924Board.org

[Carrera RSR]

That’s the early set up. Chassis rail mounted as on my turbo. My race shell has the later version as per GT and 944’s
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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

[Cedric]

I helped wrench a bit on a 82 931,it had both the later air blower system and the late sway bar design.

You are probably better of making some adapting yourself, the 944 version is crappy with the flimsy brackets.
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1980 924 Turbo
www.instagram.com/garagecedric/

[kondzi]

Put this car to the freezer until spring. My 1st thing to do is rear torsion bars change. 300lbs spring in the front coilovers and stock on the rear is a no go. What diameter should I go to match fronts? I'm used to do setups with either torsion bars F/R or coilovers F/R but not a mix
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[Cedric]

My 28mm rear bars i calculated to match 350/60 N/mm springs. So without recalculating i would guess around 26-27, i bought the cheap vw ones.

But It depends on many things, what anti roll bars and what tyre widths you use for example.
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1980 924 Turbo
www.instagram.com/garagecedric/

[kondzi]

Thanks Cedric, I will not chase 10ths of second on a lap, so a guesstimate works fine with me I have 19mm adjustable ARB at rear from 968CS. Wheels are 7/17, tires 225/50 all corners.
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[kondzi]

Been a while...

So I finally replaced the torsion bars with 27mm ones.



I still need to do suspension alignement, but the car is back on wheels.

It took way too much time, I was not expecting it will be that much time consuming. Maybe if it was just replace and reindex it would be less time, but "while in there" syndrom added some hours to the total - more about that later.

I was quite lucky it seems, as I removed the torsion tube only twice, or maybe not lucky, but did the math

First install and I was about 20mm to high.



So I did 3 CCW and 3CW on inner/outer spline et voila
Just final adjustments on the eccentric bolt.

As of the "while in there" syndrom I cleaned all the splines. One bar I had to carefully operate with a rather big hammer to remove it from torsion tube.
In the end of brushing the splines and using a copper grease the torsion bars was a smooth slip in/out. Exactly what I wanted for ease of reindexing later on.



While I'm not an expert of history of these cars / models / variations, the extra mounts for the gearbox made me curious.

The good and bad thing is I have the G31 gearbox, aka snail shell:



One day I will need to remove the gearbox completely, as the 1st gear synchroniser is most probably dead (fortunately it's 1st gear, so I use it only from stop position). For the time being I replaced the differential shaft sealings, flushed the gearbox twice with engine flush + oil + going through all gears with engine running and leaving that mixture overnight (twice). You can imagine it must have been very dirty as I decided to do it twice.

Is there an LSD available for this gearbox as aftermarket? Read somewhere these came with factory LSD as well?

Torsion plates cleaned, covered with reactive primer and with black epoxy paint. Splines brushed to smooth slip in of tbars + copper grease.


Some idiot has screwed in the oil plug for the inlet so hard it took me 2 hours to remove it - finally the TIG torch helped. I ordered aftermarket one for VW Bug with a magnet.



More around rear axle in post to come.
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[kondzi]

So while I was there...

Removing the torsion tube few times and disassembling everything to pieces made me think a little bit towards the 944 Turbo Cup idea of the torsion tube mounts.

I was checking what is available on-line, and while I like the Lindsey Racing ones:

https://www.lindseyracing.com/LR/Porsche/LR-944-TTUM.html



I didn't like the price, especially for me, when getting it from US in the end the price would be almost twice

I found a company in Germany, that is selling something similar:

https://partworks.de/en-partworks-de-Porsche-944-Support-bearing-for-Porsche-924-944-968-rear-axle-TOP-STARR-L-R.html



But it's just a piece of steel and when I asked some guys that bought these, they were not happy with the quality. The design with very narrow piece of steel, not really supported by the body frame was another concern...

So I decided to do it on my own from scratch.

I started with measuring everything on a bench, as I got everything out for torsion bar replacement.

I buit a prototype in CAD.



Well in total I built few prototypes and 3D printed them and did all the measurements on the car while working with torsion bars at the same time.







Fitment test, glad I had to replace the torsion bars, just for doing this it would be a lot of pain...




Then I asked a friendly CNC shop about a minimum order quantity that would make sense from price per set perspective. Agreed and ordered...







