There's still a lot of confusion about engine braking. All good, perhaps more content on it! In the meantime, a few clarifications. How does engine braking work in diesels? Here you go! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-o8Cta2cC2Co.html Also confusion about downshifting. It is 100% fine to downshift, and yes, downshifting will provide greater engine braking because your engine will be spinning at a higher rate, thus the energy lost through pumping losses (as a result of the closed throttle) will increase. More energy lost = slows your car down more. Rev-matching your downshifts means no clutch wear, so it's no big deal at all. If you're into Snapchat, I have no way to please you. But if you're on the Instagrams feel free to follow! instagram.com/engineeringexplained/
Does engine braking by downshifting without the rev matching really do significant damage to the clutch? In driving schools here we're taught to break on the engine by downshifting, but we're not taught to do rev matching.
Normal engine braking (ie leaving it in gear while coming to a stop, or holding a gear during a long downgrade) is perfectly fine. The potential problem arises because of the the helical cut gears in the transmission. All modern gearboxes use these for forward gears because they're quieter. Problem is, they also create an axial load. So there's a thrust bearing there to take up the load in the normal direction. When loaded in reverse, however, the thrust is in the opposite direction. There is a tiny little thrust bearing in most transmissions for this opposite load, but there are two things to remember. 1. It is design for normal opposite loads... not inertial loads (ie when downshifting without rev matching) and 2. whenever you're going from a negative load to a positive load, you're "passing the zero".. ie you're going from one thrust washer to the other via a gap. The axial acceleration in this clearance causes an impact to the washer. It can take it... but only for so long and so many times. Basically, under normal deceleration, you're fine if you rev match. But do it wrong, and you're looking at a costly transmission rebuild instead of a simple brake job.
What is the meaning of life? How much wood could a woodchuck chuck? What is the mechanism of engine braking? All very important questions that need answering.
You're probably right. I am American and I did fail both Thermodynamics I and Thermodynamics II in school. That may also explain why I have a hard time justifying all of the explanations about engine braking.
There's a 2.5 km downhill section near where I live. If I go just the right speed at the top of the hill, I coast down the entire section exactly at the speed limit (70 km/h) and without having to touch the throttle. Love it every time.
Ridiculous. Deliberate engine braking offers the capable driver a remarkable amount of additional control over the vehicle, and is also one of the most enjoyable features a "manual" car comes with.
Agreed, mate...after my father died 7 years ago (he'd always sworn that the day he purchased a car with an 'auto' transmission would be the day that he died & unfortunately, those words proved to be 100% prophetic!), my mother purchased a new V6 Accord - her first ever automatic - & ever since then, she's forever offering to wash my 'manual' Civic Type R or to fill it with petrol, as she so misses driving a 'manual' & having so much control over the car...as well as her enjoyment of the exhaust sound upon my car vs hers!!
Use the brakes, they are much cheaper to replace than a clutch assembly and it's not the clutch components but the labor involved to replace it is were the expenses lies. Smooth gear charges and avoid sliding the clutch as much as possible will mean long clutch life.
I think all you really needed to say to people who think engine braking is bad because of clutch wear is "if you're wearing out the clutch, you are not engine braking, you're just doing it wrong" xD
also people who worry so much about "clutch wear" should stick to automatics and let torque converter do the job. really whats the point of having a manual if you cant engine break!
Rodolphe "really whats the point of having a manual if you cant engine break".. How about; control, reliability, gas mileage, cost of maintenance, cost of repair. Yes engine braking has it's advantages. But it's not "the reason" for a manual transmission. Honestly if you feel the need to engine bake outside of winter weather driving, steep downgrades, racing, or fast breaking situation (got cut off or brake checked) then you are; (A) not getting off the gas or on the brakes fast enough (B) speeding beyond the capabilities of your brakes/tires for the situation you are in (C) following too closely. Anything beyond that you are just using it as a toy, and your brakes would have been more than capable of doing the same thing.
Engine braking is one of the things you use to get MORE control, REDUCE fuel usage, INCREASE reliability and DECREASE cost of maintenance and repair... you seem to have everything completely backward... do you actually know what engine braking is? did you even watch the video you are commenting on? Engine braking is just any time you have your foot off the throttle and are in gear, this causes the car to slow down slightly more quickly than if doing the same thing in neutral; and just so happens to have a stronger effect the lower the gear you're in, it's a way to control your speed when going downhill without requiring braking, this means your brakes last longer and won't overheat when going down a long hill so when you need to emergency stop you still have full stopping power (brakes are not made to be in use constantly like you would if going down a hill and not using engine braking at all) , it causes no additional wear to the engine or gearbox so long as you don't slip the clutch when doing it... you should have been taught how to avoid that in your driving lessons early on engine braking isn't about racing or getting more stopping power out of your car, it is about efficiency, it can be used in those ways but noone is suggesting them here are they...
