Honda Insight Owners Are Hacking Their Cars For More Power With Super Cheap Components

Honda Insight 40 Power Boost Ts2
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When we think about performance tuning, we tend to think of certain vehicles. Usually, it’s some classic American muscle, or a JDM hero car, or increasingly these days, some kind of big ol’ truck. Hybrids are the last thing that comes to mind. Meanwhile, it turns out the original Honda Insight is actually pretty easy to tune with some incredibly low-buck mods.

Tuning an engine for more power can be easy or difficult depending on what you’re working with. If you’ve got an old emissions-choked Malaise era donk, you might just pull off some emissions equipment or fit a new carb. If you’re working with something fuel injected, you can swap out a few components or bolt on a turbo, and then retune or replace the ECU. For a hybrid, though, it can be more complicated. It’s difficult to tune either the electric motor or the engine without fully replacing the factory management systems. And that’s no easy task—there aren’t a whole lot of aftermarket engine computers out there for the job.

And yet, there are people out there tuning the Honda Insight quite easily, using what is called a “current hack.” It doesn’t require the wholesale replacement of Honda’s engine management system, nor does it require the replacement of expensive electronic or mechanical components. It’s all achieved by tricking the controller for the Insight’s hybrid motor, making it think the motor is drawing less current than it actually is.

Performing the hack involves modifying the Insight’s Motor Control Module (MCM) and Battery Control Module (BCM). The MCM is equipped to sense the current flowing through the motor, and the BCM is equipped to sense the current flowing through the battery. To enable the Insight to send more current to the motor to make more power, it’s necessary to modify both.

Sensing current is performed with a current shunt. A current shunt is essentially a resistor of known value. If you then measure the voltage drop across that resistor, you can calculate the current flowing through it using Ohm’s law, where the current, I, is equal to the voltage divided by the resistance.

Here’s the trick: the Insight’s control hardware is calibrated to a known resistance for the current shunt. If you change that resistance, you can trick the controllers into thinking less current is actually flowing than it is. For example, if you halve the resistance of a current shunt without recalibrating, the controller will allow twice as much current to flow.

In the case of the Insight, the so-called “40% hack” is the most popular. It’s so termed for the amount of extra power it enables the car to run. Where the Insight’s Integrated Motor Assist delivers 13.4 hp stock (10kW), with the 40% hack, it delivers 18.8 hp. The hack involves adding resistors to the MCM and BCM so they only read 70% of the actual current value.

But wait, how does that add up to 40%? Well, let’s imagine the modules are set to a current limit of 100 amps. Then, the current shunt’s actual resistance is dropped by 30%, so that the controllers only see 70 amps when 100 amps is flowing. In that case, if the controller is seeing 100 amps, it’s actually outputting 142 amps – 42% higher. It’s referred to as the “40% hack” for ease. It’s also possible to use different value resistors to run a “20% hack” or a “60% hack” if you want to change the current limit of the motor by a lesser or greater degree. In the latter case, the higher current flow tends to throw codes as the transistors that control the motor can’t keep up. The 40% hack is considered a “safe” boost for stock cars without major modifications.20240129 145047

Modifying the BCM in this way is fairly easy. The stock current shunt consists of two large resistors that are readily visible on the board. Soldering in another resistor in parallel helps reduce the total resistance of the shunt by the appropriate amount. It’s a little counterintuitive, but yes, adding another resistor in parallel actually cuts the total resistance. Why? Think of an electric wire like a pipe. A bigger pipe can flow more water. Adding on an extra pipe to the two already there allows more water to flow—i.e. there is reduced resistance!

The MCM is harder to modify—mostly because it senses the current flowing to the motor in eight wires. Each has its own current shunt which requires modification. However, to get around this, a forum user called Bull Dog (no relation to Bob “Bulldog” Briscoe) along with another named retepsnikrep whipped up an easy solution. It’s a PCB that’s already preloaded with resistors for each shunt. It’s designed to drop onto the MCM’s existing board with solder points in all the right places to hook the resistors into the right points of the circuit. It’s not a beginner job, by any means, but it’s about as easy as installing a modchip in a console. The latest versions even feature tiny DIP switches to select 20%, 40%, or 60% current boosts.

