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I've tryed to fit the M3 eprom in the 320is ECU but it really dont fit.
The car started but it has idle problems, etc.

I've tryed also to copy both the ignition advance and the injection timing of the M3 eprom file into the 320is eprom file, the copy was successfully, but the 320is performs really poor.

To the ones that tryed to simply fit the eprom of an M3 in the 320is and they were not able to start the car: i can say that it dont depends on the values in the eprom file but only on how BIG is the file.

In other words: all the eprom files in every 320is/M3 are 32kb (eprom # 27c256) or 16kb (eprom # 27c128) only.
A 32kb eprom in an ECU slot that is made for the 16kb eprom won't make the car start.
The same problem switching 16kb for 32kb.

I run a 320is eprom in my M3. it works fine, so you're right that it does not depend on the actual values for ignition timing and fuel delivery but on the size of the data.
320is ignition values are 'hotter' (more advance) than M3 values so no point in putting an M3 eprom in your 320is. Fuelling is probably also tuned more towards power than low emissions in 320is, not the least because it has no cat, so also in that respect you don't want to put an M3 eprom in your 320is

...for the reply.

After those runs i described in the first post, i've added more advance to my 320is at low and medium load sites (cause adding at high had given loss of power even if without knocking).

The dyno test reported almost the same power (186cv tuned vs 184 original) but +10Nm ( ) torque in the 2000-2500 rpm range with the original airbox.

i've set the rev limiter to 7800 rpm cause the power/torque curves where almost straight lines from 1500rpm to the stock rev limiter.

The dyno owner tells me that he had never seen anything like that in a 16 years old car (or in other cars ) and that this power diagram shape was really 'weird' without having tuned cams. He did repeat the test (free of charge of course ) but with the same results.

This 'tuned cams' issue remind me something that my machanic told me.

He said, after the head gasket work, that he had 'well' tuned the overlap during the engine refitting.