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Subaru Sti R180 differential and Axle conversion. (Revised)


Nizzan

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That's about 350+ more then the R180 can take in a 2WD application. :-)

John, I wouldn't doubt that at all.. but from where I'm sitting.. I have a better chance at keeping the STi rear end together than the old r180 or r200.. I made 432hp on the dyno and took it to a open track day. the diff held up fine and I hooked up very nicely in the corners. We'll see in a year how the diff holds up after I switch to e85 and make bigger numbers.

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  • 1 year later...

Sorry to bring this back up but does it hold now?

 

Wedge,

Not sure if you're talking to me but it does hold. However, John is probably right as far as its capabilities with holding down the power. I haven't had any issues yet at 400+hp and a handful of track days but I'm going to bet it'll eventually fail. I talked to OS Giken about getting a new diff for the r180 and they didn't recommend it. The said nothing they make will hold down the power reliably.. I would suggest getting a r200 with custom axles and getting a OS Giken diff for the best locking power. For what I'm going to need it'd probably best I sell my setup down the line and get a r200 or r230. But for a 400hp max setup I don't see why not.

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This swap was fairly reasonable for what I paid and my time spent. I am NOT mechanically inclined and I was able to do it all on my own. It was pricey for the axles but I picked the mid-grade setup. The diff on eBay ran me $200. Axles were 1300 and I used parts off my old r180. All in all it grips great and I am pleased with the results.

 

Maybe when this diff breaks I'll do new axles with the r200/230.

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  • 3 years later...

Hey guys, I know it's kind of a dead horse at this point, but I thought I'd kick the topic a few more times for good measure

I just completed this conversion, here's a few of my choices:

I found a brand new '05 WRX STi diff for sale on ebay directly from a dealership for around $1500 shipped. I figured this was my overall best bet, figuring the cost to buy and then rebuild a used diff (I'm going to be racing with this). Got the stub axles from Wold Creek, and also purchased the CV conversion at the same time.

Since I was going everything brand new, I left the stock Subaru input flange on the R180, and when I had the driveshaft balanced, along with new Nissan u-joints, I had the guy put an output flange on the ds to match the subaru flange. Overall way less effort. I then used 4 grade 12 hex bolts, 10mm 1.5 thread- note you WILL have to bevel a spot on the bottom edge of the head to get the bolts to sit flush. This route is overall a little more costly, but you end up saving a lot of effort and upgrading the durability of the pieces.

 

You also must first put the press in bolts into the stub axles before inserting them into the diff, they are just too long otherwise. I got brand new OEM nissan bolts and nuts- the nuts are special and really narrow. Also be careful when tightening these bolts (4 per stub axle) as it is really easy to cross thread them.

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Hey guys, I know it's kind of a dead horse at this point, but I thought I'd kick the topic a few more times for good measure

I just completed this conversion, here's a few of my choices:

I found a brand new '05 WRX STi diff for sale on ebay directly from a dealership for around $1500 shipped. I figured this was my overall best bet, figuring the cost to buy and then rebuild a used diff (I'm going to be racing with this). Got the stub axles from Wold Creek, and also purchased the CV conversion at the same time.

Since I was going everything brand new, I left the stock Subaru input flange on the R180, and when I had the driveshaft balanced, along with new Nissan u-joints, I had the guy put an output flange on the ds to match the subaru flange. Overall way less effort. I then used 4 grade 12 hex bolts, 10mm 1.5 thread- note you WILL have to bevel a spot on the bottom edge of the head to get the bolts to sit flush. This route is overall a little more costly, but you end up saving a lot of effort and upgrading the durability of the pieces.

 

You also must first put the press in bolts into the stub axles before inserting them into the diff, they are just too long otherwise. I got brand new OEM nissan bolts and nuts- the nuts are special and really narrow. Also be careful when tightening these bolts (4 per stub axle) as it is really easy to cross thread them.

 

Did you get the CV conversion from wolfcreek/futofab also? Any pictures of it? That's my eventual plan for mine. 

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