Hey I just got my 5.13's in my Rubi and I have that blue procomp accupro calibrator and set my speedo (35's) and set the gears to 5.13's, but i still would like to see the shift points shift at a little higher RPM. So if I program it to 4.88 or 4.10 what would that do???? Would it hurt anything or will it change the shift points or what??? Anybody have an idea what I could do???

 

if you purposefully set it off, your speedometer will be off and so will your shift points.

 

well the speedo won't be off because i set that to my tire size, but i wonder what putting 4.88 or 4.10 will do to the shift points. anybody tried this??

 

Not exactly.. The programmer uses the tire size and gears to give u an accurate speedo.. 35's with 4.10's and 35's with 5.13's will give you a different speedometer setting

 

tire size and gear ratio are different. speed is measured at the wheel not at the transfer case like on TJs. Changing the gear ratio does nothing to affect your speedo reading. Will affect shift points though. I dunno what it will do to it telling it that it has something else.

 

Thats what I thought about the speedo....I guess I'll have to play with the gear size setting and see what happens.

 

I confirm this! You should have gotten the Max Energy programmer. It lets you change the shift points separately from the gear and speedo mods. It'll also change the max rev limit, top speed limit and tune you engine for more hp depending on what octane you use.

 

While slowing your speedometer down will raise shift rpm, it will also promote gear hunting at highway speeds under load. For most that seems to a bigger issue than where the transmissions shifting under roll out acceleration. A programmer will assist in tuning shift points to achieve better drivability while a calibrator will only return to stock shift points for new tire and gear changes.

Shift points are determined by three things, throttle position, manifold pressure and speedometer. Messing around with just one of the three isn't likely to deliver the desired effect and would be best addressed by a programmer.

 

This has been discussed, and even argued, ad nauseum on JK-Forum. I thought the final conclusion, after someone discussed it with a very experienced Jeep mechanic at his dealer, was the speed reading comes off the transfer case; gearing does affect the reading.

 

I'd suggest that you concentrate on what the programmer was designed for: Setting the proper tire size and gearing. How did you determine to set 35 inches? If you just went by the fact that you've just installed 35s, then your speedo may still be off (as is everything else tied to it, including odometer, trip computer, etc). If that's what you did, I suggest that you first check out your speedo against a known good source (a vehicle you trust, GPS, cooperative cop, etc). Most of us have found that we must set the tire size about 1 to 2 inches below the expected size to get proper readings. For example, I've got my Hypertech set to 31.25" with 33" tires, and it has checked accurate against three standards (my son's truck, GPS and radar gun).