The Engineering Behind the BEST car America Will EVER MAKE - Dodge Viper ACR

(car engine roar) - The Dodge Viper is like baseball or driving on the right side of the road, it's the most American thing there is. So when Dodge shut down production of the Viper in 2017, it hurt the man. And I hope I'm wrong when I say this, but it

will

be the last American-made supercar with something banged up under the hood, and that hurts even more. But instead of dwelling on the past, today I'm going to pay homage, we'll look at the most track-capable production car

ever

built in America, the Dodge Viper ACR. First, let's talk about that acclaimed pushrod V10 engine.

And then we'll dive into some of the incredible

engineering

that went into the Snake's aerodynamics, (mumbles) helping it set 13 records around the world, all at a quarter of the cost of a European supercar. , let's go to America. (upbeat music) The Viper has always had the reputation of being a car that tries to kill you. The first one in 1992 had an eight liter V10, no automatic transmission, no air conditioning, no exterior door handles, no windows, no airbags, no analyzed brakes. That gives you an idea of ​​what Dodge was going for with the Viper. They built a wild horse that was muscular and mean.

And if you could just go ahead and stay, you could have the time of your life. But be careful because this

will

cheer you up and it's not a matter of if, it's a matter of when, clip of a guy driving one of these things off a cliff. (car engine roaring) (woman screaming) Now, the fifth-generation Viper ACR is definitely trying to kill you, too. It's still the same wild horse (beep--), but now it's even tougher and even meaner with that new v10 under the hood. But, this time, Dodge has also kindly provided you with a cute little saddle, so you can ride a new little pony, and that saddle is streamlined and with their combined powers, it's one crazy beast that you can gallop around, your little one and happy.

Hit the slopes around the world. So let's talk about the horse. Why and how is this so crazy? This is the fifth-generation Viper and it has things like ABS, electronic stability control because it's federally mandated, but you can turn off those devices and experience what it's like to control 645 horsepower from a naturally aspirated aluminum V10. So what

make

s this engine so special? Well, first, it's what's called a pushrod motor. And today there are two main types of engines in mass-produced vehicles: overhead cam engines and pushrod engines, also called overhead valve engines. Now the Viper uses the more simplistic of the two and that is the pushrod.

And I say it's simplistic because overhead cam engines are typically more mechanically complex and more complicated to operate, and from a production standpoint, they came on the scene much later in the history of American-made automobiles. So, let's explain the difference between the two engines starting with the overhead camshaft design. Now, we've talked about this a lot, but in an internal combustion engine, you need a way to get air in and a way to get exhaust gases out. And a few weeks ago, we talked about the four cycles in a four-stroke engine using the sweet acronym SS BB, suck, squeeze, hit, hit.

Now the piston draws air and fuel into the cylinder through the intake valves, squeezes it, a spark plug ignites the air-fuel mixture and there is an explosion, bang, boom, and the piston expels the exhaust gases through the valves. escape, the process begins again. again. Now, the timing of the window intake and exhaust valves opening and closing to let air in and exhaust gases out may seem like magic, but in reality, it's just very cl

ever

ly designed mechanical components at work. and that magical piece of metal whose job it is to control everything that is timing, the camshaft.

Now, in overhead cam engines, you have a camshaft that sits above the combustion chamber in the cylinder head, with the valves below it, and the camshaft is shaped like an avocado, people compare say Pear shaped, but I'm going to say avocado shaped. because I'm great. Now the camshaft has these avocado shaped lobes called cams, and the camshaft is driven by the crankshaft by a belt or chain and that's called the timing belt or timing chain. So, when the camshaft rotates, those avocado-shaped lobes push down on the valve stems, causing them to open and allowing fresh air to flow in and out.

So what about pushrod motors? ♪ What! ♪ (upbeat music) Well, the difference between a pushrod and an overhead cam engine is in the location of the camshaft. A pushrod engine has the camshaft located inside the block instead of in the cylinder head. And in a V-shaped engine like the Viper, it's right between the V, right between the two rows of cylinders. Now it is still connected to the crankshaft by a chain or by gears, but it operates the valves in a very different way. So, as the camshaft rotates, the lobes push the rods, the rods push the rocker arms, and the rocker arms push the valves.

