Auto gearbox tuning - Upshift pressure MOD time limit

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
Stringyweevil
Posts: 8
Joined: Fri Aug 24, 2012 12:12 am
cars: VY V6 Auto

Auto gearbox tuning - Upshift pressure MOD time limit

Post by Stringyweevil »

Im changing my shift pressures on my VY V6 for some quicker, firmer shifts and I came across these tables called Force Motor - Upshift pressure MOD time limit and I have no Idea what it is for. I changed the values slightly and didnt notice any difference in how it felt. Does anyone know what it is for? Thanks in advance!
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charlay86
Posts: 586
Joined: Thu Sep 17, 2009 4:00 am
cars: VT S1 SS (L67)
Location: Perth, WA

Re: Auto gearbox tuning - Upshift pressure MOD time limit

Post by charlay86 »

It is the period of time since the start of a gear change that the force motor pressure control logic uses the upshift pressure modifier value until it reverts to using the Gear vs. TPS pressure offset.
Stringyweevil
Posts: 8
Joined: Fri Aug 24, 2012 12:12 am
cars: VY V6 Auto

Re: Auto gearbox tuning - Upshift pressure MOD time limit

Post by Stringyweevil »

I don't fully understand the upshift pressure modifier either. Stock it's set at 3PSI. I have only used the table of TPS vs KMPH to change the PSI of the shifts. Say I have a shift pressure set at 90 on that table, does the shift pressure modifier set at 3PSI mean that it will shift at 93PSI?
ejukated
Posts: 426
Joined: Wed Mar 04, 2009 10:52 am

Re: Auto gearbox tuning - Upshift pressure MOD time limit

Post by ejukated »

Yes but no... Pressure is max limited
Jervies
Posts: 199
Joined: Wed Nov 09, 2011 7:35 am
cars: Vt v6 wiith a gt35/40 turbo e85 399rwkw
Mazda e2000 with a cammed vx ecotec motor
Location: Victoria

Re: Auto gearbox tuning - Upshift pressure MOD time limit

Post by Jervies »

Some of the xdf's have ghe max pressure defined so you can up the max pressure so it will shift at 90 + the modifiers