View Single Post
AFM744 AFM744 is offline
Cynical Misanthrope
 
AFM744's Avatar
 
Join Date: Dec 2001
Location: Campbell, CA
Posts: 382
Send a message via Yahoo to AFM744
Alan, do you have the C2T WUR? I've found my C2T WUR is a more complicated animal than the basic ones on the earlier 930s. I have a top bimetallic with your described two-resistor switch, plus a lower bimetallic and a bottom diaphram for altitude adjustment.
The top bimetal has two parallel resistors, and the switch you describe is a tiny bimetallic thermoswitch that ungrounds the second resistor on the top bimetallic at sub-freezing (approx) to warm up the WUR more slowly and provide longer enrichment during winter driving.
My lower bimetallic also had a heating resistor (it broke).
From my research the bimetallic strips should be OFF the spring seats at warm temperatures, so tweaking them should ONLY affect cold enrichment. The threaded inner concentric spring seat you mention I believe is warm adjustment, it's what I had to tweak to reach my 60psi warm CP. I have both my bimetallics completely retracted right now and accordingly I have NO cold enrichment. My car starts right off the key (credit the start-up injector) and runs great from cold with 4bar CP.
I tried lowering the threaded inner concentric spring seat and got asphyxiatingly rich CPs, but it seemed this was strictly warm CP. I could adjust this down to get <12 at WOT/redline, but it made for 12:1 cruise and <9:1 boost onset . This was a hot CP around 2bar
Sorry I could ramble on this for hours, but I was just in there A LOT and spent hours reverse-engineering the thing. I would love to tweak on the spring rates to adjust boost onset enrichment.
__________________
X-1, AFM744, Jon, '92 C2 Turbo
JE 8:1 pistons, 964 cams, 38mm intakes ported/polished/twinplugged, ARP hardware, B&B headers/exhaust, 355whp. Full-blown GT35R 3.2 intake EFI pending...
Where my misspent time and money is currently going.
Old 07-03-2008, 09:33 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)