Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Freezing the Slushbox. Torque Converter on-demand lockup switch.

RH77 · 11-24-2009, 11:44 PM

I finally got around to trying this and it works great...

Background:

My TC is a 2-solenoid type, "A" and B". There is essentially one wire into each solenoid, at +12V, that activates each. The shop manual mentions that a "click" should be heard if the lead is applied to battery voltage. Each one demonstrated the clicking sound and is working properly.

3 levels of lockup occur under normal operation, with full lockup at 35 mph under modest throttle. With both activated, lockup can be half (stage-2 of 3) at light throttle or idle. Full lockup (3rd lockup stage) kicks-in after that. (This comes in very handy later...)

Modification:

The 2 lockup wires were cut just before the connector to the solenoids (the source wires from the TCU were isolated). The two wires to the TC were tied together, and hooked to a wire that was run into a toggle switch on the dash. On the other side of the switch, a wire was run from a temporary battery clamp. With the vehicle off, the clicking sound coincided with the throwing of the switch. When not in use, the clamp is removed from the battery to prevent drain.

Operation:

Check Engine Light and Transmission "D4" light blinks indicating a transmission fault.

The vehicle runs normally without the switch engaged (but with no TC lockup).

Flipping the switch engages partial lockup at any speed or gear (including while stopped).

When Stopped: Engine speed decreases 200 RPM, but idles smoothly.
Acceleration from Stop: Just after starting out, the TC fully engages at about 1200 RPM. Each gear shifts as expected, but more harshly and at lower RPM based on throttle input.
Cruise: Very light throttle uses only partial lockup. Full lockup occurs with modest throttle (in every gear), with a noted increase in FE a lower speeds and the engine lugging similar to a vehicle with a manual transmission. It was possible to cruise in 4th gear, Full TC Lockup at 20 MPH using only idle throttle (Note: 9 TPS = 0% throttle input; 90 TPS = 100%). At 11 TPS, full lockup occurs and gives that "direct connect" between engine and road. This mod definitely allows higher engine loads, lower speeds, increased FE, and a more "manual transmission" feel at city speeds. At highway speeds, the TC remains locked.
Downshift: A generous throttle input kicks-down to a lower gear as normal, but the action is pretty harsh. With the TC engaged, there isn't a lot of shock dampening. It's also better to "lift shift" for normal acceleration gear change.
Deceleration: Decel is normal until you get down below 35 MPH. From 35 to a stop, the transmission shifts at the latest stall speed, with some lugging and vibration noted. Flipping the switch to disengage lockup will allow longer DFCO decels and smoother downshifts with a more economical idle.
Stopping: Even if the switch is forgotten, the transmission will shift down through each gear to first, but very late and abruptly. Once stopped, the TC is partially engaged and idle speeds are slower, but the vehicle does not stall.

Conclusion: This is great! I finally have control over the pesky TC. The plan is to mount the switch on the shifter stalk, locate an accessory-only power source, and install some inline diodes with a "Master Power" switch to operate the transmission normally or in Manual TC or "MTC" mode

RH77

11-24-2009, 11:44 PM	#178 (permalink)
RH77 Depends on the Day Join Date: Nov 2007 Location: Kansas City Area Posts: 1,761 Teggy - '98 Acura Integra LS Sports Cars 90 day: 32.74 mpg (US) IMA - '10 Honda Insight EX Team Honda 90 day: 34.76 mpg (US) Tessie - '06 Acura TSX Base 90 day: 28.2 mpg (US) Thanks: 31 Thanked 41 Times in 35 Posts	Test Successful I finally got around to trying this and it works great... Background: My TC is a 2-solenoid type, "A" and B". There is essentially one wire into each solenoid, at +12V, that activates each. The shop manual mentions that a "click" should be heard if the lead is applied to battery voltage. Each one demonstrated the clicking sound and is working properly. 3 levels of lockup occur under normal operation, with full lockup at 35 mph under modest throttle. With both activated, lockup can be half (stage-2 of 3) at light throttle or idle. Full lockup (3rd lockup stage) kicks-in after that. (This comes in very handy later...) Modification: The 2 lockup wires were cut just before the connector to the solenoids (the source wires from the TCU were isolated). The two wires to the TC were tied together, and hooked to a wire that was run into a toggle switch on the dash. On the other side of the switch, a wire was run from a temporary battery clamp. With the vehicle off, the clicking sound coincided with the throwing of the switch. When not in use, the clamp is removed from the battery to prevent drain. Operation: Check Engine Light and Transmission "D4" light blinks indicating a transmission fault. The vehicle runs normally without the switch engaged (but with no TC lockup). Flipping the switch engages partial lockup at any speed or gear (including while stopped). When Stopped: Engine speed decreases 200 RPM, but idles smoothly. Acceleration from Stop: Just after starting out, the TC fully engages at about 1200 RPM. Each gear shifts as expected, but more harshly and at lower RPM based on throttle input. Cruise: Very light throttle uses only partial lockup. Full lockup occurs with modest throttle (in every gear), with a noted increase in FE a lower speeds and the engine lugging similar to a vehicle with a manual transmission. It was possible to cruise in 4th gear, Full TC Lockup at 20 MPH using only idle throttle (Note: 9 TPS = 0% throttle input; 90 TPS = 100%). At 11 TPS, full lockup occurs and gives that "direct connect" between engine and road. This mod definitely allows higher engine loads, lower speeds, increased FE, and a more "manual transmission" feel at city speeds. At highway speeds, the TC remains locked. Downshift: A generous throttle input kicks-down to a lower gear as normal, but the action is pretty harsh. With the TC engaged, there isn't a lot of shock dampening. It's also better to "lift shift" for normal acceleration gear change. Deceleration: Decel is normal until you get down below 35 MPH. From 35 to a stop, the transmission shifts at the latest stall speed, with some lugging and vibration noted. Flipping the switch to disengage lockup will allow longer DFCO decels and smoother downshifts with a more economical idle. Stopping: Even if the switch is forgotten, the transmission will shift down through each gear to first, but very late and abruptly. Once stopped, the TC is partially engaged and idle speeds are slower, but the vehicle does not stall. Conclusion: This is great! I finally have control over the pesky TC. The plan is to mount the switch on the shifter stalk, locate an accessory-only power source, and install some inline diodes with a "Master Power" switch to operate the transmission normally or in Manual TC or "MTC" mode RH77 __________________ *“If we knew what we were doing, it wouldn't be called research” ― Albert Einstein* _ _ Last edited by RH77; 11-24-2009 at 11:50 PM..