bob
no zen here just a little practice and some technology. my shift point is set
at 5800rpm on the light and due to the delay from the light to the time i shift
i hit at 5900 rpm. for those of you with some dyno results try this link out.
http://www.prestage.com/carmath/dynochart.asp
otherwise hit the track, start conservitive and keep going up a couple hundren
rps until you time starts to fall off. then and only then will you know where
to shift.
chris
>Stu,
>
>I too believe in confirming theory with experiment. Actually, if you think
>about it, a chassis dyno does about the same thing you are suggesting. Some
>work different than others, but a lot of them calculate horsepower by
>accelerating the rotating mass with the rear wheels. Pretty equivalent to
>accelerating the mass of the car. If you do the G-meter tests, we can easily
>calculate the horsepower curve. We do need to know the speed of the car and
>it's mass. BTW, one of the guys that runs a dyno here in San Diego thinks
>torque is "real" and horsepower is just "theoretical", because you have to
>multiply torque times rpm to get horsepower. But just minute here; torque is
>force times distance, so I guess it's all just a mirage!! Maybe I'll start
a
>new fad by talking about the down "force" of the pistons as being what
>"really counts", or come to think of it maybe it's really the compression
>pressure in the cylinder times the piston area that produces the down force,
>that creates the torque that produces the power that's really important.
>It's all so very confusing!!! Maybe Chris Vaught's Zen approach to drag
>racing is more satisfying. Of course, he may be at a bit of a disadvantage
>in a car he has never practiced his meditations in. You probably wouldn't
>last long as a NASCAR or CART driver with that attitude either. I'm pretty
>sure with a $100k motor, they don't want you using the seat of your pants to
>decide when to shift - just guessing, but if it was MY race car I'd want
>details like that nailed down pretty tight.
>
>When the green flag drops, the b.s. stops
>
>TTFN,
>
>Bob
>
>
>-----Original Message-----
>From: owner-tigers@autox.team.net [mailto:owner-tigers@autox.team.net]On
>Behalf Of Stuart Brennan
>Sent: Wednesday, February 21, 2001 9:33 AM
>To: tigers@autox.team.net
>Subject: When to shift?
>
>
>Torque curves? Horespower curves? Red line? Hmmmm....
>
>If you really think about it, you should shift either when the engine is
>about ready to explode, OR when the next gear up would give you more
>accelleration, as in when an engine runs out of breath at high revs. I
>would say that you should use a "G-Analyist" or whatever that thing was
>called, to plot your accelleration vs speed for each gear, idle to red line.
>Overlay these plots, and it should become obvious where to shift. This way
>you would not have to compensate for any other factors. You are directly
>measuring the result that you want.
>
>Stu
>
66 Sunbeam Tiger, 289, Performer RPM intake & cam, Holley 600 DP, Mallory
ignition, aluminum radiator, 4 speed toploader, centerforce gold clutch,
headers & flowmasters
http://albums.photopoint.com/j/AlbumIndex?u=1434439&a=11228074
88GT CHP 342, 58cc AFR 185's, Holley SysteMax II intake, Pro magnum Rockers, ED
cam, Pro-M 77, 38# Lucas injectors, Walbro 317 255lph pump, Romac, A9L, 3.55's,
Aluminum driveshaft, 70mm Accufab throttle body, PRO 5.0
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