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Posted: Thu Jan 17, 2008 11:36 am 
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frankieh wrote:
hmmm, its definately a 90 series... so what the heck is it?

This is the relevant line from the cams manual relating to EA and VN.

Quote:
VN/VP Commodore:
Only the T5 manual five-speed Borg-Warner gearbox as fitted by GMH as original equipment may
be used (Production option M78-V6).
EA/EB Falcon:
Only the T50D (Part No. 87DA-7003-AA, 87DA-7003-AB, 90DA-7003-AA, 91DA-7003-BA) manual
five-speed gearbox as fitted by Ford Motor Company as original equipment may be used.
"


The whole thing is here: (google html version)

[url]
http://209.85.173.104/search?q=cache:hk ... =firefox-a
[/url]

If they are that unknown, perhaps I should be looking at a whole diff rather than just the center...
[/quote]

when you say 90 series do you nean the prefix 90da
if so that prefix is pretty much the year of manifacture not the series of the diff centre.. or gearbox
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Posted: Thu Jan 17, 2008 11:47 am 
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if your car has the original factory diff you can get a rough idea what series it is by looking at the flange on the tailshaft..

if it has a round flange on the diff with 4 m10 bolts. its more than likely a 78 series diff. also look at the bottom bolt bolt on the diff cover it should be a drain plug..

and if it has a flange with 2 hoods and 4 small 1/4 " bolts and it doesnt have a drain hole its more than likely a 75 series diff.

but in saying that both housings can use both 75 and 78 series centres..

otherwise take your diff cover off and look on the ring gear it will have the series and the ratio stamped on it..
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 Post subject: looks like a 75 series LSD??? photos...
Posted: Fri Jan 18, 2008 12:52 am 
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Got some photos so the experts can see what it is..

Image

Image

Image

Image

Image


From your description, this is a 75 series yes?
That would be a good thing for finding a cheap 3.9-4.11 LSD center wouldn't it?

Before I get carried away, I should wait for the expert analysis.

Whats the word?
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Posted: Fri Jan 18, 2008 8:52 am 
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gday
thats a ea 75 series diff...
and looking at the pics it looks original..

the only set back is the 25 spline axles..
where as the 78 series has 28 spline axles (stronger)...

what is written on that small tag?
i think the tag should have the series on it aswell as the ratio...
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Posted: Fri Jan 18, 2008 11:34 am 
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I'm fine with it being a 75 series because I can't see an NA i6 ED motor some strags and a cam having to much power for it.

Am I right?

I'm a little annoyed because I was offered the whole ED Fairmont that my motor came from and I didn't take it. I should have at least checked the diff ratio on it, but didn't know what I wanted at that stage.

With a 75 series and 3.23:1, does that mean that if I found a Pintara lsd with 4.11 I could just swap the whole center in?

rgds

Frank
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Posted: Fri Jan 18, 2008 1:23 pm 
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as far as i know .. yes..there are a few ratios that fit straight in
..3.77/3.89/4.11..

and you will find them in cars like r31 skylines and pintara ( 4 cyl skyline)
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Posted: Fri Jan 18, 2008 1:26 pm 
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Quote:
what is written on that small tag?
i think the tag should have the series on it aswell as the ratio.


The top line of that side tag said:

P/N: 90DA-4005-AB

The bottom line said:

Ratio: 3.23:1 s/n: xxxx

no mention of series.. but you can see where I got the 90 series idea... must be an internal part number at BW or ford.

My question now is.. did any pintara's have LSD, as that would seem to be the easiest way.. just grab an entire 4.11 center lsd and all and stick it in.
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Posted: Fri Jan 18, 2008 1:39 pm 
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im not sure if pintara has lsd??

but the gears should fit on your lsd centre.
and in the process of changing the ratio you need to remove the centre and pinion anyway so it would not be difficult to swap the ring gear from the std centre to the lsd....

or you could retro fit a edxr or efxr diff complete( only 3.45)though.
and it depends on your budget??

either way there is a bit of work involved..
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Posted: Fri Jan 18, 2008 2:02 pm 
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I found a really excellent page on the nissans and their diff ratio's and LSD etc..

http://wiki.r31skylineclub.com/index.php?title=R31


There is a really good table about it here:
http://wiki.r31skylineclub.com/images/5 ... IDinfo.jpg


If there is such a beast as a "Pintara silhouette" and it looks like there is (though I'm by no means certain as I don't do nissan).. it apparently will have a LSD.. though I'm thinking that pulling the whole center from one and taking it and my car to a diff expert as a diff is the only thing in a car I've never pulled down before and the whole shimming thing has me concerned.

