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View Full Version : JDM ECU...HP Increase?


huck369
06-20-2010, 06:37 AM
I have in my possession a JDM SVX ECU (and TCU), anyone know if it would give any gains in HP or Torque, when plugged into a USD SVX?

Sean486
06-20-2010, 07:46 AM
Where did you find that? I thought they very hard to come by.

1986nate
06-20-2010, 08:36 AM
I have in my possession a JDM SVX ECU (and TCU), anyone know if it would give any gains in HP or Torque, when plugged into a USD SVX?

I don't believe so Huck. The main difference is that the JDM won't look for anything related to the EGR since JDM motors didn't have them.

huck369
06-20-2010, 12:49 PM
Where did you find that? I thought they very hard to come by.
A XT buddy Down under bought a JDM clip, I got a few things from him before he scrapped it.
I don't believe so Huck. The main difference is that the JDM won't look for anything related to the EGR since JDM motors didn't have them.
I was hoping for a more definite than "I don't believe so"...anybody know for sure?
Thought I might drop it into FrankenWedge(which is currently running a 95 US-ECU...)

Cam
06-20-2010, 12:52 PM
Test it with your butt dyno :D

huck369
06-20-2010, 12:55 PM
I may throw it in to see if I can "Feel" any difference...I don't figure it can hurt any.

longassname
06-21-2010, 08:41 AM
I'll trade you a stage 1av1 for them. That will make your car faster.

huck369
06-21-2010, 11:00 AM
I'll Probably take you up on that Mike...

Sean486
06-21-2010, 11:13 AM
My though was that the TCU would be extremely valuable to someone looking to swap in a JDM auto transmission. Especially since they are available and cheap. But even better would be to have someone reverse engineer it then offer it as an TCU upgrade option on their website. (hint, hint LAN) :lol:




Not sure if such a thing is possible, but I can hope!

b3lha
06-24-2010, 05:56 PM
I have in my possession a JDM SVX ECU (and TCU), anyone know if it would give any gains in HP or Torque, when plugged into a USD SVX?

Do you know what year they are from?

The JDM ECU maps are different to USDM, they are optimised for higher octane fuel. Like Nate said, no EGR. I've run a JDM car on a UK ECU which is similar to maps and didn't notice any performance difference.

The TCU won't work properly with a USDM gearbox.

even better would be to have someone reverse engineer it

Already been done.

TomsSVX
06-24-2010, 06:40 PM
Do you know what year they are from?

The JDM ECU maps are different to USDM, they are optimised for higher octane fuel. Like Nate said, no EGR. I've run a JDM car on a UK ECU which is similar to maps and didn't notice any performance difference.

The TCU won't work properly with a USDM gearbox.



Already been done.

JDM TCU hardware is different as well.... Needs to interpret the speed sensor signals properly. Even with JDM firmware the US TCU will not take into account the proper speed from the #1 sensor to match the #2

Tom

huck369
06-24-2010, 07:02 PM
I don't recall, and Michael has them now, he might be able to cross reference the numbers to find out.

b3lha
06-25-2010, 03:26 AM
JDM TCU hardware is different as well.... Needs to interpret the speed sensor signals properly. Even with JDM firmware the US TCU will not take into account the proper speed from the #1 sensor to match the #2

Tom

Are you sure you're not confusing it with the Euro/Aussie TCU? JDM and USDM use the same speed sensor arrangement.

I've inspected the hardware of JDM, USDM and Euro/Aussie TCUs. The JDM and USDM are almost identical. The only difference is a couple of extra components on the USDM (presumably to handle the atmospheric pressure signal).

I built some custom TCUs for Ron based on JDM firmware running on USDM hardware and they work very well.

The Euro/Aussie unit is very different. They use the different speed sensor arrangement and don't work properly with JDM/USDM firmware.

