and component wear. Of course, mileage/tank varies on each tank since it's not an exact science and can't be taken literally on each measurement.

I should also note, for the last ~60k miles I had the same pads on (Duramax Gold Cmax's), which I just replaced and they still have about 4mm left on the fronts. So I'm very easy on my braking and gas...minus those special circumstances.

 

[Ferzerp]

You can go into neutral and - use less gas

:sigh:

Some gas > 0 gas

 

[Arkaign]

I guess the difference is minor at best. I think with any modern fuel injected vehicle you may use slightly less fuel by downshifting and engine braking, but I almost never do that any more. With judicious use of neutral, and calm and aware driving I handily exceeded the rated fuel economy numbers for my Focus by a large margin. It comes down to preference. Granted this is Texas and the streets are flat as a pancake. On road trips with descending hill stops I revert back to ds/engine braking.

 

[JulesMaximus]

I've been driving manual as long as I've been driving, but my last 2 vehicles that I've driven exclusively for commuting and as my primary vehicle (my current is my only vehicle and is manual).

1. You can downshift and - be able to decelerate faster; be able to quickly accelerate; wear more on the engine, transmission, clutch, engine mounts, suspension, your foot, ankle, leg; wear less on your brake pads and rotors; use more gas
   [*]You can go into neutral and - use less gas; wear less on the engine, transmission, clutch, engine mounts, suspension, your foot, ankle, leg; rely more on your brake pads and rotors; be slower in response to accelerate again

With above said, it depends on the situation. If I'm slowing to a stop-light and know I won't be going again until I've completely stopped or longer (I look at the adjacent light for changes or some lights I just know how long they take to change), I'll go into neutral and decelerate using my brakes only (there's absolutely no need to brake very hard and engine brake hard). The biggest thing is to anticipate and plan way ahead of what most drivers with automatics do.

Crazy story...when I replaced my clutch and was in the break-in phase, I got 38.8mpg since I was being gentle on it; allowing the flywheel to mate evenly with the pressure plate. Needless to say, I was very easy on the gas, never rode the clutch, and didn't decelerate much and the result was incredible mileage. My normal highway mileage is around 32mpg. So driving style makes a very large impact on your mileage and component wear. Of course, mileage/tank varies on each tank since it's not an exact science and can't be taken literally on each measurement.

I should also note, for the last ~60k miles I had the same pads on (Duramax Gold Cmax's), which I just replaced and they still have about 4mm left on the fronts. So I'm very easy on my braking and gas...minus those special circumstances.

This is complete and utter nonsense. First of all, and this has been beat to death here repeatedly, your car actually uses no gas when decelerating in gear because the fuel injection system shuts off the fuel injectors completely in this situation. Idling in neutral uses gas. Still, I doubt you'd notice any difference in fuel economy.

Oh, and you put far more stress through the drivetrain and suspension under acceleration and cornering than you do while decelerating in gear. If you think you are saving wear on your car by coasting in neutral you're nuts. It is neglible.

When I drove a MT, and I did for nearly a decade with 2 different cars, I would downshift maybe to 3rd or 2nd but almost never into 1st, sometimes not even to 2nd, depended on how lazy I was feeling at the time. I would coast up to a stop and if the light was long I'd leave it in neutral until the light was about to change. If it was short I'd put it in 1st and wait in gear until the light changed.

When just cruising I would always be in the proper gear, uphill, downhill, flat surfaces, always in the correct gear. Never did any coasting to "save wear" on anything, any coasting in neutral I did was approaching a stop and was out of pure laziness, nothing else. Only thing I ever replaced was a clutch (and throwout bearing for good measure) after about 60,000 miles. Never wore out an engine or motor mounts, or transmission, or driveline parts. Both cars were Mustang GT's and I pounded on them for nearly 100,000 miles before I got rid of them. The best thing you can do to keep your car in good shape and reduce wear is to maintain it properly and drive it per the manufacturer's recommendations.

Brakes are cheap but transmissions are made to be shifted, use them both. Oh, and rev matching is cool...

 

[kitatech]

This is complete and utter nonsense. First of all, and this has been beat to death here repeatedly, your car actually uses no gas when decelerating in gear because the fuel injection system shuts off the fuel injectors completely in this situation. Idling in neutral uses gas. Still, I doubt you'd notice any difference in fuel economy.

