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Kenodog
Joined: 25 Jun 2003
Posts: 2669
Location: Vancouver,B.C.
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 Posted: Sat Nov 19, 2016 10:50 am Post subject: Trans code info please |
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So I will be getting the 924S tomorrow for the main reason that it has a transaxle from a 944S which I am *pretty* certain has the hardened ring & pinion like the 951's. Now I am trying to find the article I read that in but for the life of me cannot find it ! Does anyone here have a link ? (It's not on the Clark's Garage list....
TIA,
Leigh
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1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
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joecitizennn
Joined: 12 Sep 2005
Posts: 2096
Location: no mans land
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| Posted: Sat Nov 19, 2016 11:52 am Post subject: |
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The s2 has the same strength of ring and pinion as the 951. The 944s.. not so. The difference is in the thickness of the teeth on the ring and pinion. The turbo and the S2 have the thick teeth. The S does not. They all have different ratios. 944s 3.889 944s2 3.875 and 951 3.375. What are you needing a beefy r/p for?
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87 924s
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447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
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Kenodog
Joined: 25 Jun 2003
Posts: 2669
Location: Vancouver,B.C.
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| Posted: Sat Nov 19, 2016 12:39 pm Post subject: |
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The problem i'm having is conflicting reports on whats what. I did read on a few different sites however that the 944S for 1987 got a beefed up R&P. This would make sense as the car was now 190 hp in the US and just over 200 in Europe. How was it expected to handle the extra power without a tweek on the weakest part ? I know it was now the same ratios as the 951 up to 5th gear which was different between the 2 cars.
I want something that will be able to handle my cars bumped up output reliably. It will be in the 220 hp zone by the time I fit IC.My old 931 had a fully rebuilt g31 w/LSD so that was no issue at the 220 range but these Audi boxes are bad for flexing, skipping a tooth and then breaking the next tooth off...
Me
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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140 |
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Kenodog
Joined: 25 Jun 2003
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Location: Vancouver,B.C.
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Sat Nov 19, 2016 1:39 pm Post subject: |
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Check the parts catalog. A different ring and pinion will have a different part number.
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- WeiBe (1987 924S 2.5t) - 931 S3
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joecitizennn
Joined: 12 Sep 2005
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Location: no mans land
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| Posted: Sat Nov 19, 2016 2:33 pm Post subject: |
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The general concensus seems to be that the S ring and pinion is weaker than the 951 and S2. I have read several places of cases where someone puts the S ring and pinion in his 951 because he wants the lower gearing and the turbo destroys the ring and pinion. For this reason alot of 951 guys say to use the S2 r/p specifically if you want lower gearing in a turbo. I have no idea if the S r/p is stronger than a standard 944, it very well could be. The S tranny may work ok with 220 horsepower. Its obviously hugely dependant on how you drive. No 944 transmissions were made for clutch dumps and drag racing. I ran a 924s transmission behind a 440 horsepower lt1 for two years and had no problems, but i was careful with it.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold |
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joecitizennn
Joined: 12 Sep 2005
Posts: 2096
Location: no mans land
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| Posted: Sat Nov 19, 2016 3:42 pm Post subject: |
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| Kenodog wrote: | So I will be getting the 924S tomorrow for the main reason that it has a transaxle from a 944S which I am *pretty* certain has the hardened ring & pinion like the 951's. Now I am trying to find the article I read that in but for the life of me cannot find it ! Does anyone here have a link ? (It's not on the Clark's Garage list....
TIA,
Leigh |
I did some searching.
Is this what you were looking for? This article supports the theory that the S transmission is on par with the 951 due to similar design improvments and build code.
http://www.gt40s.com/forum/gt40-tech-powertrain-transaxles/23996-g31-transaxles-audi-016-083-transaxles-pete-tinucci.html
The following quote and link refer to the 944s r/p lack of strength compared to the s2 and turbo. I can only guess that this means the 944s is stronger than early 944 transmissions but not as strong as the turbo?
| Quote: | The Ro is a installation/spacing measurement for the depth of the pinion shaft relative to the ring gear. Its the distance from the center of the ring gear to the face of the pinion gear. That is not an indicator of the diameter of the pinion gear or the tooth size or count. 083D Ro = 58.15mm, 083F Ro = 59.65mm, 016 = 59.65, what does the 1.5mm difference tell us with regard to tooth count or size?
The 9:35 (3.889) S pinion has smaller teeth. The pinion head for the S is slightly smaller than the turbo pinion, and it has one more tooth, so it absolutely has to have smaller teeth. Have you ever looked at an S pinion gear right next to a turbo pinion? And since the ring gear is approximately the same diameter and has 8 more teeth than the turbo, the ring gear teeth also have to be smaller.
The car that I am aware of (this was 12 plus years ago) was a standard turbo (non-Turbo S) with Authority Stage II chips, so approx 270 bhp, and was a dual use street/track car. Failed around 10k miles and broke the teeth off the pinion, ring gear survived. I do not know anyone that has installed an S ring and pinion in a Turbo in the last decade. |
http://rennlist.com/forums/944-turbo-and-turbo-s-forum/240059-944s-ring-and-pinion-for-a-951-a-2.html
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold |
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edredas
Joined: 09 Dec 2004
Posts: 861
Location: Charlotte, NC
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| Posted: Sat Nov 19, 2016 4:57 pm Post subject: |
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I have a 944S transmission, so thanks for digging up all that info, Joe.