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The Battery Control Module can be modified for higher current output by adding a single resistor. Credit: Peter Perkins
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The motor control module requires multiple resistors to be installed to complete the hack. This is easy to achieve using a PCB designed for drop-in installation on the stock PCB. Credit: Peter Perkins

There’s just one thing left to do to enable the power boost. There’s a fuse that serves as a further limit on the output from the Insight’s battery. This has to be swapped out to allow higher current flow. A 150 amp fuse is recommended for using the 40% hack. It’s difficult to change out, requiring the removal of the hybrid battery to gain access. Plastic tabs also have to be removed to make room for the larger 150 amp fuse, compared to the 100 amp stock part. However, this swap is necessary to avoid blowing the stock fuse with excess current draw from the motor.

Based on forum posts, the cost of the hack is usually well under $100. The 5.3 hp boost might not sound like much, but it’s a bargain at that price. Compare it to people buying cold air intakes for $1,000 which maybe add 5 to 10 horsepower, if you’re lucky. By comparison, this is allegedly a sure thing as long as your Insight doesn’t have a completely worn-out and tired battery that can’t deliver the extra current.Image2711

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Installing a larger fuse requires trimming away some plastic, but it’s otherwise a bolt-in part.

It bears noting that this “current hack” technique isn’t just limited to Honda hybrids. I know this, because I’ve actually done it myself! It’s a popular way to get more power out of a cheap electric scooter. I used this trick to boost the power of my Razor E300, albeit with often smoky or fiery results.

In the case of the Insight, there are plenty of users reporting success with the 40% boost. On YouTube, Insight owner gray25xt posted a video showing the acceleration of their 2003 Insight with a 40% current hack installed along with an aftermarket lithium battery pack. It’s similar to the third-party lithium-ion packs developed for the Toyota Prius. However, in this case, the 40% current hack allows them to make the most of the extra current capability of the lithium-ion batteries. They report slashing their 0-60 mph time down to 9.0 seconds, down from 10.5 seconds when the car was stock and factory-fresh. That’s a big drop to claim for just 5.3 additional horsepower from the hybrid system, and it’s worth noting that it’s not a scientific comparison with multiple runs averaged out.

There is still plenty of praise to be found out there for the hack. YouTuber 100PercentJake noted the hack was transformative in the way the Insight drives. “It’s like a real car now!” he exclaims as he does a pull in second gear. The original Insight was infamous for its slow acceleration. In a car like that, it’s clear that it doesn’t take much additional power to make a noticeable improvement. He finds little numerical difference in acceleration tests, which he puts down to his weak battery, but says the car has more “pep” when driving around town. In a later video, he fits a lithium replacement pack which he credits with drastically improving the car in concert with the 40% hack.

Should you expect great things from the 40% hack? Well, it really depends on the state of your first-gen Insight. The newest examples are pushing 20 years old, with hybrid batteries that aren’t necessarily at their best anymore. On a car like that, you can always throw $100 at doing the hack to see if it works for you. It’s cheap enough that if it doesn’t make much difference, you’re only out a few cases of beer. If you’re doing a lithium battery swap, though, the upgrade seems like a much stronger proposition, given the fresh batteries are more capable of delivering the greater current flow enabled by the hack.

Ultimately, the current hack will only net around 5 horsepower at most, but it’s probably the cheapest 5 horsepower you’ll ever get. If you’re confident working on electronics and know how to work with a hybrid battery safely, you might find this is a great mod for your first-gen Insight. If not, best leave it to the pros. With or without the hack, your Insight isn’t beating anyone at the stoplight drags anyway.