When I think about it, I usually apply a combination of engine braking and foot brake. Depends on the rate of deceleration. I prefer engine braking exactly for one of the reasons mentioned: fuel economy. One physics lesson I remembered and applied early on is the fact that regardless of how braking is applied, it's converting kinetic energy to heat which is essentially a waste of energy. So anticipating the road conditions ahead, for instance a yellow light about to turn red should trigger the reaction to ease off the accelerator. I always challenge myself to drive as smoothly as possible without having to brake. When fuel prices are as high as they are in the NL driving economically is a must. And of course the added effect of lowering emissions that way isn't a bad thing either.
hahaha you drive the exact same way as me, exept that traffic in morocco is crazy enough that its hard to anticipate but i try most of the time... also im not really good with thermodynamics but i assume that it will consume less during engine braking than when putting in neutral and leaving the car to coast in idle.... also may i ask how much are oil prices in netherlands ? here its about 80 cents for diesel.. and nearly 1 euro for petrol, so i'm planning to switch my high consuming petrol for a tdi
I too do that on my bike, but I pull in the clutch, so that I can reach the desired distance and then apply break Instead of applying engine braking why not just stop accelerating and pull in the clutch ( do not shift it to neutral in case some emergency arrives and u need to stop or accelerate quickly) Btw fuel price in India are approx INR 100 ( 1.21 USD ) per liter For both petrol and diesel
@@warbot2544 if I understand you correctly you are pulling your clutch but not shifting into neutral. What that does is, you wont get the benefit of 0 fuel consumption or slowing you down because the engine will have to burn fuel in order to stay on (because you detatch it from the gearbox). And the thing with emergency brakes is: when you have to stop very quickly and you then Release the clutch so that the engine slows you down as well thats actually affecting your breaking Performance negatively. You see, the engine has its own rate of slowing down because of its own moment of spinning weight. If you then want to slow down quickly, its actually bad for your breaking Performance because you will need to slow the engine down faster than it would normally do as well... Hope I could explain that understandably.
Some people think he is advocating replacing using the brakes entirely by engine braking. Its meant to ASSIST slowing the vehicle, not replace the brakes. It will lessen wear and tear on the brakes, also with the higher vacuum the brake booster will be more effective. The other advantage is, in the event you suddenly need power, you will already be in the juicy part of the engines power band. No need to waste time stirring in the gear box like a food mixer to find the right gear. And no, you don't engine brake with the rev counter touching the red line, that is called engine BREAKING!
Yep. I remember my grandmother would shift down and avoid braking like the plague, at that point you would have to worry about replacing transmission fluid and likely a seal.
Just in case somebody reads this, if you are almost redlining on a descent for a longer time (which means an incredible steep decline), you better use engine breaking. Your brakes will stop working in about 20 seconds. If you are over the redline, just brake hard and stop the car. And after your brakes have cooled try a lower gear. Never keep on braking on a decent. You won't even get you licence in most first world counties if you don't know that.
@@chasemiller7974 Don't say stuff on the internet that isn't true. People might take it for a fact. Since you are in gear your transmission fluid is fine. Everyone who drives in the mountains in an older car (new cars with better brake cooling and bigger disk and better heat resistant pads don't fade that easily) knows you can go for hours engine braking, without any negative effect. And yesss, you should avoid braking downhill like the plague. Overheated disc brakes are not funny especially downhill. In the US most cars have automatics, and people don't have to go through at least 50 hours of driving lessons and a really hard theory test to get their licence. So this kind of information apparently is not common knowledge. Please don't make it worse.
@@foeke8740 The transmission shifts down automatically at a very low RPM, near idling speed and for good reason downshifting at a high RPM puts extra strain on the clutches, I'm talking about for everytime she had to stop she would shift down early. This causes the engine to rap out, sometimes the tachometer would hit 3,000 rpm. I'm sure that's not good on the transmission, nor the engine either since it spins faster thus more wear. Sure engine braking is great for controlling speed when going downhill, but it's not good to do it all the time everytime you stop or slow down.
I've had many manuals and I've always used engine braking (as Dad taught me). It's especially effective in slowing down a motorcycle , given the relatively high power to weight ratio. It's important to note that oil pumps are mechanical and driven off the crankshaft, so the engine is getting proper lubrication for its speed regardless of whether or not the throttle is open. Great video!
Well, first the engine is designed to do that, it cuts off the fuel to save it during engine braking. Even before the electronic injection, some carburettors had 'engine breaking valve'. Also, in high mountains you have to engine brake, because otherwise even modern ventilled brakes will overheat. In most instances they will not stop working completely, but there is a good chance that ABS sensors will burn out. Consequently, ABS, EBD and ESP will shutdown and then you're left non-ABS car without brake bias corrector, so any hard breaking means instant spin.
@@NerdyCatCoffeeee A car without ABS from the factory has brake-bias corrector, so unless the corrector fails, it should not spin. But if ABS fails, you don't have a brake-bias corrector, so it's likely the car will spin or at least goes sideways. I've seen that happen.
