Hi! I was just wondering about my 200B diff, in the manaul that I have for the car it says for a sedan without IRS it will have a Borg Warner which will be 3.89:1 regardless of whether its an auto or manual. Is this the "H165"?? Its a khanacross/autocross car, so I figured that the lower the ratio, the better it will be. It has a 45DHLA, extractors, and a 2" system, and a stripped interior, so it goes *OK*, but the faster the better, eh? Currently the diff is open, but a locker will be going in when I find the right ratio. I figured about 4.11:1 and up would be best. Where do I find these ratios? I heard something about a C20 van having about a 4.9:1 ratio, but I dont know whether the centre will go straight in... What other diffs are there that will bolt in without major mods, H190 and the like? Once you've locked a diff, is that that centre locked for good? Or can you still change ratios? Because if I find one of these low ratio diffs I didnt want to ruin it by welding it. Guru help would be good, someone like Baz would be beneficial to answer in this topic

Is there a 3.5 diff ratio? I’m an concerned about freeway fuel consumption in a 200B?

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Datsun 200B

Epic thread revival!

Solid 200B diffs came as a 3.9:1 or 4.11:1. I am lead to believe that some series one and/or two Bluebirds came with a 3.7:1, although I think these would be quite hard to find these days. I've never heard of a 3.5:1 for a solid 200B diff.

Here's a thread I started many years ago when I was trying to get my 200B to rev a bit lower on the freeway: http://www.ozdat.com.au/forum/viewtopic ... 47afd53a65
Based on what is said in this thread, it may be easier to try and find an R31 gearbox and swap the bell housings over. I ended up with a 240K five-speed in mine and then left it revving at 3,000rpm at 100km/h.

Alternatively, if you have a 3.7:1 diff ratio, a Datsun five-speed with the 0.864 fifth gear, and 195/65/14 tyres, you will be revving at just under 2,800rpm at 100km/h.

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green200b - aka Alistair

The fleet:

Australia:
'80 200B GX - the green200b - hibernating
'81 RX-7 - 12A extend port - daily
'74 RX-2 - 13B bridgeport - cruiser

Europe:
'93 200SX - CA18DET - tourer