Kubota Diesel-Powered Honda Insight With a Supercharger Averages 73 MPG
The supercharger itself almost equals the engine in displacement.
Over the past five months, YouTuber Robot Cantina has been working on a Kubota diesel-powered Honda Insight. The channel host specializes in oddball engine swaps, like putting Harbor Freight 670cc "Predator" engines in old Renaults. However, this Kubota-propelled Insight is among his more interesting projects, because it originally involved a different car. Oh, and, did I mention the thing's supercharged?
Robot Cantina first started by putting the Kubota three-cylinder diesel in a Saturn coupe. However, the rest of the Saturn was in such bad shape that they decided to scrap the vehicle but keep the engine for a future project. That project turned out to be this first-generation Insight.
Ironically, to get the Kubota diesel to fit in the Honda, it had to be put back in the Saturn, as it wouldn't work with the Insight's transmission. However, once the Kubota/Saturn powertrain was planted into the Insight, it was time to get tuning. They had used a turbocharger on the Kubota diesel in the Saturn, but it didn't make much boost low in the rev range and really had to be revved out to produce decent power. This time around, Robot Cantina opted for a supercharger.
The supercharger in question is an AMR500, which packs almost as much displacement as the engine it's now bolted to. At 500cc, the AMR500 isn't considerably smaller than the 719cc Kubota engine. Fitting such a supercharger required making custom drive-belt pulleys and mounting brackets for the motor. Since the Kubota is so tiny, they were able to fit it all.
Once the supercharged Kubota was fired up, it ran smoothly and made 10 psi of peak boost. It sounds absolutely hilarious, too, as if the little Insight had a bad batch of White Castle the night before. The supercharger provides the diesel with a sorely needed boost in power. Consider that without forced induction, it took the Insight 35.19 seconds to get from 0-50 mph, but that dropped to 22.96 seconds with the supercharger—a 12-second improvement. But what about efficiency? After the supercharger was installed, Cantina was able to average over 73 miles per gallon in normal driving conditions, considerably better than the original Insight's EPA combined rating of 53 mpg.
This guy certainly isn't done tinkering with the Insight, so I can't wait to see what he does next. It's certainly one of the strangest projects I've seen in a long time.
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