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.
I really like the new Prius. I’m interested to see how this turns out
I know there’s a Prius somewhere in these pictures, but the only think I have flashing in front of my eyes is “…Clean title WRX for $4k, Clean title WRX or $4k…“
I wonder how the Everyday Driver guys are doing with theirs… they had a couple videos where they were trying to get their Prius to be more hot hatch like too.
Every time I see those nightshade wheels on a sport Camry I do a double take and can’t believe they put something that cool on an Uber/Lyft appliance.
Adding tire to a Prius is a pretty great mod as the car has plenty of launch torque but no way to get it to the ground on the stock tires. So it gets a bit zippy with not much downside other than a tiny mpg hit.
Looking forward to seeing this project.
I love this idea and I am looking forward to parts 1+. Please include whatever metrics you can: Costs, hours, performance, MPG, weight, emissions, etc. As well as compromises. What did you sacrifice for the greater good?
Then flush with your success of creating a fuel sipping track monster do it again…with earlier generations of hybrids. Make the toecutters and cheap bastards among us proud!
Freedom (to modify your car) is the right of all sentient beings.
Within reason of course.
I’m trying to understand the goals here. How does an upgraded suspension turn an economy hybrid into a “hot hatch”? Would love to hear about possible drivetrain improvements along the lines of a larger battery or more powerful electric motor.
Following the old school view of a hot hatch (hoonible economy car), Bozi explains his thinking in a comment below that I copied here:
The perception of hybrids versus the reality is quite different. The Prius Prime makes more power than a Civic Si and is only a tenth ofa second slower to 60 mph. One fun comparison I did the other day is the fact that the Prius Prime basically matches or exceeds many of the enthusiast cars of my childhood. Here is a comparison of the base Prius which produces less power than my Prime to the Prelude Type SH: https://x.com/BoziTatarevic/status/1802855651116302494
Wait What you’re saying is there ain’t gonna be a coffee can sized exhaust tip, new hood scoop with aftermarket air filter and airplane sized wing bolted on the back??? My neighbor won’t be interested. Hehe.
Seriously, I think this may the coolest project that I’ve read about all year. Keep going!!!
Bozi, don’t use those wheels. Totally the wrong choice; you’re taking out too much sidewall and putting in too much unsprung weight. You’re pushing ~3600-3700lbs with driver, so you’ll end up compromising ride quality way, way too much for little gain. (Also remember, stock tires aren’t just narrow but formulated to have about as much grip as glass, for ‘fuel economy’ reasons.)
You want to run something around an 18×7 or 18×7.5 with P225/50R18’s. Which, yes, keeps you in the P4S. But seriously, I’d probably run Conti DWS06+’s on a daily. (Yes, speedo will need recalibrated. I bet you know a guy.) That’ll put back a decent chunk of road compliance and still crank friction through the roof. Personally I’d prefer P205/50R18, but tire selection there is “no.”
Math works out like this; 225/50R18 on 7.5 jumps the rolling radius by only 12mm and the contact patch by ~+50cm^2 to ~287cm^2! Stiffness increases from 24kg/mm to 28kg/mm, so it doesn’t completely destroy ride quality. Deflection goes from 20mm to 16mm too. Those are really, really solid numbers. Talking meaningful decrease in braking distance kind of numbers.
235/45R19 on 8.5’s? Me no likey. Yeah, you take out another 1mm of deflection. But stiffness goes to 31kg/mm, kiss your spine and fillings goodbye. And the contact patch? You get 1cm^2 more. That’s it. And it nets you a 330mm rolling radius – +20mm! So basically you’re trading off all road comfort for no contact patch improvement, no deflection improvement, and minimal braking improvement over the 225/50’s.
In terms of wheel choices, 18×7.5’s a “weird” size. But I’ve got you covered.
SSR Professor SP7
Ray’s gramLIGHTS 57FXZ (aren’t you glad I didn’t say TE37?)
Ray’s Homura 2X7FT SPEC-M (… fine yes they make TE37’s too. Please don’t.)
Work M.C.O. (Standard Custom Order)
Work VS XX (COP)
HRE 521 – but they can do down to 7″ on all 18″ barrels
Oh, and I forgot to mention unsprung weight savings, like a derp.
Those Toyota wheels are RIDICULOUSLY heavy – something like 32lbs/ea! (Good gods, are they putting lead slugs in ’em? Using Chinese slag casts?)
Ray’s gramLIGHTS 57FXZ’s are 22.4lbs for 18×9.5, so call it 20-21lbs. 2X7FT’s are supposedly around 19-20lbs, but couldn’t get a real spec. Work MCO? ~20lbs. VS XX, no specs available I could find. And HRE monoblocks will probably tip in around 25lbs/ea.
The goal here, IMO should be to take the handling and performance as far as they can go without hurting fuel economy and without turning it into a boneshaker.
Reasonable suggestion and definitely something that I’ll consider.
I love this! I just want to say from personal experience a thicker rear sway bar is one of the best first moves. I did it in my Sportwagen and immediately felt a major difference.
Same thing on my Mazda3… grabbed a thicker one from a MS3 and never looked back!
