Quote:
Originally Posted by theaveng
.... All I have to do is run octane 91 gasoline (which would be considered 'standard' in Europe).
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Actually, they use a different octane scale. (RON, as opposed to AKI.) So their 91 is basically our 87.
A number of cars over the years have used variable-length intake manifolds--most of them done by having a butterfly valve that closes off a longer section, or opens up a resonating chamber. I recall that some later Honda Preludes did, as well as the aforementioned Alfas and Toyotas, some Porsches, and some of the more exotic Italian metal. I'm sure others have also had some way of either making the path longer or making the air "think" it was longer.
A very, very few have used variable-length exhaust manifolds. I think it's too expensive to make articulating bits that will hold up over the long term under the high heat and moisture content of exhaust gases.
-soD