Octane
#1
![Default](https://5series.net/forums/images/icons/icon1.gif)
I've heard some people say that getting higher octane gas is pointless unless your car is "tuned for it." What does that mean? Aren't there clear performance gains from using 93 over the 91 CA residents use? Why won't 94 (if available) be better? I asked someone about using race gas in particular and they told me it would do nothing unless my car was tunes for it. I didn't think you needed a mod to use race gas or higher octane fuel in general.
I figured all cars benefit from higher octane fuel, not just turbocharged ones.
I figured all cars benefit from higher octane fuel, not just turbocharged ones.
#2
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by E60714' post='1027458' date='Oct 8 2009, 02:13 AM
I've heard some people say that getting higher octane gas is pointless unless your car is "tuned for it." What does that mean? Aren't there clear performance gains from using 93 over the 91 CA residents use? Why won't 94 (if available) be better? I asked someone about using race gas in particular and they told me it would do nothing unless my car was tunes for it. I didn't think you needed a mod to use race gas or higher octane fuel in general.
I figured all cars benefit from higher octane fuel, not just turbocharged ones.
I figured all cars benefit from higher octane fuel, not just turbocharged ones.
Basically, the timing of the the plug spark in conjunction with the stroke (compression of the piston) location as well as the octane rating (think detonation pressure/temperature and burn rate) are used to optimize the power output of the engine. You obviously want to have no forces working against you while you are compressing the fuel/air in the piston by having the mixture explode 'early' (hate it when that happens...honey, I swear it's never happened to me before...
![Smile](https://5series.net/forums/images/smilies/imported/smile.gif)
The burn rate, also a function of Octane, will determine how fast or how slow the fuel air mixture burns in the cylinder...which also effects the rate of delivery of the power to the piston head and then eventually to the wheels.
To take class a step further, you may hear drag race strip people chatting (or the buddy down the streen that has a distributor cap on his 69 camaro or another buddy that has the software hooked to his Honda to electronically remap the ignition for his street race) where they'll mention "Advancing" the timing or "Retarding" the timing....this means that they are changing the point at which the spark happens to ignite the fule, either "Advancing" it to happen prior to the TDC (top dead center - point at which the piston is at its highest in the cylinder) or "Retarding" it to happen after the TDC point of the piston. This is done to optimize current race or environmental conditions to maximize, again, the power output of the motor...for the conditions you are racing in....OR also to account for where you need your most power delivered...early in the race or down the strip..as in older cars...there was no 'on the fly adjustment, of timing by a computer in the car...you chose where you thought the power would help you most in the race...
Was this more than you'd ever hoped to hear about?! Hope it is helpful and clarifying.......
![Wacko](https://5series.net/forums/images/smilies/imported/wacko.gif)
#5
Contributors
Join Date: May 2009
Location: SoCal
Posts: 10,496
Likes: 0
Received 2 Likes
on
2 Posts
My Ride: 2008 550I LOADED, all options except HUD and NV
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by E92-Lighting' post='1027700' date='Oct 8 2009, 09:05 AM
just dont use ARCO gas
.............or Valero, or Thrifty, or any other cheap gas. Also, keep in mind your manual says Premium Fuel required.
#6
Members
Join Date: Apr 2008
Location: MALLORCA, SPAIN
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2007 525I CARBON BLACK WITH CREAM LEATHER AND SILVER INSERTS,
FULL CUSTOM KEVLAR AND CARBON KIT, BUMPERS SKIRTS SPOILERS, CARBON VENTED BONET, CARBON MIRRORS, M5 WINGS, PURE HID FOGS, PURE WHITE EYES, XENON ADAPTIVES, CUSTOM GRILLS, 19" ONE OFF RIMS, APEXI SPRINGS -30MM, GROOVED DISKS AND EBC PADS, 40MM SPACERS ALL ROUND, CARBON DYNAMICS AIR INDUCTION KIT, CUSTOM MADE 80MM EXHAUST SYSTEM FROM CAT BACK WITH TWIN SQUARE EXITS, RDS CHIP TUNING, LIGHTENED FLYWHEEL, IPOD INTERFACE, AUX IN, MEDIA CENTER PC WITH ACTIVE INTERNET THROUGH 3G, MUTLIMEDIA INTERFACE, 2 ALPINE 7"TVS IN HEADRESTS, 2 1000WRMS ROCKFORD AMPS, 2 ALPINE XSERIES 12" SUBS SEALED ENCLOSURE, 2 JBL GT 12" SUBS PORTED ENCLOSURE, 2 FARAD CAPACITOR, KEF MIDS 8 AND 4S,
COMING SOON PROFESIONAL NAVI.
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by pjinca' post='1027709' date='Oct 8 2009, 06:15 PM
.............or Valero, or Thrifty, or any other cheap gas. Also, keep in mind your manual says Premium Fuel required.
#7
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by infinityjk' post='1027789' date='Oct 8 2009, 01:40 PM
this sounds daft but on my gas cap it states i can us btween 84 to 107 octane fuel so i presume the engine has different maps for different fuels......
Thread
Thread Starter
Forum
Replies
Last Post
GT Premi
E60, E61 Parts, Accessories and Mods
13
10-01-2008 03:18 AM