[200q20v] RE: speedo calculations

Mike Miller mikemilr at blackfoot.net
Wed Aug 30 11:44:22 EDT 2000

----- Original Message -----
From: "Beer, Jerry" <JBeer at boosecasey.com>

: Chris
:   Numbers make sense, but I can tell you  I have seen the speedo read 130
: 4th with 245-45/16. The speedo was about 5-7% optimistic. I find with
: 225-55/16, the speedo is just about dead on(1mph higher than actual at
: Regards,
: Jerry
: 91 200q

I'd suggest taking the car out and measuring the speed indicated in 4th and
5th at 2k, 3k and 4k  rpms to get an idea of how many mph per 1000 rpm.
4th is linear around 19 mph/1k and 5th comes in at just shy of 25 mph/1k
with 215/60/15 tires. Like I said before, even 18 mph/1k in 4th will yield
over 128 at 7150 rpm.

As I recall from real world experience:

1st  = about 4.5 mph/1k rpm
2nd = about 8mph (why we cant get to 60 without going to 3rd)
3rd = about 13 mph
4th = about 19 mph
5th = about 25 mph

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