Been using engine braking since I passed my test 17 years ago and my fuel usage has always been excellent only problem is you always get the moron behind on your rear because they don't see a red light so don't notice you slowing down
jc1982discovery this happened to me at an intersection one day. Was in first and going to make a right turn, but someone started crossing the street. I let off the throttle and stare at the SUV in my rearview to just hear a screeching stop, then the lady started flaring her arms around l. 😐😐 morons indeed
And unfortunately in the UK you may fail your driving test if using excessive engine braking because it slows the car down without turning on the brake lights.
Engine braking on cars is not problem at all because its considered that light brakings like engine braking are allowed without turning on brake lights
simple solution, if you want to be extra safe while engine braking put a tiny bit of pressure on the brake pedal, the lights should come on before the pads actually contact the disc ^_^
My son said he hates following me when I'm driving my Ram.. not only does it have low gears in the rearend (3.73, where 3.42 is the standard gear ratio) it also has a exhaust brake utilizing the turbos variable geometry sliding vanes, and can provide up to 225 exhaust brake up to slow down the pickup. Case in point, coming down the North side of the Siskiyou pass on I5, pulling a trailer with my F150 on it, GCVW was 14,100 lbs in 6th gear I would slow down too much and have to disengage the exhaust brake to stay above 50 mph. So running empty, it really slows down good and I'll have people coming up my ass fast when I use it to slow down at a stop light.
I honestly come here partly for the engineering talk, but largely because I just like the feeling of being in the passenger seat while you're explaining things to me
Is it bad for a manual transmission? Nope, in fact semis do it all the time is one of the first ways you slow down, your brakes are more to assist in decelerating and making the final stop. (Unless ofcoarse you MUST stop in a short distance) but ideally you down shift to control your speed.
you mean this "accidental emergency brake" when you subconscious try to change gear"? - Yes that's normal when you drive manual for years and then after decades first time an automatic. I put my left foot in a 90° angle behind my right leg for the first kilometers in an automatic. Just to not be able to "automatically" using the leg for pressing the left pedal.
Have you seen the signs going down mountain roads that say "Heavy Trucks Gear Down"? Most heavy trucks (20 tones +) would overheat their wheel brakes very quickly going down long mountain roads. They have to engine brake and use J-brakes (another form of engine brake) in order to go down the mountain at a controlled pace. Yet, these trucks have engines that last millions of miles. If engine braking was bad then how could these truck engines last so long?
Hehe as an European, and ence a manual gear driver, I can't understand those doubts:) Engine braking is not just unharmfull it is also advisable in steep roads, for example.
An European? I'd love to hear how you pronounce your own continent if you think it's preceded by "an." Anyway, both of my cars are from 1988 (because I love '80s sports cars), so the throttle body doesn't shut itself off when you're not accelerating. I always shift into neutral when going down a hill to save fuel. By the way, I would argue that most viewers of this channel are Americans who drive manual cars or at least know how to, so your smugness is really unwarranted. In fact it's more impressive to grow up here where you can go to a dealership and find only one car on the whole lot that has a manual in it and still choose to learn manual shifting, compared to growing up where that's your only choice so you just deal with it. I bet if you were born here you'd have been one of the lazy 94.5% of people to drive an automatic.
Rok Bleki I think no because let’s say you climbed in 1st (the biggest gear available to the rear), when in a bike you’re going fast and put a big gear and try to pedal the pedals are going to spin too fast by themselves because as you move them they connect to the wheel movement and they’re hard to recover
ArneBergsch I believe this is taught anywhere with manual cars. I don't understand why so many people in the comments sounds so stressed about it. This is a everyday thing for me.
Here in the USA, driving is a "right" so they hand out drivers licences to anyone that can breath. The "tests" are a complete joke, you could pass one blindfolded! Oh wait, they say "driving is a privilege " but really, everyone feels entitled to be crappy drivers here. People here take zero pride in car care, tire pressure checks, tire choices, alignment choices, etc. THEN, they will follow you at the same distance regardless if you're moving at 5 mph or 85mph. This is best demonstrated when you take off from a red light to a green light, everyone WAITS til they have that 2 car length space BEFORE they even begin to start to move. So half the number of cars actually get through each light, and yet, once you're moving from 5mph up to around 45 mph, they still have the same exact following distance. I love seeing just HOW fast I need to go to get someone to not tail gate. It's fun when you get them up to around 90mph and they have that sudden realization that the speed limit is 55, and then they freak out and brake abruptly. People here believe the rear view mirror is for checking themselves out/taking "selfies" rather than watching what is occurring behind them, then the same morons: "the cop just came out of nowhere" when they are crying about their speeding ticket. Duh! We need more hot blond attractive German women who were not raised on a diet of processed and preserved foods in the USA to teach these people how to freakin drive here!
