Q&A Forum
Hi team,
Is there a way to cap or filter the displayed torque curve when torque converter multiplication causes artificially high values at flash RPM?
For example, I’ve had several auto cars that report peak torque around 2000 RPM — sometimes showing 650Nm — even though the rest of the run averages closer to 500Nm once the converter is fully coupled. This artificially high torque skews the dyno graph and also shows up incorrectly in the peak torque readout at the end of a run.
In one particular case, the car came on boost right at converter flash, and didn’t fully settle until around 3500 RPM, with a redline of 6000. I don’t want to set the dyno to delay the start until 3500 RPM, as it would ignore almost half the usable data range.
What I’d like is a way to apply a user-defined torque filter, such as:
“If torque > X at RPM ≤ Y, then don’t display or include that value in the graph or summary.”
That way, we can preserve the full run data, but filter out misleading peak torque values due to converter multiplication, and instead display the actual peak engine torque.
Is this possible, or could it be added as a future feature
Hi,
If you have an auto gearbox and run with fixed gear ratio, then the torque reading will be wrong. This is because the gear ratio changes during the run and torque is dependent on the gear ratio. In the beginning of the run the gear ratio is very low, so torque is very high.
You have a few options.
- Turn off torque display on the Splash screen and only display power (which is not dependent on the gear ratio)
- Use a direct engine RPM data channel and click Use variable gear ratio
Thanks for the reply Jostein.
Do you mean the gear ratio changes because of the torque converter torque multiplication?
Basically majority of the vehicle I tune are GM.
They are 4 speed autos
Diff ratios are generally between 2.87 and 4.11
before a run i will set the gear ratio by locking the trans in 3rd gear (1:1) through my tuning software, bring rpm up to the set rpm in yourdyno and hit the lock gear ratio button. then I will start the run from 1500rpm in 3rd gear only. The gear itself remains in 3rd the entire run (doesn’t shift 1st, 2nd, to 3rd)
Yes. If you have locked it in gear then that is better, but the gear ratio still changes due to the torque converter. The issue will be less noticeable if you start at higher RPMs where the torque converter locks up harder.
Awesome.
Thank you for the help. I may try set the software to lock converter down low and release it before the torque comes in heaviest. The 4l60e doesn’t really like being lockup up at wot!
appreciate your time 🙂