924Board.org

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

These cars are actually a bit tricky to install an intercoller onto but has been done by many people here in many different ways..

CareraRSR put a 944 turbo intercooler under the nose panel like the 944 turbo which is a great setup but requires body work under the nose panel and he also changed his intake manifold a lot.. He might give you some links to check out..

Rasta Monsta did a pretty good one where he put an air to water IC in his battery box and the water to air exchanger in the front somewhere, which required little body work and other modifications to make work..

Here http://www.924board.org/viewtopic.php?t=28534 is another way to do it by RC that I think could be done with the stock turbo and intake.. A FMIC plumbed down by the headlight lifting bar..

Mine I like very much and requires little to no body work but will only work with an upgraded turbo. I don't think it will work with the stock turbo having the integraed BOV in the compressor housing..
It is more of a usual FMIC setup but you have to be able to turn the compressor housing upside down to blow toward the bottom instead of up..

You can see how I spaced the bottom of the radiator back to fit it and made a mount plate for it..

Can still get it here for $65 ON EBAY and fits perty gerd..

You can see it (somewhat) here..
https://youtu.be/X2jbkENELMk vid 1
https://youtu.be/1wk3QW90cbM vid 2
And my install thread but my pics are gone..
http://924board.org/viewtopic.php?t=41250&postdays=0&postorder=asc&start=0

Cedric did one pretty similar to mine in the middle of this thread http://924board.org/viewtopic.php?t=40495&postdays=0&postorder=asc&start=90

Morghen did a pretty nice FMIC that would work with a normal turbo but I think requires a 951 front bumper..

You can also do it the Porsche way with a top mount carreraGT IC and hood scoop..

Many ways to do it but none of them are super easy..

I admit that I like mine the best but I might be biased

While you are at it click the blue "slightly modified" link in my sig just under this line to hear the incredible sound (IMO) at the end to give you some inspiration
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80 Turbo - Slightly Modified

chuck21401 · Joined: 20 Feb 2005 Posts: 532 Location: Annapolis, MD

chuck21401 · Joined: 20 Feb 2005 Posts: 532 Location: Annapolis, MD

I had some time yesterday to work on the 931 so I decided to install the used boost control line.

The short story is that I was able to replace the line and that it didn't make difference...car is still generating 14psi-15psi after a short test run. I'm convinced that the answer lies within the wastegate.

Here's the longer version.

I have drive up ramps but they don't elevate the car high enough to provide adequate access to the wastegate area. I read a number of threads about jacking up a 924 and where to put your jack stands. I ended up putting the jack stands under the front cross member. I set the E brake and chocked the rear wheels. Also disconnected the battery.

Once I was convinced that I could crawl under the car without getting squished, I removed the boost bolt with a 17mm open end wrench. With the car higher in the air I found it a lot easier to get a wrench on it.

But first, here is a picture of the boost control line, there is a sharp turn, but the line is not kinked.

Here is the bolt and washers. One is copper and the other is steel (or aluminum?)...later I figured that the silver washer might not provide the best seal so I replace it with an other copper one. There's nothing magical about the Porsche sealing rings right? Looking up the part now, apparently the Porsche part is aluminum 90012304330

https://www.pelicanparts.com/More_Info/90012304330.htm?pn=900-123-043-30-OEM

But I don't think that this area is leaking...I didn't get bubbles when I tested it previously with soapy water and compressed air down the line.

Anyway, removing this line is not easy. There is a bolt that holds it to the block. To get to that bolt (and to make room to remove the line) I found it necessary to move some things including the distributor and the positive wire to the battery. Not a big deal, just took some time.

The bolt holding the boost control line to the block took many turns to get loose...but finally the line was free.

Here are the two lines side by side. The control line I removed was not clogged or anything.

So now it was time to install the used control line. As they say in the manual "installation is the reserve of the removal procedure." Well, sorta.

The revised part with additional rubber hose at the banjo fitting was a good idea. It was not easy to get the hard line installed. I quickly found that you have to start at the banjo bolt, then reinstall the bolt holding the line to the block, then attach to the intake and there is only one route for the line to go. Takes a while to figure that out by fishing it back and forth.

Once the line was connected I reinstalled the distributor and reconnected the wiring. I reset the timing based on the process detailed in a very helpful thread. I'll have to look it up again and post a link. Edit - Here is the link:
http://www.924board.org/viewtopic.php?t=37216

So now I was ready to try it out. I removed the jackstands and backed down the ramps I set up under the wheels just in case. The car started right up. I backed up and noticed that the car was leaving a trail of coolant. WTF? Turned off the car and opened the hood.