So if both engines do the same thing, they

make

the valves open and they just do it differently, while overhead camshaft engines are considered technologically better. Well, the first thing is the placement of the valves. Now, in an overhead cam engine, because you have individual camshafts that operate the intake and exhaust valves, you can place those valves at their optimal angle, which in turn helps the engine breathe better and, therefore, it can generate more power. And with a pushrod engine, the intake and exhaust valves have to be in-line simply due to the nature of a pushrod engine's design.

Now, because it only has one camshaft, you can't get complicated with intake and exhaust valve placement. Second, overhead camshaft engines can rev faster. Because the motion transferred from the cams to the valves is more direct with fewer moving parts, there is less reciprocating mass to deal with. Remember, with a pushrod engine, that movement from the cam has to travel along the rod to reach the valves. So those extra pieces, that extra mass, are harder to move and it's harder to move them faster. I mean, look at this, when I'm next to this light switch, I can turn it on and off very quickly.

My finger is in direct contact with the switch. Now, if I step back and try to turn that switch on and off with a broom handle, it's much harder to do the same task quickly, even if I'm really good at it, like I'm the

best

. Damn broomstick light switch flickers all over the free world, I'll never be able to match the speed if my finger was directly on the switch. To be clear, the broomstick is like a push rod and the camshaft motor is my finger. I don't know if I was clear enough, I hope so, I don't want to leave anyone out.

So the last advantage I want to talk about is that with overhead cam motors, you can alter the timing and lift through clever ways like VTech or NVTC. Now, we talked about variable valve timing and our 300ZX episode you should go back and watch it. But VVT is a way to advance or retard valve timing using a specially designed camshaft. And that's a great feature, because it allows the car to be more fuel efficient, it can produce more power, and it can have better throttle response. There are many good reasons why you would want to have that.

And then with a pushrod engine, you don't have the luxury of using multiple cams to alter your engine's performance on the fly—well, unless you have a Dodge Viper, since it turns out that Dodge engineers are They became jealous of the VVT, and they came up with their own clever way to use variable valve timing in a pushrod engine. And I'll get to that in a second, but first I want to talk about the advantages of pushrod engines in general. I mean there has to be a reason Dodge still uses them and not just Dodge, what about Chevy with their LS engines, one of the

best

engines ever made? (car engine roar) First and foremost is the size of a pushrod engine, they are smaller than overhead cam engines.

A single camshaft placed in the center of your V means you have smaller cylinder heads, and smaller cylinder heads mean a smaller overall engine package and that's great on two fronts. For one thing, when you don't have a large chamber above the engine, you have more room to work with when designing the location of the engine. Take the 300ZX for example, that car is (bleep--) for work and that's because it has four (mumbles) and it's a big engine packed into a very, very small space, people hate working on that car, you can place the engine lower in the chassis, which then lowers the center of gravity.

Having a lower center of gravity is obviously great when it comes to stability and handling. There's a reason F1 cars are low to the ground and you want as much mass to be as low on the car as possible. Not only that, but the engine itself has a lower center of gravity, with the camshaft being in the block rather than on top of the cylinder heads. Secondly, pushrod engines have tons of torque at low rpm and the reason they have that torque in the low rpm range is because they use two valves per cylinder and more valves may seem like a better option, but let me explain to you At low RPM, the air entering the cylinder is more restricted and then that air is accelerated because of that, that accelerated air is more turbulent and causes better air-fuel mixing.

Higher air speed plus a better air/fuel mixture creates a better boom and that means more torque. And the ACR has the most torque of any naturally aspirated gasoline engine, in any production car ever built. It has 600 foot-pounds of torque. Think about that for a second. Think about all the cars that have been manufactured throughout automotive history. The fifth-generation Viper ACR sits at the top of the podium in that category, that's crazy. So while the Viper has plenty of torque, what about horsepower? How does that archaic naturally aspirated pushrod v10 manage to make 645 horsepower in the ACR?

