If it wasn't super obvious, I wanted this video to explain the logic behind rear-engine placement, rather than history, heritage and tradition of the 911 (I think I just yawned). And while I didn't mention this in the video, I did in the video description "Porsche decided to put the 911's engine in the back, behind the rear axle, way back in the day when the 911 was first designed. Since then, that engine has remained there, and while some might say it's out of stubbornness, there are legitimately wonderful reasons for having a rear-engine car." Again, the focus was to discuss from a performance standpoint why rear-engine sports cars make sense. There are other reasons for rear engine designs, like improving passenger space vs a mid-engine layout. But you don't want a history (nor English) lesson from me, because it would probably be terrible. Hope everyone's having a wonderful day! If you think the shirts I'm wearing would increase your chances of driving a Porsche (who knows, stranger things have happened), I wish you the best of luck wearing it: bit.ly/2BHsiuo.

"hello everyone and welcome! in this video we're gonna be moving my honda S2000 engine to the back..." nice job as always!

your dry erase board has taught me more than 4 years in auto tech, and i visually can remember almost every "lesson". text books just cant visually teach the way that your methods do. sincerely, thank you.

Flawless drawing logic

I once asked you yearsssss ago if you were working at Ferrari yet, but honestly you've become so good at what you do, and have become the best at it to where even large companies reach out to you. Teaching is truly where you shine and more people can benefit from that than if you were to do something else... Keep up the great work! you inspiring figure you...

Your passion to explain and teach is notable, thanks Jason and wish your the best with your channel!

Also in regards to weight transfer during stopping, most cars even rear engine vehicles have larger equipment up front to carry more of the work . Also modern Porsches benefit greatly with modern stability controls, when I was young a 911 was known to chase it's tail while going off the road

Another great video! Seems like you had a blast drifting through those corners ☺

This was a very very nice and detailed video on a topic that most of us take for granted. It was quite a pleasure to discover the ACTUAL benefits of a rear engined vehicle. Great job.

Yes yes, that is of course a sports car because it's red.

The engine is in the rear because Porsche makes them thicc

I'd love to see the advantages and disadvantages of rear engine compared to mid engine cars.

That all makes sense if you're going in a straight line, but seems to conspicuously neglect what happens if you want to turn. To get balance with a rear engine, you're going to need fatter rear tires and skinnier front tires, which, as you say, gives more traction for accelerating / decelerating in a straight line. But less traction for the tires doing the turning. (Where a front engine car can have a 50/50 balance and the same tires at all corners, and turn well.)

Modern 911's have done away with a lot of the design quirks that's inherent to the rear engine design. The short wheelbase ones had high oversteer, which they ironed out by widening the rear tires, then eventually lengthening the wheelbase.

The left most Red sports car is an ultra rare Red Monte Carlo SS. the right most is some sort of pickup truck. :)

I've been a faithful subscriber for years. I think it's time you invite me along on one of these trips.

I'm interested in the analysis of the rear engine layout which in the case of the 911 is typically 38/62 weight distribution and compare this to mid engine layout like the Lotus Exige (and other mid engine sports cars) which also have a 38/62 weight distribution. It seems weight distribution is the important factor, not hanging the engine out back to get it. You put a lot of emphasis on the positives the 911 of having the engine in back of the rear axle. The lotus has the benefit of a much lower polar moment of inertia while having the same weight distribution which seems in theory to give it all the same advantages you attribute to the 911 without the high polar moment of inertia. This would then avoid the 911's propensity to be difficult to stop the rear end from continuing to spin around due to the engine hanging out the back with that high polar moment of inertia. The lotus on the other hand would be much easier to control and have all the same weight transfer benefit characteristics derived from the 38/62 weight distribution purposefully designed into the car with a much lower polar moment of inertia. It seems to me that since: * Neither Porsche nor anyone else has a patent on hanging the engine out the back behind the rear axle and everyone in racing and high performance sports cars wants every advantage they can get to win and sell more cars. If the 911 layout was truly the best option then they would not be the only ones with that layout. * Why are all the purpose built race cars from Porsche and everyone else largely mid engine (mid rear or mid front) if the 911 layout superior. Don't get me wrong, I have been a Porsche fan for decades I love the 911 and the many of their other products throughout the years. The 550 is one of my favorites. So the question for a Engineering Explained video is: If you compare a rear engine sports car and and a mid engine sports car which are both exceptionally well designed and proven. Both built by top level engineering like Porsche and Lotus, each having the same optimized weight distribution for instance 38/68. Which is better and why. Thanks

