[Tareq_328xi]

Hello all

How many of you use engine braking? and whats the proper way to do it?

I usually get 2 opinions:

Group 1 says when u downshift make sure to "blip" the throttle to rev match and make the transition smooth. However, I noticed that this technique doesn't slow the car much, and makes me think I should've just used the bakes

Group 2 says when you downshift, there is no need to rev match, just release the clutch slowly until it engages. This technique tends to slow the car, however, it is not very smooth, and some say this puts stress on the transmission since it does rev matching for me?

I usually try to use the first technique as I am exiting a highway or as I am approaching a red light.

Kindly advise

[GaryS]

Originally Posted by Tareq_328xi

Group 1 says when u downshift make sure to "blip" the throttle to rev match and make the transition smooth. However, I noticed that this technique doesn't slow the car much, and makes me think I should've just used the bakes

Besides going downhill, this is the only way I ever use engine braking, just to slow a little faster if I'm gaining on the car in front of me. If I want to slow the car more, I use the brakes and usually heel-toe the downshift.

Another way to slow the car more is to blip the RPMs way up and downshift two or three gears. I never do that, but some people think it's fun.

I don't understand what the Group 2 method you mentioned is. If it means using the clutch like a brake, don't do that.

[Tareq_328xi]

Originally Posted by GaryS

Besides going downhill, this is the only way I ever use engine braking, just to slow a little faster if I'm gaining on the car in front of me. If I want to slow the car more, I use the brakes and usually heel-toe the downshift.

Another way to slow the car more is to blip the RPMs way up and downshift two or three gears. I never do that, but some people think it's fun.

I don't understand what the Group 2 method you mentioned is. If it means using the clutch like a brake, don't do that.

To clarify, the 2nd group said as you are exiting a highway, for example, going 100km, shift from 6th to 4th then dont blip the throttle, just release the clutch slowly until it engages, then repeat after shifting from 4th to 3rd to 2nd. So clutch in => downshift => clutch out slowly until it engages without bliping the throttle. It works to slow the car down, but I am concerned of I am doing any harm to the transmission. I have asked 3 mechanics who drive 6MT BMWs, and they tell me this is perfectly fine, but I dont trust them

With regards to bliping the RPM high, thats the opinion of the 1st group, it will eventually slow the car down since you downshifted, but doesnt give immediate braking effect.

Sometimes I tell myself just use ur brakes!!

Thank you for your input

[ngng]

You have brakes, use them. Shifting from 6 to 4 without rev matching is going to destroy your clutch.

Rev matching has nothing to do with engine braking.

[JoosyJoos]

Engine "braking" is a pretty antiquated term from a time when automobile brakes weren't strong enough to cope with the forces enacted on them. Today, engine braking isn't necessary at all... just use the brakes. They are a lot cheaper to replace and thats the whole reason you have them.

Don't get engine braking confused with rev-matching which is meant to simply balance speed in another lower gear so you can accelerate out of a turn faster than in a higher gear.

[Tareq_328xi]

Thanks guys ,,, will focus on using the brakes instead

[The HACK]

Engine braking is the effect of the compression of air inside the engine cylinder causing a drag on the driveline. The second you let off of gas on any car while car is in gear*, you are effectively ENGINE BRAKING. The higher the compression ratio, the larger the engine braking effect. The lower the gear, the higher the difference in speed between road speed and engine speed, the larger the engine braking effect.

You should NEVER go from a higher gear to a lower gear then let the clutch out slowly because you're in essence using the friction material on the CLUTCH to act as the brake to bring the engine speed to equal the driveline speed. Imagine the clutch as a big ol brake with the flywheel acting as the rotor and the pressure plate acting as the brake pad. That is exactly what you're doing by letting the clutch out slowly. EVERY TIME you do it, it's the equivalent to dragging on your brakes...Except clutch pressure plate material is about 1/10th as thick as brake pads, and LESS surface area total.

Engine braking is as vital to slowing the vehicle down as brake braking. You should NEVER leave the car in neutral or with the clutch depressed and rely purely on the brakes to slow you down. In ANY car, manual or auto. The driveline is the only thing keeping your engine connected to the drive wheels, if you have it disconnected, i.e. coasting in neutral or with the clutch depressed, there's no way to effectively balance the chassis with throttle when the rear end steps out of line, or if you have to make an emergency maneuver when someone cuts you off, you can't apply power to the drive wheels to escape the lane if you have the driveline disconnected. It's simply bad practice.

The proper, and the ONLY way to drive a manual when slowing down, is to learn how to heel-toe properly so you can always be in the right gear at the right time. Don't rely on keeping the car in high gears, brake only, then clutch in and drop to a lower gear when you need power, because you can't react fast enough when an emergency arise. Human reaction time takes around 0.7 seconds from sight to action, and it'll take the best of us anywhere from 0.3-0.8 seconds to execute a shift. You're looking at 1-1.5 seconds before any action is taken if you have to downshift from 6th gear to 2nd as you're slowing down. That's a freakin' eternity in an emergency.

If you can't properly execute a heel-toe correctly all the time, you should probably stick to driving an automatic. No offense.

*The effect is more pronounced on manuals than automatics, because on an automatic when the engine and driveline spins at different speeds/loads (i.e coasting in gear with foot off gas), the torque converter takes up the slack.

[Tareq_328xi]

Thanks for your input, very informative.

