Mitsubishi Evolution X - How The AWD System Works (S-AWC, ACD, AYC) 

Evo X 2014 GSR owner here. Turn off traction control and AYC brake. Floor it into corners, when in doubt. Flat out. Amazing. I really want to have this car until it dies, giving it up would make a small part of me die. It is just so god damn fun. Terrible on fuel, feel every bump in the road, still love it.

I had an Evo X and I was always amazed by the AWD system. Ok, mine was lowered, had 1" wider wheels & tyres, and some Whiteline suspension bits. BUT, it always blew my mind! It also scared the p00p out of unsuspecting passengers LMAO. In heavy rain, I drove in 'gravel' mode, and she was STUCK to the road. The Pirelli P Zero Rosso's also helped. I really miss that car.

Great Video! I hate how these facts are well known in the Evo community but other people keep saying random stuff about. When I saw your Evo review, I was a bit disappointed because you of all the people got it wrong....so thanks for clearing it all up in this video. MMC actually publishes papers in their tech reports. I'd like to add a few things. 1. Since you draw that 2nd diagram, you probably know that all the complexity is happening in the front axle. This is obviously cause by the Evo being based on a FWD Lancer with a transverse-mounted engine. Because of this, you get the hilarious turning radius in the Evo. 2. The S-AWC computer is desperate from the main ECU. Again cost reasons with the base Lancer production line probably. 3. You didn't talk about all the sensor in the car. G sensors, wheel speed, gear, wheel angle..etc. Which is what controlsthe S-AWC computer that controls the AYC and ACD. That I think is the heart of the system. They actually started out with being able to control the power in each four wheels. It worked for track time but everyone who drove it felt uncomfortable and in term induce less confident. This ACD + AYC set up together with the tuning of the S-AWC computer, in my opinion the beauty of the Evo X and why I ended up getting it. 4. I believe if you go through the manual of the Evo, Mitsubishi claims the stability control is part of the S-AWC system. There is actually something call AYC-braking (which is on top of the normal AYC system) that helps cornering by apply brakes on individual wheels. You can disable it but requires holding the ASC button for two seconds.

This is a really amazing amount of work and technology. I can barely even absorb how it all works yet Mitubishi freaking BUILT it to be reliable and efficient enough to sell it as a consumer car. Cars are so awesome.

that's mitsubishi engineering, pioneers of advance technology across the globe.

Your previous comments helped undermine the car. And most of the viewers never watched this video. The evo deserves another review.(manual/final edition maybe)

Nice fast and furious reference lol!

A very through explanation. The Evo has arguably the most advanced sport-oriented AWD in the world, too bad Mitsubishi doesn't apply the technology across their lineup & the fact the Evo is going to disappear by 2016. If your local Mitsu dealer has a Evo X Final Edition sitting on the lot, take it and run. It will be a guarantee future classic

I always keep coming back to this video. You've done such a great job, Jason, of visualizing how things work from a mechanical perspective. Do keep up the good work, even though I selfishly regret that there's hardly anything left of Mitsubishi on the performance front to expect videos about Mitsubishi on your channel. Nonetheless, the S-AWC system that Mitsubishi put in place in the Evo is such a cut above so many others' systems in that it pioneered the design in the Evo IX (ACD) and X (ACD+AYC), and it's still one of the best TV systems out there. It's such a shame that inept leadership at Mitsubishi doesn't seem to get how to properly market this thing. Alas, though the budget S-AWCs in the Outlander family (w/c includes the Eclipse Cross) is but a fraction of what this "full" S-AWC system can do, it's still something. It still puts a smile on my face whenever I talk to people about how there is NO braking involved in engaging the rear AYC clutch packs for the Evo. And how all it does is truly coax power to one axle like a mechanical diff would. It's why friends just go aghast with the fact that, compared to a Subie or Ford, you really just have to step on the friggin' accelerator to get back in control in an apex. So unreal. It's insanely counterintuitive - but that's the Mitsubishi that gearheads love (and miss). True shame what they've done to themselves.

Top right diagram is on point, this confuses so many people, one of the best explanations and diagrams that I've seen. I do love how they have literally 3 axles spinning concentrically on the same axis, looks funky when you pull them down :) The one thing you left out is that both the center ACD and rear AYC diff pressure is variable. This affects both the ACD driving mode and for the AYC based on how hard you are turning around a corner etc.

Another reason the Evo is miles ahead of anything subaru! Oh and the Evo is hands down reliable unlike a Subaru!