Here in Spain (probably all of Europe, or at least the mountainy parts of it) there are actually signs that say "Remember to use your engine as brake" in downhill mountain passes
Engine braking is also super good for offroading and other poor traction times when you don't want to touch your brakes because it takes almost nothing to lock the wheels up. Creeping down hills in 1st gear is a solid option.
Every time I am deeply impressed by your in-depth knowledge of engine technology. There are a lot of channels on RU-vid that deal with engines, but often it is half-knowledge and hear-say. You, on the other hand, provide real knowledge. You also never have to think long or get vague in your statements because you really know what you are talking about. Great when people have really learned their profession and know what they are talking about.
I've been doing this for years in all my manual cars never had an issue and the clutch had always lasted a long time. My brakes always lasted a long time too.
All new drivers in the UK learn to drive manual and are taught to engine break as a 'proper' way to drive a car. If you didn't do it you wouldn't pass your test.
Harry Brookman I don't know how different The test was back then, but the only time you are taught (and this is only as part of your theory) to engine break is when travelling down hill to help avoid brake fade. You would not be marked down on your driving test to be in 5th gear even when travelling down hill.
Just go light on both, brakes and engine braking. They work less hard together. Another advantage is if you downshift while braking, you are then ready to accelerate if you have to, such as approaching a red light but then it turns green.
Haha, well I'm not sure, but I've had people ask about it. We all have to learn from somewhere; no harm in asking questions. But proper engine braking will mean no wear of your clutch at all, as it's fully engaged and not slipping.
Michael Kreitzer, I once heard a story where this guy told me his brake stopped working and he just slowed down by riding the clutch, once he was slow enough he just used the emergency brake and called a tow truck. It might wear your clutch but if it saved his life in an emergency then it worked.
John Andrew Serrano Garcia, naturally emergency maneuvers are emergency maneuvers. Nobody's gonna judge for doing what you've got to do. atxformfactor, what are you talking about? Riding the clutch has nothing to do with a "more intimate connection with the vehicle." It's just an amateur thing to do and using the wrong tool for the job. The clutch is not a brake and is far more expensive to replace. If you're going too fast to down shift w/o redlining and you're not slowing down enough with engine braking, then that is exactly what the _actual_ brakes are there for. If you can down shift without redlining, then why are you riding the clutch?
Downshifting and rev-matching (not riding the clutch) is still using engine braking. If the RPM is higher, the engine braking effect is stronger, when the throttle is closed.
Engine deceleration is vastly important to get the full effect of your braking systems when you're on a motorcycle, and though mentioned that going lower in gear and letting out clutch in a car is bad, its actually encouraged in a motorcycle because the clutch is designed vastly differently and is engineered to be slipped between gears in that manner with minimal wear
It's also vastly important in cars when driving in the mountains, to avoid overheating the brakes, burning ABS sensors, and being left in a car without ABS, EBD or ESP, and without brake bias corrector. Instant spin on every hard breaking.
@@dbclass4075 rear braking is not recommended on motorcycles. The majority of your breaking power comes from your front brake, on account of the way the weight shifts on the bike when decelerating, which makes the rear brake ineffective. Typically you should use a combination of front and rear brakes, with front brakes doing the majority of the work.
@@dbclass4075 most motogp racers claim to almost never use the rear brakes. I’ve been riding for years and also rarely use my rear brakes for anything other than sitting at lights and emergency situations. You can, and a loooot of people do, get by using only front brakes.
@@argh1989 an explosion is also a combustion. In order for an explosion to occur a combustion reaction must be initiated. The more energy diffused the bigger the bang. What are you talking about mate?
@@BigUriel No, knocking is not the same as your engine exploding. It can lead to it, but I'd say the difference is: Knocking wears your engine, exploding disintegrates your engine. I know it's a finicky technicality, just wanted to share a "fun" fact.
Excellent! Many years ago I had a 1964 flat windshield Chevy van DIY camper conversion. I put in a 1957 Chevy OD transmission to lower highway RPM, darn thing just snapped into place. The OD transmission had a freewheeling clutch, a planetary gear high/low range --6 gears! Sorta -- and a cable controlled freewheeling lockout. Loved it, clutchless shifting, gear choices when negotiating New England snow, and a little better fuel economy. But, there is a certain risk with a freewheeling clutch in the mountains. All was fine if you remembered to lockout the clutch, and the cable wasn't seized. Had some exciting moments on the edge of total brake fade.
