Engine braking ok?

[VEGASRIDER]

This is absolutely absurd! Engine breaking is perfectly fine! I down shift and let the clutch out to use engine breaking EVERY time i stop. I match RPM when doing so as well.

"the brakes are for stopping, and the engine is for go" I had never heard this until now and i think its a pretty dumb statement, you put no more stress on the engine and tranny engine braking than you would when accelerating hard.

Youngun and I, we ride alike. There are many times I will come up to a stop llight without even using my brakes. Engine braking is a technique I use on a daily basis. Technique, because at times, you have to ease in the clutch depending on how much you want to slow down with the engine. Popping out the clutch when downshifting may cause a very jerky motion.

But again, different strokes for different folks. Just like many members on this forum ride cruise between 3-4 thousand rpms. I ride between 6-8000 rpms.

Plus one on the powerband comment, I agree, very critical for you to be in the correct powerband at all times!

 

[urbanj]

Engine braking is perfectly fine and won't hurt the motor unless you're dropping into a gear way lower than what your speed calls for. I used to drive semi's for a living and if you didn't have a Jake brake (an engine brake in itself), you sure as hell relied on engine braking for what it was worth when hitting a 6% grade (generally not much when you're hauling 45k of paper rolls).

It ISN'T effective for emergency stops unless your emergency gives you enough time to roll through the gears, but it's great for moderate decelerations while coming to stop lights, for example. I generally make sure I'm using a little brake at the same time so that I have an illuminated brake light warning those behind me. There's nothing worse than attempting to resume travel or quickly get out of the way while you're slow and in 6th gear...if you're complementing normal braking with engine braking, you'll be set to resume in the right gear.

you had to have some form of supplementary brake setup on your rig. electric, hydraulic, engine or exhaust? diesels have no throttle plate and create no intake manifold vacuum and create next to nothing in braking effort. all the air drawn in is compressed to high levels and then when nothing is done with it (energy can not be created nor destroyed blah blah blah) it expands and pushes down on the pistons again and acts on the drivetrain. compression release (jake brake) opens another exhaust valve right when the compression is the most , killing all potential energy.

thats diesel

in a gas motor the braking is provided by high intake manifold vacuum. the piston on its way down on the intake stroke (throttle plate closed) has to essentiallynsuck on the way down with nothing to suck (no air), slowing down the piston. thats vacuum.

if you are going to engine brake thats fine but there is no need to use it as a primary braking device. hydraulic brakes are primary. sure keep the engine in its power band but brake and downshift accordingly. dont just let it run down from high rpms and downshift and wear the clutch and trans. and let it run down again. this isnt a race, no need to be braking and keeping the engine at ridiculous levels.

 

[vdbergj1]

I think it is a matter of your own style - what floats your boat. I use engine braking with the front brake (break light will always indicate). I rarely use the back brake but my foot is always with it. But then again I'm new to motorcycling and learning every day.

What about the latest on bikes with the 'Slipper Clutch'? Why I remembered this is - thy recon the standard Triumph Daytona 675, which I love, don't need it because they managed that function with the ECU and fuel injection and apparently it works great - for standard use, it comes with the race setup.

Quote: The bike doesn't have a slipper clutch (the race kit includes one), but the effect of engine braking from high rpm downshifts was negligible. Not once did the rear wheel lock or slow savagely to upset the chassis especially when banked over. This is down to the ECU and Keihin fuel injection working out throttle position against crank rpm (amongst other sensors) and allowing the butterflies to partially open and allow air through to the cylinder head to reduce the effect of engine braking.

...or maybe I don't understand the concept...

 

[wrightme43]

Oh MY GOD WE ARE ALL GOING TO DIE!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Oh wait wrong thread.

LOL


I use engine braking all the time, in cages, on bikes, on four wheelers, it hurts nothing.

 

[Hellgate]

This is absolutely absurd! Engine breaking is perfectly fine! I down shift and let the clutch out to use engine breaking EVERY time i stop. I match RPM when doing so as well.

"the brakes are for stopping, and the engine is for go" I had never heard this until now and i think its a pretty dumb statement, you put no more stress on the engine and tranny engine braking than you would when accelerating hard.