TomsSVX
06-25-2010, 04:45 AM
Positive... Even with the JDM firmware loaded into the US TCU of mine, the forward speed sensor was not reading the same as the rear

Tom

longassname
06-26-2010, 07:48 AM
I got the JDM ECU and TCU from Huck. They look to be 94 JDM units matching what Phil already has on his website.

stevek
07-14-2010, 02:15 PM
Well, if it helps I have a JDM SVX, which I run on 'Tesco 99'. It appears to be significantly quicker than the wife's 3.0 A4 Quattro. Both have similar weights and claimed bhp. Audi brakes, however, are awesome.... sorry guys.

NeedForSpeed
07-17-2010, 10:58 PM
Positive... Even with the JDM firmware loaded into the US TCU of mine, the forward speed sensor was not reading the same as the rear

Tom

Were you running your 3.545 VTD box with JDM firmware?

b3lha
07-19-2010, 06:10 AM
Were you running your 3.545 VTD box with JDM firmware?

That would definitely explain it. There's a value in the TCU that needs to be calibrated to the diff ratio to make things work properly.

longassname
07-29-2010, 09:05 AM
Does it work the same on the US type as the VTD? If you could publish it that would probably be a good thing for all the people running 4.11s and 4.44s to modify on their cars.

That would definitely explain it. There's a value in the TCU that needs to be calibrated to the diff ratio to make things work properly.

b3lha
08-09-2010, 08:30 AM
Hey Michael,

How's your software coming along? The one that lets people tune their ECU?

Phil.

longassname
08-09-2010, 11:34 AM
I haven't worked on it since getting it to work for downloading that 96 TCU bin. I'm going to release it as copyleft freeware so even if I don't finish it I'll publish what i do have done complete with source code.


Hey Michael,

How's your software coming along? The one that lets people tune their ECU?

Phil.

BRZCory
05-15-2013, 02:38 PM
what software are you working on now?

I might have a go at decoding some of the ECU if I get bored.

bishop
05-15-2013, 02:47 PM
Check your dates, you bumped a thread from 2010.

though i am curious about an option to tune these cars ourselves, i do have a friend with a 4 wheel dyno i wouldnt mind throwing my car on eventually to try and tune.

'E'
05-15-2013, 03:49 PM
Well, if it helps I have a JDM SVX, which I run on 'Tesco 99'. It appears to be significantly quicker than the wife's 3.0 A4 Quattro. Both have similar weights and claimed bhp. Audi brakes, however, are awesome.... sorry guys.

My brembo brake kit would fix the Svx braking for you....

http://www.subaru-svx.net/forum/showthread.php?t=60338

BRZCory
05-15-2013, 04:04 PM
Check your dates, you bumped a thread from 2010.

though i am curious about an option to tune these cars ourselves, i do have a friend with a 4 wheel dyno i wouldnt mind throwing my car on eventually to try and tune.
True true.

If you check the alcyone website, everything you need to tune yourself is on there, it just takes a bit of learning before you can use it.

For example, they've got rom dumps of all the different SVX ECU's, so with rom raider you can look at this in a nice graphic format, and change values (after you find a definition file that works for them, the alcyone website definitions file wouldn't work with the 1994 usdm SVX ecu .bin file that they hosted, but I found another one that would work). Next step would be to build yourself a memory adapter that he posts a blueprint/diagram for (or buy one from ecutune, your final price is the same, but the ecutune is easier, vs the DIY which nets you 3 instead of 1 board). Then you just go to ebay and buy a $20 chip burner, digikey for the electronic components, and assemble it all together.

Then you get the fun of changing values, plugging the chips in, testing, going back and chanigng more values, plugging in, testing, and on and on until you have a tune you like.

The problem I'm having is that we've only got addresses for the fueling, timing, and timing advance tables. So, if you want to switch mafs or injectors, I still need to find the addresses for those scaling tables.

Which is where we get into disassembly, and a whole lot more guessing and checking. Disassembly literally involves changing the binary code into hex, and then hoping you can convert the hex into subroutines with your mind by looking for certain markers (Hint, the values for things like the coolant temp sensor and maf are easily found from the SSM subroutine), and then follow those subroutines to see where they get their data from, which is the scaling tables!

Then you add those locations to the Rom Raider definitions, and you get more nice pretty tables to modify, burn, test, re-modify, etc.

So yeah, this isn't exactly for the feint of heart, or the people with busy lifestyles!