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Discussion Starter #1
Hey guys

I know this will vary depending on car, build, altitude etc however just wanted to get an overall understanding about our cars.

For the guys running 9s and 10s what are your typical shift points between gears? I am not looking for exact numbers just ballpark idea.

1-2??
2-3??
3-4??

What have you experimented with and what has or hasn't worked?
Are you short shifting any gears?
 

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Are you talking commanded RPM's/MPH's or milliseconds of the shifts themselves?

My laptop is dead and at home with my HPT so I won't be able to check mine for you now unfortunately.
 

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you and I could have the same shift MPH's in the tables, but because other areas of my tune are correctly addressed, my transmission completes shifts un 200ms or under, and yours might be 300ms or more. this will cause the actual shift to be at a different point.

so the actual shift time, the commanded shift speed, shift pressures all create many variables.

you really have to look closely at the logs and be logging the correct information to be able to accurately get shift speeds in the tune to create the shift at the actual rpm you want.
 

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you and I could have the same shift MPH's in the tables, but because other areas of my tune are correctly addressed, my transmission completes shifts un 200ms or under, and yours might be 300ms or more. this will cause the actual shift to be at a different point.

so the actual shift time, the commanded shift speed, shift pressures all create many variables.

you really have to look closely at the logs and be logging the correct information to be able to accurately get shift speeds in the tune to create the shift at the actual rpm you want.
You mean you don't just max out the line pressures and WEEEEEEEEEEEEEEEEEEEEEEEEEEE?
 

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that is one way to do it......albeit not the correct one.
 

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Discussion Starter #6
you and I could have the same shift MPH's in the tables, but because other areas of my tune are correctly addressed, my transmission completes shifts un 200ms or under, and yours might be 300ms or more. this will cause the actual shift to be at a different point.

so the actual shift time, the commanded shift speed, shift pressures all create many variables.

you really have to look closely at the logs and be logging the correct information to be able to accurately get shift speeds in the tune to create the shift at the actual rpm you want.
The variables and details, I have only logged when doing 1/2mile events so I will look at those today between 2-3 and 3-4 and see what they look like.

What is the ideal?
Under 200ms?
 
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stock transmission you aren't going to get much under 200ms if at all.
 

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Discussion Starter #8
stock transmission you aren't going to get much under 200ms if at all.
mine was rebuilt by Tim King with Billet internals/shaft
 

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From what I have seen or experienced (non turbo or nitrous). You need to cut a 1.4 60' with a 138ish mph. I leave in drive with a slightly higher rpm at the launch, but not to much, it takes some seat time to get it right. I think your right there being your mid 700. I have a built Circle D trans and there shifts point goal were anywhere from 25 to 75 ms for all shifts.
 

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mine was rebuilt by Tim King with Billet internals/shaft
150 will be the best it will shift likely. did tim tune the TCM? those guys have a good handle on the 6l90
 

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From what I have seen or experienced (non turbo or nitrous). You need to cut a 1.4 60' with a 138ish mph. I leave in drive with a slightly higher rpm at the launch, but not to much, it takes some seat time to get it right. I think your right there being your mid 700. I have a built Circle D trans and there shifts point goal were anywhere from 25 to 75 ms for all shifts.

25ms shift? really?


F1 cars perform shifts at 25ms, most DCG Ferrari's are around 100ms. the V3 is somewhere around 175.

I had a build Circle D with countless hours of tuning, and it never shifted faster than 150ms.
 

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from the GT3 press release.


Ready for the racetrack:
“lighting shifts" with extremely short reaction and gearshift times
Gearshifting strategy and response times of the 911 GT3 PDK were designed for maximum
performance, and are fundamentally different compared to other Porsche sports cars. This
becomes apparent to the driver during manual upshifts in the form of a “lightning shift",
which permits reaction times of less than 100 milliseconds. To enhance driving performance,
lightning shifts are implemented with a torque overshoot, and the gear change is conduc -
ted with a highly dynamic adaptation of the engine speed to the newly selected gear. The
switching times are in a range that was previously reserved for the world of motor sports.
 

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25ms shift? really?


F1 cars perform shifts at 25ms, most DCG Ferrari's are around 100ms. the V3 is somewhere around 175.

I had a build Circle D with countless hours of tuning, and it never shifted faster than 150ms.[/QUOTE


Actually put the lap top on it yesterday to check things, make sure it didn`t learn anything stupid. After clearing the adaptives shifts and turning up the line pressure (slightly) we are back to an average of 50 ms. Circle D is tuning the TCM.
 

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I don't see how that's possible, the 6l90 is still a mechanical transmission. too fast and you get clutch bind because the fluid cannot have the offcoming and oncoming clutches move that fast.

please post a log, im curious to see how this is possible.
 

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Ready for MIR again...
 

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Anyone know at what hertz the ecm is communicating with hptuners?

I would think it would depending on how many PID's are being polled, but anyone have this info?
 

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the tcm spits out time of last shift as a pid.
 

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If you were closer I could give you a ride lol.
 

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Evil V, I`m not the tuning guy and don`t have the log from Circle D. All I can tell you is that, it is shifting at an average of 50 ms.
 
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