Warm up regulator - I don't have one, should I add

[Tidybuoy]

I just stole this photo from another thread.

I have a '74 and it does not have this warmup regulator. Would there be any benefit to adding this and can I even add it (i.e., is it electrical).

I'm wondering if (besides tuning), is there anything I can add to my '74 from the later years that would improve CIS management. I figure that the factory added components for a reason (besides emissions).

Anyway, I'm just goofing off at work so I thought I'd ask.

[Flat Six]

Originally Posted by Tidybuoy

I have a '74 and it does not have this warmup regulator.

'Spose you could; at one point an update/retrofit kit was offered (though now NLA):

Porsche 911 & Turbo CIS Fuel Injection - Page 10

WUR appears to be a a serious chunk of change . . .

[Wyvern]

Interesting that you dont have one ..
The WUR . is used to aid hot / cold starts. but most importantly it is the pressure regulator, it regulates the high system pressure to the operating pressure for the CIS system (do you have a pressure reg in the system somewhere?

[Flat6pac]

I know the 73 had a warm up regulator and the 74 used the same one for a while so I m sure you have one or you will have a problem controling your fuel pressure.
WUR works all the time to control pressure from the pump to injectors and I know the system needs one.
Bruce

[john walker's workshop]

yours just looks different.

[Tidybuoy]

Just to clarify, I have a WUR. I don't think I have the warm up regulator - where would this be located as I may have overlooked it.

[snbush67]

Warm Up Regulator

[Tidybuoy]

Originally Posted by snbush67

Warm Up Regulator

Oh my gaud! I'm an idiot. What I meant to say is that I don't have the round air valve that is shown in the diagram (on the left side). I don't know what that is called.

It's been a long day - MY BAD!

[ossiblue]

The round device is a vacuum diaphragm that engages during wide open throttle, causing the sping and pin in the wur to drop slightly allowing for a richer mixture (edit: this statement has been corrected by snbush67, in his later post, below.) Your early set up does not use that device but rather has a throttle positioner valve in the intake coming off the fuel distributor that is designed to perform the same basic function.

I would not suggest adding components individually, hoping to improve CIS management. The 74 (and 73.5 as well as the 75) are simple, straight forward systems that do not include components that "automatically" warm the car up. Once warm, your system operates like later models (except the Lambda cars) with fewer parts to go bad and cause problems. In my experiences with CIS, I prefer the simpler set ups, like yours. Just my opinion.

[john walker's workshop]

your car does not use that part. that's a later diagram.

[snbush67]

The round device is the Thermal-valve for 77-78 and some 79's. The device opens and closes vacuum based upon the ambient temperature surrounding the device.

"Holds off vacuum from the warm-up regulator when engine is started cold ('77 - '79 engines). Power is applied to the thermal valve when engine is started, and approximately 30 seconds later, the valve opens. When the valve is open, vacuum to the WUR is then determined by the intake manifold. --The vacuum holdoff results in a mixture richening at warmup. The inner hose connects to the intake vacuum source and the outer hose to the WUR.

Failure mode: An open circuit in the internal heater will keep the mixture from properly leaning out as the engine warms (Williams, n.d.)."

Reference CIS Primer by Jim Williams, CIS Primer for the Porsche 911