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They
Make You Faster:
Even on a relatively stock setup, 1/4
mile gains of .6-.7 are extremely common. On more modified
cars, gains around one full second have been seen. Amazing
bang for your buck!
1.
Higher
RPM
Launches: Largely
similar to "dumping" a clutch at a higher
RPM, a higher stall
converter allows your car to leave the line with more power
hitting the wheels as you launch.
Here are a couple of examples of how the
launches change when you step up to a performance
converter. Variables such as different brakes, tires, and
gear ratios effect how the converter stalls, but these will
give you a general idea.
Example
1- Assume your
stock stall is around 1600 RPM. Get into
the car and hold your foot on the brake. Now at the same
time you let off of the brake, stab the throttle like you are
at the track. Keep a close eye on the tach. It will
jump to about 1600 RPM and start
climbing from there. If you moved to a 3200 stall, it
would jump to about 3200 and start climbing from
there. It gives you a huge punch by launching at a higher
RPM and at an
RPM that is more in
the meat of your powerband.
Example 2-
Again, assume a
stock stall of 1600 RPM. Now, in drive, hold your left
foot on the brake as hard as you can. Now slowly rev the
engine with your other foot. Notice that about 1200-1300
RPM the tires start to break loose. Now imagine that you
have a 3200 stall. You could now spin the motor closer to
3k before the tires started to brake loose.
2.
Torque
Multiplication: When an
automatic transmission is launched, the torque converter
actually multiplies the input torque. That multiplication is
called the Stall Torque Ratio or STR. If you
raise the STR, the amount of
torque you have on launch also becomes greater. With a sticky
tire, launches with a high STR can be down
right brutal. STR
3. Shift
Extension: Most automatic
cars experience a dead spot immediately after the 1-2 and 2-3
shifts. It will feel really strong all through first gear
(with LS1's particularly at the top
RPM because that is
where LS1's like to be, high RPM's). Notice
immediately after the 1-2 shift (and 2-3, if you get that
high) that it seems to fall flat on its face for a couple of
seconds. That is the dead spot and can feel like more
than a couple seconds at the track. It feels weak until
the RPM's get to where
they should be, and the power feels like it comes back. With a
stall converter, the RPM's do
not fall like they do with a stock converter. Expect the
RPM's to stay
considerably higher after the shifts with a stall converter,
completely getting rid of the dead
zone.
4.
Reduced
Weight: (Does not apply to stock style
converters)
A stock converter on an LS1 Camaro weighs 53
lbs. Our basic 245mm conversion weighs 30 lbs. While
23 lbs. of weight reduction does not sound like much, it
is entirely rotational weight. The engine is now required
to spin 23 less lbs. It now revs faster and considerably
more freely.
Example-
Take a short
pole with a 53 lb. weight at its end and one with a 30 lb.
weight. Try turning the one with the 53 lbs. and turn it
by hand. Now try the same thing with the other
pole. The lighter pole is considerably easier to
spin. The same is true for the engine. The lighter one is
easier not only to spin faster but to start
spinning. | 
