2004 - 2009 Prius P112 Hybrid Transaxle (eCVT) Operation

Рет қаралды 776,241

13 жыл бұрын

Weber State University (WSU) - Automotive Technology Department - Transmission Lab. Toyota Prius Electronic Continuously Variable Transaxle (eCVT) model P112. How an eCVT Works. GM, Ford, and Nissan eCVTs are similar. The Honda Integrated Motor Assist System (IMA) is completely different.
eCVTs allow the engine to operate (when necessary) at the RPM for peak efficiency while increasing and decreasing the transmission drive ratio to change vehicle speed.
Questions:
1. List the four major components of an eCVT transmission
2. What is the purpose of the MG2?
3. To which piece of the planetary gear set is MG2 connected?
4. What is the purpose of the MG1?
5. To which piece of the planetary gear set is MG1 connected?
6. What is the purpose of the Internal Combustion Engine (ICE)?
7. To which piece of the planetary gear set is the ICE connected?
8. What are some advantages of an eCVT?
9. What are some disadvantages of an eCVT?
10. Tell me one thing you learned or found interesting in this video.
This video helps satisfy NATEF Task A2.C.24. "Describe the operational characteristics of a hybrid vehicle drive train. (eCVT)", a priority 3 task.
CVTs are different and are demonstrated in another WeberAuto video.
www.weber.edu/automotive
Join us for hybrid and electric vehicle training with two online courses and in a 5-day on-campus boot camp with Professor John D. Kelly. See www.weber.edu/evtraining for more information.
This video was created and edited by Professor John D. Kelly at WSU. For a full biography, see www.weber.edu/automotive/J_Kel...
Visit my other youtube channel / vibratesoftware to see the amazing NVH app for vibration diagnosis!
Please consider a donation to the Department of Automotive Technology at Weber State University here: advancement.weber.edu/Automotive

Пікірлер: 440

@4nz-nl 5 жыл бұрын

Another car enthusiast here. I already appreciated the Prius, not for being an enthusiasts car, but for being an extremely reliable and quite comfortable runabout. Now I see how it works, and how advanced yet simple it actually is, I'm starting to see this car somewhat as an enthusiasts vehicle :-)

@jeffsond 11 ай бұрын

Fairly reliable, this CVT has its issues too. Overheating, slipping, lurching or jumping. It’s vulnerable for issues as any CVT. I do like Toyota’s and their reliability but they do have issues. Just poke around on google and there are groups who have complaints about this costly CVT

@4nz-nl 11 ай бұрын

@@jeffsond lol, I don't know what you're on about - technically it isn't even a CVT :) only issue I hear that comes up regularly is the cooling system failing (and resulting issues after continued driving without appropriate cooling)

@symmetry08 10 ай бұрын

This car is loved by places and countries that have remote driving area and poor service distribution, as it is much reliable than conventional cars transmission and engine is, also, very robust for those markets. Because, most of the time cars do not drive fast long enough and have to slow down or break often, and accelerate again. Up and down hill offer good petrol saving, and engines do not overheat as much.

@jeffsond 10 ай бұрын

@@4nz-nl maybe try doing more research and you will see what I’m talking about. It’s real simple

@4nz-nl 10 ай бұрын

@@jeffsond That's not how you get away with not supporting your claims ;)

@artysanmobile 4 жыл бұрын

Toyota’s Prius holds a well-deserved place in the history of great technical accomplishments. Ingenious, groundbreaking, bold, and most amazingly, a smash sales success. Kudos to Toyota.

@samkhalil3784 3 жыл бұрын

I recently bought a 2007 with super low miles on it.....the more I learn about the Prius the more I appreciate it.

@WeberAuto 3 жыл бұрын

Good to hear! Thanks for watching

@WeberAuto 11 жыл бұрын

Hi, thank you. You are absolutely correct regarding reverse. I realized my error after shooting the video, but nobody ever said anything until you. What I should have said is that MG1 will spin the opposite direction of MG2 in reverse because the planet carrier is stopped with the engine off. This allows MG1 to start the engine if necessary (which mine usually does upon cold startup) while backing up.

@blairo15 5 жыл бұрын

I just bought a prius and am a motor mechanic. I just learnt something new! What a clever transmission!

