automatic ECU on manual car

[Cervantes]

I just found out that I'm running an automatic ECU on my manual transmission Legacy. It has not caused any issues at all, but is it hurting my car? Does it work the same for a manual transmission vehicle?

[chuckthefuk]

I cant say for sure but IIRC Auto vs Manual ECU's have specific tunes from the factory. They take into consideration the gearing and power output.

I know that the majority of Auto -> Manual swaps who keep the Auto ECU have to ground out the Pins for the TCS.

Regardless if you tune your car at one of the many local Japanese shops you will be laughing~!
-Chuck

[Cervantes]

The 2 ECU's are identical, no extra ground wire, and it plugs right in. I just swapped them out and can tell a difference in performance. The original ECU has the car responding better and accelerating faster. The auto ECU is a Mines 1, but the original ECU seems to out-perform it.

[ouch1011]

Mine is a BD and non turbo, so a little different, but the only problem I had using a 4EAT PCM with my 5MT conversion was that it never idled right, regardless of whether the trans selection wire was grounded or not. And actually, I'm running a 98 2.5RS 5mt PCM now, and it runs perfect.

And I don't think the tune is any different between the 4EAT and 5MT. I think the only thing that changes is the behavior during shifting, which is basically just the TCM sending a signal to the PCM to reduce the requested torque, basically the same as if you let off the gas pedal a little. And, of course, the idle.

[hansvonaxion]

The autos make less power, torque and have a lower redline iirc, so it makes sense that a manual ECU will outperform an auto. They also have a different final drive ratio.

[Matty2Hotty]

Hmmm wonder if I would blow up my tranny if I swapped in a 5MT ECU in my Auto.

[PHATsuby]

Hmmm wonder if I would blow up my tranny if I swapped in a 5MT ECU in my Auto.

If you could swap them, likely not as the TCU is the still controlling the tranny and it is just taking certain inputs from the ECU. As long as the pinout for those inputs are the same it will likely be fine.

That being said, the ecu trigger info for the manual BE's is different than the Auto's(at least in the US for the 2001 models it was) so it would actually not run your car at all.

Ben

[ouch1011]

The autos make less power, torque and have a lower redline iirc, so it makes sense that a manual ECU will outperform an auto. They also have a different final drive ratio.

This is probably true on the pre-04 Turbo cars, but not the N/A. Just throwing that out there.

[hansvonaxion]

Right, he was talking about his 2000 turbo so that's what I was referring to, NA's are a different story.