View Single Post
911st 911st is offline
Registered User
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
The IA head gets is its increased fuel flow from having the builder adjust it to out of specs. This is done by playing w the tension of the springs around the internal orifices and the orifice height.

(Doing so was my idea and was a result of my conversation w the builder on behalf of the first guy that did this.)

This screws up everything in the design of the CIS system. If you set the idle A/F correctly, your cruse A/F will be to rich. You know with it dose to the A/F's on boost. It also adds to lag in that people start playing w increasing WUR's control pressure settings or delaying enrichment on boost.

It can only really be tamed w a mappable system that can take control of control pressure and all rpm points and load conditions.

Other wise one would have to change the cone shape the metering plate moves in so it moves slower than it is supposed to. One may get away w trimming the stock plate to balance things back out.

I believe the only real physical mod they make is when converting a US head that has the frequency valve/ lambda loop set up to make it into a euro head.
Old 06-16-2008, 07:36 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)