FA20Club.com Stage 1 Flash AutoTrans

[Visconti]

Why has a tuner been selling flashes with a raised rev limiter when the tranny does this?

Anyone care to comment?

[feldy]

Originally Posted by Visconti

Why has a tuner been selling flashes with a raised rev limiter when the tranny does this?

Anyone care to comment?

In this case I asked for it.

I autocross a ton and my local club as a lot of turn around stuff where if you didn't get back into first you were stuck in the tq dip of the stock ecu tune. The car shifting back into first when we wanted it to tended to gave us a hard time. So I wanted to see if the raised rev limit would remedy the issue. (Yes I should have bought a manual however wife dictated the auto. )

Even with the raised rev limit the car was still not letting me down shift any earlier that was the first thing I tested. Kinda sad... Then I had been testing getting 1st and 2nd to 8k red was not seeing the issue you brought up. Then I noticed it in 3rd yesterday. Now real sad.
@FA20Club.com did try to test some things yesterday after I emailed him about the issue. He sent me over a new flash file with some tq adjustments to see how it affects the trans. I don't know if the trans just does not like the extra tq at that rpm range or if it just plainly disengages no matter what. He is going to have his shop car back on the dyno this weekend I'm sure he will be testing it.

Have you tested a stock tune on a car with just the rev limit increased? Wondering if it would play nicer with stock hq and tq levels.

Also I know our trans is based off the is250 trans and looking at that the redline on that car is 6500 rpms or something. So it maybe the trans is already pushing hard to get to the stock 7400 redline.

The plan is to still shift the car at 7400 but now I don't have to deal with the jarring redline cutoff.

[naikaidriver]

I have been scouring the Technical Service Manual for the TX6A and what I have been able to come up with is that it looks like the Locking Clutch Assembly is controlled by several sensors including the Linear Line Pressure Sensor as well as Turbine Shaft Input Sensor, Vehicle Speed Sensor and ATF Temp Sensor.

It seems that in the event that the locking clutch mechanism disengages for any reason more than twice in a drive cycle, a P2757 code will be stored. One of the failure thresholds is if pressure to the Lock up Control Solenoid Instruction Valve reaches 513 kPa or more.

My first guess is that there is an threshold algorithm that is a combination of line pressure values, impeller speed, vehicle speed, and transmission gear that is being exceeded when RPMs exceed +/- 7500RPMs which would result in the locking clutch disengaging suddenly. I'm willing to bet that it would do this in 4th, 5th and 6th as well but please for the sake of public safety, don't try it on public roads!

My second guess (and more likely) is that the transmission control module (TCM) is trying to get the transmission to shift into 4th based on impeller speed and engine RPM but the manual shift control circuit is not allowing it to happen.

Of course, this is purely academic and I would STRONGLY suggest you do NOT allow the clutch assembly to disengage at that RPM due to the damage that it can cause to the clutches, the heat that it will generate and dramatic fluid pressure spikes that will result.

Scott

[feldy]

I took the trans to 8k more then once in the same drive cycle and never had a code pop up. I have been driving around for a bit testing it in first and 2nd with no issues. Then tested 3rd.

Like I said before I plan to shift at 7400 rpms still. And when ever Tony has a moment I will have him send me a revised flash with the rev limit set at 7500. Maybe this is something EcuTek can play with since there seems to be a ton of variables to play with. And looking up a new trans is a little over 3grand I don't want to be the one to have to replace one first.

[Captain Insano]

Originally Posted by naikaidriver

I have been scouring the Technical Service Manual for the TX6A and what I have been able to come up with is that it looks like the Locking Clutch Assembly is controlled by several sensors including the Linear Line Pressure Sensor as well as Turbine Shaft Input Sensor, Vehicle Speed Sensor and ATF Temp Sensor.

It seems that in the event that the locking clutch mechanism disengages for any reason more than twice in a drive cycle, a P2757 code will be stored. One of the failure thresholds is if pressure to the Lock up Control Solenoid Instruction Valve reaches 513 kPa or more.

