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Brabham

Diff Ratios

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You are dead right Nato. My 3.36 LSD is the only one I have heard of or seen in a car. I wouldn't be selling it even if I was offered $1,500-. (I have plans) So I would be surprised if Brabham found one. Any R200 LSD is hard to find these days let alone the ratio you want. Took me a year to find my 3.9 LSD and that was through word of mouth.

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Is an LSD really necessary for salt lake racing though?  You've got heaps of time to reach your top speed so the bit you'll loose taking off shouldn't make any difference.  I'm not saying it's going to make it any easier to find the ratios you're after but there's no point spending the extra on an LSD if you don't need it for the application you're using it for.  They're heavier and may actually cause a little bit of drag depending on what the pre-load is set at so it might marginally reduce your top speed compared to an open diff??? Just a thought.

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Why not chase up an R180?? For the high speed salt lake type work you won't be putting the torque loadings through the diff that you would with a shorter ratio, so shouldn't have to worry about breaking them. Plus I've found the difference in strength between the R180 and R200 for a circuit car to not warrant the extra weight of dragging around the R200.

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I'm not really sure Brabham's priority was to do the Salt Lakes thing. That was more a plan for me. Since I have a diff for the proposed trip I don't see any need to look for another one. I think my 400klw motor might push an R180 to the brink. Something not worth testing at a real high speed!!

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A mate of my dad's built a Falcon for the salt lakes.  He said there is no traction at all.  Sounds like you wouldn't even break an R160 from what he said no matter how much power you were putting through it!

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Howdy,

 

Brabham, try Nissan part no.38100-N3405 which is a 3.154 ring and pinion set listed for an R200 in the Datsun Competition parts list. I very much doubt they would be avalible new, but try US sites, as they were sold there new. Dont waste your time with Nissan Aust, the US is the answer, if you want one.

 

Also try www.locost7.info/gearcalc.php and dial in your numbers, It will tell how many RPM you will need to do what speed in what gear, It will be up to you to get the power to pull the numbers!!!

 

If you can get hold of a DVD called 'Big white Dyno', done at Lake Gardiner in '04 it will show you how hard it will be....

 

If you look at the DLRA results not mant cars do 200MPH (320kmh) goooood luck.

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Thanks for the info blue rat. It is something I will look at. At the moment I have the 3.7 and will just keep a casual eye out for anything that turns up on ebay or through word of mouth. I am still restoring the body on the car and have not fully decided on the drivetrain yet, but the diff will be an R200 with an L-series engine of some description, possibly turbo and methanol-water injection looks interesting, have been reading up a bit on that lately for a bit more power and extra cooling. :) :). Not sure what corrosive effects it would have on the engine though. Any thoughts? Singapore F1 tonight yay :)

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How did you go with this Brabham?  I'm after something around 3.00:1 for a R200 which seems impossible but no harm asking.

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Whatever diff you use, fit a Spool type centre, ie locking both axle splines together.

Dont try a CIG Welded centre, as you will never get the weight balance from one side to other, with the plates, and gobs of weld, etc, and at high tailshaft rpm ( useing a 0.75 fifth gear, engine, say 7000, tailshaft will be spinning at 9500 rpm !) a welded centre will vibrate the living crap out of the car.

A LSD if plates are really pre-loaded, will do it, but the inertia losees will be greater than a Spool

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