Date: Fri, 28 Jul 00 23:28:49 GMT From: amesnopsamrak.demon.co.uk (Andrew Stephenson) Subject: Re: How hot is too hot?
In article <4xng5.20174$o71.1295761nopsamsc04-news.ops.worldnet.att.net> sea.brooksnopsamdnet.att.net "William Brooks" writes: > I was climbing up a long (3+ miles) steep grade at about 70 mph > in 90-degree weather this afternoon and watched as the > temperature gauge on my 1988 9000 Turbo climbed up past the 3/4 > mark to almost the 7/8 mark about two miles into the climb. > > The turbo needle was pretty far into the yellow, so I know the > engine was working fairly hard. I chickened out and turned off > the a/c and was getting ready to open the windows and turn on > the heat, but the coolant temp didn't climb any higher. > > [...] Cannot help with a yes/no, or even absolution for your misdeeds. But let's do some sums. Not knowing how heavy your car was that day, or what the average gradient was, I'll have to work in terms of 1,000 Kg mass (1.102 short tons) and slope of 1:6. At 70 mph, the power you were asking the engine to deliver, just to lift the car up that hill, was approximately (1000*9.81)*(70*0.447*(1/6)) = 51159.15 watts which is 51159.15 / 745.7 = 68.6 horsepower (roughly) Adjust the figures to suit reality. I'd say you were working it pretty hard, especially when you allow for AC, power loss in the transmission and at the tyre/road interface and, at that speed, maybe also air resistance and momentum lost to bugs smacking the bodywork <g>. Some (over)heating should be too surprising. -- Andrew Stephenson