Image credits: L. Day, Peter Perkins, 100percentJake via YouTube screenshot

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84 thoughts on “Honda Insight Owners Are Hacking Their Cars For More Power With Super Cheap Components”

  2. I was quite bummed when 100% Jake had his Insight crushed in a rear end collision as I was curious how much effort he was willing to put into his Li-Ion IMA upgrade. The NiMh packs are pure garbage. My ‘Citron’ green Insight was a beloved vehicle taking me across the country on a monthly basis for my job and the 70 mpg I attained was fantastic when paid by the gov’t rate for miles driven. What was not so cool was the three expensive IMA battery failures I experienced, two of which were paid for by me. Technically there were four as the IMA light came on the day I sold the car to a local shop doing a K20 swap …

    Speaking of simple hacks for more herspers – I also owned a 220hp K20a swapped Insight that was like driving a Patriot missile. Eventually the thrill of risking my driver’s license wore off and now someone else enjoys the risks and rewards.

    https://davesanborn.blogspot.com/2017/05/my-insane-honda-insight-k20-swap-is-for.html

    1. That thing is awesome!

      If Honda wanted to sell more of them, they should have offered it with RWD and a K20, and kept it more or less the same price as the Insight we actually got. It STILL would have been a halo car for fuel economy, and would have out-performed cars costing 2-3x as much.

      1. The torque oversteer in mine was like wrestling an angry python. Despite that, had the Insight been given tiers of engine options they’d have sold briskly. A car that should’ve had the K20 was the CR-Z. What a missed opportunity.

        1. The torque oversteer in mine was like wrestling an angry python.

          To me that’s a selling point. But that’s because I love wrestling pissed-off snakes and eventually taming them. I even kept a western-diamondback rattler that I named Nippy(he was never pissed off and surprisingly chill though).

          I’d want to tame a K20 Insight!

  4. I’ve owned my 2000 Insight for about 10 years now, and it has been not only one of the best cars I’ve ever owned, but one of the best purchases I’ve ever owned. In over 100k miles of driving, I’ve had to do 2 control arms ($200), a temp sensor ($8) and a grid charger ($150).

    I flew to Texas and paid $3000 for it with a non working IMA system, and drove it back to WI without hybrid power. I then bought a grid charger for $150, and nursed the battery back to life. It’s not a suggestion; owning a grid charger is a REQUIREMENT for owning a 1g insight, because the BCM does not keep the battery balanced properly; over time different sticks have different top/bottom levels and stop the whole pack from charging or discharging, as it becomes more unbalanced. Grid charging massively helps this, but eventually, even that will not work.

    Then you need to do what is called a “deep discharge”. My battery was pretty much junk before I tried this, but basically the idea is to flatten the pack with a load, I used a house spotlight and a $3 bulb base, and bring all the sticks all the way down, which balances them all at the bottom. Then grid charge. Then flatten. Do it a few times. I did a video on this if you’re interested, click here

    At this point, the fuel savings has paid for the car several times over, the best example was I drove from Madison WI, to Denver, went skiing at Winterpark 3 days with it, and drove home, for under $100 in gas. Blows my mind.

    I want to do the current hack, but my battery isn’t great; maybe if it ever dies I’ll do that at the same time. The other modification I really want to do is swap the transmission from a Honda Civic Hybrid. The gear ratios are MUCH sportier. 5th gear on a stock 1g insight is rarely usable; it pretty much cannot maintain highway speeds unless you have a tailwind or are going downhill. HCH gearing = faster acceleration and you can use 5th

  6. I was half a day away from buying a own owner 1st generation Insight with a little over 100,000 miles. Always thought the single purpose focus of the design (and the fact I like small cars, and that they look like something out of a science fiction movie) pretty cool. As shown by the article, there is an active community that is devoted to keeping these running, getting great MPG, and mods and improvements. Still on the lookout for a silver manual in good shape.

  7. Interesting. I can’t help wondering if this will eventually lead to premature failure of some expensive electrical components down the line. It seems unlikely you can just pump an extra 40% power through the system without some impact or Honda would have done that in the first place.

      1. I was thinking more of the inverter and electric motor. Maybe it’s not the case on the Insight, but on my Prius those are two things you don’t really want to burn up because they’re on the expensive side to replace. Luckily they’re also pretty reliable as long as you don’t do anything stupid, but I wonder if that would still be the case if I shoved an extra 40% current through them?

  9. The Insight was a huge missed opportunity for Honda.

    The Insight should have been called the CRX.

    And the hybrid version should have been the CRX HF.

