Gabe's 2016, 35mph upgrade... and more!

Want to share where we are at so far on performance increases. 2018 E4 with all stock parts and factory 5kw motor. Started with installing one of my lithium batteries, 234ah, 60v(slight increase over stock). Then the computer reflash to 35mph. Gem accelerated faster with the lithium pack and now hit a top speed of 35mph. Everything works like it came from the factory( speedometer accurate, odometer accurate, and battery gauge) it just has a higher speed and longer range, 60-70 miles. Gem is much more enjoyable to drive and feels safer because you are not blocking traffic and having cars pass you. As much as I liked it, I wanted more. Top speed was fine but wanted more acceleration, like the modified classic Gems. Collaborated with Dave and Gabe on ideas and started tuning the Sevcon controller. What I found was Polaris had significantly reduced power in their programming, to get as much range as possible out of the lead batteries. Was able to remove those and let the motor have the power it required. This put a smile on my face, yeehaw this thing accelerates fast. Tuned it to pull hard to 30mph and then to slow down as it approaches the 35mph limiter. At 35mph it is only getting the power it needs to maintain the speed without having to hack voltage and cause the Gem to surge. It is very smooth. The motor has a great sound under hard acceleration but goes back to factory quiet when cruising… The only thing you hear is some tire noise. The Gem accelerates to 25mph in 6.5 seconds, stock it was 10.5. Big difference. A lithium upgrade, Gabe’s level 1 speed increase and my level 2 power increase is a winning combination for these newer Gems.


Looking for testers with hills. Agressive torque map can sometime cause issues not experienced on level ground.
I can test it eventually but am neck deep in pmac tuning right now.
Pm @LithiumGods or @djgabriel2004 to pick the appropriate mod.
Simplest for those with access to dvt but not required.


Speed limit removal can be done and car will run as OEM, even on hills. So far it has been tested on Flat level by @LithiumGods and me, then some hills in California and @Inwo ’s big hill in MN with no problems.


Dave was meaning the power increase I added. The 35mph speed increase should be no problems on hills. The power increase might. I programmed mine all the way up because we have no hills. But would like to try max power on on that has hills. I think it should work fine but it would be nice to test it.

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Yes, I think it will be fine. If you sell an upgrade, I can drop everything and get it tested.
Or better yet, client can test it. Worse case comes back for fine tuning.

Just after I finished the 35mph speed upgrade I went to California. While I was there I got a chance to meet up with @Erniea15 , really wanted to drive his Gem and see how it did on hills, Since we don’t have hills in Fl. . Well Ernie’s Gem is awesome, fast and powerful. Had a ball racing it up the hills and testing its speed. When I was driving back to Carlsbad I kept thinking “I need my Gem to go MUCH faster” Ernie’s Gem had ruined me, there was no way my current acceleration rate was going to cut it. Didn’t sleep much that night researching Ideas to try. Once you have driven a performance Gem, you can never go back. Thanks again Ernie and really enjoyed meeting you!


Hey @LithiumGods! It was great to meet you as well and thanks for enduring the traffic to come down to SD to play. I haven’t driven many of the modified 2016+s so I have no idea what mine is like in comparison and how my driving conditions are… Like, is my hill a really big hill or not?? Gear box noise etc. Always good to get that feedback from someone who’s been in a bunch of these things.

I really wish I could take more credit for my ride. I sent a note to the crew here when I bought it saying, I wanted to go all in, best of the upgrades available at the time. @inwo said PayPal $$$ here. Next thing I know, a bunch of parts show up and a very long thread began.

I’m just an ■■■■■ who can follow directions from a bunch of really smart and helpful forum members. Having DVT software and programming hardware helped too. I don’t know what most of the sevcon settings do but it was easier to share files back and forth and make suggest config changes. I’d usually work on the car at night, after my kids were in bed, and it always amazed me how many folks in the eastern time zones were responding at all hours.

Once we got my DCF dialed in, the car has been working awesome. I haven’t really had to do much to it. I drive it everywhere I can and the kids love it. One of my favorite stats is the BMS uptime… I’m at 265days of up time. I have a main fuse breaker that I pull if I’m doing anything major so it’s been a while since I’ve had to muck with anything.

These new body styles have so much potential when freed from the factory speed cap… And in my case, adding lithium and high voltage.

Thank you gem forum!


What I noticed about your GEM @Erniea15 was how tight the tranny was and how quiet it was. The performance was really nice but as for the ride, the tight tranny really makes it a smooth all around ride.

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That’s @Old_Houseboater 's handy work. He did an early gear swap for @MikeKC. Mike ended up using a legacy tranny so I bought those gears from him. Skateboard bushings and all!


Must resist… Too easy…


Just saw this…am I reading this right that someone finally cracked the code and we can do software mods vs gearing now for speed increases? Where do I get in on this? I am in San Diego as well…maybe I can hit @Erniea15 for some assistance

That’s correct, Speed limit can be raised to 35mph reprogramming it.


Always happy to help… You’re more than welcome to check out my gem and come take it for a spin. I’m out in San Carlos (near SDSU).

(was going to insert tight tranny joke… but again, just too easy)

If you want I can send you a Reprogammed ecm so he can test if he is ok with Repro or he wants to go all in like you.
Would you help him to get it installed ?

Would you help him to get it installed ?

Is itsrixter bringing Cheese?

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Hey get in line, I haven’t got my cheddar yet.

Yes to both. We could even do some hill testing for you and @LithiumGods

I’m in the line too!! :slightly_smiling_face:

I have a great hill. On Del Mar Heights road there are two hills. One is good and expected for those in hilly areas. The other is a beast and would mimic San Francisco style hills.
Let me know what/when I need to do anything.

Do you have 5kw or 6.5kW motor?