(car engine roaring) - The Dodge Viper is like baseball or driving on the right side of the road, is the most American thing ever. So when Dodge shut down
production on the Viper back in 2017, it hurt man. And I hope I'm wrong when I say this, but it will be the last
American made supercar with a beaten under the hood,
and that hurts even more. But, instead of living in the past, today, I'm gonna pay homage, we're
gonna look at America's most track capable
production car ever built, the Dodge Viper ACR. So first, we're gonna
talk about that acclaimed pushrod v10 engine. And then we're gonna dive
into some of the incredible engineering that went into
the aerodynamics of the snake, (mumbles) which helped
it set 13 track records all over the world, all while
being a quarter of the cost of a European supercar
brethren, let's go America. (upbeat music) The Viper has always had
the reputation as a car that is trying to kill you. The first one in 1992
had an eight liter V10, with no automatic transmission, no AC, no exterior door handles, no windows, no airbags, no analyze brakes. So that gives you a sense
of what Dodge was going for with the Viper. They built a wild horse
that was buff, and mean. And if you could get on and stay on, you could have the time of your life. But watch out 'cause
this is gonna buck you up and it's not a matter of
if, it's a matter of when, cue clip of a dude driving one
of these things off a cliff. (car engine roaring) (woman screaming) Now the fifth gen Viper ACR is also definitely still
trying to kill you. It's still that same wild (beep--) horse, but now it's even tougher
and it's even meaner with that new v10 under the hood. But, this time, Dodge has
also kindly provided you with a nice little saddle, to
raj a new little buff pony, and that saddle is the aero
and with their powers combined, it is an insane beast that you can gallop, your happy little tush around
the tracks all over the world. So let's talk about the horse. Why, and how is this thing so crazy? Now this is the fifth gen Viper
and it has things like ABS, an electronic stability control because it's federally mandated, but you can turn those
gadgets off and experience what it's like to control 645 horsepower out of an aluminum
naturally aspirated V10. So what makes this engine so special? Well, first, it's what's
called a pushrod engine. And there are two main types of engines in mass produced vehicles today, you got your overhead cam motors, and you got your pushrod motors, also called overhead valve engines. Now the Viper uses the
more simplistic of the two and that's the pushrod. And I say it's simplistic
because overhead cam engines are typically more mechanically complex and are more complicated to operate, and from a production standpoint, they arrived on the scene much later on in the history of American made cars. So let's explain the difference
between the two engines starting with the overhead cam design. Now, we've talked about this a bunch, 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, bang blow. Now the piston draws air
and fuel into the cylinder through the intake valves, squeezes it, a spark plug lights that air fuel mixture and explosion happens bang, boom, and the piston blows the exhaust
gas out the exhaust valves, the process starts all over again. Now the timing of windows
intake and exhaust valves open and close to let air in, and
exhaust gas out might seem like it's magic, but in actuality, it's really
just very cleverly engineered, mechanical components at work, and that magical metal
piece whose job it is to control all that
timing is, the camshaft. Now in overhead cam
engines, you have a camshaft that sits over the combustion
chamber in the cylinder head, with the valves sitting below it, and the camshaft has these avocado shaped, people compared they say pear shaped but I'm gonna say avocado
shape because I'm cool. Now the camshaft have
these avocado shaped lobes on them called cams, and the camshaft is being
driven by the crank shaft by either a belt, or chain and that's called the timing
belt, or the timing chain. So when the camshaft rotates,
those avocado shaped lobes push down on the valve stems,
which caused them to open and that lets fresh
air in and exhaust out. So what about pushrods engines? ♪ Whuu! ♪ (upbeat music) well, the difference between a pushrod and a overhead cam motor, is in the location of the camshaft. A pushrod engine has the
camshaft located inside the block rather than in the head. And in a V engine like in the Viper, it's right between the V, right between the two rows of cylinders. Now it's still connected to the crankshaft either by a chain or by gears, but it operates the valves
in a much different way. So as the camshaft rotates,
the lobes push on rods, the rods push the rockers, and the rockers push on the valves. So if both engines do the same thing, they cause valves to open
and they just go about it in a different way, while a
overhead cam engines considered technologically better. Well first, is in the
placement of the valves. Now in an overhead cam engine, because you have individual camshafts, operating the intake and exhaust valves, you can position those valves
at their optimal angle, which in turn helps the
engine breathe better and therefore you can make more power. And with a pushrod engine,
your intake exhaust valves have to be inline simply due
to the nature of the layout of a pushrod engine. Now because you only
have a single camshaft, you can't get funky with
where you position your intake and exhaust valve. Secondly, overhead cam
engines can rev higher. Because the motion transferred
from the cams to the valves is more direct with fewer moving parts, there's less reciprocating
mass to deal with. Remember, with a pushrod engine,
that motion from the cam, has to travel all the way
up the length of the rod to get to the valves. So those extra parts, that
extra mass, is therefore harder to move and it's harder
to move them faster. I mean, watch this, when I
stand next to this light switch, I can flick it on and off really fast. My finger is in direct
contact with the switch. Now if I take a step back,
and I try to turn that switch on and off with a broom handle, it is 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 flicker in the entire free world,