Thanks for giving EVO some love ! always wanted to know how my S-AWC work ! now i know

The only thing that is not made loud and clear is that THE EVO X ON A HARD TURN CAN MAKE IT'S OUTSIDE REAR WHEEL TURN FASTER THEN THE OTHER WHEELS. IT IS ONE OF VERY FEW CARS IN HISTORY THAT DO THIS. OTHER CARS LIKE THE SUBARU STI USE BRAKES TO TRY TO ACHIEVE THE SAME HANDLING CHARACTERISTIC BUT TO NO AVAIL. THUS THE EVO HAS GREATER HANDLING CHARACTERISTICS. @EngineeringExplained LET PEOPLE KNOW.

Very neat explanation. Something to add is when the differentials are locked they restrict differences in drivetrain speed so that the wheels rotate at the same rate or some rate between open and full lock, if there is allowable slip. Only the AYC can direct torque between wheels.

Saw that new 2024 GTR has a front LSD so now I'm going back watching all your old videos with the evo, gtr and Subaru to relearn how all the systems work haha. Great videos as always bruh!!! Very informative

This is the best video yet, awesome explaination, thanks.

Evo is God of awd

You should also do a similar video on the 2016 Ford Focus RS' AWD system at some point. It also has a rather curious ("twinster") solution that's different from the rest.

The S-AWC is an amazing engineering achievement, but in the long term, it's going to be a major headache because of it's complexity, as maintenance will require us to replace 5 clutch packs (for the MR, SST gearbox). As long as Mitsubishi provides us replacement parts, we're good, because no one else is going to manufacture these components, because THIS IS THE ONLY CAR OF ITS KIND!

Should do one for the STI awd system too

Man, you can explain this complex systems with such simple words. Awesome class!

I love this video. Obviously more so because I own an Evo X. But I really hope you continue more videos like this for others cars as well. Maybe even add pros and cons of a car's drivetrain. Like I think with the Evo's system it hurts transitions back and forth during a slalom. But yes, AWESOME video.

"Rear of car sticking off the cliff"...." common scenario"?! We're lucky to have had you around as long as we have. :)

Much better explanation than the first time around, and you've even cleared up some misconceptions I had about my own car. Appreciate the video, and effort dedicated to the presentation. Keep it up, and I'll be sure to keep tuning in!

~500 likes vs 0 dislikes? You are good, Jason!

Nice video! Will you be making the same kind of video for the awd system in the STI?

Great visuals! Nicely done. If you have a chance, please describe the X-drive system used by BMW in a future video. Thanks!

+Engineering Explained thanks for making this video. I commented a while back on how AYC works

you should do a dedicated video of how the STI's awd system works and why the rind lands have been breaking so badly for so many years

One of the best videos you've made in my opinion Jason, very well done!

i need to take a evo and the track to experience this system first hand! what a clever system

Nice video Jason, On my 13 Legacy 3.6 R torque is split 45 front and 55 rear, and can go 50/50... but even then it was hard to find out what the system really does, the dealers out here in Sac are clueless as if it's magical AWD. I wished manufactures would explain things as well as you do, Thank you for making awesome videos.

In short, evo/ralliart has or tries to enforce a permanent 50/50 torque split at all times. When all 4 wheels have plenty grip, the central diff is open. The car is automatically in 50/50 torque split. When one or more of the wheels lose grip, the engine is involuntarily sending more torque % to the axil that’s losing grip. So the central diff closes, forcing front and rear axil to rotate at the same speed, thus enforcing a 50/50 torque split. On tarmac, this central diff arrangement probably won’t perform as good as AWDs with a permanent rear wheel bias in terms of cornering speed (a large portion of evo’s incredible cornering performance comes from its rear torque vectoring diff, 50/50 locking central diff alone won’t get you that incredible performance). But on lose surface like dirt, gravel, rain, snow or ice, evo/Ralliart’s central diff is what makes them the beast they are. In winter, my Ralliart is usually the only car in my local ski resort without snow chain on the tyres. Don’t need them.

I own a Evo X and thanks for explaining it so well!

Regarding the first example you give: If you're trying to accelerate in a straight line, how much of a problem is it to have a power disparity between the right side and the left? Wouldn't the car veer in the direction of the slippery patch? What happens if you're cornering and the outside wheels go over some ice, would the diffs lock up and send you wide?

The quality of your videos is amazing. So informative and helpful. Thank you

The evo acd is just an electronicly controlled lsd, it will not differ the torque percentage from front to rear, it will just maximize the torque output to the the drivetrain that’s not spinning freely. In a straight line, either opened or locked, it will output the same percentage to both trains. On the other hand, the subaru DCCD will output 65% torque to the rear and 35% to the front, only when it’s opened! Due to the different leverages inside from the housing to the ‘planetary gears’. Both cara, when you lock it, send the same percentage to both front and rear

Great Video, I don't know how you keep a straight face with the humor, well done.

