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4EAT Paddle shifters


presslab
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from what I remember (don't have anything in front of me, but have worked on many of both harnesses), the EG33 and EJ TCU plugs are the same. so swapping between those TCUs would be easy. if not, getting my hands on the plugs will be quite easy, so 3 sets of plugs would also be doable :lol:

 

 

You're probably right, the connectors do look the same. I know for sure however that the circuit board of the Legacy TCU vs the SVX are very different. It looks like the microprocessor is a different variant as well, although they have the same instruction set.

 

I also want to dig through some FSMs, and compare gear ratios, otherwise when the TCU compares the speed to what gear it should be in, things will work out. (my buddy had that problem when he put a jdm wrx 4EAT in his impreza LX. it worked fine, except the gear ratios were all off, and then when he put the jdm TCU in there, it was expecting a 7k redline, but the ECU would only allow 6200.)

 

I have found the gear ratio map:

seg006:D74D GearRatioMap:   fdb $B24                ; DATA XREF: CalcVSS1+4oseg006:D74D                                         ; 1st gearseg006:D74F                 fdb $62E                ; 2nd gearseg006:D751                 fdb $400                ; 3rd gearseg006:D753                 fdb $2C6                ; 4th gear

 

So it shouldn't be too hard to fix that problem, too. The TCU uses the gear ratio map to calculate the input shaft speed after the torque converter. This in turn is used for TC lockup and Duty C calcs.

 

Redline shift points are adjustable as well:

seg006:CDFF engineRedlineMap:fcb $5F                ; DATA XREF: LookupShift+4oseg006:CDFF                                         ; Gear 1seg006:CE00                 fcb $61                 ; Gear 2seg006:CE01                 fcb $62                 ; Gear 3seg006:CE02                 fcb $FF                 ; Gear 4seg006:CE03                 fcb $61                 ; Gear 1, manual modeseg006:CE04                 fcb $62                 ; Gear 2, manual modeseg006:CE05                 fcb $64                 ; Gear 3, manual modeseg006:CE06                 fcb $FF                 ; Gear 4, manual mode

 

For example, 1st gear $5F = 95 ($5F in decimal) * 64 = 6080 RPM

 

 

Another issue is with the differences in VSS signals; on the Legacy TCU the VSS2 was no problem as both the Legacy and the GL10 have 4000 pulse per mile. However it expects a 4.11 rear diff with larger tires so that ratio was off. I found the constant for VSS1 and corrected it. There is also a constant for the AWD slip detection that might need to be changed. Mine was only 6% off so it was no problem and I didn't change it.

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  • 3 weeks later...

wow. simply awesome work.

 

another solution to the rpm signal "issue" was presented to me this week. Tom'sSVX mentioned over on RS25 a digital speedometer signal modifier that can be adjusted to correct a VSS pulse for different tire sizes. he suggested it could be used to correct a tach signal to use a 4-cyl tach after an EG33 swap....

 

I'm thinking I could easily rig up a 4-cyl EA82 tach (only takes 3 wires...power, ground, and signal), and use it to calibrate the converter. then a 4-cyl TCU could be used pretty easily (that is, if reprogramming the code doesn't work...).

 

 

 

I'll definitely be in touch once the weather warms up. then I can get in there and wire in a set of EJ TCU plugs....make a wire to plug in my laptop....and start digging into code.

 

I was looking into FSMs, and a FWD 4EAT legacy has the exact same gear ratios (including a 3.7 axle ratio) as the XT6 AWD 4EAT. it just happens my EJ22 donor was a FWD 4EAT, and I saved the TCU (somewhere). might try to download the gear ratio maps and VSS signal stuff from it and program into an AWD TCU.

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I'm sure it's possible, but I believe it uses a different CPU; I haven't cracked the cover open on my ECU. It's a lot different, like Macintosh vs Windows. (Although those use the same CPU now.) :lol:

 

Are you interested in hacking the EA82 ECU?

Im gonna get my spare one, open it up and see if i can get some information on the CPU.

