BRX/FRS diff the same as IS300? - Page 4 - Lexus IS Forum
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post #46 of 184 (permalink) Old 03-01-2015, 06:33 PM Thread Starter
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That cusco is pretty but, it's not $750 in pretty.

Aluminum Rear Differential Cover for FT86 GT86 Subaru BRZ Scion Fr s 13 Blue | eBay

Cheap Chinese knockoff.



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post #47 of 184 (permalink) Old 03-02-2015, 04:58 PM
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Wow I didn't realize these existed ... and for $180 it's a steal!
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post #48 of 184 (permalink) Old 03-04-2015, 06:04 PM
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I am getting some new rear coil-overs in the mail here shortly, when i change those out I will take measurements and let you know specific dimensions. I think it is better to press out the bushings as well but I was lazy and just wanted to see if it would even work. Coil-overs should be here tomorrow or friday (O_O)... I saw those diff covers too lol yes chinese knock-offs but who knows maybe cusco got them made there??? many different colors too
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post #49 of 184 (permalink) Old 03-04-2015, 06:22 PM Thread Starter
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The cusco ones have deeper fins. It's pretty obvious by eye that the cusco ones are made better. Still unless you're tracking your car, this is a pretty useless upgrade.
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post #50 of 184 (permalink) Old 07-04-2015, 04:35 AM
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So essentially instead of Swapping 4.30/LSD we trade a brz/far guy and we both win, bolt in application a 4.4 rear frs/brz diff sounds about perfect, although I'd settle on a 4.1 if I had to. I do have a 4.3 supra/LSD. Diff already but I'm worried about backlash and all that jazz by swapping the gears over.

I currently have a m98 diff. 3.91/LSD. I figure the 4.4 vs 4.3 won't even be noticeable and will be bolt in. HOWEVER. Are the brz/frs diffs identical in strength to ours? As in stall launching at the track on stickies?
Real goal is to get nitrous involved in the car again. Spraying from first gear at 3500rpm to 6000rpm. Would that diff take it? Beating on it in "open spaces", drifting around, ect.
Sorry to bump an older thread just looking for good information myself.
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post #51 of 184 (permalink) Old 07-04-2015, 07:47 AM Thread Starter
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I'd probably go to a BRZ forum where they're boosting them and see what their experiences are.
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post #52 of 184 (permalink) Old 07-04-2015, 09:31 AM
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Quote:
Originally Posted by JamesM View Post
a 4.4 rear frs/brz diff sounds about perfect, although I'd settle on a 4.1 if I had to
There's a 4.4 final drive from the factory on the BRZ/FR-S? What are you referring to here?

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I do have a 4.3 supra/LSD diff already but I'm worried about backlash and all that jazz by swapping the gears over
So you're aware that the backlash is adjustable, just don't trust yourself to do it? It doesn't seem that complicated, though you'll need a set of shims to work with.
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post #53 of 184 (permalink) Old 07-04-2015, 10:02 AM Thread Starter
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though you'll need a set of shims to work with.
And if you get it wrong need to wait 2 weeks for the next set to arrive. I've done it one time and have no desire to do it again. I just buy complete pumpkins these days. I am tempted to put a 3.50 in my V8 though so I might have to go back on my pledge.
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post #54 of 184 (permalink) Old 07-04-2015, 10:05 AM
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Quote:
Originally Posted by reklipz View Post
There's a 4.4 final drive from the factory on the BRZ/FR-S? What are you referring to here?



So you're aware that the backlash is adjustable, just don't trust yourself to do it? It doesn't seem that complicated, though you'll need a set of shims to work with.

Yes brz/frs came with 4.1, 4.4 & 4.6 according to their website. It's like 4.667 or some crap, but same difference lol these are a direct swap from my understanding, only needing a 1/2" spacer at the 2 lower bushings because brz/frs have shorter bushings. Simple enough.


Swapping 4.3 mk3 supra gears into the is300 pumpkin I would assume you would need to at least check and possibly set back lash and pinion depth and what not.
However the 4.30 supra swap thread by member avenier(sp?) says its a direct swap just use is300 shims. I'm pearly about that though.. It just seems like their would be a variance in the gears or depth or something to just grab the gears & toss em in using the existing shims. I pm'd bezik777 about this, hoping to here back soon.
I have a 4,3 diff in my garage but if its going to require us to set backlash and what not, I'll leave that to a shop. And preferably skip it all together, unless its a last resort.
My point is brz/frs guys apparently want our 3.73/3.91 diffs with LSD. So I'm thinking I can find a frs guy with a 4.1 or 4.4 LSD diff and just do a swap with him. If he wants my 3.9/LSD, I'll gladly take his 4.1-4.4/LSD. Win win, no worrying about setting up gears. That was my biggest point about bumping this.
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post #55 of 184 (permalink) Old 10-14-2015, 09:24 AM
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A buddy is giving me an extra brz diff he has in his garage for $250 so i will be doing this swap in the next couple weeks. It will probably be the only modification i will do to the car. 04 Eshift with 120k that i picked up as a daily. The comment above notes that the brz came with options for final drive, will i be able to find out that info from the part numbers once i pick up the diff?
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post #56 of 184 (permalink) Old 10-14-2015, 09:29 AM
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also for the guys that have done this - where exactly am i putting the .5" spacer? and is it just to fill the space where the bolt isnt threaded long enough? Im wondering if the bolts from a brz will be a less sketchy option.
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post #57 of 184 (permalink) Old 10-14-2015, 04:28 PM
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Not sketchy at all. Your using the spacer on the front diff bushings. There is 2 of them 1 per side. Wile I didn't complete this swap. I did do a 4.3 LSD supra swap and its fun as fuck. Wth basic bolt ons its more than enough.
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post #58 of 184 (permalink) Old 10-15-2015, 07:19 AM
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That makes sense. picking it up tomorrow after work so it will be a lot easier to see whats going on with it in my hands rather than just looking at pictures.
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post #59 of 184 (permalink) Old 10-15-2015, 09:15 AM
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I'm excited to see some video's!

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post #60 of 184 (permalink) Old 10-15-2015, 12:31 PM
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What ratio is the diff?
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