911 is just my golf in reverse

One thing you missed: while a rear engine layout improves on the possible braking distance, it is also much more unstable under braking - one of the reasons trail-braking was such a no-no in older 911s and 930s (before electronic brake systems compensated for the lack of stability.) Try balancing a pole on your finger. Not too hard, right? Now, add a heavy weight to the top and see the difference.

Nice explanation of the advantages a rear-engine car holds when accelerating or decelerating in a straight line. However, "less eager to turn" and "higher tendency to oversteer" are definitely not advantages. Those two traits of a rear-engined vehicle were glossed over in this discussion.

At this point, tradition. There's better places to put the engine, like in the middle. Strange how that wasn't mentioned as one of the options.

Yey, you finally drove the 911!

Nice to see the ice track. I still remember how much fun I had racing my beetle on the ice in Finland in the 70ies.

Great video! Although 911s are amazing sports cars there are two "flaws" with a rear engine: 1) turn-in understeer and 2) if the back end comes around it'll be difficult to save (pendulum effect) vs a front engine RWD

I hoped this would explain why the Porsche 911 uses Rear-Engine instead of Mid-Engine. I still think Porsche is purposely holding back the Cayman.

Looks like you had a lot of fun at the Porsche Camp! 😂

I'm not 100% sure about this, but its my understanding that 911s were originally conceived to be the sport version if a VW Beetle. Hence the rear engine, etc. I need to look into that more but I could swear I've seen that on the Velocity channel somewhere. Great episode btw, I need to watch the rest of it later. Been an embedded software engineer 37 years but your explanations are clear, concise, and great to watch. Thanks for what you do.

Everything you said correct and if sportscars just went in straight lines, accelerating and braking, RR's would be king of the world. But sportscars need good handling and it's obvious that MR > RR in that respect. The only reason the best Porsches are 911s and not Caymans are because Porsche markets them that way trading on its heritage. RRs worked in the 60s when air-cooling made sense but now the only vehicles that use it are buses/coaches to maximise the low floor space. The Cayman MR platform has more potential. If Porsche poured the same amount of time and money in MR platform, it would far exceed the RR platform.

So you are trading handling for better straight line acc. and braking?

You should be my teacher.... wait ... you are ! :D

In theory rear engine Porsches are prone to oversteer but in reality they are difficult to break lose ( this is from experience) unless you lift off in the middle of a g-force corner. Then the rear end will come around which can also be a benefit depending.

Very good explanation, thank you. I like my 911, when it comes to turns, it has so much fun.

Hi, i gota a topic in which you could maybe enlighten me or make a video about :) considering fuel efficency: 1. is it always best to drive in the highest gear possible (in a manual car) for example my car can drive 50 kph in 6th gear but gets kinda rumbly because its only at 1400rpm (gasoline) and wether this would apply to N/A cars and turbocharged cars alike. 2. Which way to accelerate is more fuel efficent? Full throttle and fast to be in a higher gear sooner because the accelaration phase is shorter, or a long accelartion phase in which you dont accalerate at full throttle? Kind regards nelayo

I don't fully understand what you mean when you say that to get rear bias in a front engine AWD car you need to send a shaft to the rear and another to the front. The Subaru WRX STI for example has a rear bias of 66-33. It accomplishes that with the center differential(s). What am I missing?

I remember long ago reading about the 911's inherent design flaws both of which you covered well. That being: Rear weight bias and Over steer. I still don't know whether the one I drove was AWD or not( it was a 911 2.7 S. I'm guessing that is was Rear Wheel drive because of the tremendous torque. Throwing it into 2nd gear. was so much fun but watch out for fish tailing and over steer.

