1993 Marathon expected speed with upgrades

[Dpd9193]

Hi All. New to the forum. First post.

I have a 1993 EZGO Marathon 36 volt. It is run by the following:
Advanced Motors BD4-4001 Motor
700 Amp FSIP Controller
400 Amp Super Duty solenoid
Heavy Duty F&R Switch
2 gauge wires throughout
Trojan T-105 (3 weeks old- 20 charges)
18.5 inch tires inflated to max PSI
Stock height

I am currently getting 20-21 on a flat run. My intentions are to upgrade to 48 volt and a bigger motor after I replenish my golf cart fund. Is this the expected speed with this set up? I live in a golf course community and I am sick of the old people blowing by me on the way to the course.

Thanks in advance!

[JohnnieB]

Welcome to BGW!

If you are getting 20-21 MPH on 18.5" tires with stock gears (12.44:1) in the differential at 36V, the BD4-4001 must be a high-speed motor because you are getting about 30% more speed than stock and only about 3% of the gain is from the slightly tall than stock tires.

Splitting the difference and calling your top speed on level ground 20.5 MPH, going from 36V to 48V will increase both your speed and your torque by 33.3%, so you will get up to about 27.3 MPH.

That will be spinning your BD4-4001 motor at about 6200 RPM and 6500 RPM is the max recommended RPM for most cart motors, so a "bigger" motor will more than likely give you more torque, but little more speed, if any, maybe even less.

You can go up to about 20" on tire height without lifting the cart, and that will up the speed at 48V to about 29.5 MPH.

If you left the cart and go to 22" tires, the 48V speed will be about 32.6 MPH.

Or you could stick with your 18.5" tires and change to 8:1 gears in the differential and get about 42 MPH at 48V.


There are a lot of options open, so the question is how fast do you want to go and how much are you will to spend to get there?

[Dpd9193]

Thanks JohnnieB! That was exactly the info I needed.