Thread: Tuning a Turbo
View Single Post
RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
RarlyL8's Avatar
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,526
One reason for modification is the degradation of function of the stock WUR.
Manual adjustment allows you to bring the pressures back into spec. The parts themselves are still old and out of spec.

Adjustability also allows you to compensate for changes made through engine modifications that now require off-spec pressures to retain a healthy AFR.

This brings up my point about having the old unit rebuilt with new parts. The mechanicals will now be in spec for that range of function for a stock engine, no adjustment needed.
Now if you do both, have the WUR rebuilt and made adjustable you may achieve excellent tunability which is likely the reason some applications, such as mine, do not need the RPM switch.

As for rebuild kits, they are unobtainium. Bosch rabbidly protects their vendors and will not sell to others. There are several places that offer the service of rebuilding WURs. The last one I had rebuilt for $75. It was then made adjustable.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8

Last edited by RarlyL8; 08-26-2008 at 08:12 PM..
Old 08-26-2008, 08:09 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)