I’m Going To Turn This Prius Prime PHEV Into A Hot Hatch

When people learn that I work as a professional racing mechanic they often expect that I have some sort of hot hatch or something equally rambunctious at home, but most would be surprised to learn that I now spend most of my time in a Toyota Prius Prime. While the Prius Prime is almost exactly the opposite of a hot hatch out of the box, I believe that the Toyota TNGA-C platform that it’s based on allows for it to be turned into something fun without too much effort.

The goal with my daily driver is to combine my skill set as a parts manual enthusiast with my skill set as a professional racing mechanic and modify the Prius Prime to handle as well as it looks and take you guys along with me in a written build series we’re calling PROJECT: OPRIUS PRIME.

I spend a lot of time on the road between my various gigs so I’ve always sought something fun and engaging as my daily driver which is how I ended up with a new Subaru WRX in 2015 that I ended up putting over 200,000 miles on. As the WRX was reaching that 200k mark, I started looking around for my next daily, and while the new WRX seemed to offer similar handling characteristics I just couldn’t get along with the looks of all the new cladding. My attention turned to other similar cars but nothing really stood out.

The Prius wasn’t in contention, initially, but I had an opportunity to borrow one for a week in January and after just a few hours of driving I started to seriously consider getting one for myself because of how well it handled in spite of being more focused on efficiency than being an enthusiast vehicle.

I brought that borrowed Prius into my shop and quickly discovered that much of the suspension mimics that of what you might find underneath other TNGA-C based vehicles like the GR Corolla, which gave me hope that I might be able to find parts to make it drive in a more compliant manner if I decided to purchase one.

All of this consideration for the Prius really sprouted from the striking redesign which took the Prius from an oddly shaped efficient appliance to a fun modern wedge. As with previous generations, much of the design was focused on aerodynamic efficiency which resulted in a slippery body with a drag coefficient of 0.27 cD. In comparison, the Lexus LFA has a drag coefficient of 0.31 cD and my old WRX is rated at 0.34 cD. After spending a week in that borrowed Prius I decided that I needed to find one for myself but, because I wanted a fun color, the search ended up taking multiple months.

My Base Prius

Eventually, I found a Prius Prime SE in Supersonic Red near me in Charlotte, North Carolina and was pleased to find out that it didn’t have a bunch of random options tacked on as that $425 special color was the only additional charge on the window sticker, which brought the MSRP to $34,495. I ended up trading in my WRX for $4,300 and leasing the Prius Prime to get $4,500 in lease cash that was being offered by Toyota.

As soon as the lease account was created I went to my credit union and bought it out which resulted in a net cost of around $31,400 plus taxes and fees that ended being brought down to $27,100 plus taxes and fees with my WRX trade. My net financed cost after all was said and done ended up being $28,480 which I was extremely pleased with considering that I was able to find a color that I liked.

As soon as I left the lot I started monitoring the fuel economy because my competitive nature always finds new benchmarks to chase and, since the car was filled up and fully charged, I ran on EV mode for the first 39 miles so of mostly highway driving. Once the EV range was depleted, the internal combustion engine switched on and I drove around like that for a couple of days and, with my driving style, I ended with a 57 average MPG number on the dashboard.

Eventually, I started plugging the car in and it started figuring out my driving style, which resulted in that EV range hopping up as high as 45 miles, though I typically saw around 40 or 41 miles of range with the air conditioning cranked up. While my charging has been somewhat inconsistent, I’ve been able to raise that average fuel economy number to 76 MPG, which is more than a 50 MPG improvement over my WRX and has resulted in me using only 69 gallons of regular gasoline over the two months that I’ve owned it, compared to the 210 gallons of premium that I would have used in the WRX for the same period. The fuel savings are significant enough that they offset a large portion of my monthly payment.

It’s Great, But I Can Make It Great (Or Maybe Worse)

I may nerd out about the PHEV elements and the charging setup that I’m building at some point in the future, but the really fun stuff lies in what’s underneath the car and whether I can successfully turn it into a hot hatch competitor. The Prius Prime handles incredibly well for being an efficient hatchback that isn’t intended to have sporting intentions, but coming out of the WRX and enjoying North Carolina back roads pushes me to bring the Prius to higher handling standards.

One of the first things that I noticed when I took it on some back road jaunts is that the Prius is pretty compliant but tends to lean towards understeer in most situations, which isn’t unusual for this class of car. In addition to the overall handling characteristics of the suspension, it’s also pretty easy to overpower the tires as the OEM Toyos are focused on minimizing rolling resistance.

With all of that in mind, I decided to start with the rear anti-roll bar as it’s a piece that’s shared with the Toyota Corolla hatchback and the Toyota CH-R, so there were already some options on the market. Increasing the rear anti-roll bar size by a couple of millimeters would be the first step in curing some of that understeer and helping loosen up the car a bit on those curvy country roads, so I picked up a 27mm adjustable rear anti-roll bar from Progress Technology. The next step in my hunt for handling improvements was also partly cosmetic as I wanted to find some lowering springs to close up fender gaps while also increasing the spring rate just slightly.

I ended up finding some TEIN High Tech springs on Yahoo! Auctions in Japan and decided to try my hand at purchasing some parts overseas through a service called Buyee. I ended up winning the springs for around $143 and after Buyee fees and shipping fees my total cost was around $185 and I had the springs in hand around two weeks later. This was a trial run for additional purchases as there are already a lot of handling and cosmetic components available for my Prius in Japan. The springs offer a mild increase in spring rate to 146 lbs/in front and 202 lbs/in rear which should improve responsiveness, but they also introduce a bit of rake as the front gets lowered by 25 mm while the rear is lowered by 20mm which should help contribute to improving the understeer situation as well.

My initial plan was to acquire OEM GR Corolla suspension parts as my research led me to find out that most of the suspension hard points match up, but unfortunately purchasing all the individual bits and pieces ended up looking like a costly affair so the current part for the next step in this series will likely involve research for things like wheels and tires along with starting to look at coilovers. The Prius Prime rides on a 195/60R17 Bridgestone Ecopia EP422 Plus tire that’s wrapped around a 17×6.5 +40 aluminum wheel with an aero cover, and while they are functional I am looking to get something a bit more stylish and possibly larger.

They're no saladshooters, but I think they could work. pic.twitter.com/dsAuya5x8u

— McMike (@ItsMcMikeTime) June 14, 2024

 

The current top runners for OEM wheels that fit are the Toyota Camry TRD and Nightshade wheels, along with the Lexus SC430 pie plate style wheels. Once I find a wheel that I like, I will match it up to a tire but the current most likely scenario is that I’ll end up with a set of Michelin Pilot Sport 4S tires because I’ve enjoyed them so much in the past.

Before I start making any changes, I plan to take some measurements so that I have a baseline worksheet much like I’m used to in racing so that I can track changes as they are made and work towards my goal of turning the Prius Prime into a hot hatch.

For now, the Prius Prime is serving it’s duties as my commuter around town and for race weekend trips with excellent efficiency as I collect parts to improve the handling alongside setting up a permanent charger outside of my garage in order to improve my charging habits.