[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]
On 20 Sep 2005 at 20:53, Keith Park wrote: > OK, there is more involved I see > > Drive at say 11,000 feet up a hill in 3rd at 3/4 throttle and my car runs > 60-70 degree's hotter than at the same speed, same throttle (or even more) > in 4th. Think about your engine's power curve. When you downshift, you move to the right on that curve. If you're already near the peak of the curve in 4th, you'll end up over the top and maybe even worse off in 3rd. If you're just partway up the curve in 4th then shifting to third may put you close to the peak. You can start to see that the result of downshifting will depend on where on this curve you start out and, thus, where you end up. The end result can go either way. OTOH, I would have expected your engine to run cooler in the lower gear (and higher rpms) than in 4th, for reasonable choices of shift points, so I'm a little puzzled, too. Any chance that your charging system voltage changes enough for the different RPMs to offset your temp readings? -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~