Bus running too cool...

[windtrader]

If not mistaken, a retarder on newer engines performs what Jakes do on earlier 2 strokes? If so, then are there guidelines and considerations for possible overheating of the older trans?

[luvrbus]

If not mistaken, a retarder on newer engines performs what Jakes do on earlier 2 strokes? If so, then are there guidelines and considerations for possible overheating of the older trans?

Retarders where mostly on buses for quietness for the passengers for a long time, the newer engines in the buses and trucks have the Jakes integrated into the engines,my ISX Cummins even the turbo is part of the engine braking now days and does it ever have a good engine brake I have never found a place to use 3rd stage yet
   

[buswarrior]

If not mistaken, a retarder on newer engines performs what Jakes do on earlier 2 strokes? If so, then are there guidelines and considerations for possible overheating of the older trans?

Retarder is a device associated with the transmission, and its purpose is the same as a jake/engine brake, to extend the life of the brake linings by taking on some of the slowing of the vehicle.

In particular, they have allowed for higher downhill speeds in the mountains, from days gone by, as they take on the heat that would have fried the brakes and caused a run-away.

The engine brake spews that heat out with every gulp of air, and some to the radiator.

The transmission retarder puts all that heat into the transmission fluid, and then must be dealt with by the cooling system.

As luvrbus said, retarders are silent, and do not disturb the passengers or the neighbours, especially in transit bus operations. But the heat has to be managed...

Nobody explained this to the bus fleet owners or the drivers as plainly at the time, "buy this, your brake life problems will go away..." was a lot of the sales talk.

Not a lot of materials with detailed operation instructions beyond basic function.

Keep the revs high coming down the mountain, that's about all you can do, except go down the mountain more slowly, putting less energy into the fluid.

Just like managing your brakes without these aids.

Happy coaching!
Buswarrior

[lostagain]

I find retarders are usually quite abrupt engaging and disengaging. And they do put a lot of heat in the transmission. I prefer Jakes.

JC

[buswarrior]

I find retarders are usually quite abrupt engaging and disengaging. And they do put a lot of heat in the transmission. I prefer Jakes.

JC

Idiot engineers and fleet managers crank them up in the settings and then leave the driver looking like the one who is tossing the passengers around with "rough braking"

Automatic application with a brake pedal touch are horrible...

All the behind the scenes people care about is brake life, not passenger comfort.

The multi-stage, driver controlled retarder joystick on a B500 and siblings, is a lovely way to give a smooth ride, and save the brakes.

Happy coaching!
Buswarrior

[luvrbus]

The Joystick puts the driver in control only way to go IMO, on the Allison when you flip the switch you get the % the transmission is pre set for like 33,66,or 90%

[windtrader]

Since Jakes do engine decompression, thereby creating less heat to be manage, then it seems the best approach to dissipate heat generated by the engine, transmission, and brakes, correct?


Sometimes Jakes alone are insufficient to manage lower downhill speeds and downshifting transmission help keep speed down, is the transmission working overtime when working as a brake and generating much heat? Is the transmission cooling system in the MC8 designed robustly enough to carry this heat away?

[luvrbus]

Some buses used the Telma electromagnetic retarder on the drive shaft they had their advantage and dis advantages