@cplai 12 жыл бұрын

I heard that the fuel injection begins only after the engine has been spun to operating rpm by MG1. That explains why the Prius has very clean emission despite the frequent engine start and stop. In regular cars, the starter motor only turns the pistons to proper firing positions, the first few burnings may not be clean when the engine is not yet in ideal rpm.

@Trades46 9 жыл бұрын

As a car the Prius has many faults which prevent it from being an automobile for enthusiasts. I used to belong in this camp, until I've recently driven a Prius C. After driving it and doing the research behind the technology (and especially the eCVT), you have to be amazed that Toyota figured out how to use a single planetary gearset so efficiently before anybody else did and made the hybrid system blend EV & gas power so well. Well done on the explanation!

@WeberAuto 9 жыл бұрын

Trades46 Thank you for watching!

@mr88cet 7 жыл бұрын

Trades46 My understanding is that the Power-Split Device ("PSD") was originally patented by a group of California inventors. Toyota made it work though, kinda analogous with the Wankel engine having been invented a long time earlier, but Mazda made it really work.

@dstr1 5 жыл бұрын

Can you List a few of the faults?

@brkbtjunkie 5 жыл бұрын

The motor in the Lexus hybrid is even more smooth on blending EV and gas. I love it. Never thought I would like a CVT

@funposting8912 4 жыл бұрын

I have a Toyota Aqua (prius c) and I see nothing in it that prevents it from being an enthusiastic vehicle. There’s nothing inherent with a PSD Hybrid that stops you from driving, racing, or having fun with it. I’m curious what you used to think those “inherent faults” are other than “cars that were designed specifically to sacrifice performance for efficiency don’t have as much performance as cars that do the opposite”. Big surprise.

@vegajay 12 жыл бұрын

Amazing presentation!!! A true engineering marvel, clearly explained. 15 minutes that made me smarter!

@tofubeanz 10 ай бұрын

I've searched a lot of videos to understand how Toyota's eCVT works and your video is the best explanation I've seen so far.

@WeberAuto 13 жыл бұрын

@Mrcamfam5 Thank you for your comments, it is a very simple mechanical design.

@DrDaab Жыл бұрын

A terrific tutorial on how the unique Toyota Prius transmission works and it answers a lot of questions that I had. THANKS !

@WeberAuto 12 жыл бұрын

@sosarres 2. (Vehicle moving) Rotate MG2 (ring gear), MG1 rotating more than 2.6 times faster than MG2 (sun gear), the crankshaft (planet carrier) will rotate to start the engine. There is also a time when the crankshaft will be rotated but the engine is not intended to start: Full battery charge, decelerating down a long steep hill, regenerative power has to go somewhere so it is used to rotate the crankshaft with MG1 to dissipate the additional energy.

@DrHouse-zs9eb 5 жыл бұрын

Finally i understood. Thanks! Thats a pretty great invention.

@shirazoldchannel 12 жыл бұрын

this video is great! thank you. i love the way you repeat the roles of different parts in different contexts -- makes it much easier to learn!

@The8BitGuy 11 жыл бұрын

Great video. I wish the audio was a bit clearer and there was some close-up shots. But still one of the best explanation videos out there. I've seen diagrams of how this stuff works, but seeing the actual parts really makes a big difference. I actually always imagined many of those parts being quite a bit larger than they really are, especially the planetary gear set. MG1 and MG2 look small, but I think because we're not seeing them with the stators around them.

@GuruAidTechSupport 7 жыл бұрын

The 8-Bit Guy cool you’re here! You should do a video on your Volt and talk about stuff like this. Like the electrics behind it.

@garfield71988 Жыл бұрын

Funny to see you here..,10years ago lol

@m.ibrahim21 6 ай бұрын

Wow

@SpruceGoose55 7 жыл бұрын

I've always chosen to drive manual-transmission cars, because I like their mechanical simplicity compared to automatic transmissions. I'd assumed that hybrids were even more complex, so I've never been interested in them. However, after looking at this video, and the excellent companion video of the 3rd Generation eCVT, I'm impressed by the overall efficiency and simplicity of the Toyota concept. I'll definitely consider a Toyota hybrid for my next car.

@WeberAuto 7 жыл бұрын

Thanks for your feedback!