Looks nice right?
I was just bit worried how this would fit in real compared to the 3D printed model.

Fortunately and unfortunately I had to do a small fix. It seemes the ~5mm groove was not fully flat and I could not fit it on torsion bar arms.




Fortunately I found a fix to this dilemma



So with that sorted out a final fitment test happened...

















These are made from billet 5083 Aluminum that is highly durable and corrosion (salt) resistant. Much better choice than the cheap and popular 6061 IMHO.

I have few sets left, so PM me if interested. Price I ask is same as the German steel ones, so EUR 110 + postage. Hope this is reasonable
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[kondzi]

So I'm chasing down a culprit of running to rich. My o2 WB controller starts after about 35 seconds after engine fires up. I'm not running the car regularly, so once in a time I had issues with spark plugs being totally black and engine running only on 3 or even 2 cylinders.
Cold start means AFR down to 8.5, while warmed up IDLE is around 14 AFR.
I need to tune my WUR for boost anyway, so I will take it out and relocate to an easier accessible place. I set up the pressures some time ago, so need to verify, but for the way over rich AFR at startup I expect the Cold Start Valve to be doing the bad job together with the Thermo Time Switch.
I plan to replace the TTS with Coolant Sensor from BMW to get good reading for my MegaSquirt. Same for AAV to be replaced with PWM IAV driven by MegaSquirt, as my stuck and I need to knock it few times to lower the RPM during warmup.
Do you see anything wrong in my assumptions?
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[Fasteddie313]

Does your CSV leak?
Try unplugging it and starting?
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80 Turbo - Slightly Modified

[kondzi]

Well when I was checking it about 2 years ago it was spraying a nice umbrella shape pattern. I was surprised though how much fuel it was spraying when open (a lot IMHO).
I did disconnect it and checked on a mid-warm car - seemed better / leaner. Pressure rose and AFR lowered to ~14.
Plan is to do a check on a cold car after the night with CSV unplugged.

I think this is a message from this car to me - drive me more frequently

EDIT: Just thinking - need to check if hot side (+12V) for CSV is coming from starter (+12V applied only when cranking). Maybe PO messed up something and it’s spraying extra fuel until TTS times out all the time).
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[Fasteddie313]

Good thought
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80 Turbo - Slightly Modified

[kondzi]

So I checked the TTS and it seems that +12V on CSV plug behaves as intended.

I will post a long video later (almost 10 minutes) with me operating a piece of wood against AAV and observing what is going on. Starting / killing the engine, checking RPM and so on. And hitting the AAV multiple times in between. There is inconsistency in AFR that worries me. Need to sort out that, but first need to remove WUR and plug in the pressure tester.
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[kondzi]

Whatever morghen claims removing WUR from its factory location is a nightmare. It took me about hour to remove it and my hands are full of small injuries both from cuts and from press.



I am not going to put it back there, no way

The plan is to use two bolts of the inlet manifold (one keeps the fuel lines, the other one just the inlet manifold I think. I will make an adapter plate that would bolt into that two bolts and then bolt the WUR to the adapter plate.

That should make me able to position the WUR like here:




Seems rather straightforward, however new fuel lines will be needed and an extension for the wiring loom. Need to sort out the new fuel lines then I will work further on that.
_________________
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[Fasteddie313]

The steel lines bend pretty well and the old choline can be shortened and put back on barbs with a touch of heat pretty easily..

Unobtainium Ferrari parts has real choline if you need more..
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80 Turbo - Slightly Modified

[kondzi]

I need to sleep with it, maybe I'll sort out sth. Usually if I change something to non-stock, I put stock parts on the shelf. Just in case for future.

Here's the long video. You can laugh from my "tools"

http://files.bearsgarage.pl/shares/export/public/www/photos/bucket/924board/931/wur/IMG_9856.mp4


What worries me is this - I start the engine, AFR stabilises around 14. Bit to high RPM, but maybe it's AAV sticking. Then I stop the engine and start again, and the AFR is at 16, slightly lower RPM (4m:15s in the video). Then I rev the engine bit and it's back around 14 (or more 13.5). Again same story from 7m:20s in the video.

Or I am too demanding?
_________________
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)