downshifting speeds?

[leftyss]

For some reason my car will not shift down to 2nd gear while I am on the freeway unless i am below 65 mph. my car doesn't shift into 3rd gear at WOT until 81 mph. i can be cruising along at 70-75 at punch it and it just drops to 3rd. feels like s*&t. no pull at all. not sure if i have my part throttle shift tables right, but i know i have my WOT tables correct. I am right in saying that the part throttle table is what controls what speed the car downshifts at and not the WOT table? well here is my part throttle table, just want the car to grab 2nd gear at around 70-75 instead of just below 65. if it is even possible. thanks for any help

SHIFT 1-2 11 11 11 12 14 16 20 24 28 31 33 35 42 42 42 42 42
SHIFT 2-3 22 22 26 30 32 35 39 44 50 55 61 65 79 79 79 79 79
SHIFT 3-4 30 35 37 40 45 50 56 87 95 105 115 125 138 138 138 138 138
SHIFT 2-1 10 10 10 10 10 10 10 10 10 10 10 10 40 40 40 40 40
SHIFT 3-2 16 16 16 16 16 16 18 20 23 23 23 23 76 76 76 76 76
SHIFT 4-3 22 22 23 25 29 32 37 42 48 48 48 48 130 130 130 130 130

[Bill@HPTuners]

there is more then 1 shifting table...post a file, it will be much easier then posting the other 500 cells in TXT form.

[leftyss]

well i can't post a file with the computer i am on. will have to wait until i get home then i can post a file. will get it posted as soon as possible. thanks

[jimmyblue]

I prefer to keep the part throttle downshifts parallel to
the upshift, offset by -2, -3, -4 MPH for 2-1, 3-2, 4-3.
Having the big gap between upshift and kickdown does
not make for smooth action, to kick down you have to
apply a lot of throttle and then you kick into an over-
power situation when all you wanted was to move up
into the powerband.

Try something like this...

http://home.cfl.rr.com/jimmyblue/PCM_Trans_20041024.xls

Bearing in mind gearing etc.

[leftyss]

here is the bin. that i have in the car right now. All i want to do is get the car to shift in 2nd gear from 4th gear when the car is between 65 and somewhere around 75. if it is even possible.

[Russ K]

When I changed a 1999 Firebird from 3.23 gears to 3.73 and your tire height,the trans revolutions/mile is 3009.3748. Yours is 2615.3905. My calculated tire is 25.00, yours is 28.76.

Russ Kemp

[PurplePiss]

Your 2-1 downshift is set for 40, I have mine set to 30. I bet that is a violent drop down when you hammer it.

[leftyss]

i will remeasure my tires and make sure that is correct, if it is then what the computer figures should be right? or can i check with a scan and change it?

[PurplePiss]

jimmy,

Did you clean out all the formulas in that spreadsheet? What gear ratio is that for? Would it work well in a 3.4x geared GTO?

Would you recommend messing with the Force Motor Tables now that we have base shift pressure tables?

[jimmyblue]

The speeds are set for 3.42 gears and I'd leave the force
motor table alone unless you can't get what you want
from changing the commanded pressure modifiers. This
'sheet has no formulas, it's just a table-by-table capture
of what was what, as of date.

[Bill@HPTuners]

I prefer to keep the part throttle downshifts parallel to
the upshift, offset by -2, -3, -4 MPH for 2-1, 3-2, 4-3.
Having the big gap between upshift and kickdown does
not make for smooth action, to kick down you have to
apply a lot of throttle and then you kick into an over-
power situation when all you wanted was to move up
into the powerband.

Try something like this...

http://home.cfl.rr.com/jimmyblue/PCM_Trans_20041024.xls

Bearing in mind gearing etc.

I just hand manipulate as I see fit...once you can visualize the upshift downshift stuff its actually pretty easy on the A4's with the exception of the TC lockup stuff at times...you should take a look at one of the A6 or even the Allison files Jimmy lol

[leftyss]

ok-
here is my new tune. have not driven the car with this tune yet. can someone tell me if my car will shift down to 2nd gear from 4th gear when my speed is above 65 mph? and why it will or why it won't. have rechecked my tire size and with a 17" wheel and 315/35/17 tires it measured out to 25" so my tranny should be scaled right.

[Russ K]

315/35/17, 275/40/17 and 245/50/16 tires are all the same height. Don't change the tire size. just the gear ratio. This is how your speedo tables should look like.

Russ Kemp

[Special K]

I have 3:42. This is my table.

10.00000 10.00000 11.00000 12.00000 14.00000 18.00000 20.00000 23.00000 26.00000 29.00000 31.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
17.00000 17.00000 19.00000 21.00000 25.00000 30.00000 36.00000 41.00000 47.00000 52.00000 57.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
22.00000 22.00000 27.00000 32.00000 38.00000 44.00000 52.00000 78.00000 99.00000 110.00000 117.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
8.50000 8.50000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 9.00000 32.00000
15.00000 15.00000 15.00000 15.00000 15.00000 15.00000 17.00000 19.00000 22.00000 25.50000 30.00000 33.50000 38.50000 42.00000 47.00000 54.00000 69.00000
21.00000 21.00000 22.00000 24.00000 28.00000 30.00000 35.00000 40.00000 45.00000 52.00000 62.00000 77.00000 88.00000 93.00000 101.00000 107.00000 121.00000

[leftyss]

In my current tune, why is my calculated tire size different from my current tire size. I can enter 24.91for tire size and 3.73 for gears and I don't get the same values as you Russ K.

[Russ K]

What version of HP TUNERS are you using? I have 2.1.13.0. Every time I changed a stock 1999 Firebird with an A4 trans/3.23 gears to 3.73, The table is the same as I posted.

Russ Kemp

[leftyss]

I am using 2.1.10

[leftyss]

Another thing I have noticed with 2.1.10 is that I can't turn off my EGR DTC codes. Have my wideband hooked up to hp tuners through it and so I have to live with the SES light, why is this? My earlier version would let me turn those off, why not this version?

[Russ K]

Looking at your DTC's under engine diagnostics, they end at P0147. The slider bar on the right side of the table is missing. If I open another stock 1999 F-Body file, the slider bar appears and the DTC's go to U1301. Do your codes end at P0147 also? Maybe re read the VCM.

Russ Kemp

[EC_Tune]

leftyss --- Go to your customer login on the main HPT site. *(you will have to re-register if you haven't done so on the new site)

Then download the latest release. Contact support if you need the beta.

EC