AEV Procal Gear Ratio Manipulation
JK Enthusiast
Joined: Jan 2009
Posts: 144
Likes: 0
From: Doswell, Virginia--- Roanoke, VA
I corrected the speedo for my tires (35in), but the rpms are at the same level as they were when the speedo was set for 29s. Is this because it requires fewer revolutions of the tire to get to a certain speed? I was at 1750 rpms at 55mph with 29s, with 35s i am at 1450 rpms at 55mph.
JK Jedi Master
Joined: Feb 2008
Posts: 12,907
Likes: 185
From: Maine
I corrected the speedo for my tires (35in), but the rpms are at the same level as they were when the speedo was set for 29s. Is this because it requires fewer revolutions of the tire to get to a certain speed? I was at 1750 rpms at 55mph with 29s, with 35s i am at 1450 rpms at 55mph.
Regearing will bring the engine speed back into a usable range.
JK Jedi Master
Joined: Aug 2007
Posts: 15,665
Likes: 4
From: Hammond Louisiana
The Procal does not adjust shift points. This is a quote directly from them on the AEV forums:
This unit should work with the aftermarket "tuners" out there but we can't guarantee anything since we haven't tested them. Just so everyone understands, the ProCal allows users to change factory options, not data tables for engine performance, shift points or anything else. The aftermarket "tuners" are supposedly changing the tables, so if you beleive in them and want to give them a try, they are changing stuff the ProCal doesn't so they should do the same as if you didn't use the ProCal. Think of it as the difference in using an aftermarket "tuner" on a sahara with 3.73s vs a Rubicon with 4.11s, their shouldn't be a difference.
This unit should work with the aftermarket "tuners" out there but we can't guarantee anything since we haven't tested them. Just so everyone understands, the ProCal allows users to change factory options, not data tables for engine performance, shift points or anything else. The aftermarket "tuners" are supposedly changing the tables, so if you beleive in them and want to give them a try, they are changing stuff the ProCal doesn't so they should do the same as if you didn't use the ProCal. Think of it as the difference in using an aftermarket "tuner" on a sahara with 3.73s vs a Rubicon with 4.11s, their shouldn't be a difference.
Set tire height and gear ratio and it shifts in better ranges.
JK Junkie
Joined: Oct 2008
Posts: 2,118
Likes: 1
From: Twain Harte, CA
This is because the speedometer was calibrated. Before it was calibrated, the computer thought you were going one speed, when you were actually going another. But this doesnt change from the stock shift points.
JK Jedi Master
Joined: Aug 2007
Posts: 15,665
Likes: 4
From: Hammond Louisiana
Again, for whatever the reason this adjusted the shift points according to the speedo, or whatever, they did change from what I had before so they changed. I did not say they changed to some supremely divined touched by God shift points, but they did change.
JK Freak
Joined: Oct 2008
Posts: 989
Likes: 0
From: Franklinton, Louisiana
x3 on that!! I can really tell the differnece!! And if they "correct" it doesnt that mean the same thing as a "change"??? Like if I correct an answer on a test, that means I changed my previous answer!!
JK Freak
Joined: Jan 2010
Posts: 976
Likes: 1
From: Cen Cal
Anybody actually test/try this? I switched to the highest ratio (the one above 5.38) and it does seem to shift later. A little above 2.5k going from 1st to 2nd with the 3.8L, automatic, 4.10 actual gears, 35s, ProCal corrected speedometer.