Oh, and you put far more stress through the drivetrain and suspension under acceleration and cornering than you do while decelerating in gear. If you think you are saving wear on your car by coasting in neutral you're nuts. It is neglible.

When I drove a MT, and I did for nearly a decade with 2 different cars, I would downshift maybe to 3rd or 2nd but almost never into 1st, sometimes not even to 2nd, depended on how lazy I was feeling at the time. I would coast up to a stop and if the light was long I'd leave it in neutral until the light was about to change. If it was short I'd put it in 1st and wait in gear until the light changed.

When just cruising I would always be in the proper gear, uphill, downhill, flat surfaces, always in the correct gear. Never did any coasting to "save wear" on anything, any coasting in neutral I did was approaching a stop and was out of pure laziness, nothing else. Only thing I ever replaced was a clutch (and throwout bearing for good measure) after about 60,000 miles. Never wore out an engine or motor mounts, or transmission, or driveline parts. Both cars were Mustang GT's and I pounded on them for nearly 100,000 miles before I got rid of them. The best thing you can do to keep your car in good shape and reduce wear is to maintain it properly and drive it per the manufacturer's recommendations.

Brakes are cheap but transmissions are made to be shifted, use them both. Oh, and rev matching is cool...

I agree with everything here...I've always felt that driving in the gear that gives the greatest range from slowest to fastest is the most efficient, whether out of laziness or good driving practice...

A 5-speed may not be as fast up through gears as a 6-speed, but it gives more range in any one gear, and as I said earlier, I can stay in 3rd between 10 and 40mph without lugging at low rpms or dragging at the high end (2600 RPM), going up to 4th only when I know I will have cruising time faster than 40mph (@ >3k RPM)...and going into N only when at a virtual stop, and going into 2nd if it seems I won't have to stop....

My last car's clutch (a 99 Altima) needed replacement @ 180k miles, my 1st set of front pads went 100k, the 2nd @ another 90k miles, the rear drums @ 180k miles.

 

[phucheneh]

I guess the difference is minor at best. I think with any modern fuel injected vehicle you may use slightly less fuel by downshifting and engine braking, but I almost never do that any more. With judicious use of neutral, and calm and aware driving I handily exceeded the rated fuel economy numbers for my Focus by a large margin. It comes down to preference. Granted this is Texas and the streets are flat as a pancake. On road trips with descending hill stops I revert back to ds/engine braking.

People keep associating 'engine braking' with 'aggressive downshifting.' This is not accurate.

I use engine braking like crazy, and I never coast in neutral unless I'm deciding on which gear I want to use (like when there's sudden traffic or something, and I stop in the middle of an upshift).

I do not downshift through the gears when slowing down. I leave it in the higher gear, and shift into whatever gear is proper when I then need to accelerate.

I'm not even sure how people do this. Unless you want it to be jerky and akward, you're going to be manipulating the throttle, which means you're using more gas. In addition to the time spent in neutral during shifting, there's also the effect of more throttle on your deceleration. It's just a pointless exercise.

edit: also it sounds like kiatech drives exactly like me. I generally use 3rd and 4th to limit speed in 30-35 and 45-50mph areas, respectively. If I get into the RPM range where I feel significant braking when I let off the gas, I'm probably going too fast.

And I do ride third like crazy. Unless I'm doing a really slow/sharp right-angle turn (can't 'apex it' very well), I don't shift into second.

 

[pandemonium]

This is complete and utter nonsense. First of all, and this has been beat to death here repeatedly, your car actually uses no gas when decelerating in gear because the fuel injection system shuts off the fuel injectors completely in this situation. Idling in neutral uses gas. Still, I doubt you'd notice any difference in fuel economy.

Oh, and you put far more stress through the drivetrain and suspension under acceleration and cornering than you do while decelerating in gear. If you think you are saving wear on your car by coasting in neutral you're nuts. It is neglible.

When I drove a MT, and I did for nearly a decade with 2 different cars, I would downshift maybe to 3rd or 2nd but almost never into 1st, sometimes not even to 2nd, depended on how lazy I was feeling at the time. I would coast up to a stop and if the light was long I'd leave it in neutral until the light was about to change. If it was short I'd put it in 1st and wait in gear until the light changed.

