Engine Braking

[whataboutbob]

I engine brake with my auto because ... BWWAAAHHHH GRUGLE GURGLE ROOOMMM!!!!

Love that sound with the Nvidia N1!!!

[Tintiot]

Bottom Line:
you are using the engine to help stop the car, yes it sure helps a lot and it sounds great. but it means that you are engaging the engine in the process of stopping so you will wear components as usual.
Think of it this way you us the engine/tranny to go forward = Wear. You use the engine/tranny/Brakes to stop = wear.
so yes it you use the engine it will wear more, how much more?. Who knows. They use it in racing probably to safe on the brakes and have more brake power (I am not an expert).
I use it to have fun with this great car.

my 2 cents

[350z]

Saving pads??? They will wear out anyway since that's what they are made to do. If you can't shell out $100 for pads every few years you're doing something wrong.

[zooki]

Originally Posted by Ingen

Off topic: Does the compression braking / "jake brake" on a semi open the throttle and allow full cylinders of air to slow the engine? Just wondering, I know they can be very loud and intuitively it would make sense, but I am not familiar with the system beyond noise from a distance.

Actually diesels don't have throttle bodies. They suck in the same amount of air, and vary the amount of diesel injected to vary the power out put. A "jake brake" can be either a valve in the exhaust piping that closes off, or an actual setup that holds the exhaust valves closed. This keeps the spent gases in the cylinders, and makes them compress, aiding in compression braking.
http://www.zafr.com/trucktcom/retarder.htm

[Rayme]

Don't overthink people.

[Dake]

200,000 miles on my last stick, engine braking all the time. I replaced the original clutch at 130k, never had engine or transmission issues and the only reason it stopped running was a hurricane.

[butdamnbrian]

Originally Posted by ZDan

Wow, so much misinformation in this thread, with only a bare few bright nuggets of truth!

In the interests of having complete control of the car and maintaining ability to accelerate if it becomes unexpectedly necessary *at all times*, the car should *always* be in gear with the clutch engaged while driving, except when upshifting, downshifting, or while stopped.

While slowing down, you will get engine braking, which is NOT GOING TO HURT ANYTHING. The slight drag loads on the drivetrain is MUCH smaller than the loads it was designed to handle.

If you are slowing for a stop sign or traffic light, you don't have to downshift through all the gears, but it is good form. To downshift through the gears while braking with a 3-pedal car without automatic rev-matching requires heel/toe, a topic worthy of its own thread so I won't get into it here. Other than to say that if you have a modern synchro gearbox, double-clutching is NOT REQUIRED.

If you are slowing for a lower-speed curve that requires you to be in a lower gear on exit, the RIGHT thing to do is get into that lower gear *before* the curve. If braking is involved, this requires heel/toe downshifting.


Anyway, you use "engine braking" NOT as a primary way to slow the car (though that is a somewhat beneficial side-effect). You end up using engine braking because if you are driving properly, maintaining maximum control and ability to accelerate instantly at any time, you get engine braking when slowing down.


Regarding how much air goes into the engine, if it was the same whether the throttle was open or closed, then what's the throttle for?!

agree.

[Ocala FR-S]

You are correct that with perfect rev matching and no clutch slippage you can engine brake with no substantive wear and tear on the vehicle. The real question is: Why would you want to use engine braking? Extended downhill travel requires it be done to maintain speed and avoid brake fade and a runaway vehicle. For everyday driving and performance driving, it's just a bad idea. Engine breaking upsets the handling balance of the vehicle. On a curve it can result in exterme oversteer and even a spin. Front brakes are larger because that's where the braking force is designed to be concentrated, not at the rear wheels. To decelerate, use the brakes.

[dun3]

Up and down up and down.. Interesting read. I've read that the only time you need to downshift, is when you need to speed up. But I do engine brake ever so often.

[jmaryt]

Originally Posted by Ocala FR-S

You are correct that with perfect rev matching and no clutch slippage you can engine brake with no substantive wear and tear on the vehicle. The real question is: Why would you want to use engine braking? Extended downhill travel requires it be done to maintain speed and avoid brake fade and a runaway vehicle. For everyday driving and performance driving, it's just a bad idea. Engine breaking upsets the handling balance of the vehicle. On a curve it can result in exterme oversteer and even a spin. Front brakes are larger because that's where the braking force is designed to be concentrated, not at the rear wheels. To decelerate, use the brakes.

pure crap! if you know how and when to utilize compression of the engine to brake,you should never lose control,just don't use too low a gear,and you shouldn't lose control.it's a "good " idea on a regular basis ,it DOES save wear on your brakes,and the engine being under "load" is normal,because it's engineered,and functions normally under "load" you are correct in saying it is helpful when descending,as the engines' compression (braking effect) will help slow the vehicle to maintain control,AND lessen wear on the brakes.in everyday driving,it is indeed beneficial,and again,reduces wear on the brakes. have driven stick for over 40 years,and i consider myself a skilled 'stick" i ALWAYS utilize compression of the engine to slow the vehicle,and consider it part of my everyday driving.my cars have lasted on average 200,000 miles or better with zero engine issues whatsoever!

