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Loosing power/boost after driving after an hour or more
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1986
Location: Somerset, UK

PostPosted: Fri Jun 28, 2019 3:46 am    Post subject: Reply with quote

Cool feature of our WG's is that the top port can be used to become dual port and then run an air regulator to balance the boost on both sides of the diaphragm giving you your desired boost level. But you need a low spring threshold to dial up and down. Assuming you have a 1.0bar spring, you can only go up and down from 1.0bar, never lower.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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chuck21401  



Joined: 20 Feb 2005
Posts: 244
Location: Annapolis, MD

PostPosted: Fri Jun 28, 2019 4:14 am    Post subject: Reply with quote

Fasteddie313 wrote:


Are you using the test port by the brake booster to measure it or are you hooking it right up to the frequency valve?
If you don't know about the test port is a 3 wire pigtail up by your brake booster area and the black wire gives a port to measure the freq duty..


Test port. I found the testing procedure in another thread.

Quote:

Your allen AFR screw is actually perfect where it is at but speaking of that screw, you do have the hole over the screw plugged with something right?
The hole to access the screw needs to be plugged/capped to be in correct operating condition..


Yes. I had to remove a screw with a rubber washer to access the AFR screw. I noticed that the readings went haywire until I put the screw back in...or covered the hole.

Quote:

No, you can only use a boost controller to tun UP the boost.. The lowest you can go with a boost controller is what the WG spring will give you.. Unfortunately..


Well shoot.

Quote:

Fortunately you can limit the boost manually with the throttle pedal. When boost comes on just back off the throttle pedal a bit and run where the boost gauge reads 6-8 psi..


True, though not nearly as fun lol
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chuck21401  



Joined: 20 Feb 2005
Posts: 244
Location: Annapolis, MD

PostPosted: Sun Jun 30, 2019 8:24 am    Post subject: Reply with quote

I decided to test the boost control line for leaks. Figured I could slather the rubber parts of the line with soapy water, then blow some air through with the air compressor. Started at the wastegate first. Soaked up everything and hit record on my phone...no problem. Did the same thing on the top side...bingo...we have bubbles. I enlisted my son to do the filming.

23 second video: https://youtu.be/CKPAPK28EQ0

That’s enough to cause a problem I’m guessing...
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1986
Location: Somerset, UK

PostPosted: Sun Jun 30, 2019 8:18 pm    Post subject: Reply with quote

What psi did you put in the line? Potentially yes, boost bleeding from the line could reduce the wastegate opening and could cause higher boost. Ultimately this is how a boost T controller like those from Turbosmart work. Depends how much boost is lost at the WG end
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1999
Location: MI

PostPosted: Mon Jul 01, 2019 3:54 am    Post subject: Reply with quote

Maybe..

You could probably grind off those ferrules and replace that hose with a normal piece of fuel injection grade gas line and worm style hoseclamps..
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chuck21401  



Joined: 20 Feb 2005
Posts: 244
Location: Annapolis, MD

PostPosted: Tue Jul 02, 2019 5:27 am    Post subject: Reply with quote

Not sure if I believe my own theory. So I would like to test it by creating a new boost control line. Anyone know of sources for the fittings needed?

Boost control line port on charge tube -->
Male Metric adapter (what size?) to female NPT 1/4 --> Hose barb --->
1.5 ft (or so) 1/4" automotive fuel hose -->
banjo fitting with hose barb (what sized? source?)

Is the banjo bolt that connects the control line to the WG removable without removing other components? I"m thinking maybe a 17mm swivel socket?



Quote:

You could probably grind off those ferrules and replace that hose with a normal piece of fuel injection grade gas line and worm style hoseclamps..


The one on top would be easy...the other not so much. So I think running another line might be the way to go to rule out (or rule in) a problem with the line.

In other news, I found another thread (from 2008) that sounds very familiar...was getting too much boost.

http://www.924board.org/viewtopic.php?t=26671

The OP reported that the "signal line to the wastegate was clogged" and that "The banjo fitting at the wastegate had a check valve in it that was stuck shut."

That doesn't make sense. The banjo fitting is simply connected with a banjo bolt, right?

I suppose I could pull that banjo bolt to check it out.

Beyond that, seems like the WG is the next suspect.
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1999
Location: MI

PostPosted: Tue Jul 02, 2019 5:44 am    Post subject: Reply with quote

I don't recall their being a check valve in there but it's not too hard to pull the banjo bolt off the bottom and then you could blow air through it both ways..

Actually, I doubt their is a check valve of any sort in there but clogging is possible..

Your bend down there looks strange actually.. I don't remember mine having any hose on the bottom side.. I think it was straight hardline to the WG and only a hose at the top..

Possibly that kink in your hard line down there just before it meets the hose is your problem..

Has anyone else seen the bottom of the WG line look like that?

Trying to find a pic of a WG line..



I think I get that banjo bolt with an open end wrench, on it a bit crooked..
Those bolts don't take much torque.. Just until they hit bottom and a little bump from there is what I do..
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poor-sche  



Joined: 06 Jan 2017
Posts: 76
Location: Los Angeles, CA

PostPosted: Tue Jul 02, 2019 6:24 am    Post subject: Reply with quote

There's one for sale on German eBay that is a hard line...

https://i.ebayimg.com/00/s/NzY4WDEwMjQ=/z/MGkAAOSwe6ZaU31w/$_72.JPG

And there used to be one available from this site with a hose on both ends...

https://www.rosepassion.com/media/photo/31852/web93112313503.jpg?w=300&h=300&e=0

The version of the parts catalog I have shows the one with a hose on both ends.
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chuck21401  



Joined: 20 Feb 2005
Posts: 244
Location: Annapolis, MD

PostPosted: Tue Jul 02, 2019 6:39 am    Post subject: Reply with quote

This page has a picture of the control line.

https://www.rosepassion.com/en/cat/porsche-924-1979-924-turbo-coupe-manual-gearbox-5-speed/M348/turbo/turbo-pipe-and-hose/B794/turbocharging/I963/control-line/P31852

(poor-sche beat me to it...I couldn't figure out how to link directly to the picture)

There is a bend, but not quite as extreme as in my picture. I'll take another look to see if that is really a kink.

