Buggies Gone Wild Golf Cart Forum - View Single Post

JohnnieB · 11-06-2012, 08:24 AM

Welcome to BGW!

With 18.4" tall tires, I get about 19.5 MPH with a Freedom chip, and no noticeable loss in torque.
(2% theoretical loss over the stock Carlisle Links, which are 17.4" tall.)

In Freedom Mode, the PDS controller limits motor RPM to about 4,400 RPM, so the only way to increase speed is change the final drive ratio.
That can be done either by increasing tire height or going to numerically lower gears in the differential.
However doing either will also reduce torque.

To get into the mid-20's without loosing torque, you will have replace the stock PDS controller with an aftermarket on that does not limit motor RPM.
IE: An Alltrax DCX400PDS will get you into the mid-20's and give you about 1/3 more available torque because you'll increase the max Amps by 1/3. (300A Stock PDS to 400A)

To go faster than that, you'll have to change the final drive ration and/or increase the battery pack voltage.

----------------
Sepex motors don't have quite as much low end torque as series wound motors, but the trouble you are having climbing a hill from a stand still, may be a high current cable issue.
I had a noticeable increase in low end torque when I installed 2Ga cables (all 10 of them).

If any of the high current cables or connection are getting hot, electrical energy that should be converted to torque by the motor is be converted to heat and wasted.

11-06-2012, 08:24 AM	#2
JohnnieB Techno-Nerd Join Date: Jun 2011 Location: West Virginia Posts: 19,654	Re: 2005 PDS Speed Increase Advice Welcome to BGW! With 18.4" tall tires, I get about 19.5 MPH with a Freedom chip, and no noticeable loss in torque. (2% theoretical loss over the stock Carlisle Links, which are 17.4" tall.) In Freedom Mode, the PDS controller limits motor RPM to about 4,400 RPM, so the only way to increase speed is change the final drive ratio. That can be done either by increasing tire height or going to numerically lower gears in the differential. However doing either will also reduce torque. To get into the mid-20's without loosing torque, you will have replace the stock PDS controller with an aftermarket on that does not limit motor RPM. IE: An Alltrax DCX400PDS will get you into the mid-20's and give you about 1/3 more available torque because you'll increase the max Amps by 1/3. (300A Stock PDS to 400A) To go faster than that, you'll have to change the final drive ration and/or increase the battery pack voltage. ---------------- Sepex motors don't have quite as much low end torque as series wound motors, but the trouble you are having climbing a hill from a stand still, may be a high current cable issue. I had a noticeable increase in low end torque when I installed 2Ga cables (all 10 of them). If any of the high current cables or connection are getting hot, electrical energy that should be converted to torque by the motor is be converted to heat and wasted.