interesting article in Cycle years ago

[cbxtacy]

http://www.cbxclub.com/davespage/cyc80-1.html

and here's a quote from the article that explains why all my CBX's run soo good. 13 row stacked plate oil coolers make about a 100 f difference in oil temperature. And the difference gets bigger the hotter the day and harder you ride the bike.


The correction factor can compensate for day-to-day changes in air density and humidity to give consistent results, and temperature has a bearing on the correction factor because air density is a function of temperature and barometric pressure. But temperature can have a much more decisive effect than its relation to the correction factor. Some engines - like the CBX - are very heat sensitive. Remember, by Honda's own dyno data, a 25-degree hike in head temperature caused the peak horsepower to fall from 74.47 to 68.07. The CBX taxes the blower-cooling system at the Webco dyno anyway, and that's been a matter of record since Honda's engineers witnessed the first dyno of the CBX there back in 1977. Hot dry air - 116 degrees and very little humidity - would be just the thing to cause the CBX to get weak knees. The temperature difference alone 116 degrees F versus 86 F) was enough to explain how the same CBX engine could make 71.59 horsepower on one day, and 77.21 horsepower on another.

[alimey4u2]

Mine must be making 150 bhp over here.....

[Tom Neimeyer]

The temperature of the intake charge has a tremendous effect on the horsepower, here is a quote from an article on "making horsepower"....

For every 10 Degrees F reduction in intake charge temperature, a 1% increase in power will be realized. Example: A 400 HP engine with an intake temperature drop of 70 Degrees F, would gain approximately 30 HP on the cooling affect alone.

Which is why a blow through turbo (which can be aftercooled) can make more HP than a draw through (can't be aftercooled because fuel will condense on the runner walls).

Cheers, Tom