Part number is 931-123-135-03. One of the parts catalogs notes the following:
Supersession(s): 931-123-135-01; 931-123-135-02; 93112313502; 93112313501
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1999
Location: MI

PostPosted: Tue Jul 02, 2019 12:16 pm    Post subject: Reply with quote

chuck21401 wrote:
This page has a picture of the control line.

https://www.rosepassion.com/en/cat/porsche-924-1979-924-turbo-coupe-manual-gearbox-5-speed/M348/turbo/turbo-pipe-and-hose/B794/turbocharging/I963/control-line/P31852

(poor-sche beat me to it...I couldn't figure out how to link directly to the picture)

There is a bend, but not quite as extreme as in my picture. I'll take another look to see if that is really a kink.

Part number is 931-123-135-03. One of the parts catalogs notes the following:
Supersession(s): 931-123-135-01; 931-123-135-02; 93112313502; 93112313501


Pic of part shows hoses on both ends but the diagram under it show a hard line..

I didn't know they existed..
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Cédric  



Joined: 27 Aug 2004
Posts: 1987
Location: Sweden

PostPosted: Tue Jul 02, 2019 4:24 pm    Post subject: Reply with quote

The little extra hose at the WG side might be a later modification by porsche. If you ever removed and installed the WG you know exactly why they did that, it can be really tricky to get that bajo on if everything doesnt line up perfectly.

But in general, this might be the most over speced WG control line pipe/hose in the history of automobile. If you want to do a new one just buy a banjo an silicone hose. But you have to be careful with the exhaust manifold, dont route it closely. To be completely sure I put a heat resistant sleve/sock (whatever its called) when i did a new line to the top of the WG to control boost.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1986
Location: Somerset, UK

PostPosted: Tue Jul 02, 2019 7:52 pm    Post subject: Reply with quote

I have two versions of the WG line. One has a flexihose on the WG end and one doesn't.

Personally I used the flexi version for the bottom WG port. Having the hard line ensures its routed without anything being melted by heat or chaffed/cut on sharp items. The small flexi at the bottom will also help install and avoid the line snapping. You don't want this line failing...... At the top of the hard line I cut off the flexi to boost tube section and used silicone hose on top of the engine. I kept the adapters into the boost tube and kept a small tail of hose and used a barbed joiner and hose clamps to link into the silicone hose.

For the top port I used the hard line. Again only using silicone hose once at the top of the engine to avoid rubbing and chaffing at the back of engine.

But agree with Cedric, it can all be done more simply as long as nothing melts or gets trapped/cut/damaged.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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chuck21401  



Joined: 20 Feb 2005
Posts: 244
Location: Annapolis, MD

PostPosted: Wed Jul 03, 2019 2:45 am    Post subject: Reply with quote

Cédric wrote:

But in general, this might be the most over speced WG control line pipe/hose in the history of automobile. If you want to do a new one just buy a banjo and silicone hose.


OK, so would this work:

https://www.belmetric.com/eye-fittings-for-rubber-hose-c-1041_855_1135/bnjf1256clz-banjo-eye-fitting-p-12174.html



(I found the spec
on Ideola's Garage boost solutions page, the kit for the manual boost controller: 1 BNJF 12/5-6 banjo eye fitting)


Thinking that the boost control line might be a problem, I bought a used hard line from Britain (he has a thread parting out a 1980 931). When I received it in the mail it didn't look like mine so was worried it might not work. The flexible line looks OK but my thought is to cut that out and replace with new hose. At the same time I'm a bit hesitant to cut up an original line if I can fabricate a new one myself. So I just need to know what I need to plumb into the charge tube.

This thread has a picture of the brass fitting I'm looking for:

http://www.924board.org/viewtopic.php?t=37336

(ignore the boost controller for now - at this point I'm just trying to get back to stock boost)



The next reply lists the parts as (excluding the hose barbs):

1 R7963 Adapter Bushing - 1/8 NPT female x M14 X 1.5 male $6.40 $6.40
1 R7962 Adapter Bushing - 1/8 NPT female x M12 X 1.5 male $6.40 $6.40

But I'm not clear which is which...I just need the one going into the charge tube.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1986
Location: Somerset, UK

PostPosted: Wed Jul 03, 2019 4:20 am    Post subject: Reply with quote

Go to your local hydraulic hose company. They can make anything you want and should have fitting options. Or just make your own out of copper brake lines, silicone hose, barbed fittings etc. Not hard to do.

PS don't even consider a boost tee like the photo. They don't work well with our large volume WGs'
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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chuck21401  



Joined: 20 Feb 2005
Posts: 244
Location: Annapolis, MD

PostPosted: Wed Jul 03, 2019 6:42 am    Post subject: Reply with quote

Carrera RSR wrote:
Go to your local hydraulic hose company. They can make anything you want and should have fitting options. Or just make your own out of copper brake lines, silicone hose, barbed fittings etc. Not hard to do.


Good idea. I think maybe I'll create a prototype, then take it to hydraulic company to make something that is a bit more finished.

Quote:
PS don't even consider a boost tee like the photo. They don't work well with our large volume WGs'


Got it...have been reading some threads regarding boost controllers.

Hopefully I can figure out my current problem with too much boost sorted out...then will figure out how to turn it back up. Plus the intercooler.

But I did manage to get my new tags installed.


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