The Subaru WRX Proves Everyone Wrong About CVT Transmissions

Don't Listen To The Haters, They're Wrong About CVT Transmissions!

The 2022 Subaru WRX continues to offer two transmission choices which have been available in the WRX since 2015: a conventional 6-speed manual transmission, and a continuously variable transmission which Subaru calls the "Subaru Performance Transmission," likely intentionally avoiding the dreaded three letter acronym "CVT." You see, CVT is a deal break for enthusiast; they claim it's trash, that it can't perform well and it feels like a rubber band.

Well, Subaru would like to have a word. In this video we'll discuss what's the best transmission choice, and why for an automatic, the CVT is just fine - in fact fantastic - as it's used in the WRX. We'll compare the CVT to the advantages of a Dual Clutch Transmission (DCT) and see how it stacks up. Warning: you may like the results, but they're accurate.

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[siberx]

I love the concept of CVTs; boy was I disappointed when I found out that in nearly every actual use of a CVT in a vehicle, they do wonky inefficient power-reducing things just to make them "seem" more like a traditional transmission to the user. When I put my foot down, I want that needle to immediately jump to peak power RPM and stay there until I let off, and when I'm cruising efficiently I want those RPMs as low as possible for the current power demand.

[IrocZIV]

I love the idea of a CVT working like a CVT was designed (at least in eco mode)

[Slider]

One thing we discovered while researching/tuning CVTs for drag racing is there is a substantial loss in efficiency while it is continuously shifting, especially at WOT.

What actually happened is while the clutches are shifting gear ratios (constantly) and the belt is moving up and down in the clutch sheaves there is both an increase in friction and a small amount of slippage that occurs.

As a result, you lose about 10-15% in efficiency while the CVT is (constantly) shifting. You do get the benefit from running the engine at the optimal rpm for power (or efficiency if going for best fuel economy) but we found that isn't enough to overcome the loss in efficiency.

By configuring the CVT to behave as if it had discrete gears (we found 7 to 10 virtual gears was best) we were able to shave off over 0.4 seconds at the drag strip.

If Subaru is making their CVT behave as if it has discrete gears during WOT acceleration, I would bet this is for the same reason we did it - quickest acceleration.

One of the big reasons you can do better with virtual fixed gear ratios is you can get away with less clamping force in the sheaves. The slippage that naturally occurs while a CVT shifts gears requires a good ~20% greater clamping force in order to control this slippage.

[kenhoward]

This is encouraging, but my main concern is still long-term CVT durability, and the need for meticulous maintenance (likely much more often than what Subaru prescribes), especially when accommodating relatively-high output. That is what I'd like to learn about from an engineer.

[obdriver]

As a Subaru tech, I 100% agree. I was impressed with the cvt on the new WRX. It’s much improved over the last generation. That being said, reliability is another factor.

[dezee]

I actually hate the fake gear ratio thing it completely defeats the purpose of a cvt. One reason I hate driving automatics is that you can't predict when they're going to shift and jerk the car especially around a corner so a cvt is actually preferable in this regard.

[pocobueno]

CVT in my six cyl subi died at 62, 000 miles. Subaru replaced it under warranty, but I lost my faith in them. Also have a Nissan Rogue with a CVT that I've started replacing the fluid in routinely in an attempt to get more than 70, 000 miles out of the belt. Also picked up a RAV4 hybrid with an eCVT and think it is a far superior mechanical system. The new subi Crosstrek hybrid is using a variation of the Toyota eCVT. The eCVT has no belts, only gears on gears. My advice for belt based CVT owners - never manually shift.

[MaxwellWilliams]

It's a good thing for folks like me with disabilities that the auto version of this car doesn't suck! I really miss driving manual from my able-bodied days, but the reality is that my spine isn't gonna start working again. So cars that are engaging with an automatic are excellent for accessibility, since I can still drive them with hand controls.

Edit: to clarify I drive a Tesla Model 3 LR now and used to drive a '06 Miata with a 5 speed. The Tesla is less engaging, but it's good enough for me. I'm just overall glad there's effort going into experiences that everyone can use, whenever they're EV or dual clutch or CVT or slushbox.

[redbarchetta]

While I don't hate the way the CVT feels like in my Impreza I did hate having to replace the entire transmission at 70, 000 miles. They are prone to mechanical failures.

[xtnuser]

I understand they won't take full advantage, because customers will whine about the "no gears" feeling. But I wish they would let you select a mode that would let the transmission run that way if you wanted to. Completely optimized for economy at low throttle settings, and for power delivery at high throttle settings, with a linear transition between those things across the mid-throttle range. Maybe I wouldn't use that mode all the time, but it might be nice to use it sometimes.

[twotrackjack]

Fun fact: Japan's home grown battle tank uses a CVT, allowing it to drive in reverse to get back behind cover after a shot faster than any other main battle tank.

[eh]

A CVT feature I'd love to try is a manual ratio lever - kind of like a prop pitch lever in an airplane. Lever in low, pin the throttle, and manually push the lever forward for higher ratios as the car accelerates. Like a fretless bass - you can pick off tune ratios if that's your mood or learn to fine tune the ratio for your driving style. Thoughts?

[pauloakes]

The problem with cvts isn’t necessarily performance (often is), but rather their tendency to grenade.

[cantarguewithstupid]

To me, the traditional shifting with a CVT is a step back to the potential benefit of the CVT.

[graham]

The only problem I have with CVTs is their (perceived) reliability. Hopefully the newer generations of them have solved those issues but I'm not going to put down $40k+ to find out.

On another note, I really like the eCVT that Toyota uses. It's a super clever and interesting design and it would be great to get a video on how it works.

[Wesley_H]

My old Jeep Patriot had CVT. I lovingly referred to it as a “city jeep”, but it still made for a fun camping trip. RIP Patty. I still love you.

[neometalx]

I love CVT when it stays in one gear and it doesn't fake shift.

[PahaLukki]

The main problem with CVT: maintenance cost nightmare and low overall transmission life.

[tedantares]

How about reliability? You said no word about it.

[solarcrystal]

I love how this channel called Engineering Explained never even explained what a CVT is or what the acronym stands for 5 minutes in