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Post by GTCGreg on May 14, 2015 16:03:09 GMT
I thought everyone knows how to engine-brake. I only tend to use engine braking when I want to decelerate over a fairly long distance. Otherwise I would rather use the brakes. The reason is that it's a lot easier and cheaper to replace brake pads than to replace a clutch or rebuilt an automatic transmission.
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Post by the light works on May 14, 2015 16:08:05 GMT
I thought everyone knows how to engine-brake. I only tend to use engine braking when I want to decelerate over a fairly long distance. Otherwise I would rather use the brakes. The reason is that it's a lot easier and cheaper to replace brake pads than to replace a clutch or rebuilt an automatic transmission. I had to replace a clutch once... some people have to replace their brake pads as often as every 10-20,000 miles.
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Post by GTCGreg on May 14, 2015 16:15:51 GMT
I only tend to use engine braking when I want to decelerate over a fairly long distance. Otherwise I would rather use the brakes. The reason is that it's a lot easier and cheaper to replace brake pads than to replace a clutch or rebuilt an automatic transmission. I had to replace a clutch once... some people have to replace their brake pads as often as every 10-20,000 miles. I can replace pads in about 20 minutes per wheel. It took me 4 days to replace the clutch in one of my Jeep. Of course a lot of that was the learning curve.
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Post by Lokifan on May 14, 2015 16:22:25 GMT
I thought everyone knows how to engine-brake. I only tend to use engine braking when I want to decelerate over a fairly long distance. Otherwise I would rather use the brakes. The reason is that it's a lot easier and cheaper to replace brake pads than to replace a clutch or rebuilt an automatic transmission. Yup. I didn't used to bother with engine braking, but I quickly relearned it once I warped the rotors going over the local mountain ranges. Riding the brakes for 10 miles or more = not a good idea. My wife still gets confused by engine braking...and she takes better care of her car than I do.
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Post by OziRiS on May 14, 2015 17:14:55 GMT
I don't get how engine braking can be so hard for some people. Just let go of the accelerator pedal and let friction and drag do the rest. Your only task is to gauge distance and figure out when to let go. That's how easy it is in an automatic.
For a manual transmission, the only extra work you have to put in is to downshift when the revs get low enough.
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Post by silverdragon on May 15, 2015 8:00:32 GMT
No. Its taught how to hold a gear on long hills, (manual transmission of course... in UK, Auto transmission tests are see as "for wimps", and only respected when the driver is disabled) Otherwise, dropping a cog on approach to a set of lights is not a requirement, and dropping a cog to slow down without using brakes is a "no no no no", as slowing down without covering the brake is a fail.
When I engine brake, I know to always press just enough on the brake pedal to light up my brake lights.... Otherwise, you risk rear-ending by the twit behind who is driving to your lights.
This is advanced, its not taught to new drivers.... Or wasnt last time I checked?... I know the test has changed, I have to admit, I am not 100% on the newer tests.
That doesnt work sorry to say. The "extra wear" on the engine is no more than any town drive car would get, so, actually, negligible, unless you adopt "Cant find it?.. grind it!" gear changes and excessively slip the clutch....
As for the engine wont take it, which I have heard in some places, unless your swapping to 1st at over 30mph, yes it bloody well will. The forces involved on engine braking are exactly the same as hard acceleration. So if you use the same gear range as you would whilst acceleration, you just have the same force but in reverse, and yes, the engines are designed to take that.
Heck, Trucks are built WITH an engine brake. Exhaust brake, Jake brake....
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Post by silverdragon on May 15, 2015 8:01:44 GMT
BTW, is this getting to a separate thread status?... we are off on a tangent here. Is it getting to "Myth" status?.. which is better, engine brake or foot brake status?...
Suggestion here for a Mod to split off the topic to separate thread?...
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Post by the light works on May 15, 2015 14:50:26 GMT
our newer engines turn on the brake lights when the engine braking system activates. we do still switch the system off in bad weather, because it is otherwise fully automatic.
let's also get out of the way that one of our members performed tests and determined that engine braking with a gasoline engine is mostly from vacuum against the closed throttle. (I think I have heard rumors that some new diesel engines have a similar device for the purpose of engine braking.)
in fact, there are multiple engine braking technologies: the Jacobs system uses an extra valve in the engine that dumps pressure at peak pressure to prevent a firing stroke. the newer variant closes or partially closes the exhaust system which forces the engine to pump pressure against the closure. there is also a transmission retarder which essentially engages a torque converter that is held in place to resist the torque of the driveline.
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Post by silverdragon on May 16, 2015 8:09:08 GMT
We have to split this away from Trucks who use a braking system and are designed to use that system as brakes. We know those systems work.
What we are looking at is engine braking for "junior", small cars with smaller engines.
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Post by the light works on May 16, 2015 9:23:51 GMT
We have to split this away from Trucks who use a braking system and are designed to use that system as brakes. We know those systems work. What we are looking at is engine braking for "junior", small cars with smaller engines. I pretty much stopped downshifting in the Jeep after the engine transplant - it became unnecessary unless I wanted to go below 30 MPH.
