Originally Posted by MantisWorx

Most in Gt were running 8mm venturis not 9, all 9 does is give you poor mileage in a heavy car. So you are saying going from an 8 to a 7 nets you a -20% power loss??

If a smaller venturi equals less wear and tear then why is it that offroad engines dont last nearly as long as onroad engines do?

no matter what size venturi you use the engine performs best at the exact same A/F ratio. yes you have less air entering which equals less fuel which equals less castor oil for protection but as forementioned on road uses at least 2% (sometimes more!) oil for protection and lower nitro. Technically a smaller venturi could actually give more wear and tear! I dont think venturi size determines how long an engine is going to last one way or the other, especially only 1mm.

I agree with you on the rules, would love to hear the true logic behind this because as we have all seen that it makes no difference at all. a Modified MITO is every bit as fast if not faster than a 9 port with 8 or 9mm venturi!

Not sure if you have been to a national level GT race lately but they are very bit as fast if not faster than they were with open engines. and thats because as Roelof said earlier guys are just buying a cheap ison ,installing ceramics and having it modded to make more power than before with good if not better gas mileage. When a 5 port /7mm gets the same exact pit time as a 9 port, that tells you something right there!