Well we have to throw our favorite donut equation into the mix, we have more air, plus more fuel equals more power, and we can usually address the more air part of the equation by adding turbos or adding a supercharger, but for Dodge and Al Purest Viper style, they did it the old way. They made it bigger, kept it naturally aspirated, and used displacement as an ally. No turbos, no superchargers and when you're not using power induction, you need the largest displacement possible. And the Viper does it using 8.4 liters of displacement on 10 cylinders. So I'm a visual person.

So to help explain how much that is, I have a bottle here that is exactly 840 milliliters. That's 0.84 liters. The contents of this bottle will fill only one cylinder of the Viper. So imagine this multiplied by 10 (murmurs) 10 of those, meaning a lot of air is introduced into the combustion chamber. You might be wondering, hey, how is this, buddy, you have a fucking graduated bottle because that was the last place I worked in a lab, I stole it. (laughs) Don't say don't put that. (upbeat music) I previously said that the Viper has its own version of variable valve timing.

But how can a pushrod engine vary its valve timing, when it only has one camshaft, and what performance benefit does that give you? Well, like all good

engineering

devices, the Vipers camshaft is pretty ingenious. Have you ever seen one of these types of drawings? (upbeat music) Well that's kind of what Dodge did with their camshaft, it's crazy, they use what's called DuoCam, now this Duo single cam system consists of a solid intake camshaft, inside of a hollow exhaust camshaft and the solid shaft has holes for cylindrical pins, five of them to be exact, and when activated, they line up with the slots in the hollow outer shaft.

The two camshafts become one and the exhaust timing is changed. So why would you want this? Well, the Viper camshaft is considered a high performance camshaft; Normally this type of camshaft would be illegal on a production car. Now the performance camshaft is there for one purpose only: to increase performance. (mumbles) But it also increases emissions because you're basically sitting there, always churning at full speed. That's why when you listen to some powerful cars, they have that low sound (murmurs).That's a performance camera and it almost never meets emissions standards. So when you're trying to build a high-horsepower, high-torque engine that's also street legal, you have to strike a balance between performance and emissions regulations.

So to combat that problem, Dodge engineers use their new DuoCam camshaft to reduce the amount of exhaust dilution at lower RPMs, making the Viper a greener car, and the Viper was the first production pushrod engine with VVT on the exhaust valves. , quite ingenious. That was the first part of the equation. The wild horse (bleep--) hit that you bit your thighs, but how can a car with such a crazy engine stay on the road? Well, in the past with the Viper, you didn't, the car was in a constant state of trying to kill you. That's what made him so charming.

Ted Bundy was a charmer. And don't get me wrong, this ACR Viper still has the genetic makeup to put you six feet under. But at least Dodge engineers give you plenty of aerodynamics so that when you start going fast, the Viper is less angry at you. Now, the second half that makes the Viper ACR the best car to ever come out of the US is its ability to stick to the ground. We are talking about downforce. (car engine roar) Better understand downforce. I'll start by explaining lift. Now on an airplane you have a wing like this and as it moves forward you have air pushing it up and causing it to lift.

Now, if we flip the wings, the opposite happens and now, instead of the air pushing up, it pushes down, and that's called downforce or negative lift. And in the automotive world we use a spoiler or rear spoiler to do that, and in the case of the Viper ACR, they use a very large spoiler, a 1776 millimeter wide spoiler. Yes, you heard right, 1776the same year the USA was founded because of course this is the greatest automobile ever built in America. I'm trying to tell you this, I'm preaching it. I am preaching the gospel, you will be my flock of sheep.

I'm Dodge Jesus (laughs). And that is the standard ACR wing size. If you get the extreme aero package, it widens it by another 100 millimeters to 1886 millimeters. That's six feet two inches. I'm six foot four inches, that's only two inches shorter than me, just lying on the wings, the air throws you down, wild man, even the material the wing uses is special. And while most wings have some kind of central structure to support them, the ACS wing is hollow and uses only four layers of carbon fiber, but it's still surprisingly strong. And there's even structural support built into the trunk to help support all of the downforce created by this sail.

