octane rating

[keane]

Thanks to all for the advice/info/reccomendations, I have just got a fully ported set of heads with 2.19/1.72 valves, closed chambers, I think I'll try the 429 with flat tops initially, the cam will be fairly big, and I can't afford the final bits for the 508 BBf thats part built, but that will be a monster when its finished anyway!!! The optimax is supposedly good? anyone any thoughts on that? and finally just to bring it up again! can anyone say wether some off the shelf seats such as cobra classics will fit on to the dax seat bases? Thanks guys Dave

[dave]

Hi Eric.

Believe it or not I was not "Having a go"....Not on this occasion at least.

I saw the post on octane ratings and remembered that i had been sent the info so i thought I'd post it up.
I did wonder If the Germans used a different scale to us and that is where the conflicting numbers came from.
It is strange that for once the Americans rate something lower that us europeans (Their stuff is stronger than ours if you go by the numbers) unlike most other things, like BHP(Allegedly) and gallons etc.
The fuel rating info is something that people who are considering buying engines from the states should bear in mind when they see "Runs on 92 Pump gas" This actually means that 95ROn is not upto the job and you will need "Super Plus Unleaded".:thumb:

[andywsussex]

Guys,

I believe they do use different octane rated fuels on the continent - measured on the same scales - depending on the country and climate. I believe its mostly higher RON's than here. I remember reading on the Shell forum linked below that German Shell Optimax (I think its sold under a different brand name) is marketed as 101 RON, though this is a purely extrapolated performance number as 100% Octane is theoretically the limit.

There's some interesting stuff here:

http://www.shelloptimax.co.uk/jive3/...umID=1&start=0

and nice explanation of octane rating (same as Dave's) here:

http://www.prime-mover.org/Engines/G...es/octane.html

Apparently some of the variation is local taxation rate of the fuel. Maybe our low octane ratings are an excuse to fleece us of more money by producing cheaper fuel

Andy

[andywsussex]

Here we go, it seems on the continent its called V-Power - but even that varies:
In the Netherlands its 95 RON.
In Germany its apparently 100 RON and replaced the Optimax brand.

http://www.shelloptimax.co.uk/jive3/...=433&tstart=45

[osgood]

Originally Posted by dave

Hi Eric.

Believe it or not I was not "Having a go"....Not on this occasion at least.

I saw the post on octane ratings and remembered that i had been sent the info so i thought I'd post it up.
I did wonder If the Germans used a different scale to us and that is where the conflicting numbers came from.
It is strange that for once the Americans rate something lower that us europeans (Their stuff is stronger than ours if you go by the numbers) unlike most other things, like BHP(Allegedly) and gallons etc.
The fuel rating info is something that people who are considering buying engines from the states should bear in mind when they see "Runs on 92 Pump gas" This actually means that 95ROn is not upto the job and you will need "Super Plus Unleaded".:thumb:

:thumb: Eric