Make a 2016+ GEM go faster - What are my options? (7/2022)

GEM Forum
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Thought I’d start an updated thread around 2016+ GEMs and how to get better performance out of them. I did a high voltage conversion over a year ago and know we’ve learned a ton about these cars since then; batteries have changed, BMSes, controller programming, etc. Was hoping to get a discussion going as a reference guide for someone with a stock 2016 that’s looking to break the 25mph barrier.

Maybe we break this out between 48v and 72v+? Or Value to Performance?

What motors are available? (5kw stock, 6.5kw stock, 8kw, 10kw, PMAC?)
Controller options? (s4 72v, s6 72v, s6 48v, stock 48v controller)
Gears? (9:1, 12:1, 17:1)
Chargers? (Delta Q DCI)
Batteries? (So many options… what are folks stocking?)
BMS (chargery, JK, ANT)

Ideally, where’s the best place to source parts, and which forum members should we reach out to?

inviting some folks to the conversation - @Inwo @djgabriel2004 @MikeKC @LithiumGods @ScottyD @AssyRequired @JarJarJava (primarily for comedic commentary… and to make sure no pre-2005 discussion is included)

My thought is we start with the outliers. What’s the least expensive way to get over 25mph? If i’m all in, what is the best or the best?

Thoughts?

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Nothing available as of this time. A few 8kw stragglers left here and there.
Untested/configured 10kw on the way.

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I stock 80v S4 and S6 Sevcon Gen4.

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14s is ideal for 48v Gems. Options from members are SDI cells.
Tapping 8s battery modules from @LithiumGods

22s Samsung back in stock.
Hv requires charger and dc-dc change in addition to 80v controller.

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Swapping gears with accompanying proportional loss of torque. Not a huge issue as they have plenty torque to begin with.
Contrary to big name Gem builder’s opinion, high speed will lower range.

Reprogramming is available now at a price competitive with gear change. No torque loss but limited to 35mph @ 9,000rpm. We can push it to 10,000 rpm if you ask at your own peril. :slight_smile:
Requires that parts be removed and sent in to be programmed.
All oem functions and dealer access unchanged.

Controller swap can be done economically, but only with battery swap to over 50v. 14s +.
Speed is still limited to 35mph. Works with gear swap for more speed.
Working speedometer, but somewhat buggy at this time.
Added wire harness is needed, but is getting easier to do.

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I have two battery packages available for 2016+. Both come with Bluetooth BMS and custom battery cover. Both are available in:

14s = 56v use stock charger settings
15s = 60v use stock charger setting with one of our spoofs.
16s = 64v reprogram factory charger, may work with stock dc converter, testing happening now

#1 234ah, 60-70 mile range. $3195 (same capacity as Polaris’s largest lithium pack that costs $12,500)
#2 312ah, 90-100 mile range. $3950. Biggest battery available for a Gem.

#1 Also available in a 24s, 96v configuration. This is the voltage, Ah that @grantwest is running.

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Let’s not forget the eM1400, which are 48v & AC motors since they came out in 2014 all the way up to the end of the run in 2021.

< 2006 =

banstick

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eM’s are a bit of a different animal than any other Gem, ever. RWD, 4-wheel independent suspension, 4-wheel vented disc brakes, anti-sway bars, adjustable rate suspension. 7.5hp motor stock w/ 17:1 gears. 2" hitch receiver standard. They are work trucks. Mules. Tugs. Drag a 2000lb trailer around no problem. Not really built for speed, but 25mph sucks.

My 2015 is pretty much stock still, save some reprograming that Dave performed on it before he shipped it out. Raised the speed limit / RPM limit in the controller and and at my request, upped the regen. On paper, this should give 35 mph with the stock tires. I hit 33 with the worn out OE AGMs. Yeah, it’s that simple. Talk to @Inwo about a reprogram. No issues with buggy dashes (cab electronics and displays are unlike all other GEMs) everything worked great. The extra regen I requested in preparation for a Li-Ion pack blew the old azz #1 AGM battery apart, but that’s a different story.

Derrek converted his to lithium, I have all the parts to do something similar, just haven’t had time yet.

I did talk to Rodney about gear swaps, he confirmed he could put a 12:1 set in the TRIM gearbox that mine has, YMMV.

