Torque Converter Selection - Summit Racing Quick Flicks

What does a torque converter do? A torque converter is a fluid coupling device that transfers power from engine to transmission and multiply the torque being created by the engine.
There are three major components that make up a torque converter.
The Fluid Impeller is the only part of the torque converter that is physically attached to the engine. The impeller creates fluid motion within the converter to create a transfer of power. The Stator redirects fluid flow towards the impeller. The Turbine Assembly transfers the motion between the engine and the transmission. Another important aspect to understand is Stall Speed = RPM when the engine sends all available power to the transmission.
Torque converters have 2 different types of stalls that they can produce. The 1st type is Foot Brake Stall. Foot break Stall is an inaccurate way to measure torque converter stall.
Flash stall is the actual stall of the torque converter. Flash stall is always listed in range which is determined by different attributes such vehicle weight, gear ratio and tire size. The flash stall rating is the only true and most accurate stall rating that you will find on a torque converter.
A few rules of thumb to take from this video are: First select a converter that stalls at 500 RPM higher than the camshaft. Converters installed in a big block engine usually stall 300 RPM higher than a small block. Choose a converter that will stall below the highway cruise RPM. For additional information and to check out Summit Racing's selection of Torque Converters, click here:http://www.summitracing.com/redirect?banner=SocialYT415

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Closed Caption:

I'm like and I'm this installment of
something quick flicks
we're going to talk about selecting the
right for converter for your vehicle
selecting the right torque converter for
vehicle can be critical to the vehicle
performance and overall acceleration as
an end result it is difficult for a lot
of customers to select popped word
because they don't understand how torpor
operates what we're going to talk about
today is the function of a torque
converter
what it does and how to go ahead and
select the proper torque converter for
an application
so before we go about selecting a torque
converter for an application it's
important that we understand how the
torque converter operates in what order
actually is torque converter is a fluid
coupling device that's going to go ahead
and transfer power from the engine to
the transmission it's also going to
multiply the torque being created by the
engine
what this does is it gives us the
ability to leave the vehicle and gear
and come to a complete stop at the same
time
now what makes this possible in the
torque converter is the three components
that it's made up made up of torque
converter as a whole is going to look
like a fairly simple device and
internally it actually is fairly simple
as well but you're gonna have to have an
outer shell
that's going to attach on the back side
to the flex plate assembly
it has been dissected torque converter
you're going to come to find a torque
converter mainly operates off of fluid
motion centripetal force
what we're going to start with
explaining is the fluid impeller that's
gonna be the front shell of the torque
converter certainly this is the only
part of the tour de Burgh that is
physically attached to the engine and is
constant motion with the engine because
it is well it via this scene 2 the
complete assembly which is going to go
ahead and operate off of flex plate
motion as the engine is rotating
what the impellers job is its go ahead
and create fluid motion inside the
torque converter to create that transfer
of power
these fins will catch the fluid that the
converters fill it up with then we'll go
ahead and send that that fluid through
the torque converter assembly itself
the next part of the torque converter
we're going to discuss is the stator the
stator is a part that goes ahead and
redirect fluid flow towards the impeller
for a quicker reaction of the torque
converter and 44 better torque read
torque reaction in general in the torque
converter followed up by the turbine
assembly the turbine assembly is the
part inside the torture that actually
transfers the motion between the engine
and the transmission
this is the part that engages with the
input chef via the spline shaft
internally and what it's doing is it's
catching the fluid motion created by the
impeller is being forced against the
turbine and then transferring that power
and torque to the transmission assembly
we can go ahead and alter torque
converter stall by changing the fin
angles the size of the torque converter
which is going to go ahead and affect
the amount of fluid flow throughout
torque converter assembly itself
this in turn affects how high torque
converter stalls how quickly it reacts
are slowly reacts and this is what makes
it such a critical component when making
engine changes when when changing
camshafts in an engine and and and
determining how the vehicle is going to
go ahead and accelerate from a dead stop
so now that we understand how the parts
inside of work over actually operates
and what it actually does we got to
understand what stalls be really
this stall speed is basically determine
that refers to the RPM in which the
torque converter is transmitting all of
its torque throughout the transmission
assembly
there is a point in which the converter
is going to be slipping prior to this
that's going to go ahead and let the
engine reaches engine reaches RPM band
at a quicker rate of speed to bring it
up to the point in which it makes its
power
that's why I torque converter must have
stalled for it to operate correctly in
an automatic transmission application
now torque converters do have two
different types of stalls that they can
produce and a lot of times a little
confusion between the two and and the
accuracy of one compared to the other
the first type of stall that most people
tend to measure converter by at home
let's say they have their their vehicle
and hard to put a new converter and they
want to test the stall reign three of
the converter
they're going to go ahead and and test
it via foot brace tall
what is essentially is its they're going
to go ahead and put the converter the
vehicle go out
start the car up in the driveway hold
the brake pedal and the gas to the floor
at the same time the one of two things
is going to happen at this point either
one the engines and quit making rpms way
before it's max rpm . or two it's going
to break the tires lose and override the
brakes at some point in time in New York
a man this is what's known as put brakes
tall foot brake stall is actually a very
inaccurate way to measure torque
converter stalls always gonna happen
much sooner than the other type of
stalled a torque converter is going to
produce
it's actually a powerful and dangerous
because what it does is it overloads the
torque converter creates a lot of
excessive heat and a lot of excessive
wear and tear on the court reversed
itself and actually was shortened her
life
so when you do with something like a
torque break on a vehicle with an
automatic transmission
essentially what you're probably going
to end up have
what's probably happening is you're
going to end up damaging to damaging the
torque converter in the long run
the other type of stalled a torque
converter is going to produce is what's
known as flashed all flashed all is the
actual stall the tour converted the sort
of her is rated at that you're going to
see advertised either on our website or
in the catalog and what you'll notice
about the stall of a torque converter is
it's always listed in range
there's no such thing as a specific 3500
stall converter is going to stall around
3,500 rpm depending on certain
attributes of that vehicle whether it be
the vehicle weight
the gear ratio of the tire sizes using
the vehicle-mounted power the dispute
produced by that engine
those are all going to have an effect on
the stall . of that converter the flash
star rating is the only true rating of
that tour cover the actual only true
stall rating that you're going to find
on to remember this is typically much
higher than what the foot brake stall is
going to be and it is going to be much
more accurate and it's actually much
harder to figure out at home after the
tour has been installed in the vehicle
essentially is the point from a dead
stop when you're just go to full
throttle
without the brace engaged the point we
should attack already was gonna jump and
then the transmission engages in the
vehicle accelerates catching this and
figure this out as kind of a tough task
at home and at least a lot of confusion
when people try to go ahead and look at
the stall is being produced by the
converter at home and at a for personal
use any specific application so as we
understand flashed all we now begin to
understand why it's kind of difficult to
select a torque converter for an
application because of all the different
variables that can have an effect on the
stall range install rating of a
converter in a specific application
there's a lot of contributing factors in
determining what stock version of you
right for our vehicle and selecting the
right one is critical to a vehicle
performance and how it accelerates
especially in like a drag race
application which 60-foot times are very
important and can have a considerable
effect on the end result as far as
quarter mile times go
the main contributing factor to
determining what converter stall is
right for an application is the camshaft
that's installed in that engine
every camshafts going to have a RPM
story in range in which stores to make
power
now this can be affected by the
cubic-inch displacement of the engine
um and eggs as well as the vehicle ,
nation as a whole
mainly what will suggest to most
customers though and what we we suggest
that most of ourselves representatives
do is they look at the starting RPM and
that cam shaft then we'll go ahead and
select the converter that is 500 rpm
higher install range than the starting
RPM of the camshaft being used in an
engine without this critical information
about the camshaft it becomes difficult
to select a torque converter accurately
for a vehicle and engine application for
any customer
one other thing that was mentioned was
that the gear ratio tire size cubic-inch
displacement of the engine can also have
an effect on the tourists all all these
are not going to have a great effect but
they will have a a small or slide effect
on the way to torque converter reacts in
a vehicle application some things that
kind of consider is if you're putting
that that torque converter behind a big
block in comparison to a small block
typically it will stall about 300 RPM
higher behind the big block application
in comparison to the small-block
application and this has a lot to do
with the amount of torque production of
a big block type edge and it produces
much more low end torque so the
converter has a harder time keeping up
with that torque multiplication that's
happening so they don't inherently makes
it stall any higher and higher stall
speed
it's not going to be greatly noticeable
but it's significant
no this is part of the reason why torque
converters are listed be arranged
instead of a specific number things like
gear ratio to numerically higher gear
ratio is in that vehicle it's going to
start sooner because the vehicle is
going to have less load on it to get it
to move forward is going to motivate
itself to move forward much more easily
same thing goes with tire size tire size
is going to have an effect on the gear
ratio of that vehicle so if you had
let's say a set of 3 73 years and you
change from a 28 inch tall tire to a 26
inch tall tire
now what you may notice is that the
torque converter is now stalling at a
sooner . then it did previously because
the vehicles have an easier time moving
from a dead stop the other consideration
is that you want to make sure that your
torque converter stall range is going to
be below the cruise RPM of the vehicle
in the street application
this is another area where gear ratio
comes into play because if the torque
converter stalls higher than what the
cruise RPM is let's say on the highway
at 70 miles per hour
what's going to happen is it's never
going to go in the full engagement . or
stall
what that means is that the tour cover
is continually going to be slipping
not completely it may be slipping at a
percentage of let's say twenty percent
or so but that twenty percent is
creating friction inside of torque
converters well because the components
essentially are not matching up with one
another
they're not rotated same speed so not
what you have you have a turbine that is
spinning at a different rate of speed
than the impeller of the torque
converter
what this does is it creates excessive
heat that excessive heat creates where
and what can happen is you may break a
weld on the snout or you may damage the
internal components because of the
excessive heat which apparently is then
go to damage the internal components
inside the transmission because the
transmission has a certain rpm operating
range that it was operating temperature
wise which is typically anywhere between
a hundred seventy 210 degrees
much like your engine
so what are some symptoms of having the
wrong torque converter for a vehicle
stalls too low
engine shuts off when put into gear very
poor acceleration vehicle lunges tries
override the brakes essentially when put
into gear
if the stalls - hi the engine has a will
have a very small operating range
converter never reaches stall at the
cruise RPM for the transmission will
overheat or burn fluid due to the
converter never stalling
so in summary the general rules of thumb
for selecting a torque converter for a
street application are select the
converter installs roughly 500 rpm
higher than the starting RPM of the
camshaft remember converters installed
and big block applications typically
stalled 300 RPM higher than if they were
to be installed in a small-block
application and always choose a
converter that will start below the
highways probably crews are p.m.
this can be determined by knowing the
gear ratio and tire size
this is not done toward her life will be
shortened considerably
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