Yaw is love, Yaw is life #Evo4life

cool man. awesome video. i love you. i understand a little more how the AWD on my Evo works now, though I am still confused about some of the concepts like center diff lock up etc

Great in depth explanation! It's difficult to find an actual explanation of how the Evo's AWD system works when most magazines/show reviewers are busy spreading false information. I had to scour the internet for diagrams when I was learning about this system a while back. A few notes/questions: 1. I noticed this car has a pretty unpredictable tendency to oversteer whenever I would trail brake at trackdays, and I'm assuming that could've be the center differential unlocking? Minimal trailbraking would usually cause the car to rotate aggressively. I sold the car, before testing the different ACD modes to combat that. 2. When the ACD locks, the way I understand it, doesn't that cause the F:R torque split to become as close to 50:50 locked as possible(until the point of clutch slip of course)? As when it is unlocked the diff is open, and were it not to lock on acceleration, the power would get sent to the end with least traction in normal open diff fashion(which doesn't happen due to programming)?

Wonderfully instructive video, Jason. I learn a lot from your channel. Please keep them coming!

That's alot of gearing for the power to transfer. Btw, good job explaining, the diagrams are also excellent.

Pretty amazing how many things can be shoved between 4 wheels just to move people around. What is it like for a manufacturer to sit down and decide how much technology and engineering they want to shove into a consumer product (after deciding $-in and $-out)? +Engineering Explained, could you put together a kind of crash course video(s) explaining the processes of engineering new vehicles or components? Or shed some light on the inventive background of mechanical engineering. Do manufacturers have an estimated life expectancy of drive train components (or all of the vehicle components)? How long would the differentials and clutch packs last before needing to be replaced? How long before total failure? Reverse engineering?

If you ever in the Uk, your welcome to come take my Evo VI GSR for a spin and do a review!

Man you've come a long way with these videos.. Awesome

Explain the STI drive train please. On the forums the evo is praised for its ability to make more power easily compared to the STI, but people take the Subaru because of the reliability. I'm looking into purchasing a 06-07 STI and want Subaru AWD because it in my price range and safe choice for my family. Doing a detailed video on the STI will further convince myself and others why Subaru is a good choice or not? keep up the good work! hope you get rewarded in life for your intelligence and hard work.

Please, can you compare the Hondacura SH-AWD system against either the S-AWC or Symmetrical AWD please? I think the SH-AWD has a pretty trick rear diff, and I wish it was in a smaller car than the TL, like a new RSX for example (with the J while I'm earth dreaming). Thanks!

the best video explain S-AWC system

I could be wrong but in the scenario where only one wheel has traction, it isn't too difficult to assume that might be used for ice. One wheel might have more traction than the other three, therefore it sends power to that one wheel.

1. The active center diff when you say 50/50 when open: what do you mean by open? When does it actually open? 2. How does active center diff lock up? 3. What does clutch pack has to do with open and lock? The whole open and lock thing is the main confusion I have when I try to understand the video. If you can explain to me, that would be awesome. Thanks again.

I'd like to see WRX STI DCCD AWD explained in details, always there is some doubt about the system ;-D

used on outlander models minus gravel mode. runs awd all the time in normal vs most are fwd most of the time until slips.

Great video! When its out, please make a video on the awd system in the 2016 Focus RS.

This video was amazing. Everything I wanted to know I know now. Thanks

Very clever stuff indeed. Do you know if the system is able to partially lock the centre diff as opposed to having it either open or locked? Big respect for the team who developed the software to control that type of drivetrain.

Would you explain how laser ignition systems work, including the pros and cons of them?

Hey, it would be great if you could eighter move your whiteboard a little to the left or the EE-logo in the upper corner of the screen because at the moment it covers the low right corner of the board ;)

Try and make one on the Sti! So much information in 11 min. D:

This is awesome! Thanks for doing the follow-up video!

This system makes the eclipse cross a great cuv

Great break-down! kicked myself for not having notifications for your channel turned on. I missed this by 2 weeks. Now would you be willing to do one on the WRX and STis awd system? Thats a system I know very little about . Even after spending a half an hour reading one of the Subbie forums. No pictures or diagrams so it wasnt as easy to picture. Thanks for digging up the info and getting this video out.

