[mtoosexy]

Originally Posted by zero21

It's more of a hobby thing.

Hell I do it with my golf clubs, tennis rackets, gun, cars, guitar, house, suits, watches, you name it Everything gets "the treatment".

If you arent tuning these with better aftermarket parts... you are doing something wrong

[aerobod]

The S58 in the M2 probably won’t benefit from 93 vs 91 octane at an altitude of 1500m / 5000’. Assuming about 1.3 bar (19 PSI) maximum indicated boost pressure, the atmospheric pressure is 0.85 bar, so the absolute intake pressure is 2.15 bar vs 2.3 bar at sea level, so only 93% of the potential maximum air intake. This should be enough margin that 91 will allow the max boost at 1500m without ignition timing being pulled, compared with at sea level.

[Ghostrider.1127]

Originally Posted by Albator_IIII

The sticker likely will say that due to market availability of 93 octane. However, the manual clearly says 93. The car will be "fine" with 91 but will not be running optimally.

All bmw come with knock sensor , so not really an issue ( only on dyno you gonna see differences ) but yes as stated with 93(98) or 96 (102/103) sure they gonna run well

[zero21]

Originally Posted by mtoosexy

I NEVER fill my tank more than 1/2 full in anything but my daily. At 6.3 lbs per gallon, why carry around gas i won't need for a few weeks. I drive spirited, but never far. One of my garage babies only ticked 120 miles last year and 90 the year before that.
Bunch of mentions in these forums about the need for forged wheels due to weight, the need for carbon roof due to weight, hate for the electric seats due to weight. This widdle m2 ��piggie needs to go on a diet. I am going forged, the carbon roof, the carbon buckets(perhaps upgrading to a lightweight racing seat-driver side only :/), and saving +/- 40 lbs in gas Hell, i even dropped 10lbs myself to bring down the overall weight. I will likely go for an exhaust that saves another 10-15lbs. Bring on the carbon hood replacement!
To each his own thought, right?

Several exhaust solutions save more than 40lbs, but that's not the greatest place to remove weight. Unprsung and top of the engine/hood should be first thoughts.

Just FYI, short hard runs require extra attention to maintenance. The BMW manual considers this type of driving "severe duty" (trips less than 5mi). Sounds like you're probably over 5mi per trip but just putting this out there.

[RockCrusher]

Originally Posted by aerobod

The S58 in the M2 probably won’t benefit from 93 vs 91 octane at an altitude of 1500m / 5000’. Assuming about 1.3 bar (19 PSI) maximum indicated boost pressure, the atmospheric pressure is 0.85 bar, so the absolute intake pressure is 2.15 bar vs 2.3 bar at sea level, so only 93% of the potential maximum air intake. This should be enough margin that 91 will allow the max boost at 1500m without ignition timing being pulled, compared with at sea level.

That wasn't my experience with my Porsche 996 Turbo. Porsche calls for 93 but says 91 is acceptable.

Ran 91 for years then on a road trip was able to fill the fuel tank with 93. Even at 8K or more feet above sea level the engine ran noticeably better.

The reason is the engine controller always strives to allow the engine to produce the torque demanded by the driver via the pedal. Nominal boost for my Turbo was 0.7 bar at near sea level and I had to "test" boost under the right conditions to get it to read 0.7 bar.

But at 8K feet and higher the boost read 0.8 bar and even 0.9 bar. These were not glitches the readings persisted for some time before as the engine RPMs climbed the engine controller backed off the boost a bit. Which is what I had observed at sea level I might add.

[RockCrusher]

Originally Posted by sl0m0

I live in Flagstaff now, and there is nothing of the sort. I will probably throw in an octane booster every once in a while and the stuff TUD has suggested (I have the link saved somewhere but I think it's the molly stuff) alternating every few tanks. I think 91 will be fine but will also take what extra steps I can.

Been through Flagstaff a number of times driving a 217hp Porsche Boxster to a Dodge Challenger Hellcat.

91 is fine as far as it goes but I can tell you 93 would I think make you sit up and take notice how much better the engine ran. At least for a turbo charged engine. (I never had a chance to try 93 at high elevation with any of my N/A engines: Porsche Boxster, Pontiac GTO, Porsche Cayman S, Challenger Scat Packs.)

But if 91 is all there is...

Running an octane booster every once in a while is a waste. Why? Because it is at part throttle the engine controller will try to advance timing to the max. BMW probably (like Porsche) runs the engine timing just short of detonation. As much timing as is possible while avoiding detonation really pays off with better performance, fuel economy, engine response.

Fuel up with 91 and buy from a busy station.

If you visit the track arrange to fuel up there with lead free race gasoline with a higher octane rating.

[KC87ZB]

Octane is all about resistance to pre-ignition. Regardless, the way the M2 (S58) is programmed will "detune" the engine if knocking is detected. With 91 octane fuel you may not get as much performance out of the engine and may detect knocking. 91 is perfectly safe to use, 93 will be preferred and is recommended. Octane will also have a very very minor impact to fuel economy, essentially undetectable.

Very typical of modern high performance turbocharged vehicles.

[DSTR]

Originally Posted by Ghostrider.1127

All bmw come with knock sensor , so not really an issue ( only on dyno you gonna see differences ) but yes as stated with 93(98) or 96 (102/103) sure they gonna run well

Aral 102. My fave + good coffee at some location!

[ronin13013]

This is what you guys are talking about.

Originally Posted by M_Power Rob

Yes, Apollo Automotive (a good friend of mine owns the shop). When I have the car and ready for the work, if not able to be tuned in the US, the ECU will go femto in Finland.

[Ghostrider.1127]

Originally Posted by ronin13013

This is what you guys are talking about.

IUPR like this post

[M_Power Rob]

Originally Posted by ronin13013

This is what you guys are talking about.

Also why best to have the work done by someone who knows what they are doing on this specific platform. Will cost more but time, effort, stress and results makes it a no brainer to spend the extra money.