Based on many years of winter driving when I lived in the snow belt, the coefficient of friction on ice is more likely to be 0.02, NOT 0.2! My first new car was a 1964 Volkswagen. The oversteer made it impossible to corner smoothly at highway speeds; it required constant sawing on the steering wheel. Also, driving when the wind was gusty was very tiring because it required constant quick and large steering movements just to stay in the lane.

Good stuff. To my knowledge, the only 911’s that are not rear engined are the GT1 and current RSR, both race versions of the road car. I was in Daytona for the Rolex 24 and the RSR absolutely screams. 👍

4:45 my God! Look at all of those 911's!!!

This is exactly why I don't understand the fascination with 50/50 weight distribution. When you have that, in braking the front wheels get overloaded. And then in acceleration the rear wheels don't get as much load as they could. I am pretty sure there are FR cars now with more weight out back than front like Ferraris and the like.

Also, with electric cars like Tesla, specifically Model 3, handling is so good. Design wise you just can’t beat it. You have the weight so low, all between the axles, electronic-instant torque response/traction control (seamless), and then add front motor, you have no drive shaft, no slow mechanical linkages, no shifting or drops in power/traction, and literally perfect transfer of power depending on front/rear drive units’ traction.

The real reason the Porsche 911 is rear engined is because its predecessor, the 356 was rear engined. And the 356 was rear engined because it had a lot more "Volkswagen" in it than Porsche fans will admit. The original Volkswagen, which we now know as the "Beetle," had a rear engine because that was Porsche's way of getting it out of the way for interior space. Mind you, there wasn't much luggage space in the nose because the car was "aerodynamic," in the Chrysler Airflow idiom. Porsche could easily have made the 911 a mid-engined car -- which would be much better for low polar moment of inertia, and thus better handling -- but Porsche fans wouldn't have it. Instead, the company has spent 50 years and countless millions of dollars trying to reduce the extreme rear-weight-bias and pendulum effect. Once all that mass out behind the rear axle starts moving, it's difficult to stop. Today's 911s are decent handling cars, but the early ones could be a terror. Turbocharging, with the attendant turbo lag, only made them worse. To make things even worse, the extreme rear weight bias means there isn't much weight on the front wheels, and thus not much "mechanical" grip. The early 911s in particular had floaty front ends, a tendency to spin and were all but impossible for most people to catch when they did. Worse still, that lightly loaded front end meant the car could also understeer if pushed too hard. Think on it -- a car that can understeer and oversteer at the same time.

I really feel that all of this could be achieved with a mid engine, just much more rounded and a lot less oversteer

Another thing, the 911 never went mid-engine for weight distribution, they did it for the aero. The 911 GT1 (one of my favourite racing cars ever), was mid engine because it was basically a 962 with some 911 faring. The 911 used in GTE nowadays went "mid rear" in order to use a taller diffuser. It's not what I would call as mid-engine, since they literally just turned the engine and the gearbox around.

I thoroughly enjoy driving rear engined cars. It's vastly different from any other engine configuration, to include the traditional mid engine. Huge advantage of a 911 is that under braking, all 4 tires get more or less equal load, which maximizes braking force, allowing later braking and it makes trail braking easier without feeling sketchy. Disadvantage is that it understeers with throttle application, so one must wait a little longer to get on the gas at corner exit unless they want to end up off road. However, the rearward load transfer ensures that every single one of those ponies make it to the tarmac, and it accelerates like a bat out of hell. From a drag racing perspective, there's a reason why a base 992.1 Carrera 2 can run high 11s, and a lot of it has to do with the 40/60 weight distribution. I would argue that a RWD 911 launches just as hard, if not harder than an AWD car, but without the need to launch it at high revs and feathering the clutch.

Would you then say that I should put wider front tires in my f80 M3? People say that it can put more strain on other suspension components. Any thought about that? Great episode as always!

