ECU tune Transmission control unit?

[NeedForSpeed]

Originally Posted by longassname

The 97 TCU I have is much smaller. The plugs are the same as on earlier models but the electronics are different. The two letter code is MY.

Michael,
I asked Glenn/RojoRocket to take a picture of the TCU case on his ebony 97. Using a mirror to see it, the information on the case reads:

QL
31711-AD720
A64-00 DDE

I hope this information will help you determine if your MY is a 97. With the low production volume of 97s, it would seem that you may not have a 97 SVX TCU?

[cdvs]

Info collected when I had the TCU & ECU removed. I have pictures. Someday, I may post them.

OBDII USDM 96

TCU
Case: MY / 31711 AD123 / A64-000 DX5 6131
MCU: 84 pin TN87C196KH / L5284875A / (m)(c)'86'91 / White label E3FA301J
Board: A64-001 D42 [4]
Ceramic Resonator marked 8.00T / 67 ohm (2nd line not clear)
Connectors are same as OBDI

Subaru Parts has multiple numbers for 96-97

[longassname]

The 96 TCU I did was labled MQ and is under the steering column. It uses the same processor as the obd1 cars and I have done the ECUtune performance mods to it, given the firmware to Phil, and posted the code for the ECUtune mods to Phil's gearshift map thread.

The TCU I have as a 97 is the same as your MY. So I guess there is a break somewhere in 96. The MY uses a different processor and does not have an external memory socket.

Originally Posted by cdvs

Info collected when I had the TCU & ECU removed. I have pictures. Someday, I may post them.

OBDII USDM 96

TCU
Case: MY / 31711 AD123 / A64-000 DX5 6131
MCU: 84 pin TN87C196KH / L5284875A / (m)(c)'86'91 / White label E3FA301J
Board: A64-001 D42 [4]
Ceramic Resonator marked 8.00T / 67 ohm (2nd line not clear)
Connectors are same as OBDI

Subaru Parts has multiple numbers for 96-97

[cdvs]

Confirmed. I believe it is flashable, at least in theory.

Originally Posted by longassname

The MY uses a different processor and does not have an external memory socket.

[NeedForSpeed]

Michael, looks like your MY is confirmed as a 97 SVX

So, Glenn's QL, a second 97 TCU?
Also, what letters were on your 96?

[longassname]

The 96 I did was labled MQ. Does Glenn's QL look like it mounts under the steering column or on the passenger floor?

Originally Posted by NeedForSpeed

Michael, looks like your MY is confirmed as a 97 SVX

So, Glenn's QL, a second 97 TCU?
Also, what letters were on your 96?

[NeedForSpeed]

Originally Posted by longassname

The 96 I did was labled MQ. Does Glenn's QL look like it mounts under the steering column or on the passenger floor?

Not on the passenger side, it mounts under the steering column, with plugs at bottom of TCU, easy to get at. I fitted a wire to the power mode location.

[longassname]

I guess you have the 97 fsm update with the wiring diagrams? I've been told the 96 has different wiring than the obd1's and that the 97 has a bunch more wires than that. If you can post it it probably wouldn't hurt to have it archived here.

Originally Posted by NeedForSpeed

Not on the passenger side, it mounts under the steering column, with plugs at bottom of TCU, easy to get at. I fitted a wire to the power mode location.

[NeedForSpeed]

Originally Posted by longassname

I guess you have the 97 fsm update with the wiring diagrams? I've been told the 96 has different wiring than the obd1's and that the 97 has a bunch more wires than that. If you can post it it probably wouldn't hurt to have it archived here.

Sorry, neither Glenn or I have a 97 FSM

[longassname]

In addition to making your SVX drive better and be faster and have better fuel economy ECUtune performance TCUs now prevent high clutch and brake band burn out so you can now protect your transmission with a simple plug in that can be installed in just a few minutes.

Almost all SVX transmission failures are high clutch and brake bands burnt out from slipping under light cruise in 3rd and 4th gear. The TCU controls solenoid a which is a bleed on line pressure--ie the valve opens to create a leak and reduce line pressure. The higher the solenoid a duty cycle the larger the leak and the lower the line pressure. The TCU adjusts line pressure through solenoid a duty cycle mainly according to throttle position sensor readings.

The stock maps for 3rd and 4th gear are the same and look like this:



The ECUtune maps for 3rd and 4th gear look like this:



With the ECUtune maps close to full line pressure is maintained under light cruise preventing high clutch and brake band burn out.

