Quote:
Originally Posted by nioh_lbbm2
Quote:
Originally Posted by msmiljanic
Quote:
Originally Posted by nioh_lbbm2
Guys it's important to note the limitations of your local fuel. The octane rating might not be very accurate depending on where you are which is why it is important to log your runs with each map.
"Stages" are a useless arbitrary term and in reality basically just refers to how much boost the map targets.
For example: even though you might have access to 93 oct gas in your area, it might not truly be 93 oct and therefore your car might respond better to the 91oct maps regardless of either stage 1 or stage 2. And even then perhaps
Mods play a part in your POTENTIAL to run higher boost (aka higher stages) but fuel is the ultimate limiting factor
Disclaimer: I am no expert but I like to read and gather as much information as I can to make informed decisions.
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In Texas, the dept of agriculture routinely spot checks fuel stations for octane levels, water, contaminants, distillation, vapor pressure, and ethanol. The octane level cannot be lower than the posted number. If found under the number, the TDA will place penalties and stop sales on the seller.
All that said in Texas, the posted octane is what you will get as a general rule of thumb. The detergent levels are a major difference where Shell has routinely tested the highest levels in their 93.
I do wonder if the map is possibly too aggressive relying on something slightly more than 93 since its an art not science. In other words, how does Halim make adjustments right up to 93 without causing a knock without extensive testing with exactly 93 octane fuel. If you are worried about knock damage(if that can happen in the n55), then it seems prudent to go with the 91 map or maybe the last release of the 93 that wasn't as aggressive.
Question for Halim - how do you know if your map has gone over the 93 threshold? Does it matter? |
Good points but I also want to add that our USA oct rating is AKI which is an average between two values: RON and MON
So possible variances between RON and MON value can still come to a "valid" AKI number but can affect your timings. Halim is in Denmark I believe so their fuel is RON
There is good 93 AKI fuel in the USA but since it varies so much from location to location taking logs to confirm your findings is the best thing to do |
Agree - 93 AKI = 97.4 RON. So if Halim is targeting and testing on anything more than 97.4 RON than the map would be too aggressive for US 93 fuels. We need to make some assumptions, so I will assume that Shell 93 is 93 AKI based on a reputable company and a seller that isn't purposely diluting or mixing to improve profit margins due to controls. I think the main questions I am trying to sort out are:
-how does Halim target a specific octane? Is it science? is it know how with testing? Or asked another way, how precisely does the 93 map target 93 AKI fuel?
Naturally there is a second question
-Does using an overly aggressive map for the fueled octane cause any damage?
The answer to these plus somebody's confidence in their fuel will tell them how to make decisions utilizing the various maps.
I have tested a couple times on the 5.5 map and I found one knock on one pull, and no knocks on others. I would have to do a lot of testing on stock, 91 map, and 93 maps to get enough data points to start making some kind of an assessment. It would be interesting to see if the stock gets knocks on 91. That would tell me BMW doesn't care if the knock sensors go off because they have systems to deal with it and thus they are not concerned about damage.