Manifold/throttle bodys-ED:-)

[Chuck Tomlinson]

>Hey Ed, if you're the manifold guru for Ford, how come the manufacturers
>haven't gone to throttle bodies for each cylinder like on some of the 
>vettes? I know the vettes are two intake per cyl. but the advantages
>are many with one valve also, and it can't cost very much when they're
>already using port inj. Heck it might even be cheaper, being as the current
>massive aluminum castings could be eliminated in place of plastic plumbing.
>???????????????

I'm not Ed, but... ZR-1s were the only Vettes with throttle plates in the 
intake runners, and they only controlled 8 of the 16 runners.  I think 
these secondary throttles were 2-state i.e. either fully open or fully 
closed.  Otherwise, the ZR-1 engine has a regular two-butterfly throttle 
body on the front of the plenum.

In general, it would seem that balancing airflow (cylinder-to-cylinder) 
through many individual throttles would be a more complex and expensive 
proposition than having one throttle and a plenum. I thought some BMWs 
have individual throttles (M-engines?), but I don't know what the real 
benefits are.

Cadillac Northstars already use plastic manifolds with single butterfly 
throttles, as will the "Gen III" small block Chevrolet in the '97 Vette.

--
Chuck Tomlinson