[quote=spdrun]The turbo thing is annoying bureaucracy (probably dating from an earlier time, when mods had more of a chance of making a car dirtier).[/quote]Actually it was bureaucratic ignorance that caused it. The politicians & Eco-heads took the approach that only the manufacturer knew how to make the vehicle run cleanest. This is why almost any modifications are considered ‘tampering with the emissions system’. The end result was that we had new US cars running open-loop carburetors in early-mid 1980’s while the imports were almost all fuel injected & closed-loop. It wasn’t for lack of know-how. The Chevy Corvette had a port fuel injection option in the 1950s. To some extent the emission people have grudgingly (but not openly) admitted that hot-rodders were right. Changing the ignition to higher voltages, using mag-wires instead of carbon suppression, and headers really do reduce emissions. Maybe it was brought on by emissions requirements that were tighter.. and imports using stock exhaust manifolds that look like headers– and easily passing the emissions requirements.
It should only be tailpipe.. the only under-hood should be to verify vapor recovery and PCV.