So we have to divide the two questions: Why does it make sense to put the engine at the rear? and: Why does the 911 has the engine at the rear? So for the past 911 you are absolutely right. But in the present there is only one reason, why the 911 has a rear engine: tradtition and marketing. It´s not allowed to have a mid engine. In the 911RSR Race car e.g. - racing at Le Mans - porsche has turned engine and gearbox, so it now has a mid engine which is much more usefull on a racetrack or on curvy roads. Front-mid-engined cars have other advantages: you can get a weight distribution of 50/50 which is good for cornering and you can put the driver´s seat a lot far in the back wich gives you a better feeling for what´s your rear end doing but not losing the feeling for your frontend. When I drove a 911, I found it would be very light and insensible at the front compared to my TVR or Caterham. Due to the rear engine the 911 also has the fuel tank at the front which makes the steering and the grip at the front very sensitive for the load of the tank (empty-full). Even the Porsche Race drivers are confirming this and complaining about. Regards

This is legitimately one of the best channels on KZfaq. Well done, Jason.

The modern RWD 911 and the Lotus Elise both have 40/60 F/R weight distribution providing similar acceleration and braking benefits, but the mid engine placement of the Lotus also has a lower polar moment of inertia. Theoretically, that allows the Lotus to make changes in direction more quickly. This is something you can feel when driving the two cars back to back. The presence of the weight behind the axle of the 911 can be felt as a half step between the input of the steering and the cars reaction that isn't present in the Lotus

*DO REAR VS REAR-MID ENGINE*

Allow me to simplify that answer: The 911 is rear-engined because the VW Beetle was rear-engined. :P

Porsche has shown that working with constraints and inherent disadvantages can result in greater creativity and innovation. And that 911 shape is so iconic and charismatic. You love it or hate it and that's what makes it great.

That makes sense why most front engine awd cars bias power to the front wheels. Great video as always.

Your video talks about the pro's and con's of front engine vs rear engine not the reason the 911 has the engine in the rear. The original 356 was derived largely from the VW - it used the VW engine. It fundamentally had to be a rear engined car. The 911 was a continuation of the 356 tradition. Even when Porsche went water cooled with the 911 it remained a rear engined car. Porsche tried to go to front engine cars (the 924/928/944's) but they did not sell they were just not popular with Porsche's customer base. The real reason that a Porsche is rear engined is tradition! The real question is: Why was the VW a rear engined car? After all Dr. Porsche was largely responsible for its design.

The Cayman could so be more superior to the 911 because of that mid engine layout but Porsche holds it back so it doesn't eat into 911 sales. The GT4 was a good car but they detuned the engine in it.

I found this interesting, as always, but what I also found interesting is something you briefly spoke on. About two shafts, for RW biased AWD cars. I have a car which is AWD, with a 40% front and 60% rear (under standard conditions) drive bias, yet it only has one shafter going to a rear differential. It can also split as much as 80/20 front and rear and I believe another 80/20 left and right per axle.

Having the engine in the rear is also great for a cheap and simple car that does well in the snow. Just like the VW Bug. It was my first car, and there were a lot of them still running around in the 70s and 80s. And they never got stuck in the snow like most other cars. They were able to drive in conditions that would strand almost every other car.

Will you ever review a minivan again?

And this is what front engine cars are better for drifting stock

One of the best videos ever explaining the secret behind Porsche's favorite engine layout. Thank you for that amazing explanation

Hey, a video about efficiently operating a standard transmission would be cool. meaning, going over proper times to use high gear in low speed situations such as turning at green lights or something. stuff like that. cheers!

Because it’s a glorified beetle. Just kidding lol, I love Porsches. Great vid!

Since every other car “push” it’s engine, 911 Pulls.

There's one thing that always interested me. I've met my share of drivers who claim that "jerking the steering wheel a few degrees" in corners makes the car handle better or should I say - grip better. I don't really see the logic behind this. Is there any?

Great! Now I understand why a VW beetle has the engine in the rear. Thanks for the explanation.

how about mid mounted engine cars? is it just compromise or better?

