New Zealand Datsun Club

what ratios are available for r200 longnose diffs?
if possible, can you state what ratio comes from what vehicle, we could make it into a tech article.

id like to find a 4.3 ratio diff if they exist..

Available diff ratios:

3.54:1 - Z31 Fairlady Turbo
3.7:1 - Z31 Fairlady Non Turbo
3.9:1 - R30 Skyline L20et
4.11:1 - S12 Silvia FJ20e

Not so helpful to you but a 1985 Z31 Runs a 3.7

I have seen the Americans build an adapter cradle to mount a shot nose diff in place of a long nose using an unmodified cross member.

is that a potential option to get your 4.3 ?

Edit > i was mistaken I looked up the info and it was an extension piece that is welded onto the cross member/sub frame to allow fitting of a short nose.

Extension piece is attached, as far as I recall its the only way to get a 4.3 IRS Nissan diff to work

cheers for the info dude!

yeh ive had some thoughts about converting to shortnose, would prefer to stick with my longnose conversion atm, will still consider it an option.
would like a 4.3 to go behind my sr20de in the 1600, unless i decide the 4.11 i have is more suitable.

mint16 wrote:cheers for the info dude!

yeh ive had some thoughts about converting to short nose, would prefer to stick with my long nose conversion atm, will still consider it an option.
would like a 4.3 to go behind my sr20de in the 1600, unless i decide the 4.11 i have is more suitable.

Being an Sr20 box can you get a closer ratio 5th put in your box to allow full use of a 4.11 ?
Many people overlook gearbox modifications, my box rebuild wasn't overly expensive so I would imagine simply changing to a different ratio 5th gear would not be uneconomic.

if i changed the 5th gear ratio, it probly need to change 2nd, 3rd and 4th to suit, as a 1:1 5th would be the only decent option compared to the factory overdrive 0.8ish:1.
would be sweet to have a short ratio box, would be even better to be a dog box!!!!

Looked up the Factory Spec Manual & Z31 Non Turbo is 3.7 and Z31 Turbo is 3.54

According to the Silvia web site: "All S13 CA diffs are 4.3, All S13 SR diffs are 4.1, except the DET auto which is 3.9"

What size wheels will you be running? it sounds like a 4.1 might be a good option, what is it that makes you think that a 4.3 might be better?

was told sr20 silvias had 4.3s, so thought id stick to the factory diff ratio.
im running 15s with 195/50s.

Might pay to investigate the ratio, I only pulled this off a Silvia Website, but if it is correct it could save one head ache atleast. I'm sure on a conversion head aches don't need to be looked for. Lol.

I have these R200 Diffs if it helps.
When i say series 2 it means its the later type with the 17mm (M12) chrownwheel bolts.

I can't remember what the first 3 are from but i think different R31s
3.7:1 Series 2
3.9:1 Series 2
4.1:1 Series 2
4.43:1 Series 2 (factory CLSD) R31 RB20DET Skyline Auto
4.625:1 Series 2 Y31 Cedric

There is other ratios in the Series 1 diffs (M10 14mm Head chrown wheel bolts) but i havn't bothered to keep them as i plan on fitting VLSD or HLSD short-nose centers to them.
If i find a Series 1 diff ratio i can't find in the series 2 diff then i'll keep it and shim the bolts.
By the looks of it i just need one of thoes 3.54:1 items to complete my collection then once my car is finished i can start testing to see what will work for me.

Note to anyone buying or getting diffs. Always try get the speedo sender from the box that matches the diff this will come in handy later when you decided to get your speedo to work correctly.