View Single Post
mark houghton mark houghton is offline
mark houghton's Avatar
Join Date: Jul 2008
Location: Central Washington State
Posts: 3,899
Originally Posted by copbait73 View Post
I'm driving my '73cis turbo a lot this summer and find more AFR change due to the fuel I buy.

The CIS system has the air metering plate to weigh the air so within it's design limitations it does adjust for altitude variation.
Less dense air at altitude would have less mass, which in and of itself would result in a richer mixture whether or not it impacts the movement of the metering plate. But theoretically it could also result in the metering arm deflecting less with less mass/force against it, all other things considered equal (such as air velocity) so I suppose the two combined would passively counteract each other (though probably not in a linear fashion) and keep mixtures somewhat stable. For active control, Brian's suggestion of a 965 WUR would be the ticket.

Sounds like a study in Physics (it's been a zillion years since my last class on that subject and I never was any good at it)!
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 07-03-2012, 04:48 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)