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Replacing or refurbing wastegate (Tial, perhaps?)
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MOTANUL  



Joined: 19 Nov 2018
Posts: 121
Location: ROMANIA BUCHAREST

PostPosted: Mon Jul 15, 2019 2:16 am    Post subject: Reply with quote

Here is a picture with the area.
I manage to remove the wastegate without breaking any studs. (the same with turbo studs).

Instead exhaust gaskets were damaged and I had to order new. (very hard to find).

I think there is no need to dismantle the turbo or the starter.
But you need to dismantle the entire front of the exhaust.


https://ibb.co/vJ7QL0J

More pictures here:
https://ibb.co/BPKyxD7
https://ibb.co/Njp2Cm9
http://www.924board.org/viewtopic.php?t=43986&postdays=0&postorder=asc&start=75
http://www.924board.org/viewtopic.php?t=43986&postdays=0&postorder=asc&start=90
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1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2006
Location: Somerset, UK

PostPosted: Mon Jul 15, 2019 3:56 am    Post subject: Reply with quote

All the exhaust gaskets are simple to find. Just order new ones from a Porsche centre.

I have the smaller 944 turbo starter, and I cannot remove exhaust and wastegate without removing the starter. But I realised my current exhaust is mahoosive compared to the stock version.
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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: 259
Location: Annapolis, MD

PostPosted: Mon Jul 15, 2019 10:19 am    Post subject: Reply with quote

bureau13 wrote:
So the starter thing is confirmed?


Confirmed. Frees up a lot of room to work.
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chuck21401  



Joined: 20 Feb 2005
Posts: 259
Location: Annapolis, MD

PostPosted: Thu Jul 18, 2019 2:43 am    Post subject: Re: Replacing or refurbing wastegate (Tial, perhaps?) Reply with quote

bureau13 wrote:
I will very likely just buy a Tial


Here is my question...how would one mount the TiAL? The stock 931 WG has the extra bracket on the "hat" that bolts to the car.


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bureau13  



Joined: 07 Sep 2017
Posts: 308
Location: South Florida

PostPosted: Thu Jul 18, 2019 2:59 am    Post subject: Re: Replacing or refurbing wastegate (Tial, perhaps?) Reply with quote

Good question. Supposedly, the Tial is considerably lighter...perhaps its light enough that it doesn't require the extra bracket? That does seem a little dodgy though...


chuck21401 wrote:
bureau13 wrote:
I will very likely just buy a Tial


Here is my question...how would one mount the TiAL? The stock 931 WG has the extra bracket on the "hat" that bolts to the car.


_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2006
Location: Somerset, UK

PostPosted: Thu Jul 18, 2019 5:24 am    Post subject: Reply with quote

Will probably need spacers to mount on the stock exhaust. Will be smaller and lighter so no brackets will be required
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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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Mike9311  



Joined: 14 Dec 2004
Posts: 873
Location: Chicago-ish

PostPosted: Mon Sep 30, 2019 4:20 am    Post subject: Reply with quote

My favorite part about this thread is that the ebay seller is a former 'one of us' who moved on to a 930 from a 931

Engineer White.

I also bought one of his kits because it was cheap enough to not machine one myself but it isn't installed yet. Will post when I have it together. Wastegate was functioning but we had everything else out so why not go through it all
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
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bureau13  



Joined: 07 Sep 2017
Posts: 308
Location: South Florida

PostPosted: Sun Nov 03, 2019 2:53 pm    Post subject: Reply with quote

So I removed the J-pipe and was basically looking to confirm my suspicious about the wastegate. I hooked up my air compressor to the hose that leads to the wastegate from the charge pipe, and the bottom "door" didn't budge. Also, I could hear what sounded like a LOT of air whooshing out somewhere, but it wasn't any place I could feel. It sounded like it was coming from above the wastegate. If the diaphragm is compromised, causing the door to not open, does that air exit via the top port? If so, that would make sense.

Also...how hard is that door to move? I tried pushing up on it and it didn't budge.
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2038
Location: MI

PostPosted: Sun Nov 03, 2019 8:50 pm    Post subject: Reply with quote

bureau13 wrote:
If the diaphragm is compromised, causing the door to not open, does that air exit via the top port? If so, that would make sense.


Yes!

bureau13 wrote:

Also...how hard is that door to move? I tried pushing up on it and it didn't budge.


Pretty hard.. I don't think you are going to do it with your thumb, but no so strong that you can't disassemble/reassemble the spring by hand..

Maybe around 20 lbs to move the valve?

If the top of the diaphragm is about 2.5" for 5 sq inches and it should open at like 6 psi then 6X5=30 lbs to move the valve or compress the spring?

Just guessing..
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chuck21401  



Joined: 20 Feb 2005
Posts: 259
Location: Annapolis, MD

PostPosted: Mon Nov 04, 2019 3:53 am    Post subject: Reply with quote

bureau13 wrote:
So I removed the J-pipe and was basically looking to confirm my suspicious about the wastegate. I hooked up my air compressor to the hose that leads to the wastegate from the charge pipe, and the bottom "door" didn't budge. Also, I could hear what sounded like a LOT of air whooshing out somewhere, but it wasn't any place I could feel. It sounded like it was coming from above the wastegate. If the diaphragm is compromised, causing the door to not open, does that air exit via the top port? If so, that would make sense.