 

Ive read somewhere that the CPU is similar to the CPU found in Commodore64 gaming machines.

 

Ya rekon it is possible for us to go somewhere with this. My main goal would be just to modify fuel and timing.

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PressLab. hi mate, my names Rohan Maxim, i live in Queensland, Australia. (life story over) im blown away by this topic, and the other TCU modding on SVXFormums. i have a Brumby Ute with EJ22, 4EAT, 4.11 Lsd. i purchased this car off ebay sight unseen (iknownow) in the hope of saving a few bux, and buying already done. Not to be. shes a bit of a shipwreck, however i have re-wired the ECU and got the engine running. im a Fitter by trade, and NO electrician, however keen to learn.i know nothing on coding ecus. the TCU in my Ute went under water when the previos owner had it, and therefore doesnt work (to the best of my knowledge).

My Tranny is from a 93 SVX (apperently) and has a button for 'Manual' and a fuse for 'FWD', which i will hook to the handbrake (on rear)

 

could you tune up a TCU, for positive manual ectect. then sell it to me perhAPS.?? or help me work out the wiring on what is and isnt required and what hooks where? or whether i should get any other 4eat TCU?? hmm

im keen to keep the tranny as im planning on twin superchargers, and have heard that these SVXs are the strongest Subi boxs A/T or Manual.

 

More than impressed, Cheers, Rohan Maxim.

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Are you interested in hacking the EA82 ECU?

Im gonna get my spare one, open it up and see if i can get some information on the CPU.

 

Ive read somewhere that the CPU is similar to the CPU found in Commodore64 gaming machines.

 

Ya rekon it is possible for us to go somewhere with this. My main goal would be just to modify fuel and timing.

 

I wish I had a spare one, if I did I would crack it open and start hacking. So please do! Take some pics of the boards inside, the bigger the better so it is easier to read part numbers off the chips.

 

It would be very helpful to have the memory addresses for various things in the ECU. Anyone have access to a Subaru Select Monitor with a module for the EA82T? This could be sniffed to find the addresses.

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PressLab. hi mate, my names Rohan Maxim, i live in Queensland, Australia. (life story over) im blown away by this topic, and the other TCU modding on SVXFormums. i have a Brumby Ute with EJ22, 4EAT, 4.11 Lsd. i purchased this car off ebay sight unseen (iknownow) in the hope of saving a few bux, and buying already done. Not to be. shes a bit of a shipwreck, however i have re-wired the ECU and got the engine running. im a Fitter by trade, and NO electrician, however keen to learn.i know nothing on coding ecus. the TCU in my Ute went under water when the previos owner had it, and therefore doesnt work (to the best of my knowledge).

My Tranny is from a 93 SVX (apperently) and has a button for 'Manual' and a fuse for 'FWD', which i will hook to the handbrake (on rear)

 

could you tune up a TCU, for positive manual ectect. then sell it to me perhAPS.?? or help me work out the wiring on what is and isnt required and what hooks where? or whether i should get any other 4eat TCU?? hmm

im keen to keep the tranny as im planning on twin superchargers, and have heard that these SVXs are the strongest Subi boxs A/T or Manual.

 

More than impressed, Cheers, Rohan Maxim.

 

Thanks Rohan!

 

Did your Brumby come with a 4EAT? I don't think any Brat in the USA did. Or was it using a SVX TCU with the EJ22?

 

I can sure help you work out the wiring but I don't want to make a business of selling modded TCUs, I'm sure you understand. If you can find a '90 or '91 Liberty TCU it just might be the same as ours over here, that would be the easiest to get you going. Make sure it has pads for the ROM socket.

 

The SVX trannys are pretty strong, just keep the ATF clean and cool with an external filter and finned cooler. There are also mods you can do to make it even stronger.

http://www.ecutune.com/4eat.htm

http://www.levelten.com/store/subaru.htm

 

Sounds like a fun project, good luck!

