Diff swap: STI R160 LSD 4.44 Suretrac

Engine, Transmission and related drivetrain.
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Fred_L-P
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Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 21 Feb 2018 09:38

I was looking at the R180 LSDs for my swap, but I stumbled on this R160 for sale. Can't find any clear info on what it takes to swap it in a 510. Is it doable? easier than an R180?

Does anyone have information on this diff swap?

Since I'm only aiming at 180/200hp, I figured the smaller R160 is probably enough and cheaper.

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Fred_L-P
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 21 Feb 2018 10:45

It's from a JDM 2006 STI

eastbaysolo_73
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by eastbaysolo_73 » 21 Feb 2018 11:26

Do a search man Its been covered quite a bit. Doubt anyone is gonna chime in ask me how I know lol.. Good luck
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Fred_L-P
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 21 Feb 2018 19:29

Yeah... I've been reading for hours now. Still can't find any information for the the R160 Suretrac lsd swap in a Datsun, but I know it can be done. It is a mechanical LSD, similar to a Torsen. So it's not like the old CLSD where the stub bolts in. It is not a VLSD as described and shown in the DQ Volume 9 Issue 4 where you need to adapt the double spline stub axle. Maybe it's the same case, but I simply cannot find the answer anywhere.
If you do have the answer since you looked into it, can you atleast point me in the right direction?

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JordanTr
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by JordanTr » 21 Feb 2018 21:48

There was a thread with some details on this on the realm many years ago iirc. I'd search a little harder if I wasn't on my phone.
Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

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icehouse
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by icehouse » 21 Feb 2018 23:04

Will those gears swap into the 80's subi R160?
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Fred_L-P
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 22 Feb 2018 04:44

JordanTr wrote:There was a thread with some details on this on the realm many years ago iirc. I'd search a little harder if I wasn't on my phone.
I'm sure there is, it's a 12 years old diff. I can't belive I'm the first person interested in swaping it.
But I searched the powertrain thread with every key words I can imagine and found nothing (and the rest of the internet of course).
icehouse wrote:Will those gears swap into the 80's subi R160?
See, thats why I'd like to swap it. I'm in the process of rebuilding the whole rear end and was planning a R180 3.9 swap.
Since I am going N/A and aiming at maximum 200hp, the R180 is overkill.
But then I saw this cheaper, lighter, mechanical lsd 4.44 R160 for sale... If I can't find any more info by the end of the week I think I'll go for it and figure it out on my own later.

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Fred_L-P
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 22 Feb 2018 09:48

I think I managed to put every pieces of the puzzle from many sources together.

The JDM R160 Suretrac uses standard 25 spline symmetrical stub axles.
The 510 stub axles should slip right in but needs a minor modification.
It is not a bolt in stud axle like old R160, but clips in like all the recent Subaru diffs.
A groove simply needs to me machined in the 510 stub axles and you're good to go.

It sounds so simple that something feels wrong...
I do not have the diff yet, so I cannot confirm any this.
I'll go for it and see if it all works out.

If anyone does have the definitive answer and/or finds the info in an old thread, please tell me or correct me if I'm wrong. I still did not find any info on this type of diff on the realm.

Here is a little description of the Suretrac differential from the Subaru guy:
The Suretrac performs like an open differential under "normal" conditions, and automatically transfers torque to the wheel with better traction when conditions warrant. The Suretrac limited slip differential responds instantly to torque feedback, anytime, at any speed. Suretrac reduces one wheel spin-outs from disabling the vehicle and also limits shock loads on drive train components to extend their life.

Suretrac transfers torque flow by combining conventional type differential components with additional friction packs. The special coated friction plates react to movement between the gears and the differential

Sounds good enough to me for a street build.

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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Byron510 » 22 Feb 2018 12:17

I can't offer you a definitive answer. But I can say that machining the axels is possible.

I do remember reading that one guy did try to "machine" in snap ring grooves, but found the PL510 stub axles to be too short. There are two answers for this. One is to possibly remove the dust shield to allow the stub axle to slide further into the diff. The second is to use the S30 (240Z)R180 stub axles as they are longer, have the same half shaft bolt pattern to the 510 R160 so you have more shaft to play with and are the same spline count.

Keep us posted on your findings, I'll be interested to read.

4.44 gears are great, I ran them in my R190 Comp diff for years and loved them. I now run 4.375's in my R180 K diff and am happy.

Byron
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by funwithmonkeys » 22 Feb 2018 13:09

I ran the R160 for a while with 4.4.44's and I loved it. After 3 years with R compound tires the gear set in it was making a LOT of noise though. Depending on how you drive and what tires you have you may want to go to the R180 just so you don't have to worry about it.
If no one from the future comes back to stop you from doing it then how bad of a decision can it really be?

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Fred_L-P
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 23 Feb 2018 09:10

Byron510 wrote:The second is to use the S30 (240Z)R180 stub axles as they are longer, have the same half shaft bolt pattern to the 510 R160 so you have more shaft to play with and are the same spline count.
Thanks Byron, that's a good plan B if the 510 stubs are indeed too short.
funwithmonkeys wrote:I ran the R160 for a while with 4.4.44's and I loved it. After 3 years with R compound tires the gear set in it was making a LOT of noise though. Depending on how you drive and what tires you have you may want to go to the R180 just so you don't have to worry about it.
It's just gonna be a summer daily driver / occasional ''spirited'' driving in the mountains. I'd say 2 to 3k kms maximum a year. I'll try it and see how it holds up. I estimate it's going to be about 1/3 of the price compared to a R180 lsd swap, so it's worth giving it a shot.

