parish8

iTrader: (6)

i have in is300 with a ls1 and auto. plan is 700+rwhp, maybe 1000+. right now it has the stock rear, 3.90gears and a posi. works well enough but i hate the short gearing. i can't find much for options in the toyota world if i want to go with taller gears.

my thoughts are find a cheapish, strong and posi from the factory irs. swap that pumpkin in. then have custom half shafts made.

can you get complete custom half shafts made? i know i can get whatever rear i want into the car.

if i can get custom halfshafts made then i just need to pick what rear diff i want to run. wanting 2.90-3.30 rear gear range.

soo, cheapish, strong, good posi, right gears.

casey38boost

iTrader: (3)

You might want to look into the first generation infiniti q45 rear ends. I don't know any specifics on them but I know people are swapping them into other cars, and they are relatively cheap.

zipster

iTrader: (5)

turbo supra mk4, 3.13 gear, get a TRD posi. It will bolt right in. Also get the axles and wheel hub bearings.

The auto IRS from toyota is weak.

bettonracing

iTrader: (3)

Ford 8.8 IRS.

Came in thunderbirds, explorers, and mustang cobras (among others that I can't think of right now). You can probably find/ build it in damn near any configuration (ratio/ lsd/ locker/ spool/ output flange/ aluminum housing/ fabricated housing/ etc) You can think of.

Of course, "perfectly-meets-your-needs" is inversely proportional to the money in Your bank account.

Regards,

Kurt

i r teh noobz

iTrader: (4)

Z32 300ZXs came with VLSD R230s. Lots of guys pushing big power through them. I think the Q45s were R200s (which are also supposed to be pretty strong).

scorpio516

The Q45 has a Nissan R200 rear end. 200mm ring gear (7.87") but it's pretty strong, will easily hold up to 750hp+. Pretty plentiful, introduced with the 75 280z, but they changed design in 83 and again in ~1990. All the rear ends are just abaout as strong as the other ones but:
in 1984, the changed the ring attachment bolts from 10mm diameter to 12mm
Some of the early, early ones (pre-79) use U-joint half shafts, late ones used CV joints - different carriers, but swappable.
In 90, they changed the case design, differnt bolt locations and case length, but same internals.
Came in 3.3:1, 3.545, 3.7, and 3.9. Nissan Motorsports sold 4.11 and 4.375 R&P sets
87-89 300zx turbos had CLSDs. The 88(?) Special Edition 300zx had a VLSD
I don't know about the 90+ LSDs though.

The 300zx TT and the Armada came with a R230 rear diff, 230mm (9.05") diameter. All the zx's were LSD diffs too.

i r teh noobz

iTrader: (4)

90+ should be VLSD. I think the 4/87-89 Z31 turbos (excluding 88 SS models) were the only CLSD R200s.

Strokinit383

iTrader: (22)

2004 cts-v rear end! Hahaha...totally joking. I would look for an 8.8 from the mark VIII's or thunderbirds. You can even find them with aluminum center sections if desired. They are cheap and plentiful!

Tainted

iTrader: (9)

I beleive that the g35/350z had a fairly decent rear as well. when i was researching it msot people said it could hold 600hp+

rao

iTrader: (18)

I would go with whatever was produced in the greatest numbers,which will have more options and keep the costs down - that points to the Ford 8.8.

Half-shafts might be really cheap or incredibly expensive, depending on if you can piggyback on existing parts or if you have to go custom on the shafts and/or have the hubs re-splined.

gofastwclass

iTrader: (2)

Another vote for the ever-plentiful 8.8...

Just make sure you get an 8.8, not a 7.5. They have 7.5 or 8.8 cast on the cover and 8.8's have a larger cover that is bowed more. Mark VIII's all came with aluminum 8.8's while all Thunderbirds and Cougars had cast iron. Some iron 8.8's have posi's while most aluminum 8.8's don't.

Most aluminum gear ratios are 3.08 and open while I have seen iron clutch style posi's in both 3.2x and 3.4x.

parish8

iTrader: (6)

8.8 sounds like the way to go.

thanks.

eviltwin_1987

iTrader: (18)

I picked up an 8.8 IRS w/LSD at the junk yard for $75. Pretty easy to find. Mine was out of a Thunderbird SC

Project GatTagO

iTrader: (7)

I can offer another vote for the 8.8 Ford IRS. Here is a link to a ton of information about these diffs.

http://www.norotors.com/index.php?topic=5480.0

The RX7 guys have been using these for a long time, first in the FD chassis, then in the FCs. I used to sell a kit to use the Cobra diff in a FC and now Ronin is making a kit to use an Explorer diff in the FC. I also highly recommend contacting Frank at The Driveshaft Shop for custom axles. He has really come through for me on multiple projects.

Andrew

Professor_speed

iTrader: (8)

8.8s are a great diffs but if you want to go 31 spline then you need cobra axle inners and they are not cheap, neither are custom axles. (28 spline stuff will save you some money) a quick Google search reveals IS owners go with either mk4 supra diffs or GS xxx diffs,you can use supra 6sp axles. I'm no expert on Toyota stuff. I have used various r200/r230 Nissan diffs, and currently have a 8.8 under my Rx7, either way it looks like a some sub frame work is in order.

Some info here. http://my.is/forums/f114/trannys-dif...45/index3.html

Project GatTagO

iTrader: (7)

The Explorers have 31 spline diffs. Many came with limited slip and 3.55 or 3.73 gears. The inner stubs are not interchangable with the Cobra inner stubs but are very durable.

Andrew

parish8

iTrader: (6)

i read that thread. i still haven't seen any bolt in or nearly bolt in toyota applications that get me the higher(2.73-3.23) rear gears that i would like. really i am thinking silly high like the 2.73 and i think for that the 8.8 would be the only way.

i am not worried about getting it in the car or the driveshaft. i am a little worried about the half shafts. like how much will they cost and how long will they take to get. thats the only real issue.

Professor_speed

iTrader: (8)

yea if you want 2.73 8.8 or 9in are the only feasible options. if you just need center cv bars Dss would make them for $600-700 irc. 31 spline cobra axles are a bitch to find, they are not available from parts stores and ford is delusional on what a cv axle should cost. 28 spline stuff is easy to find cheap. ( all irs 8.8 buts cobras are 28) I would think that that the 28 spline should hold up ok. ( I know a fox body with 552 bbf and big shot, that only drives on et streets and yanks the front tires on a stock 28 spline 8.8 with a eaton, that still holds up) other wise the next cheapest option is to start with explorer stuff. good luck, I'm sure with your skills you will make it work one way or another

Project GatTagO

iTrader: (7)

Personally I think the Explorer diff is the way to go. It will come with the 31 spline diff and the rear cover is a very heavy, cast piece with two mounting tabs that can be easily adapted to many different chassis configurations. Stock Explorer axles are readily available in the wrecking yards and are inexpensive. The inner stubs can be robbed from the stock axles, a custom bar made by DSS, mating the bar to the stock I300 outer CVs.

Andrew