Edited by presslab
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I wish I had a spare one, if I did I would crack it open and start hacking. So please do! Take some pics of the boards inside, the bigger the better so it is easier to read part numbers off the chips.

 

I will take a few photos in hi res.

 

It would be very helpful to have the memory addresses for various things in the ECU. Anyone have access to a Subaru Select Monitor with a module for the EA82T? This could be sniffed to find the addresses.

 

Looking at the wiring diagram for the 4 plug EA82T, it seems that the select monitor plug only gives information that the ECU sees, in analogue form, like MAF voltage, o2 sensor voltage, temp and throttle position. But i'll look into it for you.

 

 

Also, another question.... do you know anything about the transfer clutch in the 3sp subaru auto transmissions?

 

I want to run a 3sp in 4wd on the road, i was thinking of replacing the 4wd switch with a duty cylce generator and varying the torque to the rear wheels, do you think its possible?

 

Cheers

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I will take a few photos in hi res.

 

 

 

Looking at the wiring diagram for the 4 plug EA82T, it seems that the select monitor plug only gives information that the ECU sees, in analogue form, like MAF voltage, o2 sensor voltage, temp and throttle position. But i'll look into it for you.

 

 

Also, another question.... do you know anything about the transfer clutch in the 3sp subaru auto transmissions?

 

I want to run a 3sp in 4wd on the road, i was thinking of replacing the 4wd switch with a duty cylce generator and varying the torque to the rear wheels, do you think its possible?

 

Cheers

 

To my understanding the 3AT is a pure 4WD transmission, meaning there is a fysical link between the front and rear axle (not transfer clutches), just like the Part time manual boxes.

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  • 7 months later...
  • 3 years later...
To my understanding the 3AT is a pure 4WD transmission, meaning there is a fysical link between the front and rear axle (not transfer clutches), just like the Part time manual boxes.

 

Nope. Hydraulic transfer clutch. No duty cycle though.....either full pressure(4wd) or none(2wd)

 

It's possible a duty cycle driver could work on the 3at......the question would be "why?"

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  • 4 weeks later...

Here's a couple shots from the inside of the wheel. I built a wireless transmitter with a PIC micro, and I used an off the shelf receiver. The paddles themselves are from a wrecked 2012 Impreza. I'm happy to share the transmitter source code with anyone that wants it; it's pretty simple though.

 

IMG_20121222_162628.jpgIMG_20121222_162602.jpg

IMG_20121222_162539.jpgIMG_20130112_114346.jpg

P2130781.jpg

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  • 2 weeks later...
  • 4 weeks later...

Whoa dude.  That is flipping awesome.  Wow.  I am now going to be emailing you on how you did this for mine.  I have so wanted to put actual paddles into my setup forever and I was just going to swap in an entire steerin column from a new leggy.  But this, this is just freaking sweet man.  You got a PM regarding this as it is now moved to the very top of my mod list...  I have no money, but I will make this happen.  Way too cool man.  Way too cool.

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  • 2 months later...

Can you set it for a automatic/or paddle shifting? or does it remove the "automatic" part?

The automatic action is retained, it works as usual when not in paddle shift mode.

 

 

Now for an update:

 

I upgraded the trans recently with 4.11s, high stall torque converter, and valve body mods for improved shifting. It's awesome. The trans just clicks through the gears with no hesitation, the car lunges forward on the shift to 2nd.

 

One previous limitation of the paddle shifters was engine braking in 1st gear.  Depending on the selector position it would either have gears 1-4 and no engine braking in 1st or it would have gears 1-3 and engine braking in 1st. I sought to remove the limitation above and after poring over the diagrams I've done it by modifying the "overrunning clutch control valve".  By blocking off the "1st reducing pressure" port and also providing a bleed, it is now possible to select gears 1-4 when the selector is in the "2" position; this also provides engine braking in 1st gear by engaging the low clutch.

 

Yes, that's JB Weld in the valve body passage.  :P   The end plug also has a small hole drilled in it.

 

post-5988-0-92382800-1369409121_thumb.jpg

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