@yutorzh7144 8 ай бұрын

Late reply but these transmissions are the most robust and reliable I have ever experienced. Never had any issues with them, even well into old age 450,000kms and beyond. The most I've seen is some leaky seals so some splash lubricant can leak but the actual mechanism used in the first and second gens are phenomenal. Can't say the same for brand new junk 😂 but our first gen Toyota Highlander is an absolutely outstanding vehicle

@RaulDukeKnife 16 күн бұрын

There is an incredibly detailed and well done software available to the public called Hybrid Assistant that allows you, in real time to monitor every possible facet of MG1, MG2, and everything from high voltage battery real time charge and decharge, temps, all combustion gauge values even high voltage fan speed. Having these values real time is crucial if not just for the fact that only a Toyota hybrid is monitoring that many systems, and just as a space shuttle launch command - after a while you start to understand the personality of your vehicle so you can understand what is going on with her before a possible incident or how to achieve performance or efficiency. I love driving my hybrid systems with all that real time data You need a good OBDII sending unit and you’re good.

@KiwiMaker 4 жыл бұрын

Great explanation! I can’t believe how small it all is and that there is no cvt belt. It’s nice to understand my car more.

@sankyppp 4 жыл бұрын

I understood the mechanism after years of trying to understand reading and watching animations. thank you.

@MrHolozip Жыл бұрын

whoa... hard to believe this is a 12 year old video. I'm not a mechanical engineer in any shape or form, but was able to follow along and understand your every point. Great information, and extremely well presented. Thank you for this!

@WeberAuto Жыл бұрын

Thank you very much

@DavidORiordan 11 жыл бұрын

This explains the hybrid transaxle operation very well. Thank you.

@Cl3gster 11 жыл бұрын

A very nice and clear explanation on the Toyota Hybrid drive system, and unusually accurate as well - Very nicely done. My only point would be that MG1 never drives the car. When going backwards it is always MG2 that provides the motive force (just like when going forwards) Whilst driving backwards MG2 is the motor and MG1 will be freewheeling, unless the engine needs to run in which case MG1 is a generator charging the battery (Providing the electricity for MG2 to drive the car)

@mini2nut67 2 жыл бұрын

Outstanding lesson!!! I have a 2022 Tundra hybrid on order with a 1.87 kWh battery and now I know the basics and understand MG1, MG2, planetary gears, sun gears, etc. I find it fascinating that an “old school” starter and alternator are not required with a Toyota hybrid system.

@yem.t.3930 5 жыл бұрын

A beautiful beautiful work of art! great invention, Thank you very much Sir!

@moonsapling 2 жыл бұрын

This is the best explanation ever, I now finally understood what my RAV4 hybrid does when driving!

@kristianhermann5971 3 жыл бұрын

Best explanation of Toyota's e-cvt I've seen to date. Thanks!

@slc9800gtx 2 жыл бұрын

eCVT is so much better a design than a regular cvt. I hope all cvt go to the eCVT design.

@tbpom1003 3 жыл бұрын

this channel is really a gem. Always have good explanation and professional knowledge. Thanks!

@MrBobWareham 5 жыл бұрын

Just about to buy a Yaris or Prius so thank you for the explanation on how the drive train works very impressive a good job well done

@WeberAuto 12 жыл бұрын

@sosarres Hi, thank you for the nice comments. Let me know if you need help transferring to WSU. We also have an online option for a B.S. degree in Automotive Technology.

@honahwikeepa2115 7 ай бұрын

I was a Diesel mechanic a lot years ago. The pace that technology and engineering growth since the 70's has been staggering.

@WallaceRoseVincent 7 жыл бұрын

Your video is a work of art!

@WeberAuto 7 жыл бұрын

Thank you!

@Flakey86 10 жыл бұрын

brilliant explanation! Thanks so much for taking the time to produce this.

@Book_of_daniel 6 ай бұрын

Best explanation of the Prius hybrid system I've seen yet, and it's a 13 year old video!

@MikeMayneMusic 10 жыл бұрын

Wow that was a GREAT demonstration. Thank you

@5Dale65 5 жыл бұрын

Wow! This is really clever desing, and rather simple.

