Unanswered Steppers moving at the wrong speed

My robo 3D had a binding z-axis motor so I am looking to upgrade. I had some steppers and drivers handy so I put them in and I thought everything was okay but it turns out they only move about half as far (turn half as much) as the originals. (sure does make for some crappy prints!)

This is the new driver: http://www.ebay.com/itm/201114247831
This is the new motor: http://www.ebay.com/itm/NEW-NEMA17-...-Robot-Reprap-Makerbot-Arduino-/161071121692?

The motors are 1.8 degree steps, the drivers allow for full to 1/32 step. and the firmware ????.

So the question is, what controls the step rate in the Robo and can I change it so these more powerful motors work?

 

wouldn't it just be a matter of calibrating your Z steps from 2560 to whatever the new one is... 5120 or whatever.
Just edit firmware in arduino and upload. you can test using the EEPROM if you wish, before flashing.

The line to edit is highlighted in one of the stickys about auto leveling at the top of troubleshooting forum.
I deleted the photo from my computer... if you search for 2560 in your config.h you'll find the line you need.

 

That fixed it. Thank you Ben!

 

Correction... it didn't fix it. While at first it appeared to be the solution, printing things with significant height shows the x-axis frequently misses a turn. The result is a squished print.

I will get an original motor and driver to make certain nothing else is wrong.

 

Squished in height is the Z axis. Have you chacked to ensure the couples are tight and the nuts are not binding on the screws?

 

I have the thing apart now. Cleaning the screws and nuts and will make sure they are nice and smooth.