I should pick it up next weekend. We'll see from there how it looks.

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JordanTr
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by JordanTr » 24 Feb 2018 18:59

My bad... All my info was locked up in a PM from a gentleman by the handle byynow. See the PM below.
byynow wrote:Jordan,

Most of the material pertaining to my former 510 went with the car. However, I have searched and found what I think you'll need to know.

I purchased the Torsen diff on ebay for $500, about a year ago. It was advertised as a used racing differential, suitable for a R160 rear end, no year specified. I don't remember the sellers ebay handle, but his name is Gordon Duax of Duax Machine in San Antonio, TX.

I remember that in his ebay listing, Gordon had a "rant" about how he disputed the "experts" claim that Subaru stub axles have to be adapted to the Datsun half shafts to use a Subaru style diff in a 510. He said he had a strategy to adapt the 510 stub axles. Gordon is 100% correct. Along with the Torsen he sent me a picture with measurements and instructions, on how to modify the 510 stub axles to work. The work involved machining two grooves, one on each axle, to a specified contour and depth, along with tapping the axle retaining bolt hole for 5/16 pipe plugs. Also needed was one retaining "snap" ring which I fabricated from piano wire.

At the time, Gordon offered to machine the stub axles for $100 plus shipping. As a novice (very novice!) machinest with a cheap and mostly worn out Chinese lathe, I did it myself with satisfactory results.

The only unexpected issue was that the 510 ring gear employs 10mm bolts, and the Torsen diff has holes for 11mm bolts. I could see several ways to overcome the size difference, but I chose to make spacers. I obtained a two foot lenght of 7/16x.035 4130 steel tube from "Aircraft Spruce & Specialty Co." ($15). I used my lathe and a 25/64 drill bit to bore the tube. I then cut off lenghts of the tube a few thou. shorter than the thickness of the ring gear flange. This gave me spacers that were a snug (slight interference) fit on the ring gear bolts, and a nice slip fit into the ring gear flange. When I assembled the ring gear to the diff, I used loctite 640 Sleeve Retainer on the outer surface of the tube spacer.

I looked on ebay today and found no similar diff's listed. I see a stock GRB Impreza front Torsen (item 181313946449) which does NOT look like the one I used, and a Kaaz DBF2015 front Torsen (item 130672226704) which looks exactly like the unit I used.

If you decide to proceed I would suggest you contact Gordon. The machine shop info is online.

Since I have only installed this one Torsen in a R160, I don't know if other Subaru diff's would install the same, but I suspect they do. I would not be afraid to try the same strategy to install a stock Subaru diff.

I hope this was helpful. If you have any other questions I will be glad to offer any help I can. I don't often have time to sit at the computer so sometimes my response is delayed.

Ken
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Fred_L-P
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 18 Mar 2018 19:42

Thanks Jordan, there's good info in there. Since I'm not swapping the internals, my case looks easier. But the paragraph on the stub axles is similar to what I think I have to do.

So, I finally picked up the R160 Suretrac differential this weekend. It does only require symmetrical stub axles with snap rings, just like the Torsen diffs.

Here's a picture of the inside

Image

I also asked for one of the Subaru stub axles so I could compare and measure and he gave me one.
Here's a side by side shot

Image

Every shoulder diameters and the splines are identical. Shoulder lengths are also pretty close, but the spline length is obviously different...
The good news is the R160 510 stub axles do slip right in like a charm.
The bad news is it's just a tiny bit too short to simply machine a groove in it. Just like you said Byron.
As you can see in this close up, the axle is just long enough to compress the ring into the differential cavity.
I measured quickly, but it looks like the first shoulder is stopping it from sliding in any further.

Image


I'll measure everything precisely this week, but I think there's enough shaft length to adapt the 510 stub axles to work with the R160 Suretrac diffs.
Byron510 wrote:I can't offer you a definitive answer. But I can say that machining the axels is possible.

The second is to use the S30 (240Z)R180 stub axles as they are longer, have the same half shaft bolt pattern to the 510 R160 so you have more shaft to play with and are the same spline count.


Byron
Does anyone have a pair of S30 R180 stub axles or have the measurements to compare? I'd love to know the difference. It might be easier to use those instead. The only info I found was a side by side picture of both, but I can't even remember where...

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Fred_L-P
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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by Fred_L-P » 18 Mar 2018 20:29

Found the picture i was looking for from this post: http://www.the510realm.com/viewtopic.ph ... hilit=stub
510 R160 left and S30 R180 right?

Image

The shafts look identical to me, only the dust shields are different.

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Re: Diff swap: STI R160 LSD 4.44 Suretrac

Post by funwithmonkeys » 18 Mar 2018 20:33

I have them both at home. They are the same except for the dust shield.
If no one from the future comes back to stop you from doing it then how bad of a decision can it really be?

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