A grown man (beep--) could stand on the end of this wing and it wouldn't break. That's a pretty big spoiler and trust me, that's the kind of school you want when you do really dumb things like this. (Car engine roaring) That guy must have lost his teeth, like he doesn't have teeth right now, like his friend had COVID and had no teeth, just gum and food. Homeboy, what are you doing? Never do that (bleep--) it's so stupid (laughs). That spoiler creates a ton of downforce and I actually read a funny story about this. A guy towing his Viper behind his truck on an open trailer was getting two miles per gallon fuel savings due to the force the Viper spoiler was pushing down on the back of the trailer, slowing his truck. as it progressed. towed down the road.

That's cool, I mean, it sucks for him, but pretty interesting. So if you have all that extra force pushing down on the rear of the car, why doesn't the Viper just pop a wheelie? (mumbles) Well, there's a lot of good stuff up front that helped create downforce on the front of the Viper. First, there's a front splitter that sticks out about five inches beyond the bumper at the front of the car, and it also juts out a couple of feet toward the center of the car. And just like the rear diffuser, there are these vertical bumps and those vertical bumps that keep the air confined to that area, trap it, so you don't lose downforce when you turn.

It is the same reason why the wing has vertical ends on both sides. It's like a bookend that keeps the air in place. Adding even more downforce are these little fins on the front bumper, and they serve dual purposes as the rear spoiler, they help produce downforce and in fact if you look closely they also have vertical edges on the side to keep the air in. its place. And the second function they have is to provide fine air to help cool the brakes. Moving on to the fenders, the ACR has grilles. And the purpose of the vents is to vent the high pressure that builds up under the car.

So what do all these aerodynamic parts amount to? Well, it amounts to the largest downforce ever built on a production car: 800 kilograms and 1,700 pounds when it reaches a top speed of 177 miles per hour. And the more downforce you apply, the better your car will grip the track. And the better your car grips the track, the faster you can take corners, and the faster you take them, the more records you will set. (car engine roar) Now all that downforce comes with a compensation and that compensation is drag, and now drag is just air resistance. It is the force that acts opposite to the relative motion of any object moving above you.

So with the aero package, it takes the low Viper with a drag coefficient of 0.37 and increases it to 0.54. That increase in drag also effectively decreases your top speed, so you lose 29 miles per hour on the top end. And what the ACR lost in top speed it more than made up for in cornering. And when it was released, it began a record-breaking streak around the world. Dodge took the old school beast with a little engineering and turned it into an incredible machine. He sucks that he doesn't exist anymore, man. It breaks my fucking heart. It's one of my favorite cars of all time and for its price there isn't a more capable car.

I hope one day they make another one and try to kill you with the same force. Thank you all so much for watching this episode of Bumper 2 Bumper. If you haven't already, hit the subscribe button. Also, we're doing something new, all of us here at Donut will be in the comments of all of our videos for the first hour, so make sure to hit that bell, you'll get a notification when we post a new video. . We will be there responding to your comments. So come hang out with us, tell us what's going on and we'll notify you when we post new shows and we post new shows every day of the week, Donut every day.

Follow us on Instagram @Donutmedia, follow @Jeremiahburton if you have a Viper ACR, you have any Viper, contact me and show me some pictures of a man. One of my favorite cars of all time. I had two posters in my room when I was a kid: I had a Viper, a second-generation blue Viper with white stripes, and a purple Lamborghini Diablo. Someday I'll have them both, just look. And by the way, we really need your help. If you would like his car to be featured on Bumper 2 Bumper, please follow us on all our social media platforms. We'll be posting some of the cars we need pictures of and future episodes, and his car might appear on the show.

So thank you very much for watching. Thank you very much for supporting us. Stay safe out there, bye for now. (car engine roaring)