[LeeMaster]

Here is my method for driving a stick and can someone tell me if im wrong.

Usually when I come to a stoplight or a stop sign I just shift the gear into neutral and let the car coast its way there and then i just use the brakes. I barely ever downshift with my brz unless the speed (rpm) dictates it.

And yes I do have another car to beat on to keep my mind fresh on downshifting and engine braking but I have only started driving manual nine months ago so I am still not confident in downshift rev matching my new car.

[rice_classic]

Originally Posted by ZDan

If you are slowing for a stop sign or traffic light, you don't have to downshift through all the gears, but it is good form. To downshift through the gears while braking with a 3-pedal car without automatic rev-matching requires heel/toe, a topic worthy of its own thread so I won't get into it here. Other than to say that if you have a modern synchro gearbox, double-clutching is NOT REQUIRED.

Everything else you typed in that post was spot on but this? Really? I got $10 that says you and I ain't hittin' on the same ladies at the bar. (which is a good thing as we don't end up fighting over the same girl)

You're right that you don't have to downshift when coming to a stoplight but why on Earth is it "good form"?

Let's use the logic you applied to approaching a slower corner in which you state you need to enter the corner in the gear you need to exit the corner. Ok, so if we're coming to a stop the "gear" we need to be in is Neutral, so let's enter that gear before a stop.

Slow down in whatever gear you're in and just before you stop shift to neutral. Why put 1-5 more shifts per stop worth of wear on your synchros, shift forks and clutch. Seems wasteful, seems like bad form.

[ZDan]

Originally Posted by rice_classic

Everything else you typed in that post was spot on but this? Really? I got $10 that says you and I ain't hittin' on the same ladies at the bar. (which is a good thing as we don't end up fighting over the same girl)

You're right that you don't have to downshift when coming to a stoplight but why on Earth is it "good form"?

Actually, I don't even do this. I skip gears on the way down on the street and at the track.

Let's use the logic you applied to approaching a slower corner in which you state you need to enter the corner in the gear you need to exit the corner. Ok, so if we're coming to a stop the "gear" we need to be in is Neutral, so let's enter that gear before a stop.

"Neutral" isn't a gear!

Slow down in whatever gear you're in and just before you stop shift to neutral. Why put 1-5 more shifts per stop worth of wear on your synchros, shift forks and clutch. Seems wasteful, seems like bad form.

It is a great way to stay in heel/toe rev-matching practice, and it's also a good way to be able to immediately respond if the red light turns green before you come to a stop!

My S2000 has 156k miles and about 25 track days on it. I have *always* downshifted through the gears when slowing down. No problems whatsoever with original synchros, shift forks, or clutch. Transmission and clutch have never seen any service other than fluids, still working just fine.

Downshifting through the gears while slowing to a stop shows good form and is a good idea for a couple of reasons as far as I'm concerned. But it's not strictly necessary.

[ZDan]

Originally Posted by Ocala FR-S

You are correct that with perfect rev matching and no clutch slippage you can engine brake with no substantive wear and tear on the vehicle. The real question is: Why would you want to use engine braking?

To be clear, engine braking is what happens when you are driving properly, always having the transmission in gear and clutch engaged while driving. Any time you're off the gas, you'll get "engine braking".

Extended downhill travel requires it be done to maintain speed and avoid brake fade and a runaway vehicle. For everyday driving and performance driving, it's just a bad idea. Engine breaking upsets the handling balance of the vehicle. On a curve it can result in exterme oversteer and even a spin.

So will hitting the brakes while cornering! Why would you do that?

Please note, engine braking is what happens when you lift off the gas when driving properly (everyday, performance, track driving, whatever). That doesn't mean that you are relying on the engine to slow the car, and it doesn't mean you should lift off the gas in a curve!

That said, of course you can use the throttle to point the car while cornering. But don't make the newb mistake of the BIG LIFT off the gas midcorner if things get sketchy. Instant spin...

Front brakes are larger because that's where the braking force is designed to be concentrated, not at the rear wheels.

"Engine braking" doesn't contribute enough to substantially change front/rear braking bias in most cases. Even in the pouring rain, I've *never* had rear lockup issues due to engine braking, in any conditions. Proper performance driving you will experience engine braking. But you're not using it to slow the car substantially. It is simply a consequence of keeping the car in gear, clutch engaged at all times.

To decelerate, use the brakes.

If you need to, of course! But with the transmission in gear and clutch engaged. Not coasting in neutral or with the clutch disengaged, at least not until you're nearly stopped.

Its' worth repeating: you don't rely on engine braking to take the place of using the brakes.