WUR for 1977 930

[TAF]

Hello,
I'm sure you've heard this one before. "I'm new to this FORUM".
I need a bit of some help with a 'goin' bad' WUR. Will a new WUR for a 1976 3.0L turbo do the job for a 1977 3.0L turbo?
Thanks
TAF

[911st]

It is my understanding that the 3.0 turbos WUR's are special in that they enrich with loss of intake vacuum instead of achieving .5 bar boost like the 3.3's do. And that they are not longer available new.

I could be off on some if this but there should not be any significant difference between the 76 and 77.

[jerseymike68]

TAF: hi, welcome to the forum...

[mark houghton]

Originally Posted by 911st

It is my understanding that the 3.0 turbos WUR's are special in that they enrich with loss of intake vacuum instead of achieving .5 bar boost like the 3.3's do. And that they are not longer available new.

I could be off on some if this but there should not be any significant difference between the 76 and 77.

Could be true. Why not just use a newer WUR and plumb in a boost line instead? There may also be differences with the internal resistance of the heating element, whereby it heats up quicker (or slower) than say an 80's version...affecting the cold enrichment time frame a bit. Not a big deal, though.

If you suspect yours is going south on you, try contacting Brian Leask about rebuilding it. mailto:930wur@cox.net

Or contact these guys Porsche Parts-Special T auto.com,Porsche CIS fuel injection parts, fuel distributors, warm up regulators- for a possible new one.

[TAF]

Thanks,
I found a new one, though it specifies 76 model year. I found it right here at Pelican.

Hey, and thanks for the welcome. I love these forums. You meet nice people who are willing to help if needed

[mark houghton]

Originally Posted by TAF

Hello,
I'm sure you've heard this one before. "I'm new to this FORUM".
I need a bit of some help with a 'goin' bad' WUR. Will a new WUR for a 1976 3.0L turbo do the job for a 1977 3.0L turbo?
Thanks
TAF

Oh....almost forgot....pictures of your car will guarentee you get the help you need!
Welcome aboard.

[TAF]

Sure.. Not to sure I know how to upload photos, but here goes.

[TAF]

and the rebuild. SSI cumstom headers

[RarlyL8]

Gee, that looks familiar.

Yes the '76/'77 WURs are the same. Welcome and nice looking car!

[TAF]

I was user on both C2turbo and 911turbo forums when they were around. I also chair the Driver Ed events for the Alabama Region PCA. You may have seen the car at Barber Motorsports Park. By the way. We'll be back at Barber in March for our first DE for 2010.

[911st]

Well done.

How about donating your old WUR for study. Maybe someone could document how to convert to a vac-sensing WUR from the boost sensing. Lee Rice used to do this on his "Rice Fueler" WUR years ago.

The boost sensing WUR's reduce the resistance of the metering plate to movement upon acceleration. Doing this would increase pre-boost response if set up right.

Of course this is not a good fit with a set up on a car that is set up to dump to much fuel on boost. However, I believe a heavily modified 930 could be set up to still work with this by getting the control pressures right for the fuel head used.

This would not only reduce resistance at the metering plate but could reduce the lean surge off idle that is typical with CIS.

That seems to be Porsches intent with the 3.0T's. Emissions were probably part of the reason for the boost triggered unit on the 3.3T's.

[RarlyL8]

TAF, was that picture taken at Billy's shop? He used to do SSI conversions.
May have met you at some point, need a name to match up with the car.
I'd love to do Barber but cannot keep my car off the lift long enough to enjoy it myself!
As for the WUR, if you did not trade it in as a core and do not need it I would be interested.

[TAF]

You are correct. Eurasian (Billy Mitchell) did the rebuild and headers. I am Tom Fleming. We most likely met at Barber. I have not done anything about the WUR as of yet. I'll let Casey at Eurasian do one last pressure test to make sure it is my problem. I feel your pain about the car being on the rack a lot. You know if it was the family ride, I would have unloaded this thing a long time ago. But, it's a Porsche and for some dumb reason I put up with the many problems that pop up. It's like a damn drug.

