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I had a friend over today that used to be into street racing many years ago. I was explaining the controversy about torque converters....drivability vs performance.
He says they used to make converters that you could just flip a switch inside the car and it would change to stall from stock to something much higher.
I never heard of such a T/C. To be honest I doubt if such a T/C ever existed. If a T/C like that existed we all would have them. I remember the T/Cs from the old days and they were nowhere as good as todays T/Cs in driveability or performance.
From: When all is said and done... there is a hell of a lot more said than done. Riverside,Texas
St. Jude Donor '05 thru '26
Originally Posted by C5magic
I never heard of such a T/C. To be honest I doubt if such a T/C ever existed. If a T/C like that existed we all would have them. I remember the T/Cs from the old days and they were nowhere as good as todays T/Cs in driveability or performance.
It sounds like he was talking about a "lock-up" switch.
You can install a switch that will allow you to control when the converter locks up.
AZC5
He is talking about an eletronic switch that would actually change stall speeds. A lockup switch does not change the stall speed of the T/C. Plus there were no lockup converters back in the old days.
I never heard of such a T/C. To be honest I doubt if such a T/C ever existed. If a T/C like that existed we all would have them. I remember the T/Cs from the old days and they were nowhere as good as todays T/Cs in driveability or performance.
Not only do they exist, but they were offered stock on many GM vehicles during the 1960's. (Aftermarket manufacturers also jumped on the bandwagon with their own offerings.) They were known as "Switch Pitch" converters, and utilized a stator with variable vanes...flipping a switch inside the vehicle changed the vane angle, and thus the stall.
I ran a 4 spd in the good ol days. Just did a search on Google and could find nothing. I agree he must be talking about a lockup switch.
Edit: Just did another search after Rob's post for Switch Pitch.
The switch pitch (SWP) THM400 and 425 of 65-67 had a torque converter 3rd element (stator) with VARIABLE VANE angle, changeable between performance and economy (instead of a compromise) as you drive. This gave 2.5 times torque multiplication, a 25% increase. It also gave a bit better mileage in the other mode. In a heavy vehicle this can provide a reduction of 0-60 time of up to 10%, and also give smoother shifts.
Not only do they exist, but they were offered stock on many GM vehicles during the 1960's. (Aftermarket manufacturers also jumped on the bandwagon with their own offerings.) They were known as "Switch Pitch" converters, and utilized a stator with variable vanes...flipping a switch inside the vehicle changed the vane angle, and thus the stall.
Switch the pitch was only on the old Buick Dyna Flow trannys of the mid 1950s. I could be wrong I think the blades inside the tranny actually switched not the T/C blades. If you remember the Buick Dyna Flows you understand why GM stopped making them.
Edit. Hmm. C5magic just deleted his post I just replied to. Kinda left me hanging. He posted it was only on Buick tranny in the 50's. Looks like I'm talking to myself again.
Indead the switch pitch converter did exist! It was stock on the Olds Toranado and Buick Riveria, THM 400-425 and it was hydrauliclly controled with a shuttle valve that was balanced between the modulator circuit and the throttle pressure valve.
Back in those days electronics inside the transmission was almost nonexistent.
In fact if I remember it was also in the old Roto Hydramatic 4 speed automatic availiable in the 61-64 model years for the larger cars.
It gave a gradual transition between launch and direct drive.
So you think all this tech stuff is new? Look back and many times you will find it's already been do with a simplier twist.
In fact the lockup torque converter was invented back in the late 1950's by an engineer I used to work with at MPG.
The carburator shaft was connected to a double switch so near full throttle one switch downshifted the transmission and the other switch changed the stator angle. The switches powered small solenoid valves in the transmission. This setup made the cars fast, smooth and delivered good gas milage. If the C6 offered this on the A4 I would trade up tomorrow.