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View Full Version : Need help on downshifting issue.



stroker97k1500
May 5th, 2008, 11:21 AM
have attached my current tune below.
I am currently trying to figure out how to make my transmission down shift from 3rd to->2nd from 55mph to 78mph over 65% tps. I have tried changing the throttle kickdown table. I haven't messed with the down shift part throttle table as of yet as I didn't know how that would affect it. I wanted to get some advice first as what I was doing wrong, or where I needed to be looking.
Thanks for any help!
Robby

SSpdDmon
May 5th, 2008, 12:23 PM
IIRC, throttle kickdown is pretty much for WOT. The part throttle tables are where you need to make your changes.

The way I usually read the downshift tables is:
Assume the value of the 50% tps cell is 30mph. So, when you're going 30mph, you will have to apply 50+% throttle to get the trans to downshift.

If you're going to be changing the trans tables, check the spreadsheet I made in the trans forum. It'll help you prevent crossing the upshifts/downshifts and torque converter tables.

stroker97k1500
May 6th, 2008, 09:19 AM
Thank you for sharing that! It makes a lot of sense now
Robby

joecar
May 6th, 2008, 09:58 AM
Remember these 2 things:
- upshift tables: operating point must cross to above the curve to trigger upshift;
- downshift tables: operating point must cross to below the curve to trigger downshift;

It doesn't matter if the operating point moves vertically or horizintally.

I moved this to the trans section.

:cheers: