View Full Version : Custom throttle curve for AXE7245

18 February 2014, 0420
I have converted a motorcycle (http://kWsaki.com) and now I'm converting a car. I would like to use the original carburetor and it's TPS to control my AXE7245 controller, which can use 0-5V input. However the TPS only has a range of 0.5-3.6V, so I'd need a custom throttle curve for the controller.

Is there anybody here who could create a custom throttle curve for me?

The curve should be slightly progressive and start with zero power at 0.5V or 10% input and end with full power at 3.6V or 70% input.

I have a drawing of the desired curve (blue line) available here:

18 February 2014, 0507
Thanks, Ted! I've also thrown them an email or three on this already. ;)

18 February 2014, 0544
Thanks! I've lent a lot of the parts for the car now, but nothing I couldn't pretty easily put back. ;) I had originally bought a Kelly for the car, but I got a model which only does 0-5k pot. I had a pot throttle, but it all seemed so flimsy and the gas pedal so light that I decided to go back to the original carburetor in the car to get exactly the same pedal feel as it had originally and use the TPS in it to get a throttle signal. Luckily I had the AXE 7245 in the motorcycle I could swap with the Kelly.

I have a 0-5k Magura twist throttle in the motorcycle so the Kelly will work fine there. I can now also choose my motorcycle battery voltage pretty freely between 24-120V, so it's just down to the number of cells and charger. Probably will keep to the same cell count though, since I have a couple of chargers set to 87.6 volts (good for 25 LiFePO4 cells bottom balanced).

18 February 2014, 0900
Hello Jsantala,

Welcome to El Moto, do you have any pics from your cycle build? What type of car are you using?

18 February 2014, 0914
Sure, you can find pictures on my blog. Latest posts first, as usual.

Motorcycle: http://kwsaki.blogspot.fi/search/label/kWsaki
Car: http://kwsaki.blogspot.fi/search/label/kWsara

The motorcycle is a Kawasaki GPX750R -87 and the car is a CitroŽn Xsara -97. Pretty basic 5-door liftback. Original weight 120 0kg or 2600 lbs.

19 February 2014, 2039
Welcome jsantala,

The answer in the following thread may not be the most convenient, but it explains what might be involved in creating a custom curve yourself (requires PIC software instruction knowledge). Or, perhaps it's also possible to contact bjn from this thread:


That is, if you don't go with the Alltrax solution in the first place.

19 February 2014, 2159
Yes, I've seen that thread, but no ready answers there. :)

However, I found this company which will sell custom curves:


I've been in contact with them and considering the very reasonable pricing they've been most helpful. I will most likely get a curve from them.

20 February 2014, 0423
No, I haven't had any replies from Alltrax. The German service was very knowledgeable, quick to reply and cheap, so I paid them gladly. I'll let Alltrax know if I have a working solution tested before they get back to me. It'll take me until the end of next week though.

I'll get the yellow curve.

21 February 2014, 1047
picoamps.de came through quick and I have a curve.hex which looks like it could work. Will have to wait until end of next week to try it though.