Having run Emmy at 33 a few times, I don’t know if I’d want to go faster than 35 though. They sit high and have very short wheel bases. With a full cab option and a steel bed with sides that’s a lot of weight up high. Stability at speeds concerns me. Emmy is basically like driving a real-live Tonka truck.

Without the cab and the bed sides, just a bare bed and the roll cage, might be a different story, they use a lot of Polaris Ranger parts as they are built on Ranger 300 steel frames, so a RWD go-fast GEM eM1400 might be a possibility for someone some day.

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I have a 2017 em1400 with 2p14s lithium battery pack and I had @Inwo reprogram my controller to get more speed. I haven’t done anything with the charger, it should be set for agm batteries and it works great. It’s a bit buggy with a full charge when pulling out of my driveway, the regen causes the BMS to cut out (set at 3.95v/ cell). I can tell the difference in performance between full charge (~54v) and partly depleted (~48v), full charge it will quickly accelerate up to 35 mph and when it’s run down a bit the acceleration is a bit slower up to about 30 (but still quick enough) and then creeps up to 35. I have been thinking about adding 2 more batteries to make a 2p15s pack which will allow the batteries to charge more and not rely on the BMS to stop them from over charging and to keep the voltage up for a longer period of time ( it should keep the the batteries in the flat section of the voltage/capacity curve).

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New to writing on any forum that is how desperate I am to get any help with my 2016 gem. 100% stock. As most on this thread i am looking for more speed. Not looking to blow the doors off. Just 35-40. I did order R4F gears because I could not find anything on 2016+ im reading a MM? Could be a easy solution on top of the gears ive already purchased. If anyone can can point me in a direction to purchase or a way to reprogram my controller to take the limiter off it would be appreciated.

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You can swap controller for a new generic programmed Sevcon,
I haven’t had the time to offer this solution for a while. If not in any hurry, I can let you know when It’s available again.
Gabe offers the Speedbox, plug-in fix.

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@Inwo I’d like to see about getting a MM for my 2011 E6. What do you need from me? Full context, I just had a lithium battery installed.

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Hey IndianaMike - Welcome to the group.

Desperate

What does that make us? It’s not like this is a singles/dating site.
Now I need to go sit and re-ponder my life choices. This may/may not include checking my belly button for excess lint.

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Just to be clear (since you might have a transition year/car), Does your car look like this?

06 Gem 9
06 Gem 9960×466 86.9 KB

Then you have a gen3 car and the remainder of this post does not apply to you.

Or does your car look like this?

2018 gem e2
2018 gem e2720×960 102 KB

Then you can continue reading.

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Make it go faster - Gear swap
The R4F gear set is the old school/first gen/brute force method of speed increase. It obviously involves removing the gearbox, splitting the case, installing gears,then putting it all back together. It’s not an easy or quick thing to do. If you have the means, talent, and tools to do this- Have at it.

What I don’t like about a gear swap (depending on what ratio you had vs what ratio you are putting in) usually changes top speed at the expense of low speed performance. It’s like trying to start off pedaling your 10 speed bike in 5th gear.
This may be a big issue if your cruise circle involves any sort of hills.

It is all about doing the math. What gears are in your car and how fast do you want to go? If your car has something crazy like 17:1 gears in it, then yes, a gear swap is probably a good idea.

Controller swap
Inwo has had success with offering a complete controller swap. The factory motor controller is locked up fairly tight and I don’t think anyone has managed to reprogram it yet. With a new controller swap, I’m not sure if all of the ancillary subsystems remain 100% functional(battery SOC%, Speedo accurate, etc). Check w/Inwo on his last efforts worked out.

Magic Magnet
This is a small plug in device that alters the speed reading value the controller looks for when you are driving.
Sorry, this particular solution is not meant for cars newer than 2015. Your car cannot use the Magic Magnet. The new Gen4?(2016+ and up) cars have way different/more complex drive systems.

SpeedBx
This is the newer version of the MMagnet meant for your car. It is a simple plug/play install, but actually quite a complex device that contains much magic. Contact the creator → @djgabriel2004 for details on what his latest version can to. Last I saw he had been doing some great updates.

More power!!!
The other thing you need to consider is a speed increase also consumes energy at a higher rate. More speed eats range.
What is the condition of your pack?

Welcome to the rabbit hole…

redballoonsewer
redballoonsewer940×935 191 KB

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“Re-ponder”, so you’ve done that before…

Pix or it didn’t happen.

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$150 to PayPal.Me
Thank you,