BRZ rear differential ring and pinion options (Help!!)

[Clash0901]

BIG EDIT:

After some research I found the Lexus LS430 rear end is a 3.266 ratio and it's a 200mm. I can't find the exact part numbers of the internals. Would the guts of this rear end fit and work without major modification in my BRZ rear end? Does anybody know for sure?

Thanks,

--Original post below, ignore this--
So I have a BRZ with a 4.10 torsen LSD. I did some research and saw a few lower OEM toyota options but i'm curious how that works.

If I put like a 3.58 gear (part number 41201-80125) or lower in the rear end, would I retain the strength of the rear end? The car will be making around 700whp and probably 650ft/lbs to the wheels. I am not exactly sure how rear ends work.

My BMW trans has a 1:1 5th gear ratio so I need something to get me into about 150mph at least with a 27" tire

Any help here?

Thanks,

[twag4]

3.58 is a higher rear end gear ratio. If you want lower gearing, don’t go 3.58.

[gtengr]

Lower numerical. Semantics aside you'll be putting less torque to the wheels than a 4.10, so there would be incrementally less stress on the axles. You would see an incremental increase in stress on the ring and pinion.

[humfrz]

Originally Posted by Clash0901

So I have a BRZ with a 4.10 torsen LSD. I did some research and saw a few lower OEM toyota options but i'm curious how that works.

If I put like a 3.58 gear (part number 41201-80125) or lower in the rear end, would I retain the strength of the rear end? The car will be making around 700whp and probably 650ft/lbs to the wheels. I am not exactly sure how rear ends work.

My BMW trans has a 1:1 5th gear ratio so I need something to get me into about 150mph at least with a 27" tire

Any help here?

Thanks,

hmmmm........ first off, what type of engine do you have in your BRZ that is making 700 whp and 650 ft lbs of torque ....??

Everything else being the same, I don't figure the ratio of the rear end (4.1 vs. 3.5) is going to be under significantly different stress.

Next, what type of racing/driving do you plan on doing that you want to go 150 mph ..... ??

With that much power, a BRZ should be able to go over 150 mph with the stock 4.10 rear end.


humfrz

[gtengr]

Originally Posted by humfrz

Next, what type of racing/driving do you plan on doing that you want to go 150 mph ..... ??

With that much power, a BRZ should be able to go over 150 mph with the stock 4.10 rear end.


humfrz

Taller gearing helps with traction.

[Clash0901]

Originally Posted by humfrz

hmmmm........ first off, what type of engine do you have in your BRZ that is making 700 whp and 650 ft lbs of torque ....??

Everything else being the same, I don't figure the ratio of the rear end (4.1 vs. 3.5) is going to be under significantly different stress.

Next, what type of racing/driving do you plan on doing that you want to go 150 mph ..... ??

With that much power, a BRZ should be able to go over 150 mph with the stock 4.10 rear end.


humfrz

2jz, and the trans is a 1:1 ratio, per the calculators online top speed would be around 120mph give or take depending on the size of my wheels and tires.

I'll be doing 1/4 mile stuff which 120mph just isn't enough for.

[humfrz]

Originally Posted by Clash0901

2jz, and the trans is a 1:1 ratio, per the calculators online top speed would be around 120mph give or take depending on the size of my wheels and tires.

I'll be doing 1/4 mile stuff which 120mph just isn't enough for.

Well, if you have 27" tires and your engine will turn over at least 7,500 rpm, your stock 4.11 differential should get you close to 150 MPH ....... according to this chart.......

(of course with the stock rear end and BRZ axles, with that much power, it might only get you there once .....)


humfrz

[Clash0901]

Yea I saw that but I don't think i'll be revving much past 6500, maybe a little. Keeping the 2jz stock internally with big turbo. Plus the 4.11 will eat the rpm band so quickly i'll just spin...

I need the 3.58 for sure

[Teseo]

@humfrz
The fuck of your ad? Are you looking coffins and shit for your funeral?

[humfrz]

Originally Posted by Teseo

@humfrz
The fuck of your ad? Are you looking coffins and shit for your funeral?

........ I didn't even notice the ad ...........


humfrz

[Clash0901]

After some research I found the Lexus LS430 rear end is a 3.266 ratio and it's a 200mm. I can't find the exact part numbers of the internals. Would the guts of this rear end fit and work without major modification in my BRZ rear end? Does anybody know for sure?

Thanks,

[Clash0901]

Originally Posted by Clash0901

After some research I found the Lexus LS430 rear end is a 3.266 ratio and it's a 200mm. I can't find the exact part numbers of the internals. Would the guts of this rear end fit and work without major modification in my BRZ rear end? Does anybody know for sure?

Thanks,

So far all signs are pointing to no on this

[Flateightysix]

Originally Posted by Clash0901

So far all signs are pointing to no on this

I know there are a few write ups on here where people have swapped either a mark four Supra diff internals, or swapped the pumpkin and internals from an is300 that has an lsd and have lowered the final drive to 3.7 or 3.9, but there are no detailed write ups on the Supra conversion or swapping the is300 diff. I do know that it has been said the is300 diff mounting pints are the same as ours. I think @mrk1 or @mr1k had the is 300 diff on his car.


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[Clash0901]

Originally Posted by Flateightysix

I know there are a few write ups on here where people have swapped either a mark four Supra diff internals, or swapped the pumpkin and internals from an is300 that has an lsd and have lowered the final drive to 3.7 or 3.9, but there are no detailed write ups on the Supra conversion or swapping the is300 diff. I do know that it has been said the is300 diff mounting pints are the same as ours. I think @mrk1 or @mr1k had the is 300 diff on his car.


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I actually just ordered an is300 rear diff. LSD and 3.73 with 115k miles from Cali so rust free as well.

Hopefully this is enough and hopefully it bolts right on as people claim.