No offence though, I'll take the word of the GT40 guys over that of rennlist. At 944 fest a bunch of us were talking about how no one should ever trust anything over there and how they must sit around waiting to argue. 
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joecitizennn
Joined: 12 Sep 2005
Posts: 2096
Location: no mans land
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| Posted: Sun Nov 20, 2016 12:10 am Post subject: |
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Considering that the 944s is supposed to have the bigger pinion bearing, .3" bigger ring gear and updated gear pattern, its interesting that it has a high reported rate of failure under high horsepower applications where the turbo reportedly holds over 400 horsepower reliably. It would be interesting to see a direct comparison of tooth counts, tooth size, pinion size and gear hardness between the two.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold |
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edredas
Joined: 09 Dec 2004
Posts: 861
Location: Charlotte, NC
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| Posted: Sun Nov 20, 2016 2:52 am Post subject: |
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I did a little snooping myself and was poking around on 944 hybrids. Everything that I've seen says that the 944S trans has the "bigger pinion bearing, .3" bigger ring gear" and that seems to fit with what I've seen.
However, in your quote from rennlist, the guys says its all a little smaller... if you've ever spent time on rennlist you will learn very quickly that people completely make stuff up just to argue...
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'84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver |
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joecitizennn
Joined: 12 Sep 2005
Posts: 2096
Location: no mans land
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| Posted: Sun Nov 20, 2016 5:42 am Post subject: |
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What size is the pinion gear on the S in relation to that of the turbo?
What is the tooth count and tooth thickness on the S pinion in relation to that of the turbo?
Unless i am mistaken, the majority of 944 r/p failures is from the stripping of the pinion gear teeth, not pinion bearing failure or ring failure. Gear tooth failure comes from bending stress or surface wear. Bigger teeth are stronger in both respects, first they flex less, second the larger tooth gears have greater radii of curvature resulting in less stress. Since the 944 transaxle is stuck with the one basic ring gear size, the changing of ratios must be done via changing the number of teeth and pinion specs. An increase in tooth count results in thinner teeth with narrower roots. Since the pinion teeth take stress loads with more frequency than those of the ring, it stands to reason that thin teeth on a pinion will fail from bending first. I dont have tooth specs for the above mentioned transmissions, but i can make a guess. If the 944s has pinion teeth that match the turbo and s2 in thickness then the claim that it is a weaker transmission is probably just crap. If it has thinner teeth, the people who claim putting one in a turbo is a poor idea just might have something.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold |
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Kenodog
Joined: 25 Jun 2003
Posts: 2669
Location: Vancouver,B.C.
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| Posted: Sun Nov 20, 2016 5:42 am Post subject: |
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Its all moot now. Turns out the trans is actually from a 944S2. Not sure if that's better or worse for my application....
Me.
_________________
1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140 |
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Lau Christophersen
Joined: 17 May 2013
Posts: 123
Location: Denmark/Copenhagen
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| Posted: Sun Nov 20, 2016 6:35 am Post subject: |
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The 944 S2 is in the same HP range which you are aiming for but it is a bigger engine and N/A. So for a smaller volume turbo charged engine... hmm... maybe the gears are to high? It is not a 6 gear version? that is the 968 gearbox, right?
I am trying with a 951 S gearbox on my 280-300hp 931 but it is not driveable yet, so i can not tell you how it works...
(by the way I have some pictures on my phone for you of the turbo cup mirrors - just need to transfer it to my pc).
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edredas
Joined: 09 Dec 2004
Posts: 861
Location: Charlotte, NC
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| Posted: Sun Nov 20, 2016 6:42 am Post subject: |
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Sorry Joe, I don't have any of that info. I'm not a transmission guy so I've never measured any of this stuff myself. I have seen others that had transmissions apart show me things but even I was skeptical until I saw post on 944 hybrids.
My transmission workshop manual seems to refer me to the (016R) 951 transmission manual for rebuilding the 944S trans. I wasn't even aware such a manual existed... unless I'm missing something... which I probably am 
Also, the Ro that Oddjob seems to be quoting is for the S2 trans not the 951 trans... so he probably just looked at some numbers in the workshop manual and speculated. What I've seen is more in line with Jet951's posts.
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'84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver |
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kevingross
Joined: 15 Apr 2015
Posts: 35
Location: Stow, MA, USA
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| Posted: Sun Nov 20, 2016 9:17 am Post subject: |
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The 944S does have a somewhat stronger pinion gear. The strength comes not from hardening of pinion (or ring) teeth but from the width of the pinion tooth root. The image below is from a presentation on 924/944/968 series transmissions I did for PCA's Tech Tactics in '08. Unfortunately I do not have measurements for a 944S r&p, and I don't have one on the shelf I could measure.
[img]http://www.connact.com/~kgross/FAQ/assets/tooth root sm.jpg[/img]
The ratios for a 944S transmission are quite close to a 944 normal, and I think you'll be fine with them in your 924S.
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Catellus Engineering, Inc.
http://www.catellusengineering.com/
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