Ski,
As mentioned, a switch, tapped in near the trans, could be switched to "off" to block the locking signel from the ECM. I was under the impression that the ECM didn't activate the TCC at WOT. If I'm wrong, I think you could find someone to burn you a chip, that would insure it didn't. LOL. Sorry, I couldn't resist. Good luck, and...

RACE ON!!!

 

Why don't you guys just program the ecm to force Lockup only after say 100Mph and no lockup in other gears?

 

Thanks! Jim. Knowing where the ALCL is really helped to make the rest of this thread understandable.

:cheers:


[Modified by JrRifleCoach, 3:04 PM 10/23/2003]

 

Jesse, I am curious of the reasoning behind their opinion. Is it because of durability? Torque multiplication diminishes with increased vehicle speed and a non lockup converter is never 100 per cent efficient. A lock up is. I can believe Mike1985 about his better times and trap speed using the lockup. When I raced my C3 with the TH400 KenneBell switch pitch, the solenoid was wired into the brake pedal switch. Since the transition from high stall to low stall took a couple seconds with the KenneBell, the timing was just right for it to change into low stall just before I got out of first gear. It felt like an extra shift. Now I see people using the new lockup converter for the TH400 the same way.


[Modified by jimtreber, 11:13 PM 10/23/2003]

 

I have been trying for months to find out if I can lock up my converter in my 94.Are the connections in the same place?I run a pcm's for less computer I guess i should of had him make it so it locks in 3rd,but I would rather do it manually.

 

Have you actually seen the size of the clutch area in a lock up converter.
I have doubts about it's long term durability under full load conditions as in acceleration as opposed to cruise mode where it is usually engaged.(little load and I believe it it is programmed to drop out of lock up when load is applied)

 

If you have an OBD-1 system, put the lockup switch & indicator lamp/LED between ALDL terminals A & F (upper right & upper left).

When the light is On the TC is unlocked; Off and the ECM or switch is sending the lockup signal to your A4 lockup solenoid.

 

I believe you could just unplug the wire that goes into the vehicle speed sensor. The downside is you also loose your speedometer, but the torque coverter won't lock up when unplugged. I learned this accidentally when the pin on my VSS snapped on the way to the track. I ran it like this and to my surprise the torque converter remained unlocked. I even got a new personal best :cheers:

 

I did not share this opinion till I spoke with the guys at precision Ind. (vigilante) and pro-built. Both VERy reputable places. I again confirmed the information with a call back to vigilante when checking up on my converter they upgraded for me. Again. He said....if your looking to get the best ET from your car...LEAVE IT UNLOCKED. He said most people that talk efficiency with converters don't even know what efficiency they are talking about. He said their converters are designed to work optimally with the converter unlocked. I said, so basically they are designed like a non-lockup, but have the lockup feature. He said, bingo, and said I seem to know what I am talking about then went into more detail. He said that as I have seen with my friends car (corky) he did not loose ET or MPH with the non-lockup. that is what I should also suspect. The only advantage he said between the lockup and non-lockup converters, at least theirs, is that the nonlockups weight about 2 lbs less, so there is a slight advantage there. But NOTHING else.

I was always the same as you guys, thinking a lockup converter needs to lockup. But from these guys are saying....that is not the case, and I'm sure they would want me to get the best results with their converter/tranny I could.

Here is what I gathered and in my own words. a converter has torque multiplication. This only happens when the motor is spinning quicker than the output shaft (to tranny). As one travels down the strip this gets less and less, as someone pointed out. And yes there is a little slippage (~200RPM from what they told me on a 4000+ stall converter). Soooo, what I think happens is when you lock your converter prematurely, it takes that torque multiplication away, and you loose some gains you would have got from leaving it unlocked. Noone can deny more output power means quicker ETs. If you could possibly find that optimum spot at which Torque multiplication ends, and lock the converter at that exact point, you might get the best of both worlds. But like in my case with my car, ITs pulling like a **** and just like an upshift, you loose some momentum, and then once the RPMs get back up, it starts to pull again. If I can feel a hesitiation in pull, then feel it a second or two later regain, then I am loosing ET no doubt. Its almost like a fuel shortage bog. When .1sec makes or breaks your goal....every less hesitaion counts in your favor.

Not real sure if any of this will make any sense to anyone else but me....as I know what I feel in my car, so try to understand....this will all be backed up with tests this weekend at the strip...So hold tight!

Jesse :cheers:

 

thanks for all the info ski. I think those guys don't want that monster of yours breaking their converter. But hey if your headed to the track take a paper clip with ya and test all the possibilities for us.


My test were back to back runs and I got .3 and 2 MPH out of locking it up. I only suggest this because i know your sooo close to your goal. Oh and i know corky beat you to the 10's so you need tp redeem yourself by going deeper into the tens. This is in a friendly way of cource.

My friend and i do the same thing, i went 12.24 first, so he went 12.23...i went 11.91 and he stepped up and went 11.52. I took motor out and told him i'll redeem myself next year. But it's all fun for us.

Good luck this weekend

 

I understand and agree with all this. My question remains, does the ECM allow for lock up at WOT? Yes! We know it can be engaged, and many people have told how to do it. But is disengagement, or prevention, necessary? If there is any question, just unplug the wires at the trans when you're at the strip. Good luck, and...

RACE ON!!!

 

how do i find petek

 

Grounding pin F will engage lockup in geaars 2, 3 and 4 unless the brake is applied.

A stock lockup clutch is not designed to handle full power and that is the reason for unlock at full throttle.
An aftermarket performace converter with multi disk clutch can handle a lot of power on lockup, more than a built th700r4.





This is for 1984 with manual transmission related removed.

 

If you imagine a torque converter as this (oversimplification but idea stands): take 2 floor fans and face them into each other. Turn one on, and the other one will slowly spin up to almost the same speed eventually. This is a basic idea of a TC. Now grab the unpowered fan blade. You can hold it steady while the other fan runs. This is the same as being in drive at a red light.

Now imagine that the powered fan makes more power when spinning at a higher speed, say at 4000 rpm vs 1500 rpm. If you have these fans locked together with a shaft (lockup clutch), you are stuck with your power output at 1500 rpms. But if you allow the fans to slip, the powered fan can spin up to 4000 rpms where its making big power. There will be energy loss across the torque converter from fluid friction but overall the TC is acting like a torque multiplier, like having another rear end if you will. Makes it easier to visualize if you watch a youtube video. This is why race cars have big stall converters, to allow the engine to get up to RPM where the cams are giving it the biggest power and skip over the lower rpms where power isn't as great. The engine can hold steady at the higher rpms while the output shaft of the TC (the unpowered fan in the example) is playing catch up. The idea being that the energy losses across the TC are not as big as the gains from spinning up the motor into a higher HP rpm range.

If it helps to think of it this way, imagine being in a manual transmission car instead. We can simulate a high stall torque converter simply by slipping your clutch pedal at a high rpm, which as we all know is the best way to get off the line faster. If you're drag racing you don't let the clutch out at 1000 rpm and then floor it. You hold the rpms at 3000 rpm (or whatever) and slip the clutch and the car comes alive. You are using your left foot to simulate a high stall converter. The difference being with the auto the car always behaves this way so driving normal in traffic can be noisy and gas guzzling because you gotta gas it up to get the car to move