terryrs@comcast.net wrote:
>I just fixed the speedometer.
>Is 3800 RPM in 4th OD REALLY 85 miles per hour?
>Tell me no because I didn't have sense enough to be scared before....
>
>
After a speedo cable failed, I've been using the tach for a speedo on my
TR4. I figured the ratios ought to work out to:
4000 rpm in 1st is 20 mph
4000 rpm in 2nd is 40 mph
4000 rpm in 3rd is 60 mph
4000 rpm in 4th is 80mph
Of course, I don't run at 4000 rpm most of the time, but it's pretty
easy to do the math -- and good practice for my kids when we're driving
around! Recently I had a chance to confirm these speeds with a GPS unit
and they're surprisingly on-the-money. Woopee for technology.
Through early TR4's the overdrive ratio was 22% I think, and though I
haven't done the math or checked with a GPS, 3800 rpm in 4th o/d ought
to be around 85 mph.
Steven
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