@WeberAuto 12 жыл бұрын

Yes, they are! They are used in conjunction with a drawn reciprocation dingle arm on the up end of the grammies for sinusoidal repleneration. :)

@WeberAuto 13 жыл бұрын

@luvmygooose 1. The P112 transaxle input damper (looks like a clutch disk) absorbs the shock that accompanies transmission of the drive force from the engine. It is permanently applied. If it slips, a P0A90 DTC will trigger for a transaxle input malfunction. 2. The vehicle can move on Motor-Generator 2 (MG2) power alone (up to near 37 MPH) or a combination of both the MG2 (driving the ring gear) and the Internal Combustion Engine (ICE) driving the planet carrier (at all vehicle speeds).

@AndrewAkaHrun 3 жыл бұрын

The best explanation of ecvt I could find! Thank you so much!

@WeberAuto 3 жыл бұрын

Thanks for watching

@TheoPhilpot 2 жыл бұрын

This is FASCINATING!!! Thank you!

@ErickMartinSucre 6 жыл бұрын

I am loving these Hybrid cars. I recently purchased a used 2008 Prius and I am fascinated with the technology that goes into these cars. The Prii are also immensely reliable. You tend to see many in the road sitting pretty at 200, 300 and 400k miles on them.

@WeberAuto 6 жыл бұрын

Yes they are, Thanks for your feedback

@ErickMartinSucre 6 жыл бұрын

My pleasure 8-)

@esaedvik 5 жыл бұрын

Funny how 200k is "immensely reliable" when a 90s Saab's break-in is like 300k miles :D Haven't had one for a while though, just got a 08 Prius too.

@ErickMartinSucre 5 жыл бұрын

@@esaedvik Shame Saab is no longer around. They were good cars indeed

@esaedvik 5 жыл бұрын

@@ErickMartinSucre They are though and NEVS just got a bit of extra cash, so there's still hope for a Saab 9-3 or 9-5 EV :)

@MrWilliam.Stewart 4 жыл бұрын

I thoroughly enjoyed this video, my hat off to you sir, you're a remarkable teacher with a natural ability to impart information. As with most engineering systems, the fundamentals are straight forward when you understand how they work as a system. Explaining these fundamentals in an easy to understand way is often not so straight forward, again, great job sir. #Respect.

@YouNameItGaming 10 ай бұрын

So this is how the sequential parallel system works. I love the simplicity of it as the ring, sun, and planetary gears are the only mechanically moving parts in the transmission, and by simplicity adjusting power/drag to MG1 you effectively control the entire ratio range. It's also ultra efficient as when MG1 is driving the sun gear for a high wheel speed, that energy ends up at the wheels too outside of friction losses, and when MG1, MG2, and the combustion engine are RPM matched, the entire transmission moves as one part, and as such there's no friction from the meshed gears

@mack86523 10 жыл бұрын

Thank you for doing this, very informational.

@roryosullivan5278 8 ай бұрын

This video gives the best explanation for how the Toyota eCVT works. I now think I understand the concept. Well done sir and hats off to Toyota for creating this beautiful y engineered system!

@antonpoddubnov4651 8 жыл бұрын

Wow! In just a 15 mins you've explained a two things that I've tried to figure out for years. Thank you very much!

@WeberAuto 8 жыл бұрын

Thank you!

@bytmeh 12 жыл бұрын

@WeberAuto you sure can't! Terrific video, you really did well with this. Excellent preperation well done

@alistairgeorge407 9 жыл бұрын

Lecturer is brilliant. Explains a complex scenario in a very logical and enjoyable manner. I am of the age where Japanese designs in the early days were mostly poor copies of European ideas, which is contradictory to todays Toyota engineers have shown by this drive system to be creative and innovative.

@johnschultz7765 5 жыл бұрын

Alistair George Except this design was originally by 4 engineers in California in the '60s.

@ksd9756 Ай бұрын

Thank you very much for your very detailed explanation.

@stevenfirst 8 жыл бұрын

Awesome video! I had know idea my lexus hybrid system so complex...and I now understand it. I always thought it was just a electric motor that replaced the flywheel or something like that. Thanks!

@WeberAuto 8 жыл бұрын

+stevenfirst Thanks for watching!

@YayAkiba 11 жыл бұрын

Very informative. To think I only recently understood how my Spitfire's overdrive works(when I was rebuilding it)

@sethwiles1255 5 ай бұрын

Thank you for a thorough explanation

@sharpnote1480 5 жыл бұрын

Very good explanation. Thanks. But wow, what an abrupt ending.

@Eduardo_Espinoza Жыл бұрын

Came back after many years, & finally understand it.

