Engine Braking Sucks(?)
#21
08-09-2009, 07:27 PM
I just recently noticed sign on a local road thru a residential area warning that " Jake Braking" was prohibited -- didn't know what it meant. Must cause a lot of noise(?)
#22
08-09-2009, 09:09 PM
Most Wanted
Confederate,
If you'll notice in my post I specifically said NOT in mountain twistys...and I never mentioned anything about 18 wheelers. However, If you're in an 18 wheeler in the mountains...I sure hope you have a Jacobs Engine Brake (Commonly referred to as a "Jake Brake" which retards injector timing to allow the engine to use compressive force to slow the truck down (thereby taking much of the strain off of the drive train).
....................................."Break" PNGRider, We will just have to agree to disagree. The term "Engine Braking" implies using the drive train to purposely slow down. I do practice the habit of staying in the gear for a given speed until it's time for a full stop...Then I STILL progress down through the gears (While holding the clutch in) to match my descending speed. Bottom line (physics really) is that the force of momentum has to be absorbed somewhere to stop a moving object. I would rather turn that force into heat at my brake pads (again in a normal...not downhill, or excessive brake need) rather than have my drive train (and YES rear tire too...the post about rear tire wear was correct) to absorb the force. By the way...the "Drive" train is engineered to "Drive" the rear wheel...not match it's speed (or the transmission...which "transmits" power FROM the engine) to the engine RPM.
-clutch-
If you'll notice in my post I specifically said NOT in mountain twistys...and I never mentioned anything about 18 wheelers. However, If you're in an 18 wheeler in the mountains...I sure hope you have a Jacobs Engine Brake (Commonly referred to as a "Jake Brake" which retards injector timing to allow the engine to use compressive force to slow the truck down (thereby taking much of the strain off of the drive train).
....................................."Break" PNGRider, We will just have to agree to disagree. The term "Engine Braking" implies using the drive train to purposely slow down. I do practice the habit of staying in the gear for a given speed until it's time for a full stop...Then I STILL progress down through the gears (While holding the clutch in) to match my descending speed. Bottom line (physics really) is that the force of momentum has to be absorbed somewhere to stop a moving object. I would rather turn that force into heat at my brake pads (again in a normal...not downhill, or excessive brake need) rather than have my drive train (and YES rear tire too...the post about rear tire wear was correct) to absorb the force. By the way...the "Drive" train is engineered to "Drive" the rear wheel...not match it's speed (or the transmission...which "transmits" power FROM the engine) to the engine RPM.
-clutch-
Absolutely. My jakes have 3 settings. Brake fade on any vehicle is no good.
#23
08-09-2009, 09:14 PM
Most Wanted
Yes they do create some noise. When you are going down a mountain or hill and let off the accelerator, the jakes come on. Sometimes though in areas that have the signs, you have no choice but to use them or you will overheat the brakes on the rig and it will not be able to stop at all. When those situations occur, I prefer to stop of course and will use the jakes, but sparingly. It's better than having an accident.
#24
08-09-2009, 09:21 PM
Jakes dont retard injector timing, they hold the exhaust valves open so the cylinder wont fire and allows the cylinder compression to act like a large drive train brake.
As far as the OP if youre using oil from excessive downshifting, you very well may have worn valve guides/seals.
As far as the OP if youre using oil from excessive downshifting, you very well may have worn valve guides/seals.
#26
08-09-2009, 10:08 PM
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#28
08-09-2009, 11:49 PM
Road Master
My Bad
Jakes dont retard injector timing, they hold the exhaust valves open so the cylinder wont fire and allows the cylinder compression to act like a large drive train brake.
As far as the OP if youre using oil from excessive downshifting, you very well may have worn valve guides/seals.
As far as the OP if youre using oil from excessive downshifting, you very well may have worn valve guides/seals.
Part of what I did during a portion of my 25 year military career was to operate a 10Ton 8X8 wrecker. The truck was made by Oshgosh & was called a HEMTT. It had a Jake brake & there is no mistaking the sound of a jake brake bellowing down a grade.
-clutch-
P.S. Here is a good link that explains the operation for anyone interested: http://www.jakebrake.com/technology/engine.php
#29
08-10-2009, 05:18 AM
Ultimate HDF Member
If you're sitting on your bike at a stop sign at the bottom of a hill and hear one behind you. Don't ask me how I know.
#30
08-10-2009, 06:31 AM
Totally disagree. Proper use of clutch/throttle during downshifting prevents most problems. The purpose of a transmission is to match engine speed with road speed--at all times. Proper riding entails downshifing through the gears as you slow down--not coming to a stop and then crunching gears down to first.
As others have said, every time you roll off the throttle, you are "engine braking," unless you have pulled in the clutch.
As others have said, every time you roll off the throttle, you are "engine braking," unless you have pulled in the clutch.