km per litre
 

a 13btt gets 10km per litre going downthe highway
and 7.2km per litre drivng around downt giving it a litlle

would a 13b large extend port use alot more going down the higway and more in and around town

Depends on how your drive it.

I found my street port got better economy on the highway because it was much more efficient at cruise RPM (3500-4000) than the stock engine. Stock engine idles nice but the ports are truely horrendous.

Let's see if I convert things right :) I was seeing roughly 10.5 l/km with the ported engine vs. about 7.5-8 l/km with the stock port engine. (25mpg vs. 20mpg if anyone wants to check my math)