Great explanation! I always use engine breaking when driving a manual car. For two reasons: less break wear and fuel saving. When you roll down a hill and you press the clutch the engine starts to burn fuel to keep itself running. Using the engine break the potential energy which pushes the car down the hill also turns the engine. But what I really didn't know is that the engine uses the pressure differences for breaking. I always have thought that the breaking comes from the friction in the engine and the gear box 🙈
In Germany in Drivers training they teach you to mostly use Enigine Braking also Downshifting and while downshifting braking so you use the engine brake and the normal brake so u have less brake wear
They need to go back to requiring Auto Shop in every grade level again. Every women I've met believes: "LOUD = BAD" when it comes to engine noise. It's because most drive fully automatic vehicles and the once in a blue moon they've had to gun it in order to get adequate acceleration, they are not used to hearing higher rpm noise... "it doesn't sound like that all the time, so that must be bad, full acceleration = bad" ??? While you're at it: Teach her to just let OFF the gas without tapping the brakes every 1.2 seconds over and over. Those people drive me f'n INSANE, why don't they just leave adequate following distance!?!?!?!!????? 90% of the time, it's a woman behind the wheel. I hate to say it, but it is. And somehow I doubt whatever they are driving has upgrade pads/fluid/rotors/ or F1 carbon ceramic brakes. THEN! Once a year when they actually do wash the car, they see all the rock chips all over the front, and cannot figure out why? "the paint on this car sucks!"
Take it from a master mechanic of 42 years experience. Excessive engine braking (downshifting coming to every light) causes excessive clutch, throwout bearing, transmission gear, u-joint, differential, engine and thrust bearing wear because every moving part is being torqued from the wrong direction. Downshift when you need to but not as a matter of habit. If you slow from 60 to 20mph and then need to accelerate again, downshift to 2nd and move on. I don't care how good you are at rev-matching because all of these other wear scenarios still exist. New brake pads are one of the cheaper car repairs when compared to any of these other items. Downshifting on a steep hill whenever necessary is mandatory, downshifting because you think it's cool is a waste of money because, eventually, you are going to wear something out that would not have normally worn out. But then, we mechanics LOVE that!
Not really. Had a 95 Honda civic for 15 years. I would engine brake all the time. In the 200k miles put on the car I changed the brakes once, and clutch at 180k. Trust me if done right there wont be problems with the engine
could u please explain throttling delay in new cars, which i face "engine is seconds slow to react if i press acceleration paddle". is it a good thing or not? should i tune it at service center?
Some new cars stop there engine if your at a dead stop. Or maybe if u press to hard in automatic car it might try to downshift b4 you move which takes time
When trucks and buses with manuel transmission were still around it was common to brake with the engine. Either with a dedicated engine break system that slows down the engine even more, or with downshifting. To reduce wear from downshifting you can go into neutral, rev up the engine to get to get it to spin more closely to what it would in the lower gear at your speed and then put in the lower gear. This way the clutch doesn't have to work so hard.
Now there is a difference between engine braking and excessive engine braking. If you just driving normally but you are downshifting so many gears causing the rpm to get near redline, that's excessive.
In the uk during driving lessons we are taught to engine brake when going down hills to prevent the brakes from overheating . I was also asked about engine braking down hills in my theory test.
Another nice vid. Engine braking is good. Lets say you are going down a hill in the snow. Go slowly & moderate your speed using the engine. You then have full control of your steering rather than depending on your ABS. Taught my wife that in the Peak District (England) a long time ago. All the best..........
Engine break 1. helps control the car better 2. saves breaks 3. makes you a better driver from the moment you start engine breaking and stop using breaks 4. saves the lights of the breaks 5. saves clutch
Also another advantage. For anyone with a tuner hooked up you'll see the a/f ratio go way lean. When you coast in gear the computer actually shuts off the fuel so it runs purely on vacuum and momentum. No gas is being used at that point
Someone needs to explain this concept to the tail gating 40-60 year old women on I-5 in Oregon. You CAN take your foot off the gas instead of tapping the brakes every 1.2 seconds (maybe the brake tapping it Morse code?).
It is extremely annoying. Thankfully some 60 year old women have driven manual cars all their life and only recently switched to automatic, and they will let off the accelerator to slow down.
I like to use engine brake, and gradually reduce gears, but I recommend either release the clutch slowly (don't release too fast and don't let it slip, this will only increase wear and put stress in the gear box) or reducing with heel and toe (best option, it's quick and smooth to both you and gear box)
@@antton9623 that's what heel to toe is. You "blip" the throttle while you're on the brake which sends the RPMs up, and then you release the clutch near where you would match the RPMs. heel toe is using both feet on all 3 pedals.
@@CRneu I know what it is and that's why I said what I said. Rev-matching does not have to include the brake pedal at all. You know you can downshift without braking?
I've noticed the people who enjoy tail gating hate it when I compression brake instead of hitting the brakes during stop/go traffic. They just go insane and do everything to go around you. They simply refuse to keep a proper following distance and see only two options: Gas OR brakes, never coasting/compression braking, that in their minds is not allowed/doesn't exist.
07wrxtr1 This is true. Especially drivers who only drove automatics in their life, they simply can't understand that vehicle can slow down without slamming the brake.
I've had my BMW 120d from new for 6 years and totalled 93,000 miles. I always engine brake and downshift gently to control my speed where possible, and use the brakes only when necessary. I've never had to change my brake pads, in fact I had my annual MOT yesterday and the technician stated that the front pads are on 11mm and rears are on 9mm. Amazing!
