To help people understand what fuels are what for a turbo BMW here are some facts. Note that it's not as simple as "the higher the octane the better". Many other factors come into it.
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Unleaded Fuels
MOTORSPORT 109
Produces more power than any other unleaded fuel. Recommended for higher boost applications with CRs up to 11:1 or naturally aspirated engines up to 13:1.
• Color: Clear
• Motor Octane: 101
• R+M/2: 105
• Research Octane: 109
• Oxygenated: Yes
• Specific Gravity: .722 at 60° F
Streetblaze 100
Oxygenated with ethanol, this CARB-legal fuel is specifically engineered for high-performance street cars including sport compacts, muscle cars, street rods and more. It's environmentally friendly and street legal throughout the U.S. In applications with anything from 4- to 12-cyclinders or engines equipped with a turbocharger, supercharger or nitrous oxide system (NOS), StreetBlaze 100 will generate optimum power and performance. In turbocharged or supercharged applications, it allows an increase in boost without fear of detonation. NOS users can also leverage their higher octane ratings to step up to a more powerful nitrous oxide system. Dyno tests with a turbocharged application proved StreetBlaze100 generates up to 14% more horsepower compared to premium grade 91 octane unleaded gasoline. Designed for use in cast-iron head engines with CRs up to 13:1 and aluminum head engines up to 14:1. Works well on the latest generation of electronically-controlled turbo engines. Contains no metal compounds and won't harm catalytic converters or oxygen sensors.
• Color: Orange
• Oxygenated: Yes
• Motor Octane: 96
• R+M/2: 100
• Specific Gravity: .746 at 60° F
MOTORSPORT 101
This 101 octane (R+M/2) fuel allows an increase in timing and more powerful nitrous oxide systems, with substantial power increases compared to premium pump gas. Designed for CRs up to 13:1 in cast-iron head engines and up to 14:1 with aluminum heads, MS101 is particularly effective in turbo- and supercharged applications. It contains no metal compounds and won't harm catalytic converters or oxygen sensors.
• Color: Yellow
• Motor Octane: 99
• R+M/2: 101
• Oxygenated: Yes
• Specific Gravity: .800 at 60° F
MOTORSPORT 103
MS103 provides power and protection equal to some leaded racing fuels. Compared to Motorsport 101, it allows even more aggressive timing and higher compression-up to 14:1 in cast iron head engines and up to 15:1 with aluminum heads. Can allow doubling of stock boost - consult your engine builder. Also contains no metal compounds and won't harm catalytic converters or oxygen sensors. AMA legal for Supercross & Outdoor Nationals.
• Color: Red
• Motor Octane: 99
• R+M/2: 103
• Oxygenated: Yes
• Specific Gravity: .743 at 60° F
Leaded Fuels
C16
Used in turbocharged engines, blown engines and nitrous applications with CRs up to 17:1. Recommended by the top nitrous oxide companies. Spec Fuel for NHRA Comp Eliminator.
• Color: Blue
• Motor Octane: 117
• Specific gravity: .735 at 60° F
VP Import
Maximum power and torque in small displacement, high RPM, all motor, turbocharged or nitrous sport compact applications. Makes 5% more power than C16 and similar nonoxygenated fuels. Works well under high temperatures due to mechanical heat.
• Color: Clear
• Motor Octane: 120+
• Specific Gravity: .744 at 60° F
Methanol
M1
99.95% pure.
M3
Same as M1 plus lubrication and combustion additives for an extra boost.
M3
M5 has upgraded combustion additives and will make more power than M3 (i.e., 5-7% more power than standard methanol).