NEHA

walterclark wrote:My take is valves and cams dont constitute "non-stock induction". Manifolds, throttle bodies, etc. do.

I agree with that. So the rules don't force the car into S5 but I stil think that is the right thing to do.

I googled things like "engine induction system" to get an idea of what others refer to when using the term induction in regards to engines.

I always saw carburetors and throttle bodies included. Mostly I saw intake manifolds. Sometimes I saw air filters/cleaners. Occasionally I saw the path between the filter and TB. Once I saw the path include from the intake manifold flange on the head up TO the intake valve - the in-head extension of the intake manifold. I never saw reference to cams or valves as part of induction.

I think we generally think of air filters as free.

The point I am making is we (the technical committee) probably need to settle on and publish a definition of where "induction" begins and ends and where "exhaust" begins and ends relative to our "non-stock" statement in classification. So someone building a car near a class limit knows at what point they are "non-stock" in these areas.

KevinGale wrote:

walterclark wrote:My take is valves and cams dont constitute "non-stock induction". Manifolds, throttle bodies, etc. do.

I agree with that. So the rules don't force the car into S5 but I stil think that is the right thing to do.

I also agree with Walter's comment. I don't think we includeed in the classes any performance benefit for types valves. Number of valves are covered. Number of cams are covered. The type of either one (valves or cams) is not covered.

The intent of Unprepared is esstentially no changes beyond minor modificaitons. If you are opening the engine to change something, you are not Unprepared.

Rabbit Farmer wrote: I also agree with Walter's comment. I don't think we included in the classes any performance benefit for types valves. Number of valves are covered. Number of cams are covered. The type of either one (valves or cams) is not covered.

The intent of Unprepared is essentially no changes beyond minor modifications. If you are opening the engine to change something, you are not Unprepared.

Steve, you do realize we are talking about the Street Prepared class, right? Modifying any of this stuff would take one out of U...well maybe not an air filter or cat-back.

I do now...

The valve type and cam type comment is still correct....

Okay, thank you for the comments. Yes, we are talking about street prepared, which states, "Engine/ driveline modifications
are allowed."

I would agree that the rules could be more clear, perhaps a list of definitions would help.

Ultimately, of course, changing cams is unlikely to make an enormous difference, but it all adds up.

Thanks again for the comments, interested to hear other points of view.