JDM ECU...HP Increase?

[stevek]

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]

Originally Posted by TomsSVX

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]

Originally Posted by NeedForSpeed

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]

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.

Originally Posted by b3lha

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]

Hey Michael,

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

Phil.

[longassname]

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.

Originally Posted by b3lha

Hey Michael,

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

Phil.

[BRZCory]

what software are you working on now?

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

[bishop]

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']

Originally Posted by stevek

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]

Originally Posted by bishop

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!