<VV>Turboglides in 1959 NO CORVAIR

[Brent Covey]

Turboglide was a special deal- It emerged for 1957 and was last used in
1961, it was a 'premium' automatic transmission offered at about $50 more
then Powerglide. It was the first one peice aluminum transmission casting
liek that GM ever did and was quite a sensational transmission.

Turboglide is a 3 speed concurrently geared fully automatic transmission (as
opposed to 'sequentially geared' like pretty much everything else) with a
three turbine, five element variable pitch stator torque convertor. Frank
Winchell was one of the driving forces behind Turboglide at Chevrolet, he
was in charge of the Corvair Powerglide and had much to do with the late
rear suspension as well, one of GM's very smartest guys.

Turboglide drives a different ratio off each converter turbine, oil strikes
the first ratio turbine and carries on past into the following second and
direct turbines if it has enough energy. In effect, you start out in first,
second AND third gear, then drop to second and third, then eventually are in
third (direct) alone with the lower ratio turbines freewheeling on sprag
clutches. The effect is much like a CVT transmission, no apparent shifts are
there as the ratios overlap and each turbine drives as long as its output is
less than engine speed. Additionally, there is a variable stator for high
stall which adds what amounts to a passing gear, or for extra getaway power
at low speeds. Turboglide equipped cars are VERY fast and burn rubber like
crazy, the bottom end power availible is enourmous. Buick offered a Triple
Turbine Dynaflow along identical lines (although a different transmission)
in 1957-'59.

Driving in a Turboglide, you have very small engine rpm variations most of
the time, and it has a nice direct push like a car with a manual trans or a
low stall converter. The sensation at full throttle is very similar to a jet
airplane taking off; the engine runs at full throttle at a constant
unchanging highish RPM and the car catches up to it like a slingshot, its
one continuous even push to about 65 mph, after which you're in direct and
the transmissions no longer in reduction (although the converter still may
be if the stator is in the 'performance' angle) and the engine can continue
gaining RPM or you release the throttle and the engine settles down to
normal cruise RPM.Uncle Tom Mc Cahill said it was 'as smooth as velvet
underpants'.

Heres a Car Life road test of a Turboglide '61 Impala with 348;

http://www.55-57chevys.com/coccc/articles/613/61asty1.html

Chevrolet Turboglide was very problematic in the 1957-'58's and was
substantially improved for '59-'61. The Corvair Powerglide uses some of the
improved Turboglide parts. Grade Retarder range engages the turbines in the
converter to create turbulence within the converter to absorb power for
downhill braking and was very effective, it has about 200HP worth of drag
availible for engine braking at higher speeds. GR is not 'low gear' all
driving is done in Drive range and you are cautioned not to use GR except
for downhill braking.

Because Turboglide maintains engine rpm under hard acceleration in a narrow
range the engine makes pretty much full HP output right at its output peak
RPM and the cars accelerate VERY fast. In normal driving direct is reached
between 15-65 mph depending on load and throttle position, TG seeks the most
modest engine speed that will propel the car. Its a very efficient
transmission and in the '57's with FI got incredible fuel economy. With the
variable stator throttle response is electric, they're very snappy.

Turboglide was not a popular option, partly due to the spectre of bad
reliability and the extra cost over a perfectly good Powerglide, and because
it felt a bit weird to a public that was getting used to automatics in the
late '50's era, it felt somewhat disconnected in some driving situations.

If anyone offers you a chance to ride ina car with this transmission, take
it, its a pretty cool thing.

Brent Covey
Vancouver BC