If I could give this video more thumbs up I would

You should make a video with s-awc compared to awc like Evo 9 and ralliart. Also when I bought my ralliart the dealership said that the ralliart has evo9 awc I don’t know if it’s true or a sales pitch

awesome explanation :D will you be doing one on Subarus soon?

really good video love the more technical topics and drawings

The system is still amazing by nowadays standards. However, as a real evo owner would complain in cold area where a lot of salt is used during winter. AYC/ACD hydraulic pump is a pain in the ass. Mitsubishi should have factory relocated it into somehwere that doesn't expose to the environment.

I am really glad I found this channel. Very informative thank you very much.

Talk about the WRX STi AWD system next and how it's different! What I've heard is that, post-2007 anyway, they have a similar center differential to the one you describe here but also have front and rear electronically-controlled LSDs, too. So, All-Wheel Torque Vectoring???

The saddest part of this (as an Evo X owner) is there is a huge problem with the pump that controls that centre diff is the most common problem on the car - it is 100% going to need to be replaced constantly. If you're outside of the US, this is an expensive ($3000 ish) service item every few years.

I wish you had moving things and animations because the internet has made my attention span almost... oooo a kitty.

Where is the Ford Focus RS AWD video?

I would really like a video on Nissan's ATTESA-ETS AWD system

How this Mitsubishi ACD compares with the new Toyota GR Four?

I've noticed that the driver control selection also changes the sensitivity of the traction control system. Meaning, if you leave it in Tarmac and drive in the snow the traction control system will go ape shit and you ayc breaking and traction control lights will flash constantly. If however, you put it in gravel and then snow the traction control will actually get less sensitived to slippery road conditions and not go into Oh shit mode all the time.

could you do a video on Acura's SH-AWD and explain the difference between it and the Sport Hybrid SH-AWD system like the one in the rlx possibly the NSX Thank you. love the videos keep up the good work.

Can you also suggest reference readings as well? Great video btw. very informative.

Pro tip: Evo X in Tarmac mode on snow feels like RWD. Turn traction control OFF (not OFF OFF) and you look like a really good driver doing second or third gear drifts while the car saves you LOL! Evo X needs 50% more hp at least so bolt-ons plus pro tune and it's alright.

The last example works best when you're stuck in a snow covered surface or a muddy offroad surface where you have 3 tyres spinning with no traction but only one tyre telling the system that there is grip available underneath it. The torque system isn't just sent between front and back but also works between individual wheels to get you out of the sticky situations. I'm surprised that a Subi owner finds it an "unrealistic scenario". Do you not take the Subaru out on a rally-esque offroad areas or put in them deep snow drifts during winter? Kinda makes me want to quote Tanner Foust from TG USA "For all you Subaru owners who think the Evo is just a pavement queen, think again."

Great video, great drivetrain!

Very good explanation, Thank You so much.

upvote for dropping the knowledge

always enjoy your informative videos. thank u

This video blew my mind. awesome

You probably didn't think of it cause its too obvious but in rally when jumping on take off and on landing at some point for a few milliseconds you are on one wheel, i've also seen a few rally cars go on two wheel in a tight curve

Superb! That is by far the best explanation of the EVO S-AWC system. Much better than Mitsu's own videos and literature I might add. Keep up the great work!

I'm sorry for not understand but simply put from all the torque the engine produces only 50% max goes to the rear wheels, otherwise it stays 100% fwd correct?

nicely explained how about the GTR?

I am curious of the difference between the different AYC systems (evo 5-6, 7-9 and 10). I know 5-6 were purely mechanical but that's about it

Really nice video, I now feel a bit smarter :)

I just bought Evo X 2014 Mr and I've noticed that the light of AWC blnk sometimes

Very informative video, thanks for the effort and explanation. Evo X's FTW! ;)

Is this why an evo 10 costs an arm and a leg cuz honestly on the outside you ask yourself why does it cost so much but on the inside and you explaining it makes sense why it's expensive

Excellent video

thank you for the video. i understand now

Great explanation. you have really done your research well (y) also very understandable and amusing (trying to save brian :D ) way of presenting the information

Thanks so much for making this! But I did have a question as to why during hard cornering, the AWC graphic on the dash lights up as (in the case of a left turn) front right tire, rear left tire. Why is it also sending torque to that rear left tire. My physics teacher said it just has something to do with the length of travel of each tire during the turn, but she said it was only a guess.

Toyota has the same one, but first goes front diff than goes transfer case also viscous

I’d like to know what steering angle the diff locks up and snow gravel tarmac, like what’s the real sic difference?

my evo thirst has been quenched, thank you