What IS engine braking anyway?

[diver 85]

i always wondered what it means when i head to Ginnie Springs

Around here you'll see signs saying 'No Jake Breaking'....think it referrs to the same thing.......

 

[Thalassamania]

In addition to the above post, engine braking is when a driver downshifts into a lower gear than the optimum gear for a given speed, whithout pressing the accelerator. The difference in gear ratios actually slows the vehicle down. The driver will see a spike in RPMs (maybe loud), but it quickly falls as the speed of the vehicle is reduced.

Just FYI: That's not engine breaking, that's wearing out your clutch. When downshifting you need to clutch, blip the throttle to match speeds between the plates and then come off the clutch pedal with the plates spinning at similar speeds, else all you do is transfer wear from the brakes (easy and cheap to renew) to the clutch (expensive and dificult to renew).

 

[fppf]

I guess Divers are not truck drivers.

That sign is directed at heavy trucks with engine brakes.

The operation of an engine brake allows the exhaust valve to pop open just at the top of the compression stroke. As said before it turns the engine into an air compressor. It does not restrict the exhaust flow. Downshifting increases the braking power because more air is compressed through the engine.

An "Exhaust Brake" is a brake the restricks exhaust flow, it is usually found on smaller trucks and pickups.

However it is NOT the engine brakes that are causing these signs to pop up. It is trucks with ILLEGAL exhausts on them. A truck with a legal exhaust will only be very slightly louder under engine braking vs full throtle.

Also if you see a sign that say's "No Jake Brakes" that town will get sued when Jacobs Vehicle Systems finds the sign. "Jake Brake" is a registered trade mark and can not be used. It also singles them out as there are other engine brake manufactures.

 

[driftin' by]

What I don't understand is that if engine breaking isn't allowed in certain areas because of the noise then why aren't loud *****, obnoxious motorcycles not allowed also!?!?!

 

[fppf]

Yep, nice huh, shoot the truckers, the people that move EVERYTHING people buy and need.

What about the punks with the stereos that shake my house.

 

[The Chairman]

You know... you can learn the most arcane things on this Board. For those of you who THINK you know clutches, tell me what a Marcel cushion is without using Google or the like. These are in danger when you power/engine brake with a gasoline car with a manual transmission.

 

[Divin'Papaw]

What I don't understand is that if engine breaking isn't allowed in certain areas because of the noise then why aren't loud *****, obnoxious motorcycles not allowed also!?!?!

Good point. "No Engine Breaking NOR Harley-Davidson Motorcycles Allowed"! I know some of you absolutely love your Harley's, but they are so &%#$@&^ loud they are just obnoxious. Not sure why (I know squat about motorcycles) but my neighboor has a Harley and it is nice and quite. But most that I experience around town just absolutely make your teeth rattle. Is it supposed to be cool or something? NOT!

 

[Divin'Papaw]

Anyone want to guess how long before the Mods move this thread?

 

[Blitz]

In addition to the above post, engine braking is when a driver downshifts into a lower gear than the optimum gear for a given speed, whithout pressing the accelerator. The difference in gear ratios actually slows the vehicle down. The driver will see a spike in RPMs (maybe loud), but it quickly falls as the speed of the vehicle is reduced.

And it sounds so cool when I do it on my bike.

 

[MXGratefulDiver]

Also if you see a sign that say's "No Jake Brakes" that town will get sued when Jacobs Vehicle Systems finds the sign. "Jake Brake" is a registered trade mark and can not be used. It also singles them out as there are other engine brake manufactures.

Hmmmm ... those signs are all over the north Cascades roadways and nobody's ever been sued. Jake brakes ... and other loud vehicles ... have been known to cause avalanches that can bury the road under 20-30 feet of snow. It's not in the best interests of the truckers who drive those roads to either use the brakes or ask for the signs to be removed.

... Bob (Grateful Diver)