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Turbo Differential


jibarnes

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I want to start by saying I do not own a turbo but was wondering if someone could verify the markings on this diff to a diff in a turbo?

Are there different gear ratios and % lock up or are they all the same.

 

Thank you,

 

James

Edited by jibarnes

72 02

73 02 tii

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It is the proper ratio with limited slip to have come from a turbo. There is also the possibility it was a special order on a European Tii/Ti. In the years before the OD 5 speeds were available this was the way to go if you spent most of your tim on the freeway. 
If you are running a 3.9:1 final drive with the 245/5 overdrive transmission you have an effective 3.15:1 final drive in 5th gear versus this 3.36:1 with the 1:1 top gear in either the standard 4 speed or the CR 235/5 5 speed that was available in the 2002’s in the day. 

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1970 1602 (purchased 12/1974)

1974 2002 Turbo

1988 M5

1986 Euro 325iC

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55 minutes ago, jibarnes said:

 

 

472A7AC8-B8C1-49CF-AB5C-69EEDE9A28AE.png

DBF071CA-C6BB-4326-B69B-90592F472056.png

C5FB1C6D-1DCF-4466-8F02-22210121FB42.jpeg

I want to start by saying I do not own a turbo but was wondering if someone could verify the markings on this diff to a diff in a turbo?

Are there different gear ratios and % lock up or are they all the same.

 

Thank you,

 

James

You could definitely find a buyer for that differential in this group…

 

Greg

January 30, 1973 Agave tii

April 24, 1974 Chamonix Turbo (German delivery)

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1 hour ago, Preyupy said:

It is the proper ratio with limited slip to have come from a turbo. There is also the possibility it was a special order on a European Tii/Ti. In the years before the OD 5 speeds were available this was the way to go if you spent most of your tim on the freeway. 
If you are running a 3.9:1 final drive with the 245/5 overdrive transmission you have an effective 3.15:1 final drive in 5th gear versus this 3.36:1 with the 1:1 top gear in either the standard 4 speed or the CR 235/5 5 speed that was available in the 2002’s in the day. 


The casting date on the housing is January 19, 1974 (“191” and “74” on the top rear of the housing). While not conclusive, that date. plus the 3.36 ratio, would certainly point toward a factory turbo…

 

Regards,

 

Steve

 

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1976 2002 Polaris, 2742541 (original owner)

1973 2002tii Inka, 2762757 (not-the-original owner)

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2 hours ago, jibarnes said:

Thanks,

I don't know what happened to the text, I edited the post.

I see it now.  I assumed you were asking if that was a turbo differential.  I guess right now with the info we have, the correct answer would be "the case appears to be that of a factory turbo." 

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1973 2002 tii

1974 2002 turbo

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Some of you here — e.g., Byron — are probably quite familiar with the difference between a turbo-only housing (PN 33111204094), and a “rest-of-the-submodels” housing (PN 33111206175). Parts sheet 33/11 (first and second photos below) points to this distinction without describing it. My guess — that’s all I can provide — is that the differences between housings, likely minor, accommodate the turbo-only bearings, which accommodate the turbo-only flanges and side covers, as shown on parts sheets 33/12 and 33/13 (third through sixth photos).

 

In brief, if this unit has the turbo-only housing, bearings, flanges — a 97% probability — then it probably began its life as a turbo unit. Given its early date, the chance that it was a factory install, rather than a replacement part, is relatively high.

 

Best regards,

 

Steve

 

 

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1976 2002 Polaris, 2742541 (original owner)

1973 2002tii Inka, 2762757 (not-the-original owner)

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And, yes, James, as @Son of Martyhas pointed out previously elsewhere, both 40% and 75% lock-up LSD’s were available from the factory. Below, parts sheet 33/19 (first photo below) shows the 75% LSD as available on all models, except for the 1502. Although this sheet oddly does not “check the box” for a 40% LSD on a turbo (PN 33141201532), sheet 33/16 shows the 40% LSD (that same PN 33141201532) as the “standard” unit for a turbo (second photo). At least that’s how I interpret these parts sheets!

 

Regards,

 

Steve

 

2C38A8FC-687E-4B39-B3EA-552E01638565.jpeg

71EEA8B7-9D01-4632-98B9-C9FCB9B9FA0A.jpeg

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1976 2002 Polaris, 2742541 (original owner)

1973 2002tii Inka, 2762757 (not-the-original owner)

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