My first guess is that there is an threshold algorithm that is a combination of line pressure values, impeller speed, vehicle speed, and transmission gear that is being exceeded when RPMs exceed +/- 7500RPMs which would result in the locking clutch disengaging suddenly. I'm willing to bet that it would do this in 4th, 5th and 6th as well but please for the sake of public safety, don't try it on public roads!

My second guess (and more likely) is that the transmission control module (TCM) is trying to get the transmission to shift into 4th based on impeller speed and engine RPM but the manual shift control circuit is not allowing it to happen.

Of course, this is purely academic and I would STRONGLY suggest you do NOT allow the clutch assembly to disengage at that RPM due to the damage that it can cause to the clutches, the heat that it will generate and dramatic fluid pressure spikes that will result.

Scott

As I originally theorized - this is tuning related. Software is controlling the disengagement in 3rd+ gears above 7500 RPM based on most likely several criteria. If it is software controlled, it definitely can be changed to stay engaged.

Is it good/safe to rev the AT to 7500+ RPM - who knows?
Is it good/safe to rev the engine to 7500+ - who knows?

Originally Posted by Visconti

Why has a tuner been selling flashes with a raised rev limiter when the tranny does this?

Anyone care to comment?

Visconti, the same argument could be made of your tunes allowing the MT engine to rev to over 7400 RPM. Is that safe? If so, why is the OEM rev limit in place??? Rather than trying to bash FA20club for working on a possible functionality enhancement for the AT requested by a customer, maybe you should contribute to the thread besides saying it is factory limited and insinuating FA20Club tunes are not safe. You don't think it's safe. Duly noted.

FA20club, possibly you could test this (or you already have) on your shop AT and let us know findings. Let us know whatever you think.

[feldy]

I was thinking of emailing Ecutek themselves to see if they have control over any of these variables and see if we can come up with a solution.

Agreed on keeping this civil. No bashing needed for any parties. Tony was simply doing what I requested.

[Visconti]

Originally Posted by Captain Insano

As I originally theorized - this is tuning related. Software is controlling the disengagement in 3rd+ gears above 7500 RPM based on most likely several criteria. If it is software controlled, it definitely can be changed to stay engaged.

Is it good/safe to rev the AT to 7500+ RPM - who knows?
Is it good/safe to rev the engine to 7500+ - who knows?


Visconti, the same argument could be made of your tunes allowing the MT engine to rev to over 7400 RPM. Is that safe? If so, why is the OEM rev limit in place??? Rather than trying to bash FA20club for working on a possible functionality enhancement for the AT requested by a customer, maybe you should contribute to the thread besides saying it is factory limited and insinuating FA20Club tunes are not safe. You don't think it's safe. Duly noted.

FA20club, possibly you could test this (or you already have) on your shop AT and let us know findings. Let us know whatever you think.

FA20CLUB has been selling a raised rev limit auto tune for a while telling customers that I simply was doing something wrong and that's why he could raise the rev limit with out issue and not me.

I've had several phone calls about this.

I'm glad finally someone post about this so people could see the snake oil he is selling.

His lack of input in this thread says it all.

I think we need to find out more info on the automatic transmission to see if it's a mechanical thing or software related.

Based on the extensive testing I've done on this months ago I'm almost 100% sure this can not be resolved with the engine ECU.

If it can be fixed with software I'm pretty sure it's going to be TCM software

Is this auto really the same as the IS250? Maybe we need to start checking out those forums to see what they're doing

-John

[naikaidriver]

Originally Posted by Visconti

Based on the extensive testing I've done on this months ago I'm almost 100% sure this can not be resolved with the engine ECU.

If it can be fixed with software I'm pretty sure it's going to be TCM software

Based on looking at the logic flows from the service manual and wiring diagrams for the TX6A transmission, I would agree.

If there are to be any significant changes to the behavior of the TX6A, it would be done through the TCM and not the ECU since it appears that the TCM primarily reports conditions to the ECU as opposed to receiving specific commands. The reasons I say this is because if you look at the component layout and wiring diagram, the VSC, Sport Mode, Snow Mode, Manual Mode buttons are all tied directly to the TCM as are most of the sensors and solenoids.