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Post by silverdragon on May 16, 2015 9:31:31 GMT
We have to split this away from Trucks who use a braking system and are designed to use that system as brakes. We know those systems work. What we are looking at is engine braking for "junior", small cars with smaller engines. I pretty much stopped downshifting in the Jeep after the engine transplant - it became unnecessary unless I wanted to go below 30 MPH. Nope... not getting that.....?...
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Post by the light works on May 16, 2015 9:37:10 GMT
I pretty much stopped downshifting in the Jeep after the engine transplant - it became unnecessary unless I wanted to go below 30 MPH. Nope... not getting that.....?... idle in third gear was just below 30 MPH - and if you stepped off the throttle, it really wanted to get there. going to second too abruptly at highway speed would bark the tires even before the engine transplant.
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Post by silverdragon on May 16, 2015 9:40:52 GMT
So you are saying stepping OFF the throttle alone would lock the tyres?...
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Post by the light works on May 16, 2015 9:45:19 GMT
So you are saying stepping OFF the throttle alone would lock the tyres?... no, just lay enough drag on them to skid.
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Post by OziRiS on May 16, 2015 16:42:53 GMT
So you are saying stepping OFF the throttle alone would lock the tyres?... no, just lay enough drag on them to skid. If my car started doing that, I'd take as a sign that I needed a new car!
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Post by the light works on May 16, 2015 16:55:40 GMT
no, just lay enough drag on them to skid. If my car started doing that, I'd take as a sign that I needed a new car! woops - that's a hard downshift that actually barks the tires. stepping off the throttle, alone,, gives about the same reaction as stepping off the throttle AND downshifting did in my Acura.
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Post by OziRiS on May 16, 2015 17:12:52 GMT
If my car started doing that, I'd take as a sign that I needed a new car! woops - that's a hard downshift that actually barks the tires. stepping off the throttle, alone,, gives about the same reaction as stepping off the throttle AND downshifting did in my Acura. So what you're saying is that you either had a very heavy vehicle, tires that produced a lot of friction/drag or both? Certainly seems that way to me with the extreme amount of engine power needed to keep the car at speed. Last time I experienced something like that was in a 1982 Mercedes GD240 with mud tires. On paved road, that thing would drop from 45mph to 30mph in a matter of seconds once you stepped off the throttle.
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Post by the light works on May 16, 2015 17:33:33 GMT
woops - that's a hard downshift that actually barks the tires. stepping off the throttle, alone,, gives about the same reaction as stepping off the throttle AND downshifting did in my Acura. So what you're saying is that you either had a very heavy vehicle, tires that produced a lot of friction/drag or both? Certainly seems that way to me with the extreme amount of engine power needed to keep the car at speed. Last time I experienced something like that was in a 1982 Mercedes GD240 with mud tires. On paved road, that thing would drop from 45mph to 30mph in a matter of seconds once you stepped off the throttle. engine with a LOT of torque. it could theoretically go from 0-100 without changing gears. (I say theoretically because I never actually took it past 90)
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Post by c64 on Jun 27, 2015 23:02:42 GMT
I had to replace a clutch once... some people have to replace their brake pads as often as every 10-20,000 miles. I can replace pads in about 20 minutes per wheel. It took me 4 days to replace the clutch in one of my Jeep. Of course a lot of that was the learning curve. With the proper tools, I can replace the clutch within an hour in my car. A spare set of clutch parts costs ~€150. Changing the brakes takes about half an hour per wheel and the spare parts cost €60 per front wheel and €80 per rear wheel! But I don't jake brake often since this blows fuel when the engine is running with less than 2400 RPM and above, the engine brakes very intense so you slow down real fast if the hill isn't really steep. The clutch usually lasts 200,000 kilometers and the pads up to 100,000 if you have good driving habits. A friend is known to destroy brake pads and clutches within 20,000 kilometers. He had failed driving school for 3 times...
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Post by silverdragon on Jun 28, 2015 8:50:38 GMT
I have stated many times I use engine braking in my car. I would expect therefore my Clutch to be fried, according to what has been said in this thread.
I dont know where, but, there is an "inspection hatch" somewhere on my car to inspect the condition of the clutch....
My friend the mechanic who does the MOT on my car knows, so, whilst in for its MOT recently, I asked him how the clutch was. He says he has had a look, and I trust he would have done that, and according to him, for an 80,000 mile, its in reasonably good condition, and if I keep the car for another 8-10 yrs, it wont need the clutch looked at (at my current average mileage)
As its Toyota, he does very little work on it, because it doesnt need any, and he is a bit vocal at times on my "paranoia" about parts wearing... "You bought a bloody Toyota, what did you expect?.. it lasts longer than you think...." etc. "Keep swapping the tyres and I will let you know when the brakes need doing..."
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