EV Fundamentals: Upgrade Limitations
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Upgrade Limitations
04.16
| 00:00 | One of the most common questions we get asked at Mountain Pass Performance is why can't I just tune my EV to get more power? The answer to that is a little bit complicated. |
| 00:09 | In broad strokes, EVs operate very precisely. |
| 00:12 | They're in a well-controlled, well-understood environment. |
| 00:15 | Unlike an internal combustion engine, which has all kinds of external environmental variables, different fuel qualities and octane levels, for that reason, EV manufacturers can push things further to the edge to get the most out of their systems and they don't need to leave as much room on the table for safety. |
| 00:30 | Even when there is more untapped power potential available, the OEs generally don't spend a lot of effort ensuring the thermal system can handle the load that would come from all that additional heat related to the additional current. |
| 00:41 | This applies to both the high voltage connections and the components themselves, like the motors and batteries. |
| 00:47 | Worse yet, a lot of these temperature limits are modeled, meaning that even if you fix the overheating issue, the control units won't care because they aren't measuring the actual temperature. |
| 00:55 | Instead, they're just calculating it based on the resistance of the original component. |
| 01:00 | The next thing to discuss is battery abuse. |
| 01:02 | The OEMs put a lot of effort into testing and understanding how the batteries will wear over their intended lifespan and what their limits are. |
| 01:09 | Pushing batteries harder at hotter temperatures will likely reduce their capacity faster and potentially cause damage to the cells. |
| 01:16 | Pushing the batteries too far outside of the envelope that they were designed for is something that should be taken on with great caution and fair warning must be given to anyone we might be helping or working with on a project so they can clearly understand the risks. |
| 01:29 | Since every battery is different, what works on one car might not work on another. |
| 01:33 | For these reasons, businesses offering power upgrades could be putting their customers' powertrain warranties at risk. |
| 01:40 | The other big hurdle is over-the-air updates, or OTA for short, which many manufacturers are now implementing. |
| 01:46 | These updates mean that even if meaningful upgrades in performance could be found, in order to keep the car up to date and the owner enjoying new features and bug fixes that the OTA provides, these updates would effectively overwrite whatever had been tuned on the control units in question. |
| 02:01 | Another big hindrance to the aftermarket investing in powertrain upgrades is the insane rate of development that OEMs are pushing out. |
| 02:08 | If we compare a Tesla to a Subaru WRX, for example, we can see that the EJ25 has had about 300 horsepower for the last 20 years, platform stable, and aftermarket upgrade parts have worked over a large range of model years. |
| 02:21 | The Tesla? Well, the Model S in 2017 with Ludicrous Mode made 270 horsepower at peak before tapering down and would overheat in about half or a quarter of a lap. |
| 02:30 | In 2021, a Model S Plaid has 1,020 horsepower, carrying it almost all the way to 200 miles per hour, and we've run the Plaid at almost full power for two or three laps without any derating. |
| 02:41 | And this isn't just Tesla either. |
| 02:42 | There are a number of EVs being released with over 1,000 horsepower. |
| 02:46 | The rate of development is wild and there's no way small aftermarket parts suppliers could keep up with the R&D. |
| 02:51 | Now, for those looking to build something outside of the OEM upgrades, you can always go to aftermarket racing, motors, batteries, and inverters, and at that point the options really open up. |
| 03:01 | However, the cost also increases significantly, as does the knowledge and experience required. |
| 03:07 | Aftermarket components still have the same fundamental limitations, but you can spec what you need to support the required power levels and run times that you're going to be running at. |
| 03:15 | Integrating aftermarket inverters with OEM motors isn't an easy task, as the motors need to be characterized and understood in order to be properly and efficiently controlled. |
| 03:25 | Kind of similar to tuning a standalone ECU for an engine. |
| 03:28 | Some motors are easier than others to characterize, but it's certainly not something you can just order, plug in, and go. |
| 03:33 | With that said, it absolutely can be done, and for race cars, it's a viable option to keep an OEM integrated drive unit and gear reduction and just change the inverter and play with the limits at your own risk. |
| 03:44 | So, to summarize this module, one of the main advantages of an EV system, it's lack of vulnerability to external variables, is also the reason there's not much, if any, headroom to play with when looking to increase power through tuning. |
| 03:57 | Even if there was, manufacturers over-the-air updates would mean that any tuning you do will be overwritten every time an update is released. |
| 04:04 | There are quite a few aftermarket options when it comes to motors, batteries, and inverters, and these are great when taking on serious builds, but they do come at a substantial cost. |