When just cruising I would always be in the proper gear, uphill, downhill, flat surfaces, always in the correct gear. Never did any coasting to "save wear" on anything, any coasting in neutral I did was approaching a stop and was out of pure laziness, nothing else. Only thing I ever replaced was a clutch (and throwout bearing for good measure) after about 60,000 miles. Never wore out an engine or motor mounts, or transmission, or driveline parts. Both cars were Mustang GT's and I pounded on them for nearly 100,000 miles before I got rid of them. The best thing you can do to keep your car in good shape and reduce wear is to maintain it properly and drive it per the manufacturer's recommendations.

Brakes are cheap but transmissions are made to be shifted, use them both. Oh, and rev matching is cool...

I said downshift...as in, downshifting through the gears, like what drivers do on the track.

You can sufficiently downshift without jerky motion and fluidly, but that takes a lot of practice and most of the time requires heel-to-toe. I wouldn't recommend it for the everyday driver.

Also, gearing ratios are vastly different between vehicles; usually depending on their engine size and their marketed audience. Obviously you can generally be lazier and shift less (have a broader range of speed in the same gear) with a more torquey engine that redlines at 5500rpm as opposed to one that redlines at 9000rpm. Point is, each vehicle can be different. Learn your vehicle's optimal ranges. Applying the same exact driving technique to each vehicle is a blatant mistake.

Typically, during everyday commute, I'll leave it in gear to assist deceleration until around 20mph, then I'll clutch in and go into neutral. There are varying situations where being in the appropriate gear to start going again immediately is warranted, but I never downshift into 1st.

In general, I try to avoid keeping the clutch in as much as possible without holding up traffic just to shift. If you're in neutral, clutch is out until you need to shift.

And yes, rev-matching isn't just cool, it's important. Downshifting and suddenly tossing your engine 4-5k rpm higher puts unecessary strain on everything involved. This is more-or-less what I was essentially getting at without actually mentioning it. I suppose I should've said so. My mistake for not be clearer.

 

[JulesMaximus]

I said downshift...as in, downshifting through the gears, like what drivers do on the track.

You can sufficiently downshift without jerky motion and fluidly, but that takes a lot of practice and most of the time requires heel-to-toe. I wouldn't recommend it for the everyday driver.

Also, gearing ratios are vastly different between vehicles; usually depending on their engine size and their marketed audience. Obviously you can generally be lazier and shift less (have a broader range of speed in the same gear) with a more torquey engine that redlines at 5500rpm as opposed to one that redlines at 9000rpm. Point is, each vehicle can be different. Learn your vehicle's optimal ranges. Applying the same exact driving technique to each vehicle is a blatant mistake.

Typically, during everyday commute, I'll leave it in gear to assist deceleration until around 20mph, then I'll clutch in and go into neutral. There are varying situations where being in the appropriate gear to start going again immediately is warranted, but I never downshift into 1st.

In general, I try to avoid keeping the clutch in as much as possible without holding up traffic just to shift. If you're in neutral, clutch is out until you need to shift.

And yes, rev-matching isn't just cool, it's important. Downshifting and suddenly tossing your engine 4-5k rpm higher puts unecessary strain on everything involved. This is more-or-less what I was essentially getting at without actually mentioning it. I suppose I should've said so. My mistake for not be clearer.

No worries.

I ride a motorcycle and find myself downshifting through 2nd gear almost all the time. Never into first unless I'm almost completely stopped.

Heel-toe shifting is an art and incredibly rewarding when you get it right. No way I'd ever downshift without rev matching any vehicle.

 

[JulesMaximus]

I agree with everything here...I've always felt that driving in the gear that gives the greatest range from slowest to fastest is the most efficient, whether out of laziness or good driving practice...

A 5-speed may not be as fast up through gears as a 6-speed, but it gives more range in any one gear, and as I said earlier, I can stay in 3rd between 10 and 40mph without lugging at low rpms or dragging at the high end (2600 RPM), going up to 4th only when I know I will have cruising time faster than 40mph (@ >3k RPM)...and going into N only when at a virtual stop, and going into 2nd if it seems I won't have to stop....

My last car's clutch (a 99 Altima) needed replacement @ 180k miles, my 1st set of front pads went 100k, the 2nd @ another 90k miles, the rear drums @ 180k miles.

Both Mustangs I bought used with about 30k miles on them so I put another 60k on the clutches of both those cars before replacement. I did my share of dropped clutch starts and power shifting. I never baby anything I own it seems, which is probably why the Maxima I just traded in was in need of a steering rack soon. :$