@PBandJsandwich 5 жыл бұрын

Excellent demonstration, I learned a lot - thank you.

@WeberAuto 5 жыл бұрын

Thank you!

@dwaynepothier6161 4 жыл бұрын

I'm on my 3rd Prius, 7 years ago I wouldn't even look at a Prius, but it's a great car for reliability I put 320k on my 2nd one with no problems at all NOTHING BROKE DOWN. I've always wondered how the assembly worked. So a big thank you for the video don't worry if you are considering buying a Prius don't worry great car for reliability

@notoco1199 5 жыл бұрын

Looks reliable :-) very good informative video. Thank you

@movax20h 5 жыл бұрын

It is really smart and very small. I was expecting the MG1 and MG2 be much bigger, and closer in size. The size of the planetary gear set is also small. Amazing.

@WeberAuto 12 жыл бұрын

@supermachoman222 Hi, I appreciate your comments, but they are incorrect. During electric only mode MG2 propels the vehicle and the engine's crankshaft is stationary; there is no piston movement. This mode is only used up through a maximum of 40 mph. Afterwards, MG1 acts like a starter motor and does start the engine to contribute power to MG2 and to slow down MG1. This is very efficient resulting in the best city fuel economy of any hybrid-electric on the road.

@alibacchus607 3 жыл бұрын

Great demonstration

@IainHendry 13 жыл бұрын

Incredible video - thanks for the explanation!

@matthewsmith988 3 жыл бұрын

Awesome description. Thank you.

@WeberAuto 3 жыл бұрын

Thank you

@lightseeker1813 26 күн бұрын

Wow! This video is old but gold. Btw, you missed the part in which the motor needs to operate in order to discharge the battery to prevent it from being overcharged.

@KayaanMistri 9 жыл бұрын

Thank you for the explanation.. Was really helpful in getting a practical understanding of the system!

@idriveyoudrink Жыл бұрын

Welp, thanks to your amazing video and knowledge I believe mg1 malfunction is why my gen2 engine won’t start after I replaced both the 12v and HV batteries. Thank you for this stunning presentation.

@oadka 9 ай бұрын

Excellent explanation. Thank you for making this video 🙏

@goons123flofy 6 жыл бұрын

Now I want a Prius!

@WeberAuto 6 жыл бұрын

Thanks for your feedback!

@patduz 5 жыл бұрын

I have a Prius 2 for 12 years now. Just great to drive and so economical. When you reach your destination in Prius, you would like more road ahead. Thanks WeberAuto J'ai une Prius 2 depuis 12 ans à présent. Juste génial à conduire et tellement économique. Lorsque vous atteignez votre destination en Prius, vous voudriez que le route continue. Merci WeberAuto

@patduz 5 жыл бұрын

143 000 km for the moment. Only the water pump + belt of the engine changed. Tires changed and usual car service done each 15 000 km..@Luca Rossi

@WeberAuto 12 жыл бұрын

@vegajay Thank you!

@eduardodelrio8439 7 жыл бұрын

Great explanation, God job!!

@WeberAuto 7 жыл бұрын

Thank you!

@GioMillz 6 жыл бұрын

A+ video. Don't see why there would be a single dislike.

@WeberAuto 6 жыл бұрын

Thank you!

@mikegrzeskowiak4100 10 жыл бұрын

Spectacular!!!

@michaelthomsen8771 5 жыл бұрын

Great explanation, many thanks!

@WeberAuto 5 жыл бұрын

Thank you!

@hwleitner2009 2 жыл бұрын

Brilliant explanation thank you.

@rrsblack2 10 жыл бұрын

Awesome video!

@Dieselboy246 5 жыл бұрын

This is a really good video Explaining how it works. I have always wanted to know.

@WeberAuto 5 жыл бұрын

Thank you

@ramishrambarran3998 5 жыл бұрын

Thanks Professor Kelly. Regards, Ramish.

@WeberAuto 5 жыл бұрын

Thank you very much!

@zodiacfml 7 жыл бұрын

Well explained and brilliant design.

@WeberAuto 7 жыл бұрын

Thank you!

@lastnameavailable326 6 жыл бұрын

Very clear and helpful. Thanks!

@WeberAuto 6 жыл бұрын

Thank you!

