View Single Post
Old 02-11-2013, 03:49 PM   #14 (permalink)
EcoModding Lurker
Join Date: Feb 2013
Location: United States
Posts: 18
Thanks: 1
Thanked 0 Times in 0 Posts
My understanding is that the Pulses Per Driveshaft Revolution (8 PPDR, in the case of MOST Jeep Products from 1991 thru 2001 or so) is a more accurate determining factor in MPGuino calibration than just Pulses Per Mile or Pulses Per Minute, especially since Jeeps have their differential(s) AFTER the VSS on the transmission/transfer case output shaft.

If I'm correct about this, then I'd have to factor in Differential Pinion-to-Ring Rotational Ratios as part of the equation, or between 3.55 & 4.10 to 1, in the case of my 1991 Jeep Cherokee Laredo 4.0L I-6 with the AW4 4-speed transmission, NP242 transfer case, Dana35 rear axle, and High-Cut-Pinion Dana30 front axle.

All calibration attempts I make will need to be confirmed with my TomTomOne GPS at 60 MPH on the local Freeway System, that is Interstate 5 and/or WA State Highway 167, both within a SHORT driving distance from where I live. I'll post my results once I've logged AND confirmed them...(8D.

Last edited by Davinator61; 02-11-2013 at 04:46 PM.. Reason: Added more info
  Reply With Quote