Oh cool I hadn’t thought of that. I love a Mazda 3. I grabbed one for a GTI with a Performance Pack. It was basically the stiffest oem that fit my car. The aftermarket stuff looked a little too intense for a daily driver. I eventually added some Moog end links (after breaking one of the stock plastic links with tthe stiffer bar) and that helped too.
definitely paying attention. I’m awaiting my LE and I’m down for more fun out of it!
interestingly enough, your PHEV mpg is about the same as a rental HV prius I had back in Jan. ~58mpg with us flogging the poor thing.
I would love it if someone around here would do a deep dive, step-by-step walk through on taking advantage of the PHEV tax credit lease loophole. This article makes it sounds like you just sign the lease and then go to your credit union and by the vehicle outright. Which maybe that really is all it is, but I’m super unfamiliar with leases and would be afraid of unseen pitfalls. So having just a little more info would be super helpful to me (or maybe even just a general primer on leasing a car).
When we bought our Rav4 Prime I asked about the lease for tax credit then buy potential, and in California, they saw that option and squashed it.
Oh man that sucks. I hope no other states follow suit.
There is definitely a bit of work involved along with doing paperwork on your own but for me it was worthwhile.
Terrific reading, looking forward to the next installment!
This is acutely interesting to me. Priuses/Priii want to be boring, but they finally zhoozhed it up enough to at least look attractive. Power will likely always be a deficiency, as will mass, but tires, brakes, and suspension can really make it fun. A few tasteful aesthetic modifications (and a badge delete) might even make it look pretty rad. Parts availability and even whole donor cars will be cheap and excellent in the long run. I always worry about the serviceability of batteries in modern EV/hybrids though. What’s the situation there?
The perception of hybrids versus the reality is quite different. The Prius Prime makes more power than a Civic Si and is only a tenth ofa second slower to 60 mph. One fun comparison I did the other day is the fact that the Prius Prime basically matches or exceeds many of the enthusiast cars of my childhood. Here is a comparison of the base Prius which produces less power than my Prime to the Prelude Type SH: https://x.com/BoziTatarevic/status/1802855651116302494
I am not worried about batteries at all. Most hybrid batteries have been proven to be greatly reliable if the cars are driven on a regular basis and Toyota provides a 10 year / 150,000 mile warranty on the battery pack anyway. Even if I drive it past that, refurbished batteries for previous generations of Prius are incredibly inexpensive.
Battery replacement on a gen2 Prius works out to about $80 per 10,000 miles.
Current gen is newer tech, but it’ll be old tech in ten years.
Hondas have never captured my interest, so it’s not a reference I totally grok, but I get your point. There is more to a car than numbers though. For instance, a Mazda RX-8 looks kinda crap on paper. Middling hp at best, no torque to speak of. It’s not a numbers car though, and is all about handling and drama. It’s just fun for fun’s sake. It’s exciting to drive at all speeds, and you can really toss it around. The output of the hybrid drivetrain may be exciting, but power to weight and handling will suffer from all that mass. May depend a bit on where you are too… I live in the Rockies, and every trip to the grocery store or to drop the kids off at school is on some winding canyon road or another. For a car to be much fun up here, it either needs to leave the road behind, or grip it with a vengeance. A ton of mass and eco tires (which you are addressing) is the opposite. If you’re in a part of the world where roads are straight ever, getting off the line may be more important. Still, this is very interesting to me. You’re not messing around with more hp (wise) and focusing on tires, brakes, and suspension. These are what could make it such an interesting proposition to me personally. EVs/hybrids are where the world is headed, and I suspect my ICE cars will eventually be replaced. I hope to not miss them when they’re gone because the cars that replace them will be even better.
Power only matters when you are drag racing. Maintaining corner speeds is much more important to “lap times” and doesn’t require hp.
What is the advantage of immediately buying out the lease opposed to waiting until the lease ends to decide weather or not to buy it out or give it back? I get you wanted the lease cash, while also wanting to buy, but couldn’t you have gotten more flexibility/risk reduction by leasing for the full term and getting to kick the can and make a decision to keep/offload later?
He’s going to be modifying the car to a significant degree. Most lease contracts have a pretty negative view on that sort of thing, since it’s technically the lessor’s car. Punitive clauses can be harsh. Putting it in public view as what appears to be an upcoming series of articles would only enhance his personal liability.
Additionally, if his goal is to own the car and drive it into the ground-ish, there’s no reason to pay interest or any more in the long run. It sounds like the financial incentives were such that leasing initially for the $4.5 kilobuck bonus was worth the extra paperwork.
Most lease agreements just typically require that it be returned to stock (or close enough they can’t tell) before you turn it in. My folks used to lease one of their vehicles and own the other, so they’ve been through roughly 8 leases that I can remember. None of their turn-in inspections have been in depth enough that the inspector would have ever known it was modified. They basically measure a couple dents (if there are any), measure tread depth or look for wear bars, and then give in the interior a super quick once-over as they check the mileage. Literally a ~5 minute inspection.
I was planning to modify the car immediately so that’s why I wanted to own it but outside of that, the longer I paid the lease the more “rent” I would have to give the leasing company which is basically interest so I would have ended up paying much more for the car if waited until lease end to buy it out.