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Axle codes


Paul Booth
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Ooh ta!

 

I'm a bit sceptical about the LSD though. There's nothing limited about the way my inside wheel slips exiting a junction under power.

 

I'm guessing, if it's a true LSD it's mechanical and built in to the diff casing; seperate from the pseudo traction control. Ergo, the button on the dashboard will have no effect.

 

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Paul I had a diff which according  to the plate was standard and gave the problems you describe.

Now I have fitted a diff from a "B" plated car the problem has gone away.

 

Hving put both uints side by side their is absolutly no way of telling them apart from the casing.

 

Just different white paint marks.

 

(Edited by Phil Wall at 11:08 am on July 9, 2001)

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Paul

 

The reason your inside rear spins up is because you havent' GOT an LSD !!

On the VIN plate codes, bit that tells you about the diff is "A02B".    It's the *first* character that says whether you've got an LSD or not.

A = no LSD

B = LSD

 

so you haven't got one which will be why one of your rear wheels is spinning away power.

 

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Hmm, ok, just found another site which gives this info so i could cross-check :

http://www.ozsupra.qld.org/windows/mainwindow7.htm

this ties in with the NZ site.    they do both say that it's the last letter of that 4-character group (A or B) that signifies whether it's got an LSD.

 

Only one slight hitch !!

This is my full code from my VIN plate on my UK TT :

3L2 LF00 B03D V160T

1st group is colour ("Renaissance Red")

2nd Group is trim (leather etc.)

3rd group is Axle etc.  BUT the last letter is "D" !!!!!!!!

uhh ???    i definitely have got an LSD (standard on my car) and that's why i assumed it was the first letter of that group that tells me about the LSD.    

Can anyone (everyone ??)else post up there codes on the site so we can all compare ?   particularly other UK owners as now i'm confused !

 

BTW, 4th group, V160T says it's a 6-speed manual.

 

cheers

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ahaaa, a UK spec diff.....

 

The UK specs have a larger diff with seperate oil cooler, I never thought that it might be a different axle code, and as the VIN plate on the UK specs is so different to the imports I never checked.

 

I suppose thats one to remember. I think the 3 in the B03D means its a manual gearbox as well.

 

If anybody else with a UK spec can confirm they have a D as well then we know that the D means a UK spec diff.

 

JB

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Guest Martin F

Tonight, Tonight guys.

 

Don't reckon the powers that be would be too happy me popping home to check my VIN plate

 

:biggrin:

 

Cause no way would i come back!!

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Quote: from branners on 11:37 am on July 9, 2001[br]nope, its the last letter as per

http://www.mkiv.co.nz/specs.htm

 

so unless you have had a non LSD diff put in or your diff is knackered it shouldnt spin an inside wheel.

 

JB

 

I can put your mind to rest...

 

(Apologies for covering some old ground...)

 

If you pull away while turning tightly (i.e. out of a junction) but you aren't accelerating hard, and the inner wheel slips/squeaks/chirps, it's *because* you have an LSD!  

 

As we know already, non-LSD Supras will readily spin up one wheel under hard acceleration.  That's because as soon as traction breaks on one tyre, all the power going into the diff goes out the path of least resistance - the spinning wheels (I can't discuss the inner design of diffs - I just hope you played with technical lego :) ).  This is the 'slip' part - the difference in rotational speeds between the two axles.

 

An LSD has a mechanism that limits this slip, keeping the rotational speed of both wheels within a certain percentage of each other - how much is dialled in by the manufacturer according to their whim.  This means that under hard acceleration you don't get one wheel easily spin up, you need to apply enough power to break traction on both.  Ergo, better acceleration, which as we all know is A Good Thing.

 

Now, when turning tightly out of a junction, the inner wheel barely rotates compared to the outer one.  However, the LSD doesn't allow that much rotational difference (it limites the 'slip' between the two wheels' rotational speeds), so the inner one is forced to rotate faster than it needs to, and so spins.

 

Hope that clarifies some stuff.  I now need a lie down after that!

 

-Ian

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Yup! it's logical, coherent and self evident (now).

 

It also accounts for my total rear end break-away when I pushed it rounding a tight-ish left hand bend. I was expecting non-LSD behaviour, as this is what I've driven for the last 20 years. Full-on rear slide caught me by surprise, a Bad Thing.

 

Now I know what to expect I'm gonna have another look at that bend.

 

 

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Paul cant explain your spin, you code is identical to the donor car I from which I removed the LSD I am now running.

 

However there is no way to tell with out looking inside I believe.

 

May be someone else knows how to check an LSD.

 

I guess checking the fluid level would be a good place to start and check for fluid leaks?

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Tail-spin is an inevitablility of an LSD, as opposed to traction-control, on tight bends.

Excess power applied and both wheels break, instead of just one with the consequent loss of applied power and forward momentum.

With the LSD both wheels will continue to spin while the engine applies power and that means no grip at the back end, rather than on wheel guiding as the other spins, as with no LSD.

Traction control 'brakes' the spinning wheel thereby preventing runaway and maintains the maximum controlled applied power through both rear wheels.

Hence Traction Control is a Better Thing.

 

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except the import traction control, which is a worse thing as it doesnt apply any braking, it just shuts off a butterfly in the manifold and kills the power. The UK cars have traction control braking on the rear wheels which works much better but it still no where near as good as the Racelogic TC.

 

JB

look, I've opened my corner shop....

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Well the UK traction control may be better than the Jap-spec traction control but it's still crap in my opinion.

So i pulled the fuse on it.   It cuts in really very often with ANY rear wheel slip (like even over a cats eye etc.) and it's most disconcerting when the power disappears.

 

The racelogic system is great I admit.   but quite expensive.

 

On the diff issue, yep Ian is right.   The extreme case of a "stiff" differential is a kart which has ....no rear diff at all.  It's a solid rear axle, and as such if you think about it, you wonder how it can go around a corner at all cos the outside tyre has to travel further but it's solidly fixed at the same rotation speed as the inside tyre.

Chassis flex let's the inside rear rise slightly off the ground and this is how it gets round corners.    It's also one of the reasons why they tend to understeer horribly in the wet.

But i digress a bit.

 

cheers

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Quote: from branners on 2:49 pm on July 9, 2001[br]except the import traction control, which is a worse thing as it doesnt apply any braking, it just shuts off a butterfly in the manifold and kills the power. The UK cars have traction control braking on the rear wheels which works much better but it still no where near as good as the Racelogic TC.

 

JB

look, I've opened my corner shop....

 

 

..... and Traction Control

..... and....

 

 

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Guest Martin F

Right the full code from the bottom of my VIN plate is :-

 

202 LF00 B03D V160

 

So the same as Stu's except the colour. I'm sure the UK LSD would have a different code to the JAP one because of the oil cooler pipes etc.

 

Martin

 

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Phil

 

5 uk codes for diffs ?   not sure i understand.   do you mean there's 5 different codes for 5 diffeerent types of diffs on UK cars ?     i thought there was only 1 diff on UK cars and that was LSD (with the diff oil cooler).

 

Interesting that Martin's is the same as mine "B03D".

Also my transmission code is slightly different.

it says "V160T".     Martins' is just "V160"    wonder what the "T" on the end of mine is ??     no web sites i've looked at mention it.

 

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