Check the first edition of Twist of the Wrist, circa 1984ish. Using your engine to primarily slow the bike is akin to using only your rear brake, we've hashed this topic out several times before, use both brakes to best control the stop/slowing. All engine braking does is interfere with your ability to sense the traction of your tires. The high vibrations tend to mask that. Also don't mistake a downshift with engine braking, that is two different things. In a downshift you are clicking through the gears, an engine brake is chopping the throttle and coasting down.

Regardless I don't give a sh*t if a person wants to the throw their bike off a cliff, it maybe stupid but its their bike, they can do what the wish.

Oh and finally, just because YOU haven't heard of it doesn't make it stupid, it only means you haven't heard of it. :thumbup:

 

[Wildcard]

I engine break, I mean brake all the time. Nothing going to hurt itself. I'll even downshift from 6th to 2nd coming off the the highway. BUT I blip the throttle and downshift to each gear so I rev-match. Fun fun fun.

 

[dako81]

you had to have some form of supplementary brake setup on your rig. electric, hydraulic, engine or exhaust? diesels have no throttle plate and create no intake manifold vacuum and create next to nothing in braking effort. all the air drawn in is compressed to high levels and then when nothing is done with it (energy can not be created nor destroyed blah blah blah) it expands and pushes down on the pistons again and acts on the drivetrain. compression release (jake brake) opens another exhaust valve right when the compression is the most , killing all potential energy.

thats diesel

in a gas motor the braking is provided by high intake manifold vacuum. the piston on its way down on the intake stroke (throttle plate closed) has to essentiallynsuck on the way down with nothing to suck (no air), slowing down the piston. thats vacuum.

if you are going to engine brake thats fine but there is no need to use it as a primary braking device. hydraulic brakes are primary. sure keep the engine in its power band but brake and downshift accordingly. dont just let it run down from high rpms and downshift and wear the clutch and trans. and let it run down again. this isnt a race, no need to be braking and keeping the engine at ridiculous levels.

You're wrong. The engine is a big air compressor. It takes energy to compress the air, which is supplied by the fuel being injected and ignited. You let off the throttle on a diesel and it's not really spraying any fuel, just enough to idle. You then engine brake, spinning the engine up fast, using the kinetic energy of the vehicle to compress the air in the clyinders. This energy that is used to compress the air in the cylinders slows down the truck, since it is a lot of energy, that isn't being provided for by the fuel.

Actually, the vacuum created behind the throttle body on a gasoline engine helps the engine to not engine brake. The vacuum disallows air to be sucked into the cylinders to get compressed, which basically means the engine is pumping no air, which allows it to spin much more freely. Try this, get in your car and let it run, rev it up and shut it off while it is revved up, making absolutely sure to have your foot off of the throttle while it is revved up. It will smoothly come to a stop, because it isn't hardly sucking any air, so it has nothing really to compress. Then do the same thing, but right when you shut it off, floor it. It'll shake when it shuts off just like a diesel. This is because it is sucking air in and compressing it. It will also stop spinning faster than without opening up the throttle, once again because it takes energy to compress the air. This effect will be more noticeable in different vehicles than others. Some, it might be really hard to tell the difference, but it will happen. One of the main ways you can tell if it's a car where you don't notice a difference is the sound and speed at which it spools down.

I can try to go into more detail and explain this to you more if you would like.

And the part where you said when the air is compressed and then when nothing is done to it, it expands and pushes the piston back down, that doesn't make any sense at all. If that were the case, we would have engines that could run on nothing, just start em up and the could run off of air.

And I use mostly my front brake to slow down, but if I'm not coming to a stop or slowing down in a rapid manner, I will just downshift match the revs and be on my way.

 

[Burnspot]

Let's face it...ANY time you let off the throttle with the clutch still engaged, you're engine braking in varying degrees, depending on what gear you're in (the lower the gear, the more extreme the effect). If there were a big fear of damaging something, we'd all be pulling in the clutch whenever we let off the throttle and that's just plain ridiculous. The engine's not going to explode or unload parts; it can take it with no trouble.