Why are they rear engined? Because 911, and that's all that needs to be said. 911 master race

Your drive event looks like it was super fun! Our local P-car club hosts a yearly drive on a frozen lake and it is a hoot! We have taken the 3.2 Carrera and the 996TT and that four wheel dive system is great! I think the weight placement traction as you mentioned can be augmented even better with the traction control. But that car drifts so well with it off - so controllable. Lucky duck for hanging out with Porsche! Great video and explanation!

This just made me realize how hard it is to come up with new car design If you are an engineer or anything that can do this stuff, be proud of yourself!

Porsche puts the engine in the trunk because.... It is a Volkswagen on steroids!

Why? Because men are stubborn. As (i think James may said) if women had run the company they would have put the engine in the front or the middle. But the stubborn men said “no, we WILL make this work”

Great explanations on the advantages of the rear mounted engine.On the other side, it took Porsche some decades to tame the oversteer behavior

Rwd can be very fun in snow. My 320hp silverado does some great snow drifts, but I can put it into 4wd auto or 4wd and safely get home when roads are bad.

because beetle... duh

i want to get into mechanical engineering how hard is it?

Very good video and well explained too. Today there is an awful lot of uneducated bias towards FWD cars (i.e. FWD is great, everything else is 2nd best, old fashioned, or even unsafe!). People do not stop to think about the dynamics that take place when a car is under power, breaking, or cornering hard. So far as FWD goes, it is possible the worst place to put the engine regarding tractive effort, sharp steering and predictable breaking goes. The mid-engine layouts may give excellent handling, but the engine takes up potential cabin space and makes maintenance much, much more difficult. Front-engine-RWD gives a combination of good balance when cornering, and better stability than FWD when breaking, but lacks decent initial traction. Rear-engine-RWD gives THE MOST traction of any layout, precise and light steering, and good stability during breaking. The cars are, however, more affected by cross-winds, will ultimately oversteer when cornering too quickly, and the boot space is less practical than a FWD hatch. At the end of the day whatever the engine/transmission layout - it is always a compromise. PS - I've spent 20-years enjoying Rear Engine Skodas, and detest every minute I have to spend behind the wheel of a FWD car.

You missed comparing to the Cayman. I did the Porsche winter exp a few years ago. The Cayman rotates more easy as it is midmounted. However that made it harder to keep it drifting as smaller adjustments made it react faster and you flipped drifting direction to easily. Pendulum 911 or seesaw Cayman.

mid engine!

10 view and 3rd like

As a German, i *VERY* much appreciate that you are able to get the name of the brand Porsche out without completely butchering it, as many or most americans sadly are prone to doing. When there is the letter "e" in a German word, we fully expect you to SAY the letter "e". Otherwise we woulda dropped it for efficiency´s sake. (If you are also able to correctly say "folksvahgen", instead of that abomination most other americans somehow manage to craft, i will name you a honorary scholar of the German language.)

​@Engineering Explained 2:45 you said under braking mass moves forward. If the center of gravity is 'below' the turning point which is the wheel hub in the back tyres, I think this will change the torque angle and will force the rear wheels to gain traction instead of the front wheels. What I'm using to rank this is this image placed here. What I've heard is that center of gravity can be found on the line where center of mass crossects the rear tyre connects with the road and the top of the front tyres. If its height is lower than the wheel radius, its inertia gain should be inverse to the the mass inertia of the car. I fancy low center of gravity cars. Please, could you look into that - for research purposes, of course!

I wish you talked more about turning and changing direction and how it’s affected by a rear engine vehicle

Marketing is the answer. With the 911, simulations in corners (braking, acceleration, neutral, left/right transitions) would be interesting, not forgetting to mention mid-engine cars.

AWD does not need to have a shaft going all the way to the rear and another shaft going from the rear forward. Please see Audi's Quattro layout, it works beautifully especially with the sport rear differential. My S6 transfers torque front to rear and side to side very well. It is like driving on rails.