[Sean486]

Originally Posted by longassname

With the ECUtune maps close to full line pressure is maintained under light cruise preventing high clutch and brake band burn out.

If we already own it, will you make it available as an upgrade?

[longassname]

Yes the upgrade chips are available on the website: http://www.ecutune.com/tcu.htm

Originally Posted by Sean486

If we already own it, will you make it available as an upgrade?

[svxfiles]

Originally Posted by longassname

In addition to making your SVX drive better and be faster and have better fuel economy ECUtune performance TCUs now prevent high clutch and brake band burn out so you can now protect your transmission with a simple plug in that can be installed in just a few minutes.

Almost all SVX transmission failures are high clutch and brake bands burnt out from slipping under light cruise in 3rd and 4th gear. The TCU controls solenoid a which is a bleed on line pressure--ie the valve opens to create a leak and reduce line pressure. The higher the solenoid a duty cycle the larger the leak and the lower the line pressure. The TCU adjusts line pressure through solenoid a duty cycle mainly according to throttle position sensor readings.

The stock maps for 3rd and 4th gear are the same and look like this:



The ECUtune maps for 3rd and 4th gear look like this:



With the ECUtune maps close to full line pressure is maintained under light cruise preventing high clutch and brake band burn out.

OK, Mike, I want to be sure that I understand exactly what you are saying.
With the new TCU chips, (got the box today)
It's not just the shift points,
that are changed, (how long it stays in the lower gears)
but also the line pressure once in gear.

So evan if people only go for the ECUTune TCU, and not the valve body, they should have firmer shifts (as well as using the lower gears better)?

And if they get the valve body it flows more ATF for longer life and cooler running.

[Huskymaniac]

Originally Posted by svxfiles

OK, Mike, I want to be sure that I understand exactly what you are saying.
With the new TCU chips, (got the box today)
It's not just the shift points,
that are changed, (how long it stays in the lower gears)
but also the line pressure once in gear.

So evan if people only go for the ECUTune TCU, and not the valve body, they should have firmer shifts (as well as using the lower gears better)?

And if they get the valve body it flows more ATF for longer life and cooler running.

OK, you (sort of) tried to hide this:

"as well as using the lower gears better"

Does the debate of the benefit of driving in lower gears live on? Or was there eventually a consensus on this subject? I have heard and read varying opinions recently.

I've read some people claim that running higher RPMs causes the oil pump to pump harder which causes flow and/or pressure to increase and then I read some others claim that flow and pressure is independent of RPMs.

I've read something about torque multipliers when in the higher gears and that this is bad but I didn't fully understand why. Perhaps related to this was a claim that running low RPMs in a higher gear results in more torque being generated which stresses bearings and other parts and causes them to overheat.

And then there was a discussion about heat generation where some people claimed more heat was created in the higher gears where others said that the system is less efficient at lower RPMs so more power would be lost causing the heat load difference to be a wash.

[longassname]

I don't think Tom was considering or mentioning that line of thought at all. He's not talking about driving in 3rd versus 4th. He's talking about it staying in 1st and 2nd longer and not having to floor the car to get it to downshift into 1st.

I think we can all aggree that you should be able to/should want to be able to/it's reasonable to want to be able to drive your car in 4th gear without worrying about your transmission failing.

That's what the modification to the line pressure maps for 3rd and 4th gear in the ECUtune performance TCU is all about. The ECUtune performance TCU gives you just about the maximum available line pressure during light cruise so you can drive your car in either 3rd or 4th gear without fear.

Originally Posted by Huskymaniac

OK, you (sort of) tried to hide this:

"as well as using the lower gears better"

Does the debate of the benefit of driving in lower gears live on? Or was there eventually a consensus on this subject? I have heard and read varying opinions recently.

I've read some people claim that running higher RPMs causes the oil pump to pump harder which causes flow and/or pressure to increase and then I read some others claim that flow and pressure is independent of RPMs.

I've read something about torque multipliers when in the higher gears and that this is bad but I didn't fully understand why. Perhaps related to this was a claim that running low RPMs in a higher gear results in more torque being generated which stresses bearings and other parts and causes them to overheat.

And then there was a discussion about heat generation where some people claimed more heat was created in the higher gears where others said that the system is less efficient at lower RPMs so more power would be lost causing the heat load difference to be a wash.