I had forgotten to tighten down the bolt holding the control line to the block. That bolt also holds down a flange related to the cooling system, I think there is a temp sensor there. In any case, coolant had leaked from that area. I was able to get a 10mm socket on that bolt without removing the distributor, etc. and tighten it down. Ran the car for a couple of minutes, no leaks, blipped the throttle, seemed OK. Now time to take a test drive.

Once up to operating temperature I gave it more throttle...and it boosted past stock boost. No change at all. I can't imagine that both boost control lines would be leaking...so the answer must be in the wastegate.

Not sure what to do next.
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1981 Porsche 931 w/S1 engine & g31 transmission. Water-cooled intercooler

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

I think it would take a hell of a leak, a lot more than a couple bubbles, in that line to raise boost that much like that..

So either you do your CIS testing and put an IC on to hold that boost or you do your CIS testing and go through your WG to lower the boost to a safe level, or just drive it easy till you figure out what you want to do..

I'm thinking that your WG has a stiffer spring installed into it, or some shims installed in it, or assembled wrong, or something..

My FMIC setup does not bother the headlights at all or the windshield washer tank..
It just requires a normal style compressor housing, grind a bit of a useless tab off the block, grind the steering rack a little, rebend the oilcooler lines a bit, move the horns a bit, piece of angle iron and some pipe for radiator spacing/IC mount/oil cooler mount, remove a couple square inches of sheet metal behind the front valance, and a bunch of hose, pipe, and clamps.. To do it again I would put the new BOV underneath like cedric did so the upper charge tube and that plumbing would stay completely the same also.. Stock radiator and fans and everything.. Still easy to service and replace the timing belt..
Quite non-invasive..
Even my V8 fuel distributor setup on top of the IC managed to clear the lights mechanism and OEM washer bottle..

If you have a 2664 turbo I have a spare comp housing that would work for you from an Audi (can put it on without even removing the turbo), or grab a cheap turbo from a 944 and swap the cold side of it onto your 931 turbocharger..

Mind you, if you have a 2660 turbo it is even more dangerous at the boost you are making..

Speaking of timing belts, you have a new timing belt on your car right?
If not, that is priority #1 without question..
Might also want to put in some NGK BR8ES plugs for safety too, and always run premium octane gas, and heavy 40 or 50 weight synthetic diesel engine oil, or car oil with a zinc additive to keep your cam happy, that you should check and adjust the lash on, and inspect the cam oiler tube and elbow..
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80 Turbo - Slightly Modified

chuck21401 · Joined: 20 Feb 2005 Posts: 532 Location: Annapolis, MD

The turbo is a 2664.

The timing belt is new. I had BPR7ES plugs in the car originally. They were gapped at .8mm which I think caused a problem at the high end. I tried B8EGV gapped to .6mm and they worked well.

peterld · Posted: Sat Jul 06, 2019 5:50 pm Post subject:

It would seem that your issue must now be wastegate related. Seeing as you have been able to accomplish what you have so far, removing the wastegate is very doable, though a pain in the arse because of space constraints.

The wastegate itself on the 924 (actually a 930 unit) is probably the most rudimentary piece of equipment I have ever seen on a car! The only biggies are not to break the diaphragm (or maybe it is torn or pinched) and for sure one or more of the studs will break.
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80/81 932/8 ROW

chuck21401 · Joined: 20 Feb 2005 Posts: 532 Location: Annapolis, MD

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

You just presurized it with your air compressor didn't you? How much do you think it leaked past the valve when you did that? Did it feel like it was loosing a ton of air or held a bit of pressure?
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80 Turbo - Slightly Modified

chuck21401 · Joined: 20 Feb 2005 Posts: 532 Location: Annapolis, MD

chuck21401 · Joined: 20 Feb 2005 Posts: 532 Location: Annapolis, MD

Today I'm going to start the process to remove the wastegate. Any tips? PB Blaster on the nuts and bolts?
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1981 Porsche 931 w/S1 engine & g31 transmission. Water-cooled intercooler

peterld · Posted: Sun Jul 14, 2019 12:17 am Post subject:

It looks brand new. Can't imagine it should be a problem getting off and out, and given how it looks as it was going together, I'm now doubting there is a problem there, unless the diaphragm has been pinched and torn.
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80/81 932/8 ROW

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

Read the thread again..

chuck21401 · Joined: 20 Feb 2005 Posts: 532 Location: Annapolis, MD

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

[quote="chuck21401"]

Carrera RSR · Joined: 08 Jan 2010 Posts: 2309 Location: Somerset, UK