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View Full Version : Gears and tunes..


Vortech347
09-05-2008, 02:09 PM
Okay I've got a tune on there now from DR setup for 3.55's. I'm getting 4.10's put in tomorrow. YAY.. I wasn't able to give Dennis much notice so I prolly won't get a 4.10 tune till monday. If I use the Xcal and adjust the gear ratio will that change the shift points too? Cause I don't want 1st to 2nd happening at 7000rpm.

Or will it re-config the mph shift points when I adjust it in the hand held?
Local Boy
09-05-2008, 04:40 PM
Not that simple, my friend...

The gear ratio change only affects the speedo...Nothing else...

With 4:10's your car will think it is moving faster than it is realy is going...Causing it to shift early and ruining your shift points and T/C lock -up schedule...

Basic hand held's cannot adjust shift points (only at WOT) or T/C lock-up schedules...Your tuner (person) does that part...

ALOHA
red
09-05-2008, 04:54 PM
You'll be fine changing the axle ratio on the handheld.
ImpalaSlayer
09-05-2008, 05:03 PM
your gona need a retune. i JUST pick my car up from getting 4.10s put in and a zack 410 tune uploaded. its the tits.
Vortech347
09-05-2008, 05:54 PM
I figured thats the only reason axle ratio is in there....
red
09-07-2008, 10:15 AM
Cause I don't want 1st to 2nd happening at 7000rpm.
There are two mechanisms for controlling shifts. First is the MPH-based shift schedule in which you define shifts as MPH vs throttle position and second is the WOT RPM shift points. Concerning user adjustable parameters, you should have access to change axle ratio and WOT shift points (in relative MPH); if you don't, your dealer has this disabled in the live loader file. Changing the axle ratio will change your speedometer as would changing your tire revs per mile and depending on which way you go with either, shifting could be effected accordingly. Your commanded WOT RPM shift points are probably around 6k (unless modified by your dealer), though the lag before the actual shift depends on your transmission. I'd log with LiveLink and observe the commanded versus actual shifts. For peace of mind, you can bump down the WOT shift points by a few MPH using the handheld tuner.


Or will it re-config the mph shift points when I adjust it in the hand held?
I don't believe axle ratio alone will modify the shift points, though I drove around for months with only the above user adjustable parameters modified and had no problems.