US 997 gets 355bhp on 91 RON

[pvernham]

Just between jobs and had an extended holiday in the US. Spent a few hours kicking tyres in a US Porsche dealer.

Surprised that the US 997 is quoted at 355bhp although 91 RON is the highest quality fuel generally available. Given all the comments on the forum about the relative benefits of Shell Vpower and so on, surprised we are not getting better outputs here in the standard car on 97 or 99 RON.

Does anyone have any views or a sensible explanation?

 

[Mark_Bennett]

Yes, they are measured in different ways.

The 91 AKI (Anti Knock Rating) figure in the USA for instance, is roughly equivalent to our 95 RON (which is actually MON or PON or something!)

Here is a pretty good explaination - from a flying website but talking about car fuel!
http://autofuelstc.softworkx.ch/index.php?id=10&L=1

 

[sawood12]

The guys in the US use PONs which is basically an average of RON's and MONs. Anyway you can read all about it via this link:-

http://www.btinternet.com/~madmole/Reference/RONMONPON.html