I will still never be able to match the speed if my finger
was directly on the switch. So just so we're clear, the
broomstick is like a pushrod and overhead cam engine is my finger. I don't know if I was
clear enough, I hope I was, I don't want to leave anybody out. So the last advantage I
wanna talk about is that, with overhead cam engines, you
can alter the timing and lift through clever ways such as VTech or NVTC. Now, we talked about variable valve timing and our 300ZX episode
should go back and watch it. But VVT is a way in which you can advance, or retard the timing of the valves using a specially designed camshaft. And that is a great feature,
because it allows the car to be more fuel efficient,
you can produce more power, you can have better throttle response. There's a bunch of good
reasons why you would want to have that. And then 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, as it turns out the
engineers over at Dodge got all VVT jealous, and came
up with their own clever way of using variable valve
timing in a pushrod engine. And I'm gonna get to that in a second, but first I wanna talk
about the advantages of pushrod engines in general. I mean, there has to be a
reason Dodge still uses them and not only Dodge, what about
Chevy with their LS engines, one of the best engines ever made. (car engine roaring) So first and foremost is the
size of a pushrod engine, they are smaller than overhead cam engine. A single camshaft placed
in the center of your V, means you have smaller cylinder heads, and smaller heads, mean a
smaller overall engine package and that is great on two fronts. For one, when you don't
have big cam sitting on top of your engine, you have
more space to work with when designing your engine placement. Take the 300ZX for example, that car is (beep--) to work on and that's because it's got four (mumbles) and it's a big motor packed
in a tiny, tiny 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 in the car as you can. And 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 heads. Secondly pushrod engines
have tons of low end torque and the reason they have that
torque in the low rev range, is because they use
two valves per cylinder and more valves might
seem like a better option, but let me explain. At low RPM, the air entering
the cylinder is more restricted and then that air speeds
up because of that, that sped up air is more turbulent and causes better fuel air mixing. Higher air velocity plus
a better fuel air mixture creates a better boom and
that means more torque. And the ACR, it has a lot of torque the most in any naturally
aspirated gas engine, in any production car ever built. It's at 600 foot pounds of torque. Just think about that for a second. Think about all the cars
that have been manufactured in the history of cars. The fifth gen Viper ACR stands
at the top of that podium in that category, that is wild. So while the Viper has loads of torque, what about horsepower? How does that archaic
naturally aspirated pushrod v10 get you 645 horsepower in the ACR? Well, we gotta bring our
favorite donut equation into the mix, we got more air, plus more fuel equals more power, and we can usually tackle the
more air part of the equation by adding turbos, or
adding a supercharger, but for Dodge and true Viper fashion, they did it the good old fashioned way. They made it bigger, they
kept it naturally aspirated, and they use displacement as their ally. No turbos, no superchargers and when you're not using force induction, you need as much displacement as possible. And the Viper does that by
using 8.4 liters of displacement across 10 cylinders. So I'm a visual person. So to help explain how much
that is, I have a bottle here, and it has exactly 840 milliliters in it. That's 0.84 liters. The contents of this bottle will fill up only one cylinder in the Viper. So imagine this times 10 (mumbles) 10 of those, that is a
lot of air getting pulled into the combustion chamber. You might be asking, hey, how this is dude have a
friggin graduated bottle because that's the last place
I worked in a lab, I stole it. (laughing) Don't say don't put that in. (upbeat music) I teased earlier that the
Viper has its own version of variable valve timing. But how can a pushrod engine
vary the timing of its valves, when it only has One camshaft
and what performance benefit does that even get you, well, like all good engineering devices, the Vipers camshaft is quite 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 insane, it uses
what's called a DuoCam, now this Duo single cam system consists of a solid intake camshaft, within a hollow exhaust camshaft and the solid shaft has
holes for cylindrical pins five of them to be exact
and when activated, they align with slots in
the hollow outer shaft. The two camshafts, then become one and the exhaust timing is altered. So why would you want this? Well the camshaft in
the Viper is considered a performance camshaft, normally this type of camshaft would be illegal in a production car. Now performance camshaft is
there for one sole purpose and that is to increase performance. (mumbles) But it also increases emissions 'cause you're basically
just sitting there, always churning at full bore. That's why when you hear some muscle cars, they have that low sound, (mumbles) That is a performance cam and
it is also almost definitely always not meeting emission standards. So when you're trying to
build a high horsepower, high torque engine that
is also street legal, you have to strike a
balance between performance and emissions regulations. So to combat that problem,
the Dodge engineers use their new DuoCam
camshaft to reduce the amount of exhaust gas dilution at lower RPMs, making the Viper a more Eco friendly car, and the Viper was the first
production pushrod engine with VVT on the exhaust
valves, pretty nifty. So that was the first
part of the equation. The Wild (beep--) beaten horse
you got bitwixe your thighs, but how do you keep a car
with such an insane engine 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. It's what made it 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 foot under. But at least the engineers