In the "old days" transmission behavior would be modified by changing out or modifying the valve body but in a modern, electronic auto, I would say that would be a recipe for a dramatic failure of the transmission without modifying the TCM.

Since this whole issue is hinged around the rev limiter, my opinion is to just keep the damn rev limiter where it is on autos. Those few extra RPMs just wouldn't be worth risking my transmission. But that's just my opinion.

Scott

[feldy]

one thing is for sure. These auto trans were built tough. Looking the numbers the turbo guys are putting down... I don't see any reason this can't handle a few more rpms if the tcm stuff can be taken care of.

[CircuitJerk]

Me personally, I think it's still a little too early in the game to be so optimistic.
Like I already suspected, and as Scott has put it into terms I think most of us can understand (thank you) you've got multiple things like the TCM, valve body and other mechanical and electronic factors to consider.
Just because the AT can handle some power, there's what, maybe 8-9 months of a few AT's on FI with numbers above 300? I'm just pulling random numbers out of my ass, but you get the point.

To me, even though it's supposedly built well and handles some decent power, I would NEVER assume that it should be okay because "They were sure built tough." There just isn't that much time and data to support that IMO.
It's almost apples to oranges on the subject of power handling capability, and where the subject is has headed.
I'd really hate to see you damage your ride

[UncleFester]

I bet its a software issue which results in a sort of safety disengage. Yes, the transmission is likely capable, but.... it was never designed to go past a certain point.

What I would like to know is when you are auto-crossing are you hitting the stock rev limiter? The auto has a taller gears than the manual. If the answer is no, then I wouldn't risk it. Thats my $.02.

[DR 86]

^ he's right. Why risk it for those few tenths? You're not a pro with sponsorship money backing you up, you autox for fun...think about how messed up you'd feel if you blew your tranny and had to fork out a few grand for a new one (not to mention labor and having to putt around in a corolla rental) lol!

[feldy]

Originally Posted by UncleFester

I bet its a software issue which results in a sort of safety disengage. Yes, the transmission is likely capable, but.... it was never designed to go past a certain point.

What I would like to know is when you are auto-crossing are you hitting the stock rev limiter? The auto has a taller gears than the manual. If the answer is no, then I wouldn't risk it. Thats my $.02.

This whole issue was not due to hitting the rev limiter in 2nd. It was always more about getting back into first earlier. Like I said before a lot of our courses are setup where if I didn't get back into first I was stuck in the tq dip in 2nd. Which then took forever to get out of. However its a moot point now since I had moved on to e85 which gets out of that dip a whole lot faster.

I don't plan to use my trans as a testing gini pig if you will. So no one get to excited. This whole thread was brought up as a review of the flash itself. Then it turned into this thread about the rev limiter in the auto trans.

[naikaidriver]

Originally Posted by DR 86

^ he's right. Why risk it for those few tenths? You're not a pro with sponsorship money backing you up, you autox for fun...think about how messed up you'd feel if you blew your tranny and had to fork out a few grand for a new one (not to mention labor and having to putt around in a corolla rental) lol!

Or a Prius! lol!

One thing about the "durability" of the TX6A. It can have the strongest planetary gears in the world and I have little doubt that while engaged, the transmission can handle a lot of power as has been well documented by AVO and FBM.

However, the times when an auto is most vulnerable to damage is initial starting from a stop and when shifting. Its difficult to make a strong valve body and I would be really concerned about fluid temps and pressures when your input shaft is spinning at >7500 RPMs and the locking clutch disengages suddenly. Besides, its been my experience that when an automatic fails, its a cascade of failure from there within the transmission and they end up looking like a bomb went off inside it.

Also, If it springs a leak at that pressure, transmission fluid goes everywhere, hits your exhaust, catches fire and burns your new car to the ground. Very nasty business indeed! I've seen it first hand!

Scott