Toyota's secret project is surprisingly competent on dirt.
Electric and hybrid cars are doing everything these days. Between Formula E, VW taking on the NORRA Mexican 1000, and Pikes Peak, there's no competition the new powertrains won't dare to go. And that includes the rally course. Toyota invited us out to the Bundy Hill Off-Road Park in Jerome, Michigan to take some hot laps in one of its pet projects, a stripped-out Prius rally car that has already put rubber to dirt in the American Rally Association's Olympus Rally in Seattle.
"This was kind of a challenge. The bosses said, 'can you make a rally car out of a Toyota Prius?' and we thought it sounded like fun," said Kyle Steinkamp, Toyota senior engineer. "We certainly thought that it was capable, so we wanted to see how it would work out."
But this wasn't Steinkamp's weird project, he started with a rally-spec Matrix hatchback in 2008. The next project was a rally Scion iM, where he was joined by powertrain engineer Brad Legris and electrified vehicle control engineer Arlo Conrad Eitzer (they typically have a team of about 10). But since about a year-and-a-half ago, Steinkamp, Legris and Eitzer were focused on this Prius.
This one-off rally car is a mishmash of parts grabbed from the Toyota bin. For starters it features stock Prius 15-inch wheels. Of course, the team added Cooper medium-compound gravel tires to the mix.
Steinkamp is a suspension designer by trade, so that area got a workout. In front, the Prius Rally has Camry front springs and RAV4 front struts. In back, it features springs from the Avalon sedan and shocks from the RAV4 TRD. The team put a rally-friendly spring rate target up, and swapped parts until they hit it. They also upgraded the brake pads, but the rest of the hardware is stock. Timing, even if bad, is always important to the story.
"We had to do a lot from home because of Covid," said Steinkamp. "It would come to my house for a week, go to Arlo's for a week, like that. We finished just in time for November's American Rally Association Olympus Forest Rally. We were the only team there on stock wheels!"
It has a full FIA-rated roll cage, and when finished was still about 500 pounds less than the stock Prius, coming in at about 2,800 pounds.
It competed in the exhibition class as there's no real way to handicap these hybrids in ARA yet. But we'll expect that to come soon as more of these electrified racers get online. It was driven by X-Games star Jamie Bestwick while Toyota test driver Matt Giuffre co-drove and did pace notes.
About that powertrain, it was also stock. That means a 1.8-liter four making 96 hp at 5,200 rpm and a whopping 105 lb-ft of torque. With the electric motor that means a total of 121 hp and 120 lb-ft of gravel-spreading twist. The team said that it wasn't ready to add more power before it added more cooling. But that is the next step.
"Once we boost the power, we can take some of those noise and vibration limitations that we put on the car and decrease them, so there's a lot of stuff in the car where we don't want to run motors in this region because it produces a loud whining noise, but obviously if we're in a rally situation we don't care. We want it to go fast and be loud.
Technicians from the ARA were rightly concerned about safety with the hybrid vehicle and its nickel-metal hydride batteries.
"The concern was mostly about the battery and the high voltage wires," said Steinkamp. "We installed a main high voltage safety switch, which kills the 12-volt power and the high voltage circuit."
If you hit that switch, give it a few seconds to discharge, you cut the whole thing up with a Sawzall and not worry about getting shocked.
But we're not concerned about any of that as we strap into the six-point harness and latch up our brain buckets. We're concerned with going fast. The course Toyota prepared was about a minute long and consisted of gravel and mud that got sloppier as the day's rain went on. There were a few straightaways, some s-curves with pointer cones like an autocross course, and few hills and a few dips. We were given carte blanche to go for fast times.
The thing about race cars and rally cars is that they always sound broken. Broken when idling, broken when at wide open throttle. Add a bunch of rocks to that equation, and nothing but bare metal inside the cabin, and things get pretty loud.
But dammit if the Prius Rally wasn't quick off the line with the four-banger pushing the front wheels and the electric motor pushing the rear. With the continuously variable transmission the revs just pin to the ceiling as we aim towards the first set of cones, a meaty hairpin that combines well with lift-off oversteering.
The course goes down through some coned esses, the gates of which were wide enough to send the hybrid through at 90 degrees, which we did a few times. Next is a tight, curved, downhill portion where we had to watch our speed (hitting cones was a penalty), leading up to another wide hairpin turn. Here we slowed to a crawl trying to stay tight on the first half of the turn. The exit was full throttle affair with booms and bangs and thunks coming up from underneath the bare floorboards.
The course then cuts over through a mud puddle - always fun - and then downhill before the final deep, sandy climb to the finish line.
What always surprises us when on dirt or snow in a prepared car is how well they actually perform. You would think wet, muddy gravel would be slippery as ice but with those Cooper gravel tires, the Prius braked, steered and accelerated right where we wanted it too. The rear motor doesn't provide enough power to kick the back end out, that was accomplished by lifting off the throttle midturn, but it only understeered a small amount. It was generally a well-performing light-duty race car.
For the record, your humble author came in second place, just 0.3 seconds off the lead cumulative time after four laps.
Any day you get to push a race car, even an underpowered one, around a closed course is a good day. But we think what Toyota was trying to get across is that not only does the company count true enthusiasts among its ranks, it also lets them play around and develop new things in the name of helping the company.
Keep your eyes out in the next few months. The ARA has six more championship events this season, and we wouldn't be surprised to see the Prius Rally getting a shakedown at any one of them. If ARA ever gets a class together for them, we'll bring that info to you, too.