top speed disappointing?

[scottyb]

I'm not a big fan of going super fast in a golf cart. I've read all the accident reports... I have a fast car if speed is the need

[cgtech]

Originally Posted by ycis

10-4 thank you...

yes, i will definately upgrade the stock motor if/when it eventually dies. I thought I had just seen somewhere someone say that an OEM motor from a 36v cart would give a little bit more performance than that on flat ground.

18mph is plenty fast enough for carrying the kids around, but im sure like everyone else wouldnt cry if it were "a little" faster.

If your cart was originally a "Freedom" model TXT, it would have went 18-19 mph on 36v and stock tires, apparently you have a "Fleet" model txt.

[scottyb]

The results posted seem right for a Series TXT.

http://www.cartsunlimited.net/upgrade-suggestions.html

[cgtech]

2 dirrerent series motors were available from the factory. Fleet models motors say "FLT SPEED", Freedom motors say "HIGH SPEED"

[scottyb]

Oh I see what you're saying...yes

[Sir Nuke]

Originally Posted by ycis

30 would be pretty ridiculous (for me anyway)...id just kinda want to cruise at normal street speeds without having to hinder auto traffic as much as I do at 18mph etc. id think topping out at 23-25mph would be ideal for a cart in my neighborhood...because id never be able to keep my foot off the floor if it could do 30 =D

Originally Posted by scottyb

I'm not a big fan of going super fast in a golf cart. I've read all the accident reports... I have a fast car if speed is the need

The fact that my cart WILL go 30 mph.....doesn't mean I drive it that fast around the neighborhood....just like your car/truck, just because you can, you probably shouldn't. but having that EXTRA power, means the drive system doesn't work as hard to go as fast as you need/want to actually go.

[bronsonj]

Originally Posted by ycis

30 would be pretty ridiculous (for me anyway)...id just kinda want to cruise at normal street speeds without having to hinder auto traffic as much as I do at 18mph etc. id think topping out at 23-25mph would be ideal for a cart in my neighborhood...because id never be able to keep my foot off the floor if it could do 30 =D

My cart has a GPSed top speed of 34 mph currently (when in go-fast mode), I need to tweak the controller programming again to bring that down a little... Over 30 and it's not a fun ride...

With the 'personality switch' I usually keep it in my middle performance mode. Top speed around 24 or 25mph (haven't GPSed it, but guessing) and it is a much more enjoyable cart. When I feel the need for speed, I change it and the thing is insane. Too insane for a cart if you ask me.

I also have the kiddie mode to bring it to a manageable speed for my daughter (13 years old). I haven't GPSed it, but I think it's around 16mph in kiddie mode and much reduced torque.

[ycis]

yea ive no idea the history behind the cart nor how fast it was prior to me getting it. it had sat for 10 years prior to me rebuilding it. next time im out in the garage ill take a closer look at the motor thanks for the tip!

the last question in "turning down" the controller, is that better or worse than buying a motor that would run my expected top speed flat out? as I understand it the controller just bleeds off power and only sends a portion of it to the motor etc as configured.

not that I fear for the wear and tear on the controller, but is it better to just give it everything vs having to run it limited like that all the time? or is that just a trivial matter in the grand scheme of things?

guess its time to start researching motors to see what options are out there! Id just imagine it would be easier/better to just buy a motor that would turn the rpm to give me 24/25mph top speed vs one thatll rip my face off that id have to turn down via the alltrax?

[bronsonj]

IIRC the pros on here recommend 400 amp as the max on the stock motor, so you can turn down the 500 amp controller to be stock-motor friendly.

I see you have a series, my cart is sepex so the max RPM limiter doesn't apply to your system. Alltrax lets you state the max rpm in a sepex system

The signal is pulse width modulated (at least in a sepex, I think series would be similar), so it isn't bleeding off power like the old resistor coils did. This is a little out of my depth, but in my mind it is giving the motor full power for a fraction of a second, then is off for a fraction of a second. The closer you get to 100% throttle the longer the full power is on. I'm sure that's at least partially incorrect (or worse) but that's how I thought it worked?... But the end result I am certain of, it isn't like the old resistor coils.

JohnnieB had a good explanation about field coil amperage and whatnot. I won't attempt to restate what he said, but there was something about increasing field coil amps meant the motor couldn't take more armature amps and wouldn't spin any faster. (Johnnie, sorry if I butchered that)

Your stock motor should be fine so long as your controller is set to be compatible. Someone will come along shortly and let you know the parts I got wrong. But if you want a faster or torquier motor you can absolutely get one with your current settup.

[JohnnieB]

A stock 98 TXT series drive with standard motor (Fleet Speed) has a top speed up to about 14MPH (12MPH to 14MPH is the spec listed.) That is with 18" tall tires, 12.44:1 gears and a 36V battery pack.

At 14MPH the motor spins at 3252RPM. Upgrading to a 48V battery pack increases the RPM by 33.3% to 4335RPM, which is 18.7MPH on stock height (18") tires

Upping the tire height from 18" to 20.5" increases the cart's speed by 13.9% while reducing the torque where rubber meets road by 12.2%, so the cart's speed should increase to 21.3MPH, mathematically, but won't be able to reach that velocity due to the torque loss caused by the increased tire height.

Pumping the tires up to the maximum recommended inflation pressure stamped on their sidewalls, will get the actual top speed closer to the theoretical top speed. If the tires are the low pressure type (less than 10PSI max pressure) the top speed will be less that that obtainable by road tires.

Since the cart is old enough to order alcoholic beverages in every state in the union, the wheel bearings, differential bearings and motor bearing may be spinning as freely as they were when new and placing an additional mechanical drag on the motor.

Also check for dragging brake shoes.

Reducing weight also increases speed.

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Basically, series wound golf cart motors installed at the factory come in three flavors,
1. Standard Speed/Standard Torque
2. High speed/Low torque
3. Low Speed/High Torque.

However, here are aftermarket motors in bigger (longer) cases that have higher than stock speed with stock torque or better, as well as long case motors with higher than stock torque with stock speed or better.

But first, you need to figure out what is keeping your cart from reaching the theoretical speed.

------------
What make/model batteries?
What make/model charger?
What model controller? (AXE if older, SPM or SR if newer)