That table seems to indicate that the whole lot of the nissans are 78 series not 75.

Wondering if I should just pick up a normal 78 series diff cheap from somewhere, and use my lsd center and a pintaras 4.11 gear, then just swap the whole diff in.
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Posted: Fri Jan 18, 2008 2:37 pm 
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i was sure the pintara has 75 series (maybe i got them mixed up) its been a while. but someone else might be able to confirm it..100%

and i never seen a pintara silhouette? maybe in japan??????
the skyline silhouette was a rb 30 6 cyl.. its the nissan equivalent to fords s pack
and the pintara of the same year is a 4 cyl..version of the skyline?

also the jap imports of the same era dont have borg warner diffs.(like the r31 gts t 2 door..(pretty rare to find in a wrecker anyway)
only the australian releast models have the bw diff..

thats about the limit of my knowlage on the pintara diffs
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Posted: Sat Jan 19, 2008 12:38 am 
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If there is a chance that the following will kill my diff..

1. ED motor.
2. ED XR6 cam.
3. Genie extractors.
4. 2.5 inch mandral bent exhaust.
5. Giant custom cold airbox with big cone K&N filter.
6. Thermo's, no engine fan.
7. Auto shift kit.
8. 4.11:1 ratio.

That will go ok, but it's not like I'm fielding a 220rwkw machine here.. but if that stands a decent chance of stuffing my 75 series diff... then I'll upgrade to a 78 before I start looking at ratios.

My thought was just that there must be a reason that ford swapped to 78 after the EA.


What do you rekkon mr Troy?
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Posted: Sat Jan 19, 2008 10:13 am 
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lol mr troy lol.

i would say it will be ok.
it depends on how much traction you have and how hard you launch.
if you have huge tyres (good traction) and say you like to dump the clutch a fair bit the ea diff will die early..( or break an axle)

i had the std ea lsd in my car before i started to mod it and with the std tyres 205 /15.
i could do burn outs and the odd roll back . and didnt have a prob. actualy i still got that diff in my shed( good spare).

so driving it hard without doing heaps of burnouts it should last a fair while.
the main thing that will destroy the diff is torque and traction...
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Posted: Sat Jan 19, 2008 12:39 pm 
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There is the answer then..

thrash the 75 till it dies, and then find a 78....

:-)
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 Post subject: re R31 Skyline diffs
Posted: Sun Jan 27, 2008 9:49 am 
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Gents
Something that you might not be aware of with the R31 Skyline diffs (Aussie built with the BW live axle)
Almost all R31's end up with a whine in the diff at around 80 to 100 Kph

I've had 3 R31's years ago and they were all the same. They were renowned for it. So much so that at one stage Nissan were relacing the diffs for basically the cost of labour (this was when the car was way out of warranty)

The diff wouldn't fail and if you could live with the noise they were fine. Some were louder than others and I think it was a bit of a lucky dip. I had one of mine rebuilt with a new crownwheel and pinion by a gear box & diff "expert" in Newcastle and it also developed the whine again. (a couple of months after the diff experts warranty ran out of course.
I was never able to find out a conclusive reason for the whine. Everyone seemed to have a different reason for it.
It might have just been a combination of different things in that set up and using the gears from one in a Ford housing might be ok, but I would be inclined to do some research before I went that way.

Hope this helps
regards
bollie7
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Posted: Sun Mar 02, 2008 1:05 am 
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Thanks for the tip bollie,

I don't care if it whines as long as it doesn't drown out the stereo or the exhaust..

I've done all I am likely to, to my motor for a while.. it's heaps better than it was, so the last thing on my list for the drivetrain was to up the diff ratio..

I really want something around 3.5 to 4.11, so time to start looking.
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