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Andyman · 03-02-2009, 07:29 PM

I wasn't sure how to vote on that one. Either the first choice or the last seem appropriate. I think that the most effective modification you can do to an automatic transmission is to make the torque converter lock up at a reasonably low speed. such as 1500 RPM after locking. Another helpful thing is to get lock up working in more gears than just the highest one.

On GM cars the locking can be controlled by an electrical switch installed in the car but my Honda locks its torque converter by hydraulic controls. I would have to take it apart and modify some springs to change its settings. Maybe I could add some kind of manual control of the torque converter by using solenoid operated valves. It locks up at about 48 MPH and slows the engine down from about 2400 RPM to 2000 RPM. A lot of my driving is on local streets with a limit of 30 MPH. It would be nice if I could be using 3rd gear with lockup at that speed. Even 4th gear with lockup might be usable at light load. The engine would be turning 1250 RPM in 4th or about 1800 RPM in 3rd. Normally it shifts into 4th at about 31 MPH but I can shift it to 4th at a slightly slower speed by shifting to neutral for a second and then back to drive.

03-02-2009, 07:29 PM	#8 (permalink)
Andyman amateur mech. engineer Join Date: May 2008 Location: New York City Posts: 112 Sporty Accord - '88 Honda Accord LX-i 90 day: 23.25 mpg (US) Dad's Camry - '01 Toyota Camry CE 90 day: 22.81 mpg (US) Artie's Camry - '98 Toyota Camry 90 day: 37.3 mpg (US) Thanks: 0 Thanked 17 Times in 4 Posts	I wasn't sure how to vote on that one. Either the first choice or the last seem appropriate. I think that the most effective modification you can do to an automatic transmission is to make the torque converter lock up at a reasonably low speed. such as 1500 RPM after locking. Another helpful thing is to get lock up working in more gears than just the highest one. On GM cars the locking can be controlled by an electrical switch installed in the car but my Honda locks its torque converter by hydraulic controls. I would have to take it apart and modify some springs to change its settings. Maybe I could add some kind of manual control of the torque converter by using solenoid operated valves. It locks up at about 48 MPH and slows the engine down from about 2400 RPM to 2000 RPM. A lot of my driving is on local streets with a limit of 30 MPH. It would be nice if I could be using 3rd gear with lockup at that speed. Even 4th gear with lockup might be usable at light load. The engine would be turning 1250 RPM in 4th or about 1800 RPM in 3rd. Normally it shifts into 4th at about 31 MPH but I can shift it to 4th at a slightly slower speed by shifting to neutral for a second and then back to drive.