wookie (11/09/82)
MSMiller at grkermit asked me a question about using a modified automatic
transmission vs buying a good 4 or 5 speed manual for use in road rallyes.
A big advantage of the manual transmission is that you can generally find
various gear ratios for each of the speeds in the transmission and thus
"tune" the unit to the needs of the rest of the car. If you have an engine
that produces torque and power over a broad RPM range then wider gear ratios
may be selected. If the engine has a narrow power range then the ratios
will have to be closer together to keep the engine operating at maximum
power as your speed increases. The same problem indicates the number of
speeds in a transmission you can get away with. An engine producing power
over a wide range doesn't need all those gears and so you could possibly
go with a manually shifted automatic (which are usually three speeds).
Another thing to watch is can the automatic in question take the abuse
of hard manual shifting. The old automatics (GM Turbo 400 for example)
could be modified and beaten into the ground and never die (I have a
1965 Pontiac 2+2 with 421 Tri-power and Turbo-400. The transmission
has been grossly abused for 246,000 miles with no trouble. Normal
maintenance was performed ie filter and fluid changes. The car is now
dead with a fatigued frame) The new transmissions (GM Turbo 200 series)
are absolute garbage.(Just check the 800 number in New Jersey for people
who have had 200 series troubles) I don't think these new automatics would
do well in Pro-Rallye. Another concern with the automatic transmissions
is the heat produced by the torque-converter. A transmission cooler would
of course be mandatory. Going back to gear ratios available; Getting
different ratios for your automatic is very difficult so for all practical
purposes you are stuck with the factory ratios.
Does anyone else have thoughts or better yet experience in using automatics
for racing purposes?
Keith Bauer
Bell Labs - Murray Hillmarkm (11/09/82)
My case for the Mopar Torque Flite . . . Last year three Dodge Ramchargers went to the infamous S. African Rallye. They weighed in at 5200 pounds each. They ran Torque Flites. Two out of three finished. There was a fourth Ramcharger, but it was a backup vehicle who's tranny did give way. Still, ANYTHING that can pull 2.5 tons for 3000-odd miles at speeds over 100mph on rough 'roads' can't be all bad. Rallye driving is quite different than racing. Reliability is VITAL, no pit crews at track side. Since traction is also ussually minimal in a pro-rallye, the slight difference between a 3-spd auto and a 4-spd std may be lost. In TSD rallyeing which I run now, speeds seldom get over 40 or 50 (unless you get lost when it becomes 70 on back roads). I have found that the only thing lacking in my TF is that I can't really control it in turns (shifter on column) and that the shifts are a bit sloppy. I figure an injection of B&M or Direct Connection magic will give me what I need. I did some pricing of this stuff - a Doug Nash 5 spd for street costs $1200, the shifter another $150. Then there's the linkage, installation . . . The A904 Torque Flite I cuurently run is recommended by Direct Connection even when modifying the car for a 15sec dragster . . . I guess I'll keep it. The B&M Transpak is under $100, the shifter is about $150. Installation (if I choose professional installation - I ain't got no garage) will be FFAARR less than dropping in a 5 speed!! I'll admit that a manual-automatic will not give all the control a standard would, but it will let me down shift when I want to, up shift when I want to and still have my left foot free to work the brake (NO, I'm not kidding - I drive Swedish Style). MSMiller GR Concord, MA