@pjwcoetzee3281 9 жыл бұрын

just want to say i watch a lot of videos, but your videos are the best i ever saw. i am a mechanic myself and love to check your videos. thanks a lot , would like to your workshop one day,i am in south africa, thanks again.

@WeberAuto 9 жыл бұрын

pjw coetzee Thank You!

@drewrichmond1692 2 күн бұрын

Best dive into the Prius gen 2 I've seen. Running 2( 2008 w/ 220,000 and 2007 w/ 290,000 ) gen. 2's currently. Love them but '07 needs at least one new batt. cell( death triangle getting consistent). Even a Prius needs some maintenance!

@getyourkicksagain 3 жыл бұрын

Fascinating and well explained. Thanks.

@WeberAuto 3 жыл бұрын

You are welcome!

@battousaihimura 11 жыл бұрын

Amazing explanation of the eCVT operation! Great Work Mr. Kelley, please keep making more videos like this one. Also, this video ends abruptly. Could you kindly explain what happens next? that is what happens at a much higher vehicle speed? how does both ICE and MG act in parallel mode via the eCVT? Thanks

@brutusmaximus5380 2 жыл бұрын

I agree this was a great demonstration.

@dzcav3 21 күн бұрын

Thanks for a very useful video

@plumkey197 7 жыл бұрын

This video answered almost all of my questions about my car's transaxle. You have explained the component in such an elegant way and you bring it to life! I feel lucky to have access to your teaching content. I'm sure your students do very well upon graduation. I have a quick question: Why does the damper system slip and for what purpose? Once again, thank you for providing your wisdom and years of teaching experience to us-- I've learned much about how my car operates and I subscribed quite a while back. Best Wishes! Keith Nettles, RN.

@YouTube.TOM.A 12 жыл бұрын

Thank you for this presentation. This vehicle is not completely a independent novel concept since it incorporates a lot of technology that may be familiar to other transportation modes such as freight trains. Having said that, it is undoubtedly the pinnacle of Toyota's engineering with conventional and electrical propulsion . I also get lost in the details of wheel and tire technology used, also weight distribution and energy use and conservation. Your poise as a teacher is also reassuring

@KoreyHite 7 жыл бұрын

Very good demonstration

@WeberAuto 7 жыл бұрын

Thank you!

@mark-qi6di 2 жыл бұрын

This is so interesting!

@alpalchevskiy3886 8 жыл бұрын

Awesome explanation!

@WeberAuto 8 жыл бұрын

+Ikera Palchevskiy Thank you!

@Jo-hannson 5 жыл бұрын

Thank you, very informative

@WeberAuto 5 жыл бұрын

Thank you!

@alankwellsmsmba Жыл бұрын

I love this guy!

@drevilatwork 11 жыл бұрын

Thank you very much for this geat and very informing video

@linkwokeup 4 жыл бұрын

Fantastic, thanks a lot man.

@WeberAuto 12 жыл бұрын

@sosarres Hi, you are correct when you state that the engine's crankshaft will rotate at the same speed as MG1 (when MG1 and MG2 are rotating at the same speed as each other); however, this is not how the engine normally is started. The most common ways the engine can be started are: 1. (Vehicle stopped) MG2 stopped (ring gear), rotate MG1 (sun gear), the crankshaft (planet carrier) will rotate to start the engine.

@WeberAuto 12 жыл бұрын

@danielthechskid Hi, that is a great point. I had not thought of that.

@ELLROMBO 13 жыл бұрын

EXELENT. thank you so much ¡ ¡ ¡ ¡ FOR THIS VIDEO

@ggchinatown7494 Жыл бұрын

Great video

@WeberAuto 12 жыл бұрын

Hi, yes there can be force passed from the ICE to help MG2 power the wheels. How much dependent upon the variable speed differential between the three components of the planetary gear set. For example, if the engine and MG2 are both rotating at 3000 rpm, the planetary gear set functions like one solid piece. At that point the torque from the engine + the torque from MG2 add together and is delivered to the wheels. If the ICE is off, the torque from MG2 is all that powers the wheels.

@Cl3gster 11 жыл бұрын

Transaxle damper has internal springs to sort out the vibration when the engine starts and stops, to reduce the shockwave through the drive train. The Friction material the there in case of a catastrophic failure or the engine at speed to make sure that the roads wheels don’t lock or destroy MG1 by over revving.