When used prudently, engine braking can be employed to great effect to SUPPLEMENT normal braking. If you're in wet weather, I wouldn't go for any extreme gear drops and clutch dumping or you're asking for some skating rink action. I never use the extreme drops...somewhat akin to someone learning to drive a manual shift car and accidentally dropping from 4th to 1st for example.

For Urbanj and my semi-truck mention...nope, I only had my normal air brakes outside of whatever effect I could get from my non-Jaked engine braking. A normal non-Jaked diesel just doesn't give you a lot of engine braking. There were MANY times I wished I had gotten a Jake installed though as it would've prevented many ass-clenching moments when my brakes started to go away while still halfway down a hill (Grapevine in CA is a challenge for heavily loaded trucks....oh the stories I could tell).

 

[necrotimus]

I never engine brake or downshift because it is so bad for the engine. Once I hit 6th gear for the first time I was screwed. Oh well my clutch control is amazing!!!

 

[abacall]

I engine break, I mean brake all the time.

Yeash, that drives me nuts. I'm glad I'm not the only one.
I would hate to engine break......

 

[ROACH1111]

I've never quite understood how to "blip" the throttle. I know racers do it a lot, but the person who told me about it didn't explain very well. Could someone who "blips" explain how they do it? Thanks.

 

[dako81]

I've never quite understood how to "blip" the throttle. I know racers do it a lot, but the person who told me about it didn't explain very well. Could someone who "blips" explain how they do it? Thanks.

Crack it open 25-35% more than where you have it or so, real quick to get the r's to come up easily when the clutch starts to engage.

 

[CravenMoorhead]

Blip... like "a blip on the radar screen"....on and off very quickly.

Its that flicking throttle twist making quick power to the rear wheel that initiates the front end jerking upward. Hard to put into words...

 

[dako81]

Blip... like "a blip on the radar screen"....on and off very quickly.

Its that flicking throttle twist making quick power to the rear wheel that initiates the front end jerking upward. Hard to put into words...

Well, not when you have the clutch in to match revvs when you're downshifting...

 

[CanadianFZ6]

Engine braking is not good all or even most of the time particularly when it is instead of using the brakes.

Remember it is cheaper and easier to replace the front and rear brakes than it is to replace the transmission...

Oh God (sarcasm)... I guess I better throw out my '02 GMC with standard... I have only been engine braking that thing since new... it now has nealy 200,000 Km... Matter of fact I have used engine braking for every standard vehicle I have ever owned. I guess they're all broken now...:spank:

C'mon no one has ever replaced a transmission because of engine braking... If it was really bad, why is there no warning in vehicle manuals not to do it? Yet, they tell you what air pressure your tires need....

 

[dako81]

I just thought of something, why did they make slipper clutches if you can't engine brake, or downshift/match revvs/whatever?

 

[CravenMoorhead]

Well, not when you have the clutch in to match revvs when you're downshifting...

I was just answering a wheelie question in another post and had a senior moment...thanks for having my back.

 

[vdbergj1]

Also don't mistake a downshift with engine braking, that is two different things. In a downshift you are clicking through the gears, an engine brake is chopping the throttle and coasting down.

... okay, that is what I do then...downshift

 

[FizzySix]

I never engine brake or downshift because it is so bad for the engine. Once I hit 6th gear for the first time I was screwed. Oh well my clutch control is amazing!!!

:rof: :rof: :rof:

I'm with the "it's fine" group, I've done the same in cars, trucks, and bikes. Generally used in conjunction with the front brake, it's a fine way to slow down gradually when coming to a stop while maintaining high enough rpms to accelerate instead if desired. It's also more amusing than just using the rear brake. Of course you wouldn't use this for emergency braking.

My house is the third one down from a stop sign, and during the summer when the windows are open, I can hear bikes decelerating as they approach the intersection. Many if not most riders can be heard downshifting and riding a short distance in a gear lower as they decelerate.

I have yet to hear a bike go "boom!" and see gears rolling down the street as a result....

 

[dako81]

I was just answering a wheelie question in another post and had a senior moment...thanks for having my back.

No problem. I figure I do it enough now when I'm younger maybe I'll be repayed when I start having more of those...