Euro 3.2 w/10:3-1 vs. Us Spec 9:3 Question
 

OK. Dumb question. Why can the Euro spec 3.2 with 10:3-1 static compression ratio run on pump gas, single plug when everyone tells me that you cannot exceed 10:1 static ratio?

It's my understanding European fuel quality (octane) is not as good (comparable) to US 93 octane.


Is it just more aggressive cam timing that 'bleeds' some of that cyl prssure off. I've gotten very different answers from other builders.

As I understand it, Europeans got a higher octane fuel than the US.
If you actually measure the compression on factory motors (including that one) you'll find they measure less. I haven't measured it myself but I've heard this from more than one engine builder. The "10.3:1" motor probably measures closer to 10:1 or less.
The Euro and US motors uses the same cams and the same cam timing.
9.8:1 was the number I've heard for the upper limit on pump gas for street use.

-Chris

I totally agree with that....and I have one with less than 1k on the new p& c. I'll put my $$$ down and say it's probably closer to an actual 9.8:1

The Euro 3.2L with these higher compression had a more aggressive ignition & fuel mapping program in the DME chip than their USA bound 3.2 brothers. That and no catalytic converters and the higher octane make it work I suppose.

Funny about all the comotion over the USA vs Euro 3.2 p/c. As I mentioned in my 3.2 cam thead, there is barely any visual difference b'tween the two...and one really has to stare and compare the two against each other in order to detect it....and it's not easy to do!!

cheers!!

The octane myth
 

It is a myth that Europe gets better gas than the US. There are two main rating systems for octane, RON and MON. Europe, or at least England where I'm from originally rates octane RON. The US uses PON which is the average of RON and MON. UK 98 octane (RON), is 90 MON or in US terminology 94 octane which is the average.

Seeing as how all I can get in California is 91 octane I'd say 94 is higher by quite abit.

-Andy