Straight line acceleration :D Getting the front wheels to turn when 75% of the weight is on the rear axle can be a challenge

I've never had an engineering mind. The math alone would cause me to have an aneurism. That said, you make things simple to understand. Good on you. Great work!

I think we all would like the engineering explained behind the addition of neon and/or LED to the many places possible in your car and how much HP and torque that gives you, besides fame and popularity of course. But in all seriousness, we need one of these fun episodes from you. Thanks!

I'd love it if you could actually explore the rotational inertia problem of an RR car. I have my doubts that it is truly worse than MR (front-engine) or MR (truly mid-engine), because the rotation isn't actually about the middle of the car in slower speeds/low-radius turns - the higher the steering angle, the closer to the rear axle that effective pivot point will be.

I think that, for Porsche, the reason is historical beacuse it was easy to do (like WV Cox) and it became a legend. Now, you can't change ...

Interesting video, well done! I have a question for you that I hope you can answer. Would a rear wheel biased AWD sports car be more effective with rear wheel steering? Like the older RX7 or even the older Porsche 928.

Nissan's Attessa system is rear wheel drive 'first' as i call it. but the transfer case is on the back of the gearbox. More like a normal 4x4 system. But it's electronically/hydraulically controlled. I am a bit 'bias' pun intended.. But i love the way the system works.. I haven't found a situation it doesn't work in.

I think you will find that Subaru gave some of its cars (some flat 6 engined Legacy models) a 45 to 55 rear torque bias - the torque bias can be engineered to be anything you like regardless of the location of the engine - it's a function of the centre differential to determine this.

You gave a good explanation of the benefits of a slight rear weight bias and the packaging benefits. I think the common comparison for the 911's rear engine design being "wrong" is against the mid-engine layout. The issue with the rear-engine design is the yaw moment of inertia not the pitch. When compared to the rear-engine, the mid-engine layout loses a little benefit in the pitch moment of inertia for a big gain in yaw performance. Porsche have done an amazing job over the years evolving the chassis and suspension to keep the 911 a relevant sports car but their high-end super cars (except the 959) are mostly mid-engine for a reason.

Also, with most of the weight/grip available at the rear, your already good turn-in is further exaggerated by the centrifugal force acting on the heavy engine. Since the engine is behind the rear axle and the rear axle acts as a pivot point, in a hard corner, the balance of the car actually helps the front follow the corner and the 911 will not push. Of course this is the theory, but I felt a sensation of this happening when I drove a 964 once. There was no mid-corner push at the front axle.

I have a Bmw e30, based on the advantages of rwd rear engine I brought a sw20 mr2 with an lsd. On paper it should have been better but the e30 feels more stable and predictable, the mr2 always felt a little nervous and if you lost the back end I doubt you would be able to catch it. But you can't argue with the rallying success lancia 037, stratos and the rear engined peugeot and renaults. But the "Bastos" e30 m3 is up there too.

Without watching the video with a rear mounted engine you can drive the rear wheels without it being lost/ diminished by the drivetrain and adds more weight/ downforce to rear wheels for better off the line acceleration

Would love to see a video on the downsides when turning and how Porsche deals with that

Let me make an historical spot: the will of F.Porsche was a mid-engined 356, and a prototype was built, then his dependents convinced him to preserve the Kafër layout. Also, at that age, the midship engine was already used in few racecars, maybe because the engine was a v16, and however we can't forget a famous example of frontship engined v16 open-wheeler

This is a very trivial question: a rear engine can help reduce the chance of getting an engine fire when you poke and the enemy shoots at you frontally. Especially for 911 since its armour is relatively weak, although very well angled. (But still lower plate is pretty flat and easily pennable) which means every tier 8 can go through its front.

Looks like a damn fun time in the snow

The reason it was originally at the back is because you can trace its ancestry back to the VW Beetle. Porsche then spent the next 50 years coming up with technical solutions to overcome the obvious problems that having an engine slung out over the rear axle causes. That they've done it so successfully is testament to their engineering capability.