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Jake Brake or Transmission Retarder, or Both
11-18-2014, 15:56
Post: #1
Jake Brake or Transmission Retarder, or Both
Now that I have 6K miles on my bus, I am a retarder convert. I was of the other camp having put many miles on my Jake Brake equipped Blue Bird. Both are excellent and both would be nice to have. Each has its advantages, but who can argue with 600hp of braking power at your fingertips. I think the manufacturers have the heat thing pretty well sorted. Transynd is up to the challenge as is the generous transmission cooler that Prevost installs. The trick is to descend the long grades a little slower than you otherwise would with a Jake. It's important on long grades to keep the speeds such that the heat generated by the transmission is being fully sunk by the cooler and radiator, an equilibrium needs to be met and an equilibrium is possible. But, for those moments as you describe, the full 600hp of braking can instantly be applied. In these cases, transient heat sink in excess of the coolant system's capability can be accommodated.

I often noticed in my BB how full Jake power resulted in about 15 to 20 psi of turbo boost. That extra intake charge compression gives us the full 350hp of Jake Brake power capability. I had my preselect moved from 4 to 5 because of what I considered engine over-revving. I'd commonly see in excess of 2350rpm on the tach during downshift to 4th and under full Jake Brake power. The DD S60 no load max rpm is 2225 and full Jake is hardly a no load condition.

david brady,
'02 Wanderlodge LXi 'Smokey' (Sold),
'04 Prevost H3 Vantare 'SpongeBob'

"there is no perfect forum there are only perfect forums"
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Jake Brake or Transmission Retarder, or Both - davidbrady - 11-18-2014 15:56



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