The Subaru WRX Proves Everyone Wrong About CVT Transmissions

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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?

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

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.

Great job on the zoom/desat effect when switching subjects or points. It focuses the viewer in on the next point very well.

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

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

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

The most informative video I have come across on YouTube (in general) 👍

Im coming up to 2 months ownership of my wrx rs cvt (mid spec in Australia) and couldnt be happier with selecting the cvt. Being almost 50 and driving manuals all my life ive paid my penance and its time to relax a little. Coming from a previous gen manual rex I think the cvt here is exceptional. In comfort mode it just cruises along nicely and particularly in heavy traffic its so good not to have that jerky start stop motion that you can get from traditional autos. Then is sport# it is a beast. You can select to have your revs exactly where you want them at any time and the power is instant. Torque right across the powerband and responsiveness that matches any DCT ive driven. Like the video said its easy to just slag off the CVT, and mostly it comes from a a background of simple ignorance.