View Single Post
Reanimotion Reanimotion is offline
umop apisdn
Join Date: Jun 2014
Location: Brisbane, Australia
Posts: 501
Further to the speed of pressure change discussion, and the relationship to available flow and volume in the control pressure circuits, a few factors may be important.

Pressure lines - on the 928 the WUR is around two feet from the FD so on the V8 all lines are small diameter steel tube, on the 911 the special Cohline nylon flex lines appear to be the norm, as they are a larger volume but shorter in length, line flex should not be an issue.

The UTCIS originally used a stepper motor which required time to spin between set points, the change in state of an injector is virtually instantaneous.

The UTCIS also utilised an analogue mechanical pressure sender. I've not had one of the exact units apart but based on similar units with he same cannister sizing there would be a small amount of pressure dampening as the diaphragm filled or emptied in response to changes in pressure. I'm using a digital sender with a dramatically smaller sensing chamber and therefore faster response with an advantage in accuracy.

How important is any of this? unknown and probably not worth verifying as long as the end result performs well enough.

As for the control valve or injector. Bosch used a 242cc injector for the Frequency Valve and the Andial kit that bypassed the WUR was 300+ but when Bosch released CIS-E or KE-Jetronic it was controlled by a DPR which I suspect is both high flow and fast response. We have one on the way for testing too
1981 928S 4.7 ROW with KE3-Jetronic and Franken8 (AEM Inifinty) follow at []
Yes! mechanical/hydraulic constant flow injection can be managed by a modern EMS

Last edited by Reanimotion; 08-07-2014 at 03:16 AM..
Old 08-06-2014, 10:04 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #55 (permalink)