Tom

[RarlyL8]

I'd be interested in knowing what your symptoms are and what Casey decides on a fix. The '76/7 WUR is unique and cannot (that I am aware) be modified in the same way as the later model WURs. I assume if your car is stockish he will simply replace the WUR. What I have found, and the reason my car is on the lift right now, is that adding headers changes the AFRs enough that an adjustable unit is needed if you want the numbers to be where the should for optimum performance. I'd say the vast majority of owners don't do this and are leaving fuel mileage, power and driveability on the table.

[TAF]

The number on the part in question is 054 which, I believe, is the same as a 78-89. It has worked fine, up till now. Now, my rebuild was around 3 years ago and up till now the car has run great. The mods are moderate.. 964 cams, boat-tailed and shuffle pinned cases, garretson IC, 1.0 spring. I have a garrett t36 turbo, however it's in need of a rebuild so at the moment I have the stock k26 installed (a little slow to spool but it has a nice whistle sound). If Casey's findings point back to the WUR, then I guess I'll go back with the same part number. I'll keep you posted.

As for the AFRs with headers installed. I messed with bikes many years ago and the first thing I would do is buy a set of headers, K&N filters and a jet kit. Without doing the re-jetting the bike would run like a turd. However, for the car We just richened the mixture a bit.

Oh sorry. The symptoms? When the turbo spools up the AF goes so rich that the car just spits and coughs and blows a lot of black smoke. Idle goes to around 1200 rpm

Man I love this spell check thing

[911st]

With you mods you are flowing more air. You might check the control pressure specs on boost of the 3.0 and 3.3 WUR. I would guess the 3.3 has a lower CP on boost and might be a better fit.

Better yet, the WUR from the 91-92 C2 Turbo has the ability so compensate for differences in barometric pressure so you would get some compensation for changes in weather and altitude. The other WUR to not do this so they can run lean on cool weather or fat with changes in altitude.

I believe the 94 3.6 WUR has lower on boost CP on boost still for even more fuel delivery.

If you have a 3.3 WUR you might send it out to be rebuilt and converted to be an adjustable unit.

You would probably love a K27-7200 turbo on a modded 3.0T. It will support up to about 380hp.

[TAF]

With the lack of o2 censors and the only brain being the rather insufficient one behind the wheel, would the later c2 WUR operate on an antiquated 77 3.0 turbo?

[911st]

The C2 WUR is just an improved 3.3T unit. It is indipendent of any electronics.

You bring up in interesting point. The Lambda O2 style systems can compensate for altitude at cruse but not on boost.

Again, I suspect what is most relevant is the boost level you are running. I believe the stock 3.0 was something like .6 bar. The 3.3's were near .8 bar. With your Intercooler and lower compression I suspect you are running more like a 3.3T in terms of boost and you will need the increase in on boost fuel that the 3.3 WUR is going to give you. If you are running 1.1 bar like a 6.5/1 CR motor can, I would get the modified WUR with lower CR on boost. Otherwise you may have to run fat at idle and cruse to get the fuel you need on boost.

Let's put it this way. If I were you and I could have my old WUR rebuilt and modified I would do so. If I had the money, wanted the best, and or liked to go from sea level up into the mountains and above the snow line often, I would go with the C2T. Or, if I could get a new 3.3 for a good price, that would be a contender.

But I am probably over thinking this.

Not and expert, just what I believe so far.

[jly535]

Originally Posted by TAF

Oh sorry. The symptoms? When the turbo spools up the AF goes so rich that the car just spits and coughs and blows a lot of black smoke. Idle goes to around 1200 rpm

Man I love this spell check thing

I had a similar issue on my 77' and found that I didn't have 12 volts to the WUR. This may or may not help.

Super rich!

[TAF]

Many thanks to everyone who jumped on this one. And thanks for all the advice and info. However, I found the problem. After calling and talking with Billy Mitchell, we call him the wizard, and asking if he would order me a new WUR, his answer was. Lets look at some other things before we go throwing expensive parts at the car. Well that made me start thinking. The short of the long is.... The problem was one of the fuel pump relays had popped out. I plugged it back in place, reset my AFM and idle and away we go. I once lovingly told Bill. If you ever die, I'll have to sell this car.