Copied ROM, how do I flash it onto ECU?

[salvi]

I'm practicing with ECU flash and I was able to copy my ECU rom and save it. 2005 USDM STI. Now, I want to practice actually flashing the ROM back onto the ECU. How can I do this?

Also, someone previously stated that the size of the rom had to be 192kb that it was 160kb that you have to make it to 192kb. The rom that I created is 1MG in size. Can someone explain this please?

[Freon]

The DBW (basically any 2.5L Turbo) are 512kb or 1024kb ROM images. 04+ USDM STI, Forester XT, LGT, 06 WRX, Baja Turbo, etc.

If you can read it, you should be able to write it. There are instructions elsewhere, but basically you just do the same thing as you did to read it out, but press the button i EcuFlash that says "write" instead...

[salvi]

Ok, so my 1MG rom image is just fine.

Now, lets say that a friend of mine uses OpenECU software and tunes his car. If we have the exact same mods, I should be able to read his Rom, save it, and reflash my ECU with it in the same way right?

[Freon]

If your ECU hardware is identical, yes, it should work. But it would probably be safer to download the other car's ROM and just copy the map data with the tuning software.

[salvi]

Which software do I use and how do you do that? I thought ECUFlash was for that?

[JRSCCivic98]

Don't take this the wrong way, but maybe you should read more before you kill something.

[intrawrx]

I'm all for trying new things, but blindly flashing on someone elses rom could be fatal..

Not just the actual re-write but the rom's parameters.

No two cars are ever "EXACTLY" the same.

[JRSCCivic98]

It's true that no two cars are the same, but if it's an OTS map... it's made for diverse conditions and setups. So, as long as it's (let's say) a performance Stage 1 map made for a "stock car" and as long as the 2 cars are the same year and model and the flash is compliant with both ECU versions, then there would be no issues. Glad I could clarify that...

[intrawrx]

Well , lets hope its for everyday enviromentals

[salvi]

If no two cars are the same, how do companies like Coob, Vishnu, etc. create maps for the great diverse of climates and locates? With their maps, they just require the parts, but the exact parts, otherwise everyone would be running Cobb DPs. If we both live in the same city and he tunes his car with the same mods as I have, I should be able to just copy his rom and flash my ecu with it right?

[intrawrx]

There are set tolerances (in theory) to how lean an engine to get too, also the great thing about the stock ecu is that since it has some smarts about knock and how badly your engine it behaving, it will reduce the amount of KC or use the HI-DET fuel map to try and save itself.

However i think there's a point where it can;t do much more and then it gives up the ghost.

Please correct me if im wrong however.

[Freon]

There are some other problems here. Realize the following:

A custom tuned map is going to have the least room for error. It should run the turbo, injectors, EGT, and/or timing, etc. at the hairy edge of safety. This is acceptable because it is a specific tune for that exact car, so you know how it is running.

Cobb OTS maps purposely are leaving more safety room since cars will vary. Even the stage 0 (no aftermarket mods) is going to leave room for a better custom tune.

Two modded cars, even with the same mods, cannot match the accuracy and tolerance of a factory built car. Factories run under very stringent quality assurance standards because their profit depends on super low failure rates. I imagine a factory car has the failure rate 1/100th a moderately modified car.

The factory engine management package is smart in two ways: the ability of the logic (to adjust to changing atmospheric conditions, bad gas, etc), and the actual data maps being properly calibrated. It's both the logic and the data behind it that make it work so well. Reflashes are mainly a data/mapping update, so the logic is still there to adjust for climate, dirty air filter, etc. This is why reflashes work at all. Changing the data only is plenty effective.

You never know what your buddies custom tune is tuned around. It could be there was a small leak in the charge air piping, and the tune had (possibly unknowingly) been tuned around that. So if you slapped it on, your car would run lean. You *think* your car may be mechanically identical, but chances are (see above about tolerance of a factory car vs. modified) there are more differences than you think.