over at Dodge give you a bunch of aero so that when you start going fast, the less angry the Viper is at you. Now the second half that makes
the Viper ACR the best car to ever come out of the USA, is its ability to stick to the ground. We're talking about downforce. (engine car roaring) Better understand downforce,
I'll start by explaining lift. Now with a plane you
have a wing like this, and as it goes along, you
have air that pushes up on it and it causes it to lift. Now if we flip that wings upside down, the reverse happens and now
instead of the air pushing up, it pushes down, and
that is called downforce or negative lift. And in the car world we use a spoiler or rear wing to do that, and
in the case of the Viper ACR, they use a very big spoiler, a
1776 millimeter wide spoiler. Yep, you heard it right,
1776 the same year the USA was founded because of course, this is the best car to
ever be built in America. I'm trying to tell you guys
this, I'm preaching it. I'm preaching the gospel, you
will be my flock of sheep. I'm the Dodge Jesus (laughing). And that's the size of the
standard wing on the ACR. If you get the extreme aero package, it widens it by another 100
millimeters to 1886 millimeters. That's six foot two inches. I'm six foot four inches, that's only two inches shorter than me, just laying there on the wings, it's getting air blasted down, wild man, even the material the
wing uses is special. And while most wings have
some sort of structure core to support it, the ACS wing is hollow and it uses only four
layers of carbon fiber, but it's still amazingly strong. And there's even structural
support built into the trunk to help support all that
downforce created by this wing. A full grown (beep--) man could stand on the end of this wing
and it wouldn't break. That is a really strong
spoiler and trust me, that's the kind of school you want when you do a really dumb stuff like this. (car engine roaring) That dude for sure lost his teeth, like he doesn't have teeth right now, like homeboy is COVID up with
no teeth, just gum and food. Homey, what are you doing? Don't ever do that (beep--)
is so stupid (laughing). That spoiler creates a ton of downforce, and I actually read a
funny story about this. A guy who was towing his
Viper behind his truck in an open trailer, was getting two miles per
gallon horse fuel economy because of how much force the
Viper spoiler was pushing down on the rear end of the trailer, slowing his truck down as
he was towed along the road. That is pretty cool, I mean sucks for him, but pretty interesting. So if you have all that
added force pushing down on the back of the car, why doesn't the Viper just do a wheelie? (mumbles) Well, there's a bunch of goodies up front that helped create downforce
on the front end of the Viper. First, there's a front
splitter that sticks out about five inches past the
bumper in the front of the car, and it also goes a couple feet in towards the center of the car. And like the rear end diffuser, there are these vertical strikes
and those vertical strikes, they keep the air confined in that area, it traps the air in, so you
don't lose any downforce when you're turning. It's the same reason why
the wing has vertical ends on the two sides. It's like a book-end it
keeps the air right in place. Adding even more downforce
are these little winglets on the front bumper, and
they have two purposes like the rear wing, they
help produce downforce and actually if you look close, they also have vertical edges on the side to keep the air in place. And the second function
they have is a thin air to help cool the brakes. So moving to the fenders
the ACR has louvers. And the purpose of louvers is
to vent high pressure building from under the car. So what does all these
aero bits equate to? Well, it equates to the most
downforce in any production car ever built, 800 kilograms, 1700 pounds when it's going to top
speed of 177 miles per. And the more downforce you make, the better your car grips the track. And the better your car grip track, the faster you can take corners, and the fast you take corners, the more track records you set. (car engine roaring) Now all that downforce
comes with a trade off and that trade off is drag, and now drag is just air resistance. It's the force acting opposite
to the relative motion of whatever moving on object you have. So with the aero package,
it takes the bass Viper with a coefficient of drag a 0.37, and it bumps it up to 0.54. That increase in drag, effectively decreases
its top speed as well, 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 it in the corners. And when it was released, it went on a run of
destroying track records across the globe. Dodge took the old school beast of a car with some engineering turned
it into an amazing machine. It sucks it's not around anymore, man. It breaks my friggin heart. It's one of my favorite cars of all time, and for the money there's not
a more capable car out there. Hopefully one day they'll make another one and it'll try to kill you just as hard. Thank you guys so much
for watching this episode of Bumper 2 Bumper. If you haven't already, please
hit the subscribe button. Also, we're doing something new, all of us here Donut are
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every day of the week, Donut every day. Follow us on Instagram
@Donutmedia, follow @Jeremiahburton if you got a Viper ACR, you got any Viper, hit me up show me some
pictures of a man's. One of my favorite cars of all time, I had two posters in my
room as a kid I had a Viper, second gen Viper blue with white stripes, and I had a purple Lamborghini Diablo. I'm gonna have both of them
one day you just watch. And by the way, we
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featured on the show. So thank you so much for watching. Thank you so much for supporting us. Stay safe out there, bye for now. (car engin roaring)
More power!!!!!! This is the American way.
People are so serious. The title is the title Donut put on the video. I assume most car enthusiasts are familiar with the Donut videos. They inject humor and some exaggeration. It's a good video that explains push rod vs overhead cam engine technology. Seems like a lot of people can't enjoy a video and have fun with it.
laughs in c8