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Cadillac STS-V Exact Shift Point Testing


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Cadillac STS-V Exact Shift Point Testing

Posted on May 10, 2013by bwnunnally

This morning I made 2 runs to determine current shift points during acceleration from a standing start.

I ran the STS-V in “competition mode”; this mode apparently uses “Cruise mode” shifting, which was a surprise to me but means a different table for the transmission logic.

run1gearshift12-1024x718.jpg

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Bruce

2023 Cadillac CT4-V Blackwing

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Cadillac STS-V shift testing, adjustment 1

Posted on May 11, 2013by bwnunnally

 

[Note the video quality can be adjusted up (click on the gear), and the video can be made full screen.]

Adjustment 1 set: Kept the 1-2 shift at 30 mph, and raised the 2-3 shift to 60 mph across all shift modes.  Raised the absolute fuel cutoff from 6700 rpm to 7000 rpm.  TM adjusted to 25%.

Interestingly, with no change in shift points the 1-2 shift revved to 6600 rpm and hit a new higher calculated hp value.

Shifttest2013-05-11max15-1024x719.jpg

 

 

Read more: http://caddyinfo.com/wordpress/cadillac-sts-v-shift-testing-adjustment-1/

Bruce

2023 Cadillac CT4-V Blackwing

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I see a source of delay -- the tires breaking loose at the 1-2 shift is wasting some time. I thought the car was slowing down -- but what I think I am seeing is 'false' indicated speed from the spinning tires until that resolves and then the actual speed

run1at15accelerationgraph.jpg

Bruce

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run1at15accelerationgraph2ReinTM.jpg

Tricky feathering the throttle to avoid wheelspin in 1 but have enough throttle to avoid the transmission early-shifting 1-2. Considering moving the 50%+ commanded shift speeds up to the WOT setting.

Bruce

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Bruce what kind of tires do you have?

Given the weight transfer to the rear wheels on launch I think it may be tires no?

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My tires this "semester" are Pirelli P-zero Nero 'summer' tires. (Tires don't stay long at my house).

For launch from a standing start, in this case on concrete as opposed to treated, sticky asphalt quartermile track, it takes a lot of driver throttle modulation. That part is my fault / user error.

My concern is that after initial launch, if I am still modulating the throttle at 20 mph then the trans early-shifts to 2nd. I think I have that fixed by adjusting the partial throttle up-shift in first.

Next concern is at full throttle on 1-2 shift the car would spin a lot. I have turned back on 50% torque management and appear to have that down to a sharp chirp. I need to test in early morning cold conditions, when the V makes more power and see where the shift points are hitting and how the tires hold.

Bruce

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Not arguing that these don't spin, but the V is going to spin any tire and is going to require some finesse off the line regardless. I found some interesting things that I needed to change so this was a good experiment. My follow-up runs were not directly comparable due to temps and heat soak, but I'll get some comparables soon. I probably need to get Texas Jim to come drive the V and see if he can get it off the line better lol, but that doesn't help me pedal it all that much.

Bruce

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