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5EAT TCU Reverse Engineering


utc_pyro

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The Cobb flash changes something in the flash init handshake to cause ECU Flash and the SSMIII to fail. If someone wanted to sniff the communications similar to what I'm working on, you could find a way to read it with ECUFlash. Probably not worth it though, might as well just buy accesstuner race or unmarry and use ECUFlash for a new tune.

 

Dont worry, I haven't forgotten about hacking the TCU. Just busy with my Embedded Systems class. I'll get back on it after I figure out how to get a FPGA to read twitter.

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I just want to say that I am so proud of you guys in this thread. To have taken the initiative and succeeded in getting this far already.

 

I am confident that the best 5EAT "shift kit" ever will come from the research and info generated by this thread.

 

Keep up the great work. You all deserve a "regular guy" beer commercial in your honor.

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How do you think the resistor will effect the minimum line pressure? I'd hate to put a constant strain on everything by increasing the "resting" line pressure.

 

It will probably increse that more than anything actually. It wont add much more strain, and it will actually make the transmission last LONGER. Clutches tend to go out before anythign else on an automatic, this will add life to them from less slip.

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Are there any theoretical ill effects from cranking up line pressure all over the map? Such as wearing out solenoids any earlier? I highly doubt it, but just want to double triple check. Haven't come across a single concern of this anywhere, but it's good to check because my plan has been and still is to raise line pressure to the highest tolerable amount everywhere (except at low rpm low throttle because of some slamming shifts associated with a pre-worn clutch pack or belt somewhere in there... yes I'm too cheap for a rebuild at this point)
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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That's exactly what I was wondering. But the more I think about it, the more I realize that if the solenoid is capable of 1690 kpa (what ever the hell that is), then increasing the minimum to 600 or 700 will probably have no negative effects. It would create more heat, but that would be negated by the reduction in heat from the clutches.

 

It would be great if we could get that 1st gear launch pressure in all shifts.

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That's exactly what I was wondering. But the more I think about it, the more I realize that if the solenoid is capable of 1690 kpa (what ever the hell that is), then increasing the minimum to 600 or 700 will probably have no negative effects. It would create more heat, but that would be negated by the reduction in heat from the clutches.

 

It would be great if we could get that 1st gear launch pressure in all shifts.

 

MORE heat? Because of pressure? Probably negligible compared to the heat produced from friction. Slipping clutches and aggressive TC stall (like brake torquing) are two things that can produce a lot of heat.

 

Either way, I still think all this talk of heat is over rated.

 

Want to hear something funny? I have been running all this time without a trans cooler, and never once did I feel the the trans act like the fluid was too thin or too hot. Granted I've never tracked it either, and don't do too much crazy too it, and have Amsoil which helps a lot.

 

On the other hand, my Avalon NEEDS a cooler for stop-and-go on the baking hot highways during Texas summer. Shifts start to get pretty crappy and rough after 10 minutes of that. Avalon yes to cooler. Subaru, doesn't really appear that necessary at least in my singular experience.

 

And now we have the means to check the actual fluid temperatures!!!

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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I agree that increased heat from the solenoids is negligible. It is probably not enough to raise the temps by a degree.

 

I feel like the fluid is thinning out after I beat on it. But I'm using stock fluid with who knows how many miles on it. I'm glad to know that I can actually check it now.

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Just a heads up guys my trans filter seemed to back itself out and leak out my ATF so just a word of advice take the 5 minutes to pull your battery out and make sure ur filter is snug.... and if you have some miles on your car why not be nice and change it.
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I've been out of this for a while (long story), but any one happen to find a M32R JTAG tool so I cant open this thing up? Some of the early EVO guys used one, so if we could find that we'd have more of a chance.

 

That or I can send the test TCU to someone else (Coby?) with pooled cash to break it open. I'd be good for $200 on that fund. He already has the tools, as he cracked the 2.5RS ECU. It's just the problem of getting him motivated on something that wont sell many more cables part.

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I've been out of this for a while (long story), but any one happen to find a M32R JTAG tool so I cant open this thing up? Some of the early EVO guys used one, so if we could find that we'd have more of a chance.

 

That or I can send the test TCU to someone else (Coby?) with pooled cash to break it open. I'd be good for $200 on that fund. He already has the tools, as he cracked the 2.5RS ECU. It's just the problem of getting him motivated on something that wont sell many more cables part.

 

I would toss in some money if it'll help

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