    And they should have made a CRX Si… and from that era, they could have used a variant of the B or D series engine… such as the D15B good for 100hp. And have an SiR version with the D15B VTEC which was good for ~130hp.

    And it should be noted that the Insight had an all aluminum body… which made it expensive, but very light. Even with the automatic, AC and the hybrid system, it still weight less than 2000lbs.

    If they had done a version with a standard D15B with the manual transmission, good chance it would have only weighed in at around 1600lbs. And that would mean even the regular D15B with only 100hp would have moved that thing very nicely… and the VTEC version would have been a screamer.

    It would have been the true CRX successor everyone wanted.

    Now back to the discussion in the article… yeah these mods they are doing unlocks power/performance for cheap. But the best bang for the buck these days would likely be to swap in an L15B out of a Honda Fit… good for around 130hp. And that would effectively double the power. And the package would likely weigh less than the old hybrid setup the Insight had.

    The biggest challenge with that is the Insight had an old-school-Honda engine in that the crank rotates counter-clockwise while the Honda L-series rotates clockwise.

    So it’s not likely to be a straightforward drop in. A more straightforward drop-in would likely be a Honda B or D series which are also old school Honda designs with the counter clockwise rotating crank.

      1. Good to know. I’ve never actually taken measurements of a Honda K series engine and compared that to the measurements of the Insight engine bay and how everything would line up.

        Yeah a K-sight would be an awesome successor to the Euro and JDM CRX SiR… one of the JDM cars that many in North America wanted, but never got.

  11. I love the fact this exists and people are doing it but I can’t say the idea of ‘tinkering’ on a car with resistors and a soldering iron gets me anywhere near as excited as a carb and some wrenches.

  12. Sure, 5 hp doesn’t sound like a lot but if you’re talking about 12 or so hp to begin with which I gather is how you calculate the 40% then that’s actually quite a big deal. But really what I would be more interested in is how much torque at zero RPM does this increase?

    And of course, if you really want an insight to scoot the engine mod is spelled with a K.

  15. 20 years ago, I also read of John Wayland’s(Builder of the Datsun 1200 EV conversion “White Zombie”, at one time the fastest street legal EV on Earth for at least a decade uninterrupted) experience driving an Insight with the 3-cylinder engine upgraded with a turbo. It did 0-60 mph in about 7 seconds with no hit to fuel economy.

    This would have been a much better car if it were RWD and came with a K-series engine, IMO. This is a mod I’ve seen a few times. Gutting the hybrid drive and 3-cylinder, and swapping in a stock K20 engine, yields a 45 mpg monster that runs 13-second 1/4 miles.

    If you REALLY want the best Insight possible, convert it to pure EV and Tesla swap it. Here’s John Wayland’s 400+ mile range 200 horsepower Insight EV conversion using a modified system pulled from a GM EV1:

    http://www.plasmaboyracing.com/silverStreak.html

    1. White Zombie was in S01E07 of Fastest Car on Netflix. I believe it crashed in a drag race. I was excited to see it on the show since I had seen it in car magazines in the 90’s.

        1. Yeah, and I think that car was Abel Ibarra’s. I was also excited to see him in the race since I recognized his name immediately from 90’s car magazines.

  16. This is interesting in that it’s trading economy for power in a car that went as far towards the economy side as you can possibly go. Drawing more current will obviously deplete the hybrid battery faster.

      1. CR-Z was about 400 lbs lighter than the last gen insight, but it also had less horsepower, too, so while it’s not a wash, the power to weight ratios are close enough. You’re the expert on Cd, so I’ll accept that it was less slippery than the Insight, but my thought is that with a slight power bump, the CR-Z would make for a better sport coupe. Plus, even though it’s completely subjective, I like the CR-Z looks much more.

          1. You’re not an aero expert?!?! Well, you are the best we have here in the comments, so you get the position. Don’t let the power go to your head.

  18. Does this sound potentially dangerous to anyone else? I know there’s a safety margin engineered into these systems, but it seems like a bad idea to override current limiting devices on a decades old hybrid. This probably wasn’t designed with that much (40%) overhead.

