Thanks. i did mean what are all the differences as to why i would want to go thru the expense to have this installed in my car

 

I see, then how is the V8VS making 15 more HP than the non S models with these newer more restrictive manifolds and extra cats? Just curious where those gains are coming from given more restrictive exhaust system.

 

Nobody is saying that the late model Manifolds+Cats is any more or less restrictive than the early model Manifolds+Cats. If there is a difference it is infinitesimal.

What is being said is that because the primary and secondary catalysts are now separated on the late model cars, with the primaries being located in the manifolds, you will not see the same results from changing JUST the secondary cats on the late model cars that you would from changing the primary+secondary integral cats on the early ones. Hence, the gains to be had from changing the manifolds on the later model car are larger than they are on an early one, and the gains from changing JUST the cats are smaller. The overall benefit of changing BOTH at the same time is more or less unchanged.

You asked why not make manifolds for the late model cars? You could, but why develop and engineer a whole new part when you can fit the cat-less header that fits to the early cars, combine it with the 200 cell cats that fit these cars and relocate the O2 sensors with a harness extension?

The only reason to develop a whole new manifold would be if you thought someone would be interested in changing the manifold on a late model car, but keeping the stock secondaries, or fitting test pipes in place of the stock secondaries. Which IMHO would be crazy. You would have to compromise the header design to include a catalyst + O2 bosses, the header would be much more expensive and then you would put test pipes in afterwards. You need a 200 cell cat in there somewhere to keep emissions within the acceptable parameters, why try to squish it in in front of the header flange when you can just put it behind, where the secondaries are now and build a great header?

So if you don't want to change the header, these new secondaries are a nice easy bolt on. But if you're serious about performance, fitting the already existing Velocity headers + 200 cell cats as designed for the earlier model cars is the way to go!

 

Oh ok cool, thanks for the clarification