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shaun240

R180 Diff Options

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Hey guys,

 

Just hoping to get some advice on our options for the R180 diffs. I have done a quick search without any luck so hoping you can assist.

 

We have recently completed the auto to manual conversion on the 240z which is now running a 260z 5 speed box however still running the original auto R180 3.55:1 diff gearing which we want to replace to help with acceleration. I have read the 4.11 would be best suited for our car, is this correct? The motor is fairly stock and is only street driven therefore I don't think there is any need to replace with an R200 at this stage, so should we look to source replacement gears such as 4.11, and are these readily available,or are we better off just replacing the entire diff?

 

Thanks,

 

Shaun

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Hi.

 

I have the R180 with 3.9 gears. It is really good ratio behind the L28.

My only compliant is the 280 gearbox's first gear is a little to short, a 260 box would fix that.

 

Cheers

PB

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4.375 ratios were Nissan Competition, now no longer avail.

4.1 was fitted to other mdels, that we did not get in Aus, unless imported.

In years past the usual Datsun shops did bring them in.

Try Stew Wilkins Motorsport, at McGraths Hill, or,

MIA Engines at Brookvale, you are about in the mddle of both these shops, they may be able to supply something.

 

3.9 is a good comromise f affordability, availability, economy and performance.

The 4.1 will be more $$$, better performance, less economy, hard to find.

 

Forget the 4.6/4.8/5.1's from the front f the various 4x4 utes, unless you go racing on tight twisty circuits, rallying, or hillclimbing!

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Jason knows his dattos. 

 

Don't bother checking SWM or MIA, i've been on a wait list with them for a 4.1 or 4.4.

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Subaru WRX STi diffs come in 3.9 and 4.44 which are factory LSDs. They are probably the best options for ease of procurement.

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Subaru WRX STi diffs come in 3.9 and 4.44 which are factory LSDs. They are probably the best options for ease of procurement.

These really are our next best option, but, add on the USD$550 plus shipping to get the new machined output stubs, to suit our halfshafts.

At least the Subaru diffs are cheap and readonably plentiful.

 

An original Nissan R180 with LSD, can be $1200-$2000

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Subaru WRX STi diffs come in 3.9 and 4.44 which are factory LSDs. They are probably the best options for ease of procurement.

Totally agree, if you want LSD, Subaru is a good option. I have both a 3.9 and a 4.625 Subaru LSD. The 2 ratios make for good ratios for different track configurations, both are fine on the street but obviously the 4.6 is not great for highway driving.

They are much easier and cheaper to find than Datsun LSD options.

 

Mick

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SWM are making the stub axles that go in the diff now to use the stock half shafts. So no USD and shipping problems there.

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These really are our next best option, but, add on the USD$550 plus shipping to get the new machined output stubs, to suit our halfshafts.

At least the Subaru diffs are cheap and readonably plentiful.

An original Nissan R180 with LSD, can be $1200-$2000

Hi

 

Do you also need to change or machine the pinion flange to suit the Z propshaft ?

 

Cheers

 

PB

Edited by PB260Z

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I knw there are three different rectangular hole measurements for R200 pinion flanges, as for R180, there are at least two measurement patterns ( rectangle) there may be mre.

 

All the R type diffs are made by Fuji Heavy Industries ( makers of Subaru cars too!)

As for the munt points up the front, they are the same, bt IIRC some f the STI WRX dff hacks, had bgger studs.

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Hi

 

Do you also need to change or machine the pinion flange to suit the Z propshaft ?

 

Cheers

 

PB

Nope different bolt pattern from my experience but easy enough to pull the Subi flange off and bolt a Datto flange on. And a quick look at the backlash etc.

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Subaru sti diff 3.9 lsd fits right into a 240z body? Or need modification?

 

Bolts in, it's a long nose R180.

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Sorry for the noob question, whats the difference between r180 vs r200 and 3.9 vs 4.11 in terms of performance and advantages?

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Hi

 

R180 v R200 is the size if the crownwheel 180mm v 200mm strength but weighs noticeably more.

3.9 v 4.11 about 200 rpm at 100km/h, the 4.11 being the higher reving one. In short better acceleration but reduced speed in each gear and ultimately lower top speed.

3.9 is regaded as a good compromise ratio, but if you do a lot of highway work go for 3.7 or 3.5.

 

Probably best to get a ride or drive in cars with the different ratios and see what suits your driving style and intended usage - gearbox ratios also play a part.

 

Cheers

 

PB

Edited by PB260Z

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Thanks pb260z!

Do you mean i cant just go from stock 3.36 and bolt right in r180 3.9 without modification to the gears?

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Thanks pb260z!

Do you mean i cant just go from stock 3.36 and bolt right in r180 3.9 without modification to the gears?

If your car currently has an R180 with 3.36 ratio, Yes you can bolt in another R180 easily enough.

You will also need to swap the speedo drive cog in the gearbox to the one for a 3.9 or your speedo will read faster than you are actually going.

 

Cheers

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Found one wrx sti v8.5 differential for sale. But seller doesnt know the specs and only know it came out from a wrx sti 2.0 6 gears. I did a search on that particular car, doesnt have any info on the differential ratio or lsd.

 

Does all wrx sti comes with stock lsd? And will this differential works for a 240z since it was for 6mt?

Will attach some pictures.

post-104110-0-71350500-1467456525_thumb.jpeg

post-104110-0-85010200-1467456534_thumb.jpeg

post-104110-0-14132700-1467456544_thumb.jpeg

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Just pull the hat off and the ratio is stamped on the crown wheel. Also you can see what sort of LSD is in the diff by looking at the carrier. All STi rear diffs are LSD but there are three different types. I would be guessing it's a 3.9 with a suretrak centre (torque sensing).

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Thanks decoy, so which type of lsd is best and how to differenciate?

Suretec or torsen?

 

I think this diff is 4.11, as the seller told me was taken from ej20 engine car. And this is what i found on a subaru forum.

 

post-104110-0-52526800-1467466874_thumb.png

Edited by locklock

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Subaru sti diff 3.9 lsd fits right into a 240z body? Or need modification?

The Stewart Wilkins Motorsport modded stubby shafts for the Subaru diff don't have the Datsun R180 half shaft centre bolt fitting so you have to source R200 half shafts or another pair of R180 half shafts and change the inboard Uni flange for the outboard ones i.e. Outboard flanges both ends. I would steer clear of the viscous Subaru diffs and plump for a Torsen or clutch pack type; the latter being harder to find.

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