Also...how hard is that door to move? I tried pushing up on it and it didn't budge.


Good idea to test it that way. The valve should move...it doesn't take much if it is working correctly. I posted this link on the other thread...a small handheld compressor will move the valve with 5-6 PSI. https://youtu.be/qg84Pz54Lqw

I agree, the air would exit via the top port.

When I had my WG on the bench I tried to push the valve up using two thumbs...didn't work so I gave up. I think it would be very difficult to do from under the car.

Unfortunately it sounds like you'll have to pull the WG and open it up to see what's going on in there. I got lucky, the WG diaphragm had simply come loose. I replaced the valve guide while I was in there. Who knows if it really needed to be done but the WG is working fine now.

I'm actually under my car again today....replacing the studs from the turbo to the exhaust and tightening everything back together.
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bureau13  



Joined: 07 Sep 2017
Posts: 308
Location: South Florida

PostPosted: Mon Nov 04, 2019 12:51 pm    Post subject: Reply with quote

Yeah, I'm not looking forward to pulling that thing out. I've heard it's pretty common to break the bolts, although everything came out easily with the j-pipe. I've been told I need to drop the starter and the exhaust, although it doesn't really look like it to me? Also, I know there's a bracket holding the top part of the wastegate in place, but I didn't see it. Not a lot of room in there...is it difficult to access those bolts? This sounds like a good candidate for borrowing my friends lift...

chuck21401 wrote:
bureau13 wrote:
So I removed the J-pipe and was basically looking to confirm my suspicious about the wastegate. I hooked up my air compressor to the hose that leads to the wastegate from the charge pipe, and the bottom "door" didn't budge. Also, I could hear what sounded like a LOT of air whooshing out somewhere, but it wasn't any place I could feel. It sounded like it was coming from above the wastegate. If the diaphragm is compromised, causing the door to not open, does that air exit via the top port? If so, that would make sense.

Also...how hard is that door to move? I tried pushing up on it and it didn't budge.


Good idea to test it that way. The valve should move...it doesn't take much if it is working correctly. I posted this link on the other thread...a small handheld compressor will move the valve with 5-6 PSI. https://youtu.be/qg84Pz54Lqw

I agree, the air would exit via the top port.

When I had my WG on the bench I tried to push the valve up using two thumbs...didn't work so I gave up. I think it would be very difficult to do from under the car.

Unfortunately it sounds like you'll have to pull the WG and open it up to see what's going on in there. I got lucky, the WG diaphragm had simply come loose. I replaced the valve guide while I was in there. Who knows if it really needed to be done but the WG is working fine now.

I'm actually under my car again today....replacing the studs from the turbo to the exhaust and tightening everything back together.

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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chuck21401  



Joined: 20 Feb 2005
Posts: 259
Location: Annapolis, MD

PostPosted: Mon Nov 04, 2019 1:05 pm    Post subject: Reply with quote

bureau13 wrote:
This sounds like a good candidate for borrowing my friends lift...


A lift would be very helpful. My car is up on jack stands with ramps under the tires just in case. Not easy to work on the car this way...but doable.
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Last edited by chuck21401 on Mon Nov 04, 2019 1:21 pm; edited 1 time in total
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chuck21401  



Joined: 20 Feb 2005
Posts: 259
Location: Annapolis, MD

PostPosted: Mon Nov 04, 2019 1:13 pm    Post subject: Reply with quote

bureau13 wrote:
I've been told I need to drop the starter and the exhaust, although it doesn't really look like it to me? Also, I know there's a bracket holding the top part of the wastegate in place, but I didn't see it.


The starter must be removed. I'm replacing the studs on the exhaust side of the turbo and was hoping to avoid removing the starter...but there is on bolt that connects the bypass pipe to the wastegate that isn't otherwise accessible.
So I had to pull that too. Luckily I didn't have to remove the J-pipe for the job I'm doing now. Be sure to remove the positive and negative wires from the battery...and put the car in neutral. You don't want to have the starter engage by mistake when reinstalling the wiring.

The bracket holding the wastegate in place is fairly accessible once everything else is out of the way. Here's a pic from when I was reinstalling the WG after fixing the diaphram and new valve guide. I left the U-clamp on the torque tube...only had to remove two bolts to get it out of there...not all 4.


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bureau13  



Joined: 07 Sep 2017
Posts: 308
Location: South Florida

PostPosted: Thu Nov 28, 2019 1:33 am    Post subject: Reply with quote

Here's a related but possibly odd question. So, for the wastegate to open, it requires both the boost from the control line and the exhaust backpressure to press hard enough to overcome the spring, right? Does anyone know what boost would be achieved if we remove the control line from the equation? In other words, if we solely rely on backpressure to open the wastegate, what be the boost limit?

No, I'm not planning on going with this type of setup, I'm just curious and doing some other experiments while awaiting a chance to change out or repair the wastegate diaphragm.
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2006
Location: Somerset, UK

PostPosted: Thu Nov 28, 2019 3:22 am    Post subject: Reply with quote

All depends on the waste gate spring installed.......0.5, 0.7, 1.0 bar boost springs?? Needs boost line pressure to control the valve, not exhaust
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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
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
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