My 2010 E6 equipped with the stock 7.0 HP motor. I reprogrammed it and it goes about 30 mph (32-35 downhill) it struggles going 25mph up any slight hill.
Will upgrading to the 7.5HP motor for $850 give me much additional gain? Is the motor build a lot better or is it just .5 more HP and not worth it at all?
Motors aren’t much different.
Want more power and speed raise the voltage. IMO
Only tested with lithium batteries, but should work with lead also.
they advertise the 7.5 motors as 11HP peak. is that somethin the 7hp motors do not have? that seems like a great difference.
Just advertising hype! They all put out more peak hp.
I have a 5hp that is rated at 12 peak hp.
The controller is what limits hp.
Your motor (any) will input 19hp at 72v and 200a. Then it’s all about efficiency.
Add another 12v and gain 3 theoretical HP.
My experience shows motor runs cooler using less amps at higher voltage.
Most dc motors are usable over a wide range of voltages.
As current is limited by controller and motor temperature, all that’s left for real performance gain is higher voltage.
No, this is not a mainstream modification. There is more money selling motors and controllers. 
Still looking for a guinea pig.
Keep an eye on Grantwest who is going to test 88v nominal battery in his Gem.
I would agree with Inwo. I have 2009 eL HD which came with 7.0 HP motor. I changed to 7.5 - 8.5 HP. Speed sensor lasted 6-8 months, could not get replacement. The 7.5-8.5 HP is supposed to have better ventilation and but does not have temperature sensor. Heat is what kills motors, the windings break down causing failure. Ambient temperature makes a big difference as well.
When I was doing my research, I contacted vendors as to HP/Speed benefit in going from 7.0 to 7.5, got a lot of muffle-muffle answers. Speed is increased by amp increase through motor, which will fry your motor in time. Increase in volts reduces amps. You can calculate using ohms law. Most motors are rated at 125% rating, but duty cycle is important to.
thanks for the info guys.
Is there a controller upgrade for the GEM cars? Im a golf cart guy and you can do so many controller/motor upgrades to make them go fast, but dont see anything for the GEMs. Are there higher amp controllers for gems? and if so how much/where to buy?
The controllers are integrated into the cars instrumentation and electronics. I don’t believe it’s practical to swap.
The common way is aftermarket motor and gearing changes.
My 48v Tomberlin was a dog until I got up to 72v. Then it pepped up from 20 to 35mph. At 48v slowed to 12mph up hill. At 72v almost no speed loss at 1/2 throttle.
you would think a company could make the same controller just with higher amps and make a fortune on gem car owners that want to upgrade. Such a shame noone makes parts for these things.I have $ to spend and literally cant make this thing faster easier.
Can’t be easier than adding a battery. I’m all lithium here or I’d test it for you.
So no guarantees from a $200 investment.
I can tell you that a $3k upgrade to a 21s or 24s lithium battery. Will give you high performance from weight savings alone.
if you really want the gem to rock , go lithium . my lithium conversion is 3 years old . with and old stock 5hp motor it well go mid 40’s . gems love voltage .
lithium conversion will last for years and perform much better then any motor/ controller upgrade .
you can get a high amp controller from ride 4 fun and a high rpm motor . but you will drain that stock gel battery pack fast .
gwest had a 9hp motor in his gem . converted to lithium and had a hard time keeping the front wheels from spinning .
you can do Nissan leaf conversion or get one of dave’s double volt packs and your cart will be fast and have Hugh range .
May i ask the price of doing a lithium pack conversion? how difficult is it to hook up to existing gem? I have the software to program the gem and it seems most of the settings get maxed out very quickly.
As I have been selling some Volt batteries, kinghappy will give you a more unbiased opinion.
That’s why I don’t jump right in on public forum pushing the lithium solution.
If money is no object. You can buy drop-in 12v replacements.
I believe a set will set you back about $6 to $8k.
Mike and I are believers in using late model salvage ev modules.
By junk yard shopping, and doing your own research and legwork, you might get It done for <$1500.
Lithium have unique requirements for care.
Basically, no cell can be charged over max volts, and no cell can be discharged to less than minimum volts.
This includes storage. When a lithium dies, it’s dead.
I just sold a 110ah set of Chevy batteries, with battery management system that shows all cell levels. For $2700
That was from a 2015 8k mile car.
It should turn out to be a >40 mile gem.
Include was wiring harness to plug in to bms. A voltage spoof allowing to run up to 100 volts, charger programming, shipping, and a bms-24.
He also bought a 25a charger for fast charging. Making it $3k
Top is a Volt pack I’m buiding.
Bottom is Spark pack left and Leaf pack right.
!
I agree with King and Dave. The weight reduction alone will make your Gem go faster Here is the PROOF. Save your $ on a 7.5 and spend it on batteries. Dave is a great source for a pack.
Thanks for the information and great video. This may be a winter project I need to take on. My batteries still last 25miles to a charge (9 8v gels) so I feel when they come closer to end of life then this lithium upgrade seems to be a no brainer. I feel most of you guys doing these upgrades are on E4s, the E6s definitely weigh quite a bit more and i think the numbers would be alot slower for the E6s.
Well weight is weight. And when you are talking about a car that has 7.5 Hp and you can eject 400+ pounds of weight that’s like 2" 200 Lb passengers don’t matter what your driving. Eject 400 pounds and your gonna notice a difference. But I agree with you on your Batterys are new so you don’t wanna throw them out. Spend your $ on other things, just don’t waste it on a Motor. IMO it’s not going to make any real difference in speed or range. You will be pissed if you spend $800+ on a motor and your car go’s no faster. Only thing a 7.5 Hp motor is gonna do is allow you to spin it faster. Higher rpms stock motors don’t like to go over 6k for any time. How about some nice wheels and tires or a stereo, or you could always look for a Used E6 that needs batteries and throw your FLA batterys in that and re- sell it I’m sure you can re-coupe your $ and then get a Lithium kit. Trust me you will love it
How much battery room in an e6?
Which seat holds the batteries?