I always give these guys proper following distance as they are going to kick up rocks and they typically need to change lanes unexpectedly (prius drivers), so I keep out of the blind spot and pass with a vengeance or just stay way back. I feel sorry for truckers that have to navigate around all these people that are for the most part indecisive on the road.
The main problem with downshift engine braking (assuming that you rev match) is that it increases wear on the upper main bearings in the engine. This is fine and won't be a problem - but it will be a problem if you are trying to use downshift engine braking during everyday driving traffic. It's fine let the car slow down in gear, but shifting to a lower gear to rev up the engine will cause that wear - but again this is only a problem if it's a driving habit. If it's a downhill only practice it works great.
nerdyengineer yeah.. but what do I do when I want to practice heel and toe downshifting I have to do it often how am I gonna get good at it if I do it occasionally? I have to practice at almost every opportunity once good I can do it less
Way back before disc brakes, drum brakes were often marginal for repeated use. Think MG-TD or Jaguar XK120/140 era cars. Downshifting was almost mandatory to preserve what little braking power those cars had, especially when the drivers were trying to emulate J.M.Fangio. Today, with vented rotors, and cooling air management to the brakes, they’re pretty much bullet proof unless intentionally abused.
@@CoreyBrass I find people who brake by lowering the gears or downshifting, they defend it to the death, I see it badly, they do not understand the stress they put on the gearbox when the brakes are for that, they have compared trucks to me and they do not understand that they have one. Special gearbox to be able to brake with it and not overheat the brakes, but I repeat it is special, it is not common and less than domestic vehicles.
@@nopochoclos I use to brake by downshifting but not in an insane way so I don't think it added additional stress as hard as acceleration would. I stopped doing it in my 2007 front wheel drive car because the clutch is so hard to get to that I don't want to change it if I don't have to. I'll replace brakes pads up the ass to avoid trying to change that clutch.
@@CoreyBrass Yes sometimes no problem or when goes slow, but common people dont know that haha, i see a lot of people doing like racing car, then ask why his new car has damaged gearbox... haha
Most cars today will go up a hill in top gear. I can overtake going up hill in top gear in mine. Top gear will not keep the car from accelerating down the same hill. Neither will 5th. You need to go down to at least 4th to hold speed and 3rd to decelerate.
This was in the owner's manual of the last manual transmission car my family owned. In my current automatic, it seems to automatically engine brake (high RPM down a hill if I'm off both pedals) good to know it isn't dangerous to the engine and actually saves fuel!
I threw my girl friends pos dodge neon in "park" @ 40mph one time. Dash lit up like a christmas tree and the trans made a funny clicking noise. Oddly nothing ever broke, and she drove it fine for another 6-7 years.
I have a 6-speed manual FRS. I use the engine to break all the time. The result was that I did my first brake job on it replacing only the pads and the original pads still had about 1/16 of an inch left on them. this was at 142,000 miles.
@@dnawrapsatl I'm or of those guys that thinks the FR-S has all the power it needs. :) I'm more into handling. I use the gears to manage the power curve, and engine longivity is paramount.
I drive a semi truck for a living, this guys explanation it too complicated. YES USE ENGINE BREAKING!!! By engine breaking this is how BIG trucks: 1. Slow down faster 2. Control speed 3. Keep traction on bad ground (snow and ice) 4. Maintain speed while descending long and steed hills 5. Save parts that degrade like the breaks 6. Prevent overheating and warping of the breaks, that could also cause a fire The engine and transmission are fully capable of slowing you down and helping you get control. However a large difference with a semi truck is that there is an additional engine break (switch) that is know as a retarder. This commonly know as the “jake break” prevents half of the exhaust valves for opening in 2, 4 or all 6 cylinders. This creates back pressure in the firing chamber helping to slow the engine, and thus the transmission and the vehicle down.
One time to not let off the gas to slow ("engine braking") is icy/snowy conditions in a front wheel drive facing downhill, then you'd rather have braking on the rear tires rather than just the fronts. It IS ideal for RWD in those conditions however, helping to keep the car straight and allowing traction for steering.
I have always used engine braking. Coming to a stop in 4th or 5th feels like the car is ' running away with you " where gearing down to 3rd or 2nd feels like you are in total control. My wife disagrees of course.
Is it that simple then , just drop a cog or two and that will save you , brakes are there to slow you down and lower gears are used to maintain that slower safe speed .
In Malaysia, not at all, they aint even teach you when to shift, some of the tutor says 3k, some say 2k, and they cant explain why. now i learned how to drive by daily driving, i shift whenever i like, like learn to handle the redline, so i won't get nervous when i need it. no mom spaghetti or if i feel like to cruise & chill, shift before 2.5 (or 2, depending on vehicle, my car has the best torque in 1.7k and 4k, on paper, so) In short, they only teach me how to ignite a car, not drive, no engine brake, no skipping gear shift, nothing at all, i gained more knowledge from youtube tbh.
