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Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Thu Jan 22, 2026 5:03 pm
by Ghia66
Thanks Tom, by run I figure you mean on the road?

Is there any other tests that I could do that may help while the car is a stationary test bed?

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Thu Jan 22, 2026 5:16 pm
by tom91
Yes on the road, currently no issues going 13000 rotations stationary. So we need to figure out what is stopping it from doing so on the road.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Thu Jan 22, 2026 7:22 pm
by Ghia66
Thanks Tom, will report back.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Sat Jan 24, 2026 2:56 pm
by Ghia66
Went for a test drive.
First run had quite a lot of traffic so didn’t get anywhere near the max.

Second run was better as there was less traffic. Didn’t have the GPS on… the hugely optimistic cable driven Speedo showed 80mph.

Third run was accelerating been frequent speed bumps.


IMG_2526.png
IMG_2527.png

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Tue Jan 27, 2026 6:25 pm
by tom91
Only first plot we see the 7000 rpm as we seen before. but not with a "steady" state cruise at that speed so hard to judge what is going on.

Ideally a log of accelerating "flat out" to max speed is best. Then we can see if the Potnom tapers off due to current draw or voltage. If it does not but the drive unit draws less power it means there is an internal limit.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Tue Jan 27, 2026 8:32 pm
by Ghia66
Thanks Tom, so try and get up to maximum speed and stay there for a while?
I will have to go searching for a good traffic free road!

Should I add any other values such as torque to the logging?

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Tue Jan 27, 2026 8:33 pm
by tom91
No, torque is potnom directly translated and too large to work nice with IDC and UDC

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Tue Jan 27, 2026 8:44 pm
by Ghia66
Thanks Tom, I will get on it.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 2:47 pm
by Ghia66
IMG_2570.png
Two runs; one in restrictive traffic…the other I was able to put the pedal to the floor and keep it there until the car would go
no faster.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 5:47 pm
by tom91
I am confused to what the graphs show, none show anything near 7000 rpm.

did you try saving logs? It be great if someone else chimed in with info on how to get better logs, I have no experience with this.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 7:27 pm
by Ghia66
Thanks Tom, I have asked Greg and he had some good suggestions on logging which I will try,
Will I log on the left: Potnom + UDC + IDC and on the right: Speed?

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 7:46 pm
by Bigpie
A good way to get logs is to use the can map to broadcast data and use savvycan to record

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 7:57 pm
by tom91
Ghia66 wrote: Wed Jan 28, 2026 7:27 pm Will I log on the left: Potnom + UDC + IDC and on the right: Speed?
Yes that is what you have been doing it looks like. Just the graphs are a bit short and do not show top speed.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 8:57 pm
by Ghia66
Bigpie wrote: Wed Jan 28, 2026 7:46 pm A good way to get logs is to use the can map to broadcast data and use savvycan to record
Thanks Jamie, is there a “beginners” blurb anywhere that I can study to see what is involved/how to get started doing this?

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 9:01 pm
by Ghia66
tom91 wrote: Wed Jan 28, 2026 7:57 pm Yes that is what you have been doing it looks like. Just the graphs are a bit short and do not show top speed.
Thanks Tom, I will try the suggestions to get longer records and get some top speed logs

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 10:02 pm
by tom91
Data points, increase that number under the graph.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Wed Jan 28, 2026 10:44 pm
by Ghia66
Thanks

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Thu Jan 29, 2026 4:14 pm
by Bigpie
Do you already have a way of can logging? If not https://lilygo.cc/products/t-can485 are a good option and can also run the can based interface so you can have it located for a better signal

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Thu Jan 29, 2026 7:54 pm
by Ghia66
Thanks Jamie, I will check this out.

Cheers Les

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Fri Jan 30, 2026 1:49 pm
by Ghia66
So recorded two runs; one in traffic and another one flat out!

Greg’s suggestion was spot on for getting longer logs…(I recently started using Windows 11) lower the display resolution. Lowered from 1920 x 1080 to 1600 x 900 and it worked!

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Fri Jan 30, 2026 5:06 pm
by tom91
Not really, did you bump the data points number as requested? Still only 88 measurements.

Oh log 14 is perfect, I just mapped it.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Fri Jan 30, 2026 5:13 pm
by tom91
So all data + Power Calcualted in kW
image.png
Now just kW + Potnom on left and speed on right.
image.png
Notice how we reach a steady state power even though potnom is flat.

The steady state of around 25-27kW is a clue. I will review some of the HTM code for the toyota prius once I have moved house. Busy moving this weekend until next one. Maybe during the week I got a few minutes, all be it without internet at my new house :(

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Fri Jan 30, 2026 5:18 pm
by Ghia66
Thanks Tom, very exciting!
Good luck with the move and internet… hope it’s not too challenging! 🤞

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Mon Feb 09, 2026 12:44 pm
by Ghia66
So during a routine maintenance inspection, I discovered this on the passenger side driveshaft!
The driveshafts have been sleeved, interference fit and pressed then welded by my local machine shop.
IMG_2664.jpeg

I decided as you do to do a quick launch in drive to see if there was any slippage.(I recorded this on my phone which was gaffer taped unsuccessfully to the body!)…so no video!!


The driveshaft didn’t appear to move, but I think it’s time to crack out the welder and do some welding that will include three plug welds of the sleeve to the shaft.

Re: Unlocking the power/torque of Prius gen 3 drive train?

Posted: Mon Feb 09, 2026 2:24 pm
by arber333
Ghia66 wrote: Mon Feb 09, 2026 12:44 pm So during a routine maintenance inspection, I discovered this on the passenger side driveshaft!
.....
The driveshaft didn’t appear to move, but I think it’s time to crack out the welder and do some welding that will include three plug welds of the sleeve to the shaft.
Here is what i proposed a while back
image.png
https://www.aircraftsystemstech.com/201 ... craft.html

https://leafdriveblog.wordpress.com/201 ... extension/

Also more video for welding driveshafts...