stupid t/c question.

[sleeperdsm]

im not all that familiar with auto transmissions, but i know the basics. i hear people talk about running (racing) with the torque converter "locked". exactly what is meant by this. i was under the impression that the converter "locked" after you hit your stall speed and then let off of the brake. by locked i mean that is isn't going to slip at all.

can you manually lock it, i would guess electronically with a switch? how do you guys lock your converters or do they do it autmatically?

somebody school me with this, it is pissing me off. on a grand national site they talk about a paper clip being involved with locking the t/c. this is probably irrevelent but it threw me off.

is there documented advantages to locking the t/c. does it ruin anything? can you have it like that on the street?

 

[SY2932]

Believe it or not, just a simple paper clip can indeed shave .2 off your overall ET... It is done by jumpering the "A" and "F" pins on the ALDL connector: http://sportmachines.com/maintenance/recipe1.php

My bud who has a *very* loose 9/11 converter told me locking his converter took off .5 his ET's at the track . You can use a paper clip but, it is very inconvenient to do so. I wired up a lighted switch in my truck and my buds so that we can lock our converters whenever we want.

By design, the transmission will lock up automatically provided the following conditions are met: vechicle speed over 24 MPH, engine at normal operation temperature (above 149 F), TPS output not changing indicating a steady road speed, brake switch closed and 3rd or 4th gears. Of course, grounding the TCC sidesteps all this...

The TCC is simply a solenoid operated valve that couples the engine flywheel to the output shaft on the transmission through the torque converter. It reduces the slippage losses in the converter which in turn, increases fuel econony. Locking it up is good for that "best ET" at the track or that "once in a blue moon" race on the street as doing it is VERY hard on your transmission. Not something that you want to do all day everyday...

 

[sleeperdsm]

thank you, very informative. i like the switch idea for locking it. as far as hard on the transmission, like will it blow apart pretty quick if you lock the tc or it isn't THAT bad but just don't do it all of the time.

one more question, can you lock the converter (via the switch) before you stage or do you have to do it on the fly. you say that you bypass all of the requirements for the stock tc to lock, so if you hit the switch while at idle in D it would be like dropping the clutch (in a stick car) and it would stall the truck..? i was wondering if it still required the 24mph to be achieved for it to lock with the bypass/switch.

 

[InvisiBill]

Yes, it won't lock up in first even with the switch. You can flip the switch while you're staging or whatever.

 

[Jimmy]

I flip mine when I'm racing @55 mph,I think the ECM commands it @71 mph.If I leave mine on at the tree,it bogs like a mofo when it hits second gear,but I have a bigger turbo and stall convertor.

 

[InvisiBill]

I flip mine when I'm racing @55 mph,I think the ECM commands it @71 mph.If I leave mine on at the tree,it bogs like a mofo when it hits second gear,but I have a bigger turbo and stall convertor.

TookyCat made that same observation. But he said that even though it did feel like it was really bogging down, it was actually faster that way.