tonytaylor

Optimax only. It is chipped and is running a fair amount of advance. I find that, in my little used bikes, Optimax doesn't go off anywhere near as fast and doesn't leave a residue over the carbs which requires a rebuild. It also cleans residues left by other supermarket fuels. Economy is worse but power is definatley up with Optimax.

Smokin

Most gas these days is all about the same from station to station... Octane rating notwithstanding. Most all stations get their gas from a small group of suppliers. The stuff you buy at BP is probably the same as what the Handy Dandy Market sells... The biggest problem (and thing to remember) is to buy your gas at a busy station. These guys always have fresh gas with no water. The small hole-in-the-wall stations that rarely see a customer will sometimes have contaminated fuel. You'll find that out on the side of the road....

JasonAndreas

DaveK,
It is possible to watch the outputs from the knock sensors realtime so you could try gasoline with different octane ratings and then see how much (if any) timing is retarded. It would be a fun little experiment just make sure the ambient air temperature and throttle inputs are around the same for each test.

Millemiglia

Don't mean to steal this thread but are there any performance benefits by using a octane of 98 or higher?
In Sweden the octane rating is 95, 96 and 98 for unleaded.
In my user's manual the recommenden octane is 95, so by using higher octane should I expect an increase in power/performance or am I just giving away more of my money to the petrolcompanies?

btw. In Germany I filled up with 100 octane V-Power on Shell just for fun and I can't really say for sure if there was an increase in performance...

C4-JohnO

Optimax from Shell, seems to give better mpg.

But I had a limit of no more than £60 per fill up when i bought the car and the Shell stuff is at £59.69/tank! One more price rise and i may have to sell!! Then again - lol.

Tom W

I'm not sure how octane is calculated in Sweden, but based on the range you mention it seems to be RON. Check your manual for the specification to see if it is for RON or (RON+MON)/2. Using gas with higher octane that required by your car will not improve your performance. It will simply ensure that the car's knock sensors don't retard your timing and degrade the perfomance from optimum. For street driving in cool climates, using gas at near or slightly above the minimum recommended octane should be fine.

Some of us goofy folk have chips for our 964s that advance the timing beyond the factory values and hence need more anti-knock protection (ie higher octane gas). Some of us goofy folk also have chips that allow lower octane gas for our 993s (in CA we can only get 91 octane and the manual says to use 93 or better). Our gas in the USA is calculated as (RON+MON)/2.

Henriks 964

Always 95 ron , but never from supermarkets.

Greetings,
Henrik

Bins

I understand thats about right Christer. The Petrol can be supplied from a number of different companies regardless of the Esso, Shell, Sainsburys, etc. Its the additives that make the difference.

I use either Shell Optimax or Standard unleaded but never super unleaded.

Kismet

I use normal 95, Shell or BP, in the Porsche unless I'm doing an event of some sort when I put in Optimax. I always use Optimax in the Teal, since I had it converted for unleaded. Its got high compression and a pretty wild cam.

Regards
Tony

craig001

I use that Shell V-Power (V-Max?) @ 93 octane here in the states as my gas of choice. I'll use anything if I'm getting low and am out in the boonies rather than run out.

JAMES J

Mobilegas super+
J.J.