Another thing to metnion - if you have AC turned on, while engine braking on descend it will actually run the compressor for AC without burning any fuel. So you recycle part of the kinetic energy to do useful work insetad of buring fuel.
@@ScripturaSola777 Yes and you also recover some of the energy from already burnt fuel back to usefull stuff like: - Turning alternator to power electrical systems and charge the battery - Running AC compressor to cool the cabin - Running power steering system - Running Water pump to cool the engine So you get the double gain. Since all of those utitliy systems are connected to engine, you actually brake by letting all those systems take the load of the gravity pulling you down. And of course no additionl fuel being burend on descend. + your brakes are cool and not wearing down pointlessly. You just apply brakes every now an then when needed before a turn or if speed goes too high.
One thing to note is that if you are going downhill in the Rokies or whatever and have the heater on, it is totaly normal for your coolant tempretature to go down. Lots of cold air hits your engine and you are asking for heat yourself to warm the cabin. Heat from engine braking really is miniscule. I am commenting on this because many thermostats have been changed for no reason. In cold environment going downhill with no throttle, engine temps can only go down no matter what, and this is normal.
Engine breaking can save the need to replace your breaks by up to 3 times the need. Down shifting is better for your car than shifting up in gears. It is also safer to use engine breaking.
I never knew but I've been doing it for years because it made sense to me than keep using the clutch. Less friction on the clutch and pivot fork was my logical understanding.
I think it will be beneficial also after the engine break-in period as it gives the piston rings "some action" if the engine is operated normally only at low rpm.
In 1987 I bought a 20' motorhome built on a Toyota truck chassis. The truck had a 4-cylander engine and a 4-speed manual transmission. I took a trip to Michigan from California and returned with my parents, my 3-year-old son, and my 10-year-old nephew. We passed through Jackson Hole Wyoming, and I will never forget climbing that highway pass and coming down the other side. Going up, I was in first gear all the way and not stopping for anything. Coming down the other side I was in first gear again, using the engine for braking, but the engine was whining way up and I had to use the brakes to assist the engine. I never would have made it on the brakes alone, I would have burned them up. That was an engine-braking experience in a manual transmission vehicle.
Love your videos, Jason!😍👌 Very interesting... I was putting engine braking to the test yesterday in the western NC mountains. Had a blast! Have a great day, buddy!🙋
Engineering Explained Awesome, man. Your S2000 would be right at home there. Yesterday, I was on 226A that goes into Little Switzerland. They call that stretch the Diamondback. Check it out when you get back home.😆 Cheers!
Your Slowbro I was in my 2014 Q50S Hybrid RWD. I was trying out my new Michelin Pilot Sports and 14" Stoptech slotted rotors. It's no S2000, but the car handles great, especially for its size. Great stretch of road... give it a go when you get a chance.
Engine breaking and down shifting is a skill every driver needs. Everyone should be taught how to slow a car down from 70mph to 3mph without using brakes, useful for at least 2 situations. Icy roads or brake failure.
Thanks, I’ve always used engine braking in my 5.0 Litre Mustang, I love the sound and now I’m assured that this method has no adverse effect on the mechanical components of my drivetrain
With the injectors off it's the wheels that are transferring power back into the engine to overcome it's inertia and friction to keep it turning and that is how the kinetic energy is dissipated. Secondly with the throttle closed, little air is coming into the engine and since there is no fuel added it is just taking the heat out of the cylinders and out the exhaust. Love your channel by the way and great video!
Here in the UK, where I learned to drive we are taught to use the engine and gears to slow you down. This causes no premature wear on clutch or transmission as can be proven by the millions of UK and European motorists who are taught to drive properly from the outset unlike americans
Downshifting is great for setting yourself up for a corner, but it does NOT help you stop faster. In fact you can stop faster by just pushing in the clutch and using the brakes alone.
@@80s_Boombox_Collector it absolutely does, not as fast as using your brakes but it definitely helps you stop faster than not downshifting. Clearly you've never touched a manual.
@@re_stricted Sorry, but in an emergency, the best thing to do is declutch and slam on the brakes. The ABS will put the tires on the edge of traction all the way until full stop. You downshifting is only going to make that process less efficient.
Heavy trucks have manual transmissions, even if they are auto shifted, and using engine braking, either by use of the exhaust brake or just the natural compression and friction in the engine, are the only way they can safely go down hills. I think a white board comparison of the heat generated from combustion vs the heat generated from engine braking would be pretty cool.
I love engine braking, one of the reasons I've only owned manuals in the last 30 years....now, if only people could learn how to coast ,(in gear, with foot off accelerator), at speed on freeway downhills (also accounting for leaving a large buffer - at least three second - zone to the next vehicle in front of them) , and not continuously use their brakes...in a manual transmission, life is easier as I only need to drop down a gear, or may be two depending on traffic, to sustain the same speed when coasting as the posted speed limit.
