aquired a stock PDS with 6:1 gears, testing...

sportcoupe

I am building a speedster ezgo pds with all the goodies, 500A, 48v, 6:1 gears, 2g cables, d&d motor, etc. I'm waiting on parts to come in for that build.

Last night I stumbled across a stock PDS cart with 6:1 gears and low profile 18.5" tires as it's only mods on craigslist. I had to grab it because price was right for a quick flip. Anyone want some testing numbers done on a stock cart with high speed gears? Let me know. I'm very curious to see what it will do with and without a speed chip. I'm also curious as to if it's really 6:1 or maybe only 8:1. I drove it and it's a total dog for the first 50 feet or so then it picks up pretty good.

Attached Images

image02.jpg (44.3 KB, 0 views)

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

JohnnieB

Tell me how fast it goes and what PDS mode its in and I'll tel you if the gears are 6:1 or 8:1.

patgrim00

What is top speed on it as is

sportcoupe

Ok I made some highly needed wiring repairs to the high current cables. They are now 4 gauge and completely clean and tight. Previous owner had a mix of 6g, 4g and 1/0 cables on that cart.

Battery pack at 38.2v, tires all aired up (they were low), I did some top speed runs with and without a speed chip (red freedom). Tires measure 18.5".

Without any speed chip --- 29-30 mph flat level ground.
With red freedom chip ----- 29-30 mph flat level ground.

Seems that little 2.5hp motor is giving it all it's got since the speed chip did nothing for gains. What gears are in this cart? Owner said 6:1 but he didn't install them himself, a shop did.

patgrim00

That's pretty fast but how long does it take to get there

sportcoupe

About 1.5 to 2 football field lengths. Not awesome but very drivable. Has zero torque from a stop. You could not drive over a curb at all from a standstill.

JohnnieB

My guess is that it has 6:1 gears.

Max RPM in All Terrain mode (no chip installed) is about 3,300 RPM, which is about 30MPH with 18.5" tires and 6:1 gears.

With 8:1 gears the motor would have to spin at nearly 4,400 RPM and that is faster than the All Terrain mode allows.

Freedom Mode maxes out at about 4,400 RPM, but it appears the rest of the drive system lacks the wherewithal to spin the motor any faster.

A higher amp controller would up the speed, but the stock motor probably wouldn't like it too much.

---------
I see you noticed the same thing I did. Non-lifted carts on nearly stock height tires are very drivable at speeds in the high 20's.

---------
Part of the reason it takes so long to reach top speed is pack voltage. It drops under load and takes time recover as load reduces. The heaviest loading is when cart is moving the slowest.

Try more gentle acceleration and you might get to top speed sooner.

sportcoupe

Thanks Johnnie, I figured it did have the 6:1 but I didn't know how to prove it other then brute force (pull pan, count gear teeth).

This is non-lifted cart and very drivable at almost 30 mph. I did build a lift 6" silver pds with 23" tires that was also very stable at 30. The trick was the drop spindles (added width), offset wheels (more added width) and 2" wheel spacers (even more added width).

This isn't my speed demon cart, that is coming real soon and will be another thread.

As info for anyone contemplating 6:1 gears you will need a robust system for cart longevity or things can go south quick. Don't even think about 4 gauge cabling at 36v, this cart has 4g cables and they get warm, especially around the 200 amp solenoid (forgot that upgraded unit was there when I wrote first post). You will also need a much better controller also to improve the great torque loss. As noted the stock motor can work but for how long is an unknown so plan on calling D&D. Lastly you will need a healthy battery pack that can take the high amp draw.

I plan on leaving no chip installed so I get maximum regen braking, that should help with slowing done from 30 mph. This cart only has stock drum brakes and stops pretty good too at those speeds, it can lock up the rear tires, probably since they are small and even lighter then stock (aluminum wheels). Less unsprung weight always helps performance.

sportcoupe

I wanted to know how much current is being drawn from the 36v pack at max cruise on this cart. I was going to temp install a shunt ammeter but those are only accruate at full throttle (due to the PWM of the speed controller). Instead I used my clamp-on ac/dc ammeter. It maxes at 300 amps so should be fine with stock controller.

Standing stop launch full throttle -- 280+ amps

Full speed (29mph), level ground -- 110-115 amps

Half throttle (19mph), level ground -- 60 amps

From what I've been told traction battery packs need to see under 70 amps at full throttle for maximum life. Excessive, sustained current draw is hard on batteries. This is one of the reasons the stock motor isn't up to the task of driving 6:1 gears, high current draw. I don't know if adding a larger controller would lower the max current draw. I doubt it.

This cart is a test bed for sharing info on installing high speed gears on a stock cart. I'm just recording what I find.

bokeasmowl

Thanks for the results sportcoupe. The cart seems to be a sound, stable and fun cart. You gonna keep it or resell it?