Automatic TCU tuning, anyone?
 

It's been a while since this post http://www.ft86club.com/forums/showt...t=46603&page=2 has there been any development in tuning the TCU on the AT, I'm assuming there's not much interest or there isn't that big of market to justify R&D (I may be incorrect?), but it seems strange that no one has unlocked the TCU and messed around with the AT trans? I'm aware there are mechanical upgrades that can be done but I'm talking about non-invasive/software tuning. Can anyone shed some light on this, are there any companies out there that have tuned the TCU on the AT twins?

Nothing Yet. I am also waiting

Nothing yet, although in techstream all you can really do is reset it to relearn the transmission. I would really like something like tactrix for it because then you could upload the latest tcm logics and such.

I have a manual....looks like the Auto box can hold more power...would it be something like a valve body upgrade?

Why do people keep asking about this? What exactly do you intend to fix? All the issues I've seen or heard about are due to hardware or fluid level or fluid temp.

I have no clue why OP wants it accessed, but I would like access to update the TCM logic alot of people have had problems where the dealership refuses to fix the weird "downshift issue" that recently had a TSB in the form of a logic update. I have it now and the shifts are much smoother and the idle feels much more stable, it'd be nice if others could get that as well.

Things like:
1. Shift points
2. Shift firmness
3.Main line pressure
4. High rpm shift hang ups
5. Torque convertor lock up
6. Stall speed rpms


This is what I would start with.

I don't think stall speed can be altered with TCU tuning. That usually requires a high stall converter.

However...that being said, EcuTek can do some of these things. Moto-East was able to increase the line pressure via their tune and also alter a few other things with high RPM shifting on my car.

What I'm not sure of it that was by directly changing TCU programming, or fooling the TCU by altering the ECU output to the TCU.

For example, a stock car with the pedal only down 20% of the way might be programmed to shift with less line pressure than if the pedal was 100% down. Once you've doubled the factory HP though, chances are you'd need increased line pressure at the 20% throttle mark. What their tuning MIGHT be doing is telling the TCU..."hey I am at 100% throttle all the time. Shift as hard as you can every shift!".

Shift points would be nice, would be able to correct for the new power band.

You can change your stall speed by locking the convertor. It is a old school trick we used on grand nationals to get a little more boost on the line. We just ran a hot wire to the convertor lock up switch and presto 800 more rpm and 5 to 8 pounds of boost added lol
I do like your theory on the tuning I wish I had a schematic to figure it out. I was researching doing away with the tcu and going full manual mode but haven't finished all the research yet.. It looks doable

Justin, can you explain more about the torque converter thing?

That doesn't make any sense to me at all. A locked converter is directly connecting the transmission with the engine. Just like being in gear in a manual without the clutch depressed. No movement = no RPM's.....

Your stall speed is essentially when you no longer have enough torque to overcome the friction between the the impeller and the turbine. I can't see how "locking" the impeller to the turbine would allow you to increase your stall speed.

What I am referring to is locking the stator in the convertor to change how the fluid is transfered.( they used to be called switch pitch convertors) So when it locked you can overcome the fluid transfer easier. Like the pitch of a boat prop. A ski boat has a low pitch to pull the skier out of the water faster.(more torque) but a high pitch prop allows the boat to displace more water so it can have a faster top speed but you give up pulling power.


I hope I explained it well enough, I know how it works but suck at trying to spell it out.
Here is a old article on a gm switch pitch 400 Kenne Bell worked on


http://www.bdub.net/tranny/TwoTimer-...11-77-text.pdf

Yes, there is something you can do.
 

If you have a way to edit your ECU, as in Ecutek, BRZedit, Tactrix, or OFT, you can open the Drive By Wire section, and edit the Calculated Torque tables to affect the TCU. I've just started trying to understand the TCU logic by modifying the A and B tables. I started simply by shifting all the columns one column to the left, saving it, and calling it +10. Then, starting from the same original file, shifting all the columns one column to the right, saving it, and calling it -10. Now I have 3 tunes I can compare, +10, original, and -10.

I thought that telling the TCU I had more power would cause it to shift later, and firmer. Absolutely, positively, not true. The TCU is programmed to shift sooner under heavier loads. It short-shifted so bad my wife didn't like it. The original was a bit better than +10, but -10 was better yet. I still don't know how far I can take it, but I might have to tell the TCU that the engine never makes over 100HP till it exceeds 1.2 load, or 5000 RPMs.

I've gone a lot farther than my -10 table. So far, I'm just making the A and B tables the same, but I think one of them is for sport mode or something. Here's some pics of my latest table, versus the original table.

I am using ssp high press torq converter and stage 3+ drag VB its pretty good handling boost

1 2 3 4 i am looking for that too