[wakeupearly95]

Hello everybody,

I have a car 335i E90 {N55 PWG}.

I did all modifications what is neccessary to flash {MHD stage2+}. My current setup is for 98RON fuel. Mostly in my country 98RON fuel is available and sometimes even more.

If I flash again {MHD stage2+} and I will choose 102RON and actual fuel will be 98RON or 100RON this will damage my car ?

Also, does it give me a better performance ?

Thanks !

[wakeupearly95]

Noone ever tried this ?

[wheela]

If you flash a map for higher RON than your actual gas, the map will be more aggressive (most likely in form of more advanced ignition timing) than your actual fuel octane can support. This means you'll likely get some knock that the dme will detect, and respond with timing corrections. It will be harder on your engine than selecting a map that matches your actual fuel, and may actually feel slower due to losing ignition timing through the timing corrections that will occur. It's your car, but I would not recommend doing this.

Always log and look for timing corrections. Alot of people end up doing the opposite of what your're proposing - they aren't happy with the corrections they see when using the correct octane map for their fuel, so they end up flashing a map for lower octane than their actual fuel to clear up the timing corrections.

[wakeupearly95]

Originally Posted by wheela

If you flash a map for higher RON than your actual gas, the map will be more aggressive (most likely in form of more advanced ignition timing) than your actual fuel octane can support. This means you'll likely get some knock that the dme will detect, and respond with timing corrections. It will be harder on your engine than selecting a map that matches your actual fuel, and may actually feel slower due to losing ignition timing through the timing corrections that will occur. It's your car, but I would not recommend doing this.

Always log and look for timing corrections. Alot of people end up doing the opposite of what your're proposing - they aren't happy with the corrections they see when using the correct octane map for their fuel, so they end up flashing a map for lower octane than their actual fuel to clear up the timing corrections.

Thanks for your time !

Your explanations are always interesting.