    I’d expect that this hack is pushing something beyond its limits. Or maybe these were just that overbuilt.

    1. This is my biggest concern – regularly running into the safety margins, particularly on equipment with unknown history is risky. 40% sounds like a LOT of margin on a modern system. I would not plan to take advantage of the “overboost” often or for long duration.

      Modern industrial machinery seems to be built with little to no overload/overcapacity margin anymore as the underlying engineering calculations are much more precise (FEA/CFD/etc…). The old industrial machines from the ’20s through ’50s were overbuilt because they had to be in order to be sure. That is why there are still in operation at throughputs and loads unimagined when they were designed! The new stuff is built to run a spec, no more and no less.

      1. One of our factories used to use some ancient machine to punch sheet metal. Mechanically, it was fine but the electronics used to go bad all the time. It was hard to find parts because it was old and insanely heavy so a lot of them got scrapped instead of moved or sold. At one point we bought a complete second one to scavenge for parts.

        The ‘programming’ was so specific to that particular version of that machine that we would have had to re-draw almost every piece of sheet metal to switch to a newer machine.

          1. I haven’t worked at that company for years. It looks like they moved production out of that factory – so I assume the large company that bought us out had some interns or outsourced contractors re-draw all the components for newer machinery.

    2. Yeah, did they review the sizing for the conductors and other components to see if they could handle 40% more current? They’re increasing the chance of failure somewhere and a fire.

      1. I’m not an engineer of any kind, but I did wonder if this is sorta the hybrid version of those mid-2000s nitrous oxide fails where they didn’t upgrade any of the internals, just added the nawwssss.

            1. Seems less popular now that so many cars are available with turbos. You can add always-available HP to turbo cars relatively easily and reliably without having to fill a nitrous bottle.

              I’m sure nitrous still has a place in drag racing, but I think it’s become less popular in street cars or today’s equivalent of a ‘sports compact.’

      2. Definitely worth considering. I think the community has found that the IGBTs can largely handle the 40% boost. Your mileage may vary of course. The 60% not so much.

    3. There are some incredibly talanted electrical engineers in the Honda Insight community who note that most of the components of the electric drive of first-gen Insights are overbuilt by more than double in many instances.

      1. ‘Most’ is what I’d be concerned with. It could be completely fine for all I know, but if there’s something not as overbuilt being pushed past its limits I hope it fails in a non-fire way.

    4. In my experience, forums of people modifying electric cars or hybrids seem to be nothing but electrical engineers talking inscrutable babble at each other so I’d imagine if you can translate everything it’s got to be fairly safe.

      I checked out the electric motorcycle forums after getting my Zero and immediately felt like an idiot trying to understand what people are saying. It’s like you need an engineering degree to signup.

    5. My worry is two-fold:

      One, a bad solder job could effectively brick the system if the solder joints on the new shunt resistor breaks and forms an open circuit.

      Two, the soldering iron damages another component on the board

      1. I’m a hack with a soldering iron, but I’m pretty sure I could pull this one off. It’s pretty straightforward and accessible. I’m way more concerned about the high-amp circuits than what’s in the control boxes.

  22. It’s worth noting that 5hp on the electric motor-side of things isn’t directly comparable to 5hp on the ICE-side as you’ll get to enjoy that sweet, sweet 0rpm torque.

    1. On a first gen Insight the motor is attached to the rear of the engine so other than the initial engine start there’s not much 0 RPM benefits to reap.

      1. While it is not 0rpm, the benefits of the power just being there instantly is huge. The insight 3 cylinder is monumentally gutless below 3k rpm, anyone who has driven one with a non working hybrid system can attest, they lean hard on the electric down low. Having extra torque and HP in the rpm range you spend a bunch of time in where the gas engine is tuned for economy transforms these cars.

        1. Don’t know if they use the Atkinson cycle like my Escape Hybrid had, but that thing was gutless off the line when the hybrid drive was overheating and locked out.

          1. It’s not fully Otto or Atkinson. It’s lean mode is fully Honda strange. Everything is current balancing. It’s that good moonshot shit that worked better for … inexplicable reasons relating to balancing the entire system.

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