When I saw a Suzuki Jimny blast off a turn at the Tsukuba Speedway at the recent 10th Anniversary Attack Conference, I knew I had to make a separate post on the curious track specs kei-off-road vehicles.
This was by far the biggest surprise of the event for me. Because it’s not every day – or ever – that you see generations of Jimnys lowered and run on circuit-spec rubber, let alone compete in timed competitions. But this is Japan, so I shouldn’t be surprised at all…
Most of the modified Jimny’s I’ve seen in Japan have knobby rubber lifts under the fenders and have off-road specific accessories. What I see here, though, are turbo upgrades, a large intercooler, and a roll cage.

Not to mention, lifting the inside of the front wheel in tighter corners. How cool is that? !

It’s all thanks to Rainbow Auto, a Jimny specialists located off RWB Road in Chiba Prefecture. The Rainbow team will transform your pocket Suzuki dirt bike into a timing weapon on the track.

I had a brief chat with the owner and he told me he really wanted people to know how much fun it would be to build a Suzuki Jimny this way.

Rainbow brought several demo cars of the latest generation Jimny.Such models were in such high demand for a period of time that they entered the used car market Lots of premium.
This red Jimny sits on RAYS A LAP-J forged wheels with Yokohama Advan Neova tires. I’ve noticed on all these Jimnys that the front wheel sticks out more than the rear wheel, this is to improve front wheel grip and cornering.

On the engine side, the initial series of modifications offered by Rainbow Auto appear to include replacing all factory silicone intake pipes with aluminum hard pipe kits, swapping the airbox for cone filters, boosting ignition power with more powerful coils, and improving the cooling strip There are coolers with larger cores.

Along with improvements in handling – at least the suspension – see brake upgrades, from simple slotted rotors and high-friction pads, to the popular GC8 Impreza 4-pot caliper mod, and finally a full compact Brembo kit, too. No surprise, mounted on a red Rainbow Auto demo vehicle.

Feel the allure of the Mercedes-Benz G-Wagon on this new generation Jimny.

This JA11 Jimny is the oldest of Attack Tsukuba’s but probably the most modified.

This is its small longitudinally mounted 3-cylinder engine. Oddly, unlike many other settings I’ve seen, this one keeps the turbo setting low.
Inside the spacious cabin, you’ll find a roll cage, Recaro Pro Racer RMS seats with Willans harnesses, a Momo steering wheel, and little else.

The increase in front track I just mentioned looks to be achieved with some significant hub extenders.

It just makes the wheels look more punchy.


Poking around the little corner of the Tsukuba paddock that Rainbow Auto and all the Jimny owners have taken over, it’s clear that while these guys do what they do for fun, they still take things seriously when it comes to setup and preparation.

Some even keep the rubber comfortable with a proper tire heating system.


This older Jimny pickup with fenders and BNR32 Skyline GT-R wheels was the quickest of the group.

Despite the grip set, it’s no surprise that Jimnys aren’t the fastest thing out there. But overall consideration, the 1’12″056 driven by this red JA11 is actually not bad.

As I mentioned in the main Attack Tsukuba post, it’s not What Your timing attack is very important.
It all depends on personal goals and satisfaction.

The only Jimny not part of the Rainbow Auto group is this JB23 from Stealth.

The team came all the way from Akita Prefecture, the northernmost part of the country, and ran a lap time of 1:12.357.

It featured one of the wildest-looking engine bays of the 10 Jimnys at the event, largely thanks to its top-mounted turbocharger and grille-mounted intercooler. I also found a Bosch electric throttle body.

Now that you’ve seen several different Jimnys all set up for track work, do you think this understated, purposeful look is appropriate for a Jimny street car?

If you’re not sure, check this out.

I spotted this Rainbow Auto-built Jimny in a Tsukuba parking lot and thought it looked disgusting.
If you’re wondering why this isn’t yellow Tie License plate because it’s the Sierra version it doesn’t just have the plastic fenders pushing its size out Tie car regulations, but also powered by a 1.5-liter four-cylinder engine instead of Tie– 660cc turbocharged three-cylinder in base model.

It’s always fun when you come across a car that makes you question what’s right and what’s wrong. But in this case, a whole lot! Big thanks to Rainbow Auto for chatting with me; I think I might need to visit them and explore this grippy Jimny trend further. what do you think?
dino dal carbonal
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