924Board.org

bnoon · Posted: Wed Jun 02, 2010 4:08 am Post subject: Adjustable WUR with pics

I've been considering doing an EFI swap, an electronic WUR install, or something more drastic like a V8 swap, but I've finally decided to go with some minor bolt-ons initially to see just what I can get out of this thing without going through some major surgery. Enter the adjustable WUR.

While researching countless EFI swaps (on Pelican boards, 928 and 911 threads mostly, but related fuel systems), I read about someone using an electronic WUR. Reading further led me to the manually adjustable WUR threads. Now, I know both EFI or the electronic WUR will no doubt give you better tunability, but the manually adjustable WUR can be made with llittle or no cost and can handle most minor bolt-ons with ease. I decided to give it a try.

Here's my WUR all disassembled. Very simple break down via 4 screws for the case, 4 screws for the metal diaphragm, a nut/washers for the bi-metalic strip, and a retainer clip for the electrical connector. One thing I did learn, is to not be rough with the vacuum diaphram. It can tear very easily. I tore my stock WUR diaphragm back in December and ended up having to buy another S1 WUR core from Dan (Ideola's Garage) to replace it. His core was clogged from noral use, so I took it apart much more carefully to clean it. I used a straight pick and poked the feed side filter out and removed/cleaned the metal diaphragm (lower right, by the screws) since it was so clogged, otherwise the WUR tested out great.

Here's the cold adjustment screw/nut I instaled. The pin that it's drilled/tapped into is just press fit into the aluminum WUR case. Loosen the nut and tap the pin farther into the body = richer, hold the screw and twist the nut to pull the pin out of the body = leaner.

For warm adjustment, you turn this 4mm allen screw. Screw it in farther = leaner, out = richer.

Reassembled, ready to go in the car.

Initial settings were great for cold starts at 71 dregrees air temp this morning. I've got to get my warm settings done though as it runs lean once it warms up (lean surge while crusing). Idle mixture screw on the dizzy was set using a vacuum gauge method (old school). Now it's time for a lunch break. Later dudes! (and dudettes)
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'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
Porscheless

Joes924Racer · Posted: Wed Jun 02, 2010 4:43 am Post subject:

Nice write up and pics..
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

bnoon · Posted: Wed Jun 02, 2010 4:53 am Post subject:

Thanks. I've had WUR's apart enough times, I can't believe it took me this long to get pics of one, LOL.
_________________
'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
Porscheless

Joes924Racer · Posted: Wed Jan 05, 2011 6:48 pm Post subject:

Maybe Ill try that manaul cold adjustment screw trick.

Is the pin just a threaded screw tapped into the body with a lock nut.
and presses on the bimetalic strip when turned in to richen.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

bnoon · Posted: Sun Jan 09, 2011 1:16 am Post subject:

You drill and tap the pin for the screw. To adjust it "in" you just loosen the jamb nut and "tap" the screw and pin inwards. To adjust it "out" you hold the screw steady and tighten the jamb nut to pull the pin back out.

A note: When you tap the pin in, do it with a SOFT hammer, such as a brass or dead blow style. I used a hard ball peen hammer and it cracked the heat up circuit resistor on the bi-metalic strip. I had put this into a junk pile and it must have slipped off of the bench into the shipping box to the guy that I sold my extra air meter to a week or so ago. Oops! Too much work to mess around with for me at this point until I get more mods anyway. I can make another one cheaper than having him ship it back to me, so I told him to keep it!

Also, if you have some extra banjo bolts and some fuel line, make it remote mount. I was going to do that so that I didn't have to remove it from the back of the intake every time I wanted to make an adjustment. Pain in the ass to do that every time.
_________________
'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
Porscheless

leadfoot · Posted: Sun Jan 09, 2011 11:03 am Post subject:

nice write up, thought about putting this to the how to section?
I remember reading the guys article on pelican saying that there can be an issue with leaking injectors when the control is low and the system pressure is high, any conclusive evidence of this?
Stu.
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...