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28995Re: [thecml] '70 shift speeds?

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  • redcad59
    Dec 25, 2013
    • 0 Attachment
      Is somebody trying to suggest the '68 CdV (or anything else for that matter) actually *shifts* from
      2nd to 3rd at 120mph ??? AND AT 4200rpm ???

      In all fairness, I suspect the data are being read incorrectly.

      My '59 Cadillac has an original 4speed Hydramatic Tranny, and exactly 2.94:1 diff, and my collection
      of data tables runs as follows for 4th/TOP GEAR of the Trans, which is 1:1 as most trannies are without O/D:

      4th: total ratio: 2.94

      20mph - 700
      25mph - 800
      30mph - 1000
      35mph - 1200
      40mph - 1400
      45mph - 1600
      50mph - 1700
      SPD 55mph - 1900 RPM
      60mph - 2100
      65mph - 2300
      70mph - 2500
      80mph - 2800
      90mph - 3100
      100mph - 3500
      120mph - 4200

      ----------------------------------------

      This means my '59 MAXES OUT at approx 120mph as TOP SPEED, with the tranny in 4th gear @ 1:1 and the diff @ 2.94 and the engine at 4200rpm. This is NOT to suggest that any SHIFT occurs at or near this point.
      This is the absolute maximum expected under any reasonable circumstances.

      Now here's my *SHIFT TABLE* which suggests at what speeds the 4spd Hydra might shift when under minimum and full-acceleration: (The RPM speeds are the approximate speeds of the Hydraulic 'governor' within the tranny which sends fluid pressure signals to the shift valves:
      .......................................

      SHIFT TABLE MINIMUMS (2.94 Rear End):
      (Shift points w/o TV Rod effect)

      1st Speed: 0 ~ 3 mph = approx.1000rpm
      2nd Speed: 3 ~ 9 mph = approx.1000rpm
      3rd Speed: 12 ~ 16 mph = approx.1000rpm
      4th Speed: 20 ~ 24 mph = approx.1000rpm

      4-3 D/S: 16 ~ 13 mph = approx.500rpm
      3-2 D/S: 12 ~ 8 mph = approx.500rpm
      2-1 D/S: 7 ~ 3 mph = approx.500rpm

      SHIFT TABLE MAXIMUMS (2.94 Rear End):
      (Shift points with FULL THROTTLE TV Rod effect)

      1st Speed: 0 ~ 17 mph = approx.4000rpm
      2nd Speed: 17 ~ 20 mph = approx.4000rpm
      3rd Speed: 38 ~ 41 mph = approx.4000rpm
      4th Speed: 73 ~ 78 mph = approx.4000rpm

      4-3 D/S: 71 - 65 mph = approx.2200rpm
      3-2 D/S: 25 - 21 mph = approx.1100rpm
      2-1 D/S: 12 - 9 mph = approx. 700rpm


      Highest possible shift I got maxes out around 4000rpm @ around 80mph under the most extreme circumstances the engineers could imagine. Your results may vary.

      -----Original Message-----
      >From: Tony Gaudenti <tonyg91326@...>
      >Sent: Dec 24, 2013 5:33 PM
      >To: "thecml@yahoogroups.com" <thecml@yahoogroups.com>
      >Subject: Re: [thecml] '70 shift speeds?
      >
      >An English magazine tested a 1968 Coupe de Ville with 472 engine and 2.94:1 axle ratio (curb weight was 4,952 lbs) and got these shift points:
      >
      >
      >Speed in gears (mph) @ rpm...
      >1st gear---- 60 mph @ 5200 rpm
      >2nd gear--- 97 mph @ 5020 rpm
      >3rd gear--- 120 mph @ 4200 rpm
      >
      >Other interesting specs were:
      >
      >0-30 mph------- 3.5 secs
      >0-60 mph------- 9.9 secs
      >0-80 mph------- 16.5 secs
      >0-100 mph------ 27.8 secs
      >
      >1/4 mile---------- 16.9 secs @ 81 mph
      >
      >Fuel mileage---- 9-13 mpg; 10.4 mpg average
      >
      >Tony
      >
      >
      >
      >
      >________________________________
      > From: "wbdeford@..." <wbdeford@...>
      >To: thecml@yahoogroups.com
      >Sent: Tuesday, December 24, 2013 8:51 AM
      >Subject: [thecml] '70 shift speeds?
      >
      >
      >

      >Anyone have the speeds at which the '70 Cadillacs shift from 1st to 2nd and from 2nd to 3rd, both for minimal throttle and wide open throttle?


      Ron Threadgill
      'Miss Scarlett' - 1959 Cadillac ElviSeville DeVilleDorado CoupeVertible Fleetisman D'EleBroughamWood VRX Hybrid
      http://home.comcast.net/~amthreadgill/
      or
      http://www.pipeline.com/~rthreadgill/

      Cadillac & LaSalle Club - Central Virginia :
      www.CentralVaCadillacLaSalleClub.org
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