Perfectly explained. Been driving manual cars for 30 years and use engine braking in my diesel SUV as it is heavy. My mom used to NOT use engine braking and we replaced the braked pads on her car every year. So yes it makes a huge difference.
The guy I drive with to work does not engine brake and man the car takes longer to slow he just holds the clutch in and gears down without releasing the clutch don't even ask why he does this.
i'd really like to know just how much you can reduce your break ware when you efficiently engine brake. given how much engine braking can cover in everyday situations i'd say some people could probably double their brakes lifetime
My father teached all of my family to do it, we pretty much had to change brake pads like every 10 years on our cars. If you combine it with "foresighted driving" (= looking for situations where you have to brake anyway, and slowly brake with the engine instead) you can decrease brake wear even further. Dont forget to tip the brake like you would tip the gas when doing upshifts.
I personally think that engine braking is more of a fuel economy thing than a preserving your brakes thing The longer you take to stop, the longer your engine doesn't have to use fuel to keep itself spinning. Braking straight up wastes energy, but engine braking at least lets that energy be used to keep the engine spinning. Plus, if you're slowly rolling up to a red light, it might turn green by the time you arrive and drastically reduce the fuel needed to accelerate back to full cruise
@@hojnikb That depends. If the oil gets injected into the air intake (just past the throttle body) it would still lack the airflow to reach the piston. I don't actually know if there's engines with oil injection directly into the crankcase or onto the bottom of the piston.
I pretry much engine brake in my manual 86 gt trd all the time. Just make sure you rev match properly so you don't stress your synchros and you're fine. I typically do it when i see a red light far ahead or need to gradually reduce speed
The question I hoped you’d answer: I’ve known people who downshift through each gear every time they slow for a stop (e.g. a stop sign), letting out the clutch after each downshift -- exactly the reverse of when they were accelerating. To me, it just doubles the wear on the syncros and all the other components involved in shifting. It's better to skip the downshifts when you are stopping, then put it in neutral and let out the clutch while you wait at a light. (leaving your foot on the clutch pedal wears out the throwout bearing.) Your thoughts please.
@@Quinney84 Right. Perhaps I didn't explain myself clearly. Although it doesn't damage the motor, or the transmission, or the clutch, every shift causes wear. Certain components (such the syncros, the throw-out bearing, and various bushings and linkages related to the clutch and shifter) will wear twice as much if the transmission is shifted twice as often. Brakes are cheaper than transmissions, and they are designed specifically for stopping. So it's better to skip all the gears when you are stopping (then shift into neutral and let out the clutch while you wait at a light.)
Even with a closed throttle there is enough air flowing into the cylinder to increase the temperature significantly when the piston starts to compress it.
I think it's easiest to think of it from an energy standpoint. The car moving has kinetic energy. To slow it down, you have to turn that kinetic energy into another form. In this case, you're using the engine to slow down the car, so there must be heat created. It takes work for the piston to pull the vacuum, there's resistance (the throttle body blocks proper airflow). This resistance generates heat.
I was told "engine braking" in driving school. 🤷♀ It's good to save gas, spares the brakepads & its saver on long downhills. Never thought that there might be a discussion about it.
Another detail you didn’t mention, particularly with the BMW you are driving, when you engine brake on those cars, the instant MPG gauge goes to what looks like battery charging. My Audi does it. It’s not a hybrid either. Was wondering if you could do a video on how it all works and why some cars do it, if you haven’t done that already.
In order to save fuel, modern cars try to use the alternator more sparsely, as it's quite significant load to the engine - during the engine braking, they'll use it to recharge the battery, acting sorta like low power regen braking.
I love your videos, they are remarkably done, no gues work. You put time, research and skill them. The motoring stuff is done superbly for the ordinary driver to understand but also for those interested in some technical stuff.....
Engine braking is also beneficial because it doesn’t tend to want to lock the wheels like the brakes do, especially when traction is minimal. The engine wants to slow the rotation of the driving wheels.
I think when people say engine breaking they are referring to that slight shock of downshifting when you ONLY let go of the clutch slowly (as opposed to rev matching)
@@robr430 rev matching means you press the accelerator while downshifting, so the engine reaches optimal RPMs. In racing it keeps the car balanced, while in regular driving it reduces wear on the drivetrain
When you use engine braking all the pressure on transmission gear faces and engine bearings is reversed allowing a slightly thicker oil film between metal parts and overall reducing engine and transmission wear.
From watching these engineering videos, I was told that the vacuum created on the intake was the key to engine braking, but a simple experiment on my motorcycle led to the opposite conclusion. I was coming down a hill in gear. I hit my engine killswitch and fully opened the throttle with my hand. There was no difference in the amount of braking with an open or closed throttle. What gives?
sac speed The rotational energy lost compressing the piston is simply regained once the piston decompresses. The friction and vacuum explanations make more sense. I'm most inclined to believe EE as he is (was) a well studied engineer who designs car engines for a living. Though, OP's experiment throws the vacuum theory out so I'm still curious for any further insight.
