To TCC lockup, or not to TCC lockup

Ok, I've got some questions about TCC lockup after doing some reading, and I realize I may have been quite mistaken about how a Torque converter really works.

I circle track a car (and the occasional road race)...it's an automatic, it's what the racing gods have given me, so going to a manual isn't an option. I'm trying to figure out how to get the most out of the transmission. I've altered shift pressures and shift speeds to get me the most out of each gear seeing how I'm always all throttle, or on the brakes, but I'm lost on the torque converter. At first I thought I could just tell it to engage at every gear at 30 mph, and disengage at 15 so it would always been engaged, but after some reading I've learned that it could hurt some of the torque because of the way it works (yeah, after all that reading, it assumes you already know enough to understand why....I don't). I'm racing it, so abuse is part of the game, I'm ok with that part. But what I thought I understood, I'm pretty unsure of now...one thing was at lower rpms disengaged it could enhance torque and act like a gear reduction...really???

So is it beneficial when racing an automatic to ever go into lockup, or always go into lockup, or only at certain times....argh! Understand my dilemma?? Any suggestions or help would be greatly appreciated.

Now the car in questions is a 2004 Cavalier. I know this is the V8 board, and I apologize for coming here. The 4 cyl board is kinda deadish, and I'm looking for some info that I believe can be applied to all transmissions, not just a 4 cyl, and this board seems to be the most active transmission board. I'll provide my tune going both ways, anyone wanting to throw some suggestions would be a great help...thanks!!!

Ok, so a week has gone by and 103 views and not one comment??? I know the application is very different than most...but still the concept is still the same, come on guys, rack that brain of yours and throw up some theories or ideas. Race is 2 days away on a road course.

Let's put it like this...I want the converter to stay locked primarily while I'm off the gas to hold the car back and keep the engine in time with the transmission, but unlocked during hard acceleration (except near the top of the rpm range). Ideas?? I drove it with the the shift speeds maxed out and when you are off the gas the converter just slips and free wheels when off the gas...it's like it's in neutral when off the gas, so when you get on the gas the motor has to rev up to get back to the desired rpm the transmission wants to see before it pulls again. Like 30 mph at 5000 rpm in first..when I get off the gas it drops in rpm but coasts...then when I get back on the gas it has to rev from 1000 rpm to 5000 rpm before it starts pulling.

Ok..help there??

A little more info would be usefull. I am assuming you never get out of 3rd. On a short circle track I would never lock the convertor as the torque multiplication would be of greater benifit and your mph is not going to climb as high. On a longer track, you could benifit from locking the convertor after you have come out of the corner and are in high gear(exact point would take some expierimenting) as you could gain some mph on the straightaway that you would not with it unlocked. This would apply for roadracing also.
Any time you shift, or step on the gas coming out of corner you are "on the convertor" and getting the benifit of the torque multiplication. However this effect does not last long. The convertor will then go to its highest efficiency lockup(not with clutch) which always has some losses as it is not 100% efficient. Locking the convertor will give you back this lost efficiency, helping you gain some extra mph. Drag racers have been doing it for years, lock the convertor after the shift into high gear to pick up some mph.
I have not done this, just based off my understanding of convertors. My 2 cents......

Also, make sure you have a good multiple disk convertor and excellent cooling system. Convetor failure will make a mess of your entire transmission.

Where I race locally, I never get out of 2nd gear. Abougt 75 on the front stretch turning about 6600 rpms. That's an issue I can work on with some experimentation like you suggested...

I am going to a road course this weekend. Last year I was 100% stock in the transmission settings and finished 2nd. However in 25 laps I went through all but 1/8 inch of my brakepads. The brakes was doing all the work, not much help from the gearing in the transmission holding the car back I believe. I'll probably be jumping around from 1st, 2nd, and 3rd this weekend. I think the way the torque converter works on the gas is good for me after much thought about it, I'm looking more for a way to have the transmission hold the car back like a manual does when entering a corner. I think that is where I am lacking, but I don't want to hurt the torque off the corner to gain something going in.

You dont have as many tables to play with as a v8, but I think you can make it work. I can see you having to tailor a tune for each track though. Your TCC Release TPS vs Speed table is zeroed. The pcm release whenever this value is exceeded, which is pretty much always. Up this value and see if that gets you what your after.

Thanks for the help...I knew I was missing something. I'll give it a try tomorrow and start making some changes to suit my needs....I'll let you know how it goes.

What I was trying was to do initially was keep it locked, then realized my mistake and have the best of both worlds...I thought the tcc apply/release vs tps vs gear table would do that since it has release tables in it, but I see now the tcc release tps vs speed is zero'd out...but it came stock that way. I think the table titles themselves and trying to wrap my head around what they do exactly according to what they say is giving me more problems than anything. I found fooling with the motor much more self explanatory and even easier...

Appreciate the help a ton...you have no idea!

remember every time you are on the brakes the converter is unlocked and there is no way to change that with the tune.

TCC lock up is for fuel economy.

Good point, hadnt thought of that. Assuming you still drive it on the street you could rig a switch so that at the track the pcm is not aware of the brake pedal. Lockup would be controled entirely by tps and mph. If its just a racecar, just supply the pcm with a signal brakes are not applied. See how the engine braking works before worrying about this.

Yeah, it's a long way from being a street car anymore...I should just be able to unplug the brake switch. As far as I know, it's the only way the pcm has to know that the brakes are ever applied.

I know lockup is for fuel economy, and my use for it I'm sure isn't what the creator of the converter had in mind, but the premise is sound. Make the transmission and engine one unit will help during deceleration, just like a manual does. I should be able to achieve this by adjusting the 0% on the tps with the correct speeds to make it work...I think, but something tells me it'll be a lot more complicated than that. And if it doesn't...ahh well, I'll just put it back to stock the way it was last year and go with it.

If memory serves, you will have to run battery positive to the pcm to defeat the brake switch, not just unplug it. The pcm sees constant 12+ untill you step on the brake, but would have to look at wiring for your car to be sure.