Proper Shifting to Reduce Engine Temperature

J-Rooster wrote:

hipower wrote:
Those of us who have some trucking experience in our backgrounds drove when pyrometers were prevalent. Measuring your exhaust temperature was almost a neccesity to keep from cracking a piston or exhaust manifold in the early days of turbocharging OTR diesels.

I don't recall the exact temps suggested but they were different depending on the probe placement, pre or post turbo. Somewhere in the dark recesses of my mind I think it was 1200 degrees pre turbo and 800 degrees post turbo, but I can't swear that is correct anymore.

The key here is that if your EGT was too high you downshifted a gear and backed off on the throttle to keep the EGT in an acceptable range. Using our coolant temps to guide us is just a less accurate way of doing the same thing.

Bottom line, if you experience temps that make you uncomfortable while climbing a grade downshift and reduce throttle input to bring the temps back down.

J-Cat, glad to hear that your really learning about your CAT Motor and what it takes to get it running good. Highpower, those were the good old days! Keeping those diesel motors right on 2150 RPM's and if you shifted into neutral with the Jake Brake on it would kill the motor! My boss perfered us to take our foot off the throttle when the pyro got to 1000.

Those were interesting days indeed Rooster. Naturally aspirated diesels making 250 HP or less in most cases. Gas engines that were lucky to make 150 HP. Five speed main transmissions with three and four speed auxiliary boxes or two speed rears. Putting the diesel fuel to them to where there was a black cloud of exhaust that nearly blocked out the sun when you pulled away from a stop and at every shift and a foot of fire coming out the stack lighting up the night sky. Cabs so hot in the summer you could hardly stand it and so cold in the winter you couldn't take off your coat and gloves and an interior ice scraper was almost a neccesity. Big loads and brakes that were barely passable on the level and scared the **** out of you in the mountains.

Makes me understand that the good old days weren't really all that good, but we had fun and made a little money along the way. Today you have a hard time finding drivers or 'wanna be' drivers that can even shift a manual transmission. Nostalgia is a wonderful thing and our memories only seem to keep the good and forget the bad.