hello everyone and welcome to another
episode of the best engines the show
where i say stuff about cool engines now
behind me is the 2018 kia stinger gt
which won an award in 2018 awards auto
10 best engines award for the 3.3 liter
v6 twin turbo underneath the hood now
this engine produces 365 horsepower at
6000 rpm and 376 pound-feet of torque
from just 1300 rpm all the way to 4500
rpm kia claims the rear wheel drive
stinger gt will hit 60 miles per hour in
4.7 seconds using launch control in my
own testing without using launch control
i was consistently getting under 5
seconds for 60 miles per hour now at
this point i'm just going to put up a
bunch of specifications on the screen if
you're super interested in them you can
pause the video and if you think they're
not thrilling at all to look at well
thankfully they are almost over having a
look underneath the hood you'll notice
the engine is tucked fairly far back
within the engine bay you'll also notice
there isn't a battery to be found up
front here that's because the battery is
located in the back of the car
underneath the spare tire now checking
out the engine's airflow we've got these
dual air boxes one on each side pulling
air from the front of the car it'll pass
through that air filter then travel into
the turbocharger where it is then
collected together in the center here
after coming out of each turbocharger
joining up together passing up to the
front of the car where it then travels
through an air-to-air intercooler and
then it comes back up travels through
this throttle body right here into the
intake manifold split between the
cylinders then traveling through the
exhaust portion of the turbocharger and
then through dual exhausts through the
back of the vehicle
[Music]
okay so now let's get into some cool
features of this engine starting with
sodium filled exhaust valves and sodium
filled exhaust valves are nothing all
that new in fact they've been used in
aircraft engines dating as far back as
the 1920s but kia says that using sodium
within the head of the valve as well as
the stem of the valve is a first in a v6
engine in this kia stinger so qualifying
statements like in a v6 don't make it
sound all that cool of a record uh so to
speak or you know innovation but it is a
very cool technology nonetheless so why
is this done well when you have an
engine here you've got your intake valve
and your exhaust valve the air that's
coming in tends to cool that intake
valve so you don't have to worry so much
about the temperatures of the intake
valve the exhaust valve of course
however has exhaust passing by it all
the time so that exhaust is heating up
that valve and you have very little to
cool it you simply have the valve guide
itself where you've got liquid cooling
through the cylinder head
and so this exhaust valve the head of it
starts to get really hot and the hotter
that gets the more likely you are to run
into pre-ignition or detonation problems
where that exhaust valve causes you know
a premature ignition of that air fuel
mixture in there and so you of course
don't want that to happen you want your
exhaust valves to be cool that way you
can maximize how much spark advance you
have and maximize how much power you
have and so you want your exhaust valves
to be cool and so by putting sodium
within it sodium is actually a pretty
neat element here in that it has a low
melting point but also a high boiling
point and has a high thermal
conductivity and a relatively high
specific heat so what does all this mean
well it means that as this engine starts
to warm up the solid sodium will then
liquefy it turns into a liquid and
because it has a high specific heat it's
able to pull in a decent amount of heat
from that
valve head now because it has a high
thermal conductivity as this valve is
moving up and down very quickly on
splashing that uh sodium around as well
as it could perhaps be boiling that
sodium if it gets too hot and then the
evaporation would come up as that sodium
comes up into this hollow stem of the
valve it transfers that heat very
quickly because of that high thermal
conductivity
to the valve guide and so the valve
guide of course cooled by the liquid
cooling within the cylinder head and so
overall if you're able to take the heat
away from the head of the valve bring it
into the stem and then pass it to the
coolant that's traveling through the
cylinder block then you can cool down
this valve and so that's the idea with
using sodium within it
and according to some numbers uh that
key was saying about this engine if you
just have a solid valve you can see
temperatures as high as 850 degrees c on
the head of that valve if you have a
hollow stem with some sodium in it you
can get temps down as low as 700 degrees
c and then if you do what they're doing
where you also have a hollow head
as well as a hollow stem where you have
some sodium in there you can get
temperatures down to as low as 650
degrees c and keep in mind that all of
this is done in the exact same
dimensions whether it's hollow or
whether it is a solid valve okay the
next first in a v6 record that kia
claims on this engine is the ability to
lock the camshafts midway through their
cam phasing range and so they've
increased the amount of cam phasing that
the camshafts have on this engine both
intake and exhaust where they have 85
degrees of range that they can phase
that camshaft and change the timing of
when those intake and exhaust valves
open and so this is a neat idea
the mid lock is done for startup they
say it's a response thing on startup to
have good response from these camshafts
and then as you start to get into
different loadings it will change the
phasing of that camshaft depending on
what you want so for example if you want
power then it will make sure that that
intake valve closes when you get to
bottom dead center that means you get
the maximum amount of air and fuel
within that cylinder before you start
your compression stroke now if you want
efficiency you'll actually push out some
of that air as the piston is on its way
up and that reduces your compression
ratio your effective compression ratio
relative to your expansion ratio so it
means the distance that the piston
travels up to compress that air fuel
ratio is less than that distance travels
down and so the amount of useful work
that you're able to get out of the fuel
used is increased so you're going to
make less power overall but you're going
to get more power out of the amount of
fuel that you used so your efficiency is
increased your fuel economy is increased
so if you're you know in a low load
scenario if you're not pressing on the
throttle too much it will change the cam
phasing so that your intake valve closes
a bit later to allow you to get better
fuel economy now the last feature we're
going to talk about is integrating the
exhaust manifold within the cylinder
head which is becoming a more popular
trend in vehicles for the variety of
advantages that this provides first of
all it saves weight because you're
getting rid of those cast iron exhaust
manifolds and second of all it saves a
lot of space by incorporating it within
the cylinder head so from a packaging
standpoint it's advantageous this also
helps to heat up the catalytic converter
faster and once the engine is up at
operating temperature it helps to have
cooler temperatures going through the
catalytic converter which ultimately
gives it longer life and while this does
reduce the temperature of the exhaust
going to the turbochargers the
turbochargers are bolted right up to the
cylinder head so there's a very short
path for that exhaust to travel helping
to spool up those turbos quickly so i
hope you've enjoyed this video learning
about the 3.3 liter v6 twin turbo in the
kia stinger gt if you have any questions
or comments please feel free to leave
those below thanks for watching