I couldn't perfect heel-toe yet, need more practice. I find that my foot is heavier on the brakes, and I dont push the gas pedal strong enough to raise the RPMs.

Yesterday I was practicing downshifting as I get off the highway. Blipping the throttle with every downshift from 6>5>4>3rd, then I start applying the brakes. VERY smooth I used to brake while leaving it in 6th until I reach the traffic light, then choose the gear appropriate for the speed I am going.

Will keep on practicing heel-toe!

Originally Posted by The HACK

Engine braking is the effect of the compression of air inside the engine cylinder causing a drag on the driveline. The second you let off of gas on any car while car is in gear*, you are effectively ENGINE BRAKING. The higher the compression ratio, the larger the engine braking effect. The lower the gear, the higher the difference in speed between road speed and engine speed, the larger the engine braking effect.

You should NEVER go from a higher gear to a lower gear then let the clutch out slowly because you're in essence using the friction material on the CLUTCH to act as the brake to bring the engine speed to equal the driveline speed. Imagine the clutch as a big ol brake with the flywheel acting as the rotor and the pressure plate acting as the brake pad. That is exactly what you're doing by letting the clutch out slowly. EVERY TIME you do it, it's the equivalent to dragging on your brakes...Except clutch pressure plate material is about 1/10th as thick as brake pads, and LESS surface area total.

Engine braking is as vital to slowing the vehicle down as brake braking. You should NEVER leave the car in neutral or with the clutch depressed and rely purely on the brakes to slow you down. In ANY car, manual or auto. The driveline is the only thing keeping your engine connected to the drive wheels, if you have it disconnected, i.e. coasting in neutral or with the clutch depressed, there's no way to effectively balance the chassis with throttle when the rear end steps out of line, or if you have to make an emergency maneuver when someone cuts you off, you can't apply power to the drive wheels to escape the lane if you have the driveline disconnected. It's simply bad practice.

The proper, and the ONLY way to drive a manual when slowing down, is to learn how to heel-toe properly so you can always be in the right gear at the right time. Don't rely on keeping the car in high gears, brake only, then clutch in and drop to a lower gear when you need power, because you can't react fast enough when an emergency arise. Human reaction time takes around 0.7 seconds from sight to action, and it'll take the best of us anywhere from 0.3-0.8 seconds to execute a shift. You're looking at 1-1.5 seconds before any action is taken if you have to downshift from 6th gear to 2nd as you're slowing down. That's a freakin' eternity in an emergency.

If you can't properly execute a heel-toe correctly all the time, you should probably stick to driving an automatic. No offense.

*The effect is more pronounced on manuals than automatics, because on an automatic when the engine and driveline spins at different speeds/loads (i.e coasting in gear with foot off gas), the torque converter takes up the slack.

[ngng]

Originally Posted by Tareq_328xi

Thanks for your input, very informative.

I couldn't perfect heel-toe yet, need more practice. I find that my foot is heavier on the brakes, and I dont push the gas pedal strong enough to raise the RPMs.

Yesterday I was practicing downshifting as I get off the highway. Blipping the throttle with every downshift from 6>5>4>3rd, then I start applying the brakes. VERY smooth I used to brake while leaving it in 6th until I reach the traffic light, then choose the gear appropriate for the speed I am going.

Will keep on practicing heel-toe!

Remember, when you depress the brake with your heel your foot is going naturally get closer to the accelerator. Practice makes perfect!

[chris328i]

Brakes are for slowing the vehicle not engine braking. Rev matching is to prevent excessive engine braking which is hard on the engine and not recommended.

[e90pilot]

Originally Posted by chris328i

Brakes are for slowing the vehicle not engine braking. Rev matching is to prevent excessive engine braking which is hard on the engine and not recommended.

Your first statement is correct. Second, not exactly. Engine braking is not hard on an engine. As Hack and others stated above, downshifting without blipping the throttle will wear out the clutch. If you slow down in neutral, you're just wasting gas. If you slow down in gear, the ECU almost entirely cuts fuel to the engine while at idle it burns more to keep the engine spinning.

On the track, the need to rev-match becomes really obvious. I was driving my friend's Hyundai Genesis Coupe and I could not for the life of me get my foot over to the gas pedal while braking. The second the clutch made contact with the flywheel the rear tires locked. Fortunately that car is pretty stable so it still it didn't get squarely but from then on I had to wait until I came off the brake to downshift. That got old really fast...

[merchomini]

yep..... i use the breaks and rev match when i downshift......if im coming up to a red light i put it in neutral typically and just break normally, unless i know the light is about to turn then ill downshift and rev match.

[chad29]

^^^ That makes sense to me.

[Tareq_328xi]

Thank you all very much!

[mastermayhm]

Originally Posted by merchomini

yep..... i use the breaks and rev match when i downshift......if im coming up to a red light i put it in neutral typically and just break normally, unless i know the light is about to turn then ill downshift and rev match.

taught him everything i know

[merchomini]

Originally Posted by mastermayhm

taught him everything i know

then i expanded on that info and perfected it and the returned the favor by teaching him what i now know.

[Fatal Flash]

Nice answers in the thread!! Never do #2 Hard to heel-toe in the streets though, as stock brake pedals usually aren't as flush as they are on the track car videos that you watch on youtube, but it's absolutely doable.

Picture this, you never see SMG/DTC downshifting without the revs immediately jumping up (equivalent to flawless computer controlled heel-toe). If it was standard to let the revs match with the "clutch, slowly depressed" DTC would be garbage