peejay

The 9" is a LOT less efficient than the 8.8, it's because of the height of the pinion angle.

It was also a lot more expensive to make than the 8.8, since the 9" has two castings that need machined, THREE pinion bearings (two in one casting, one in the other!) plus a complex banjo that needs to be stamped out and welded together. The 8.8 is one casting that needs relatively simple machining, and two tubes get shoved in and plug-welded. And the 8.8 has room for a decent limited slip. Any clutch-pack diff for the 9" can only have clutches on one side, because that third pinion bearing steals a LOT of room away from the diff. (Thus why Detroit Lockers and spools are popular for the Nine - no clutches, no problem)

I'm contemplating an 8.8 for my FB. I'm bending the housings and I plan on another 100hp next year, so I'm going to bend them faster. The 8.8 is added weight but sometimes you need that, I guess.

There are several flavors of 8.8 - 28 splin, 31 spline, thin tube, thick tube... the one to get is from the 2nd-gen Explorers, those are thick tube 31 spline units. They are HEAVY but the strongest you can get from the factory. And, they're disk and the same bolt pattern as 5 lug FC.

elwood

iTrader: (1)

This should probably become a "Toyota 8"" thread, but nontheless here are my plans so far:

- Toyota truck rear axle w/4.11 gear ratio
- Aftermarket LSD (maybe a Torsen-style)
- Machine / re-drill Toyota axles to work with GSL-SE wheels and rear brakes
- Add homemade caliper brackets / trailing arm brackets / third link brakets
- Transfer GSL-SE spring perches and swaybar brackets

The cross-car pinion location on the Toyota axle is dead center, which is about 0.85" closer to the driver' side than OEM. This seems to be perfect.

dbragg

iTrader: (7)

I really like where this is going

*subscribed*

82transam

iTrader: (18)

The little research I've done on this indicates that the 86+ 4x4 axles are the ones to get as the width is about dead on for us. Do you guys know if all the models (4runner, pickup etc) are the same? Or is there something specific we should keep an eye out for at the junkyards? I might have to start scouring the yards for one....

peejay

That is, actually, just about perfect, because the pinion flange smashes into the floor about an inch off-center.

elwood

iTrader: (1)

I measured my Wheel Mounting Surface (Pass Side) to Driver Side WMS, and it's 58.5". The axles you mention measure 58.0" WMS to WMS. That'll bring each side 1/4" inboard, which is ideal for me, since my 225/50 wheels on 35mm offset wheels contact the fender lips before the wheel houses.

I took my measurements by bolting drilled u-channel to each hub, then measuring from side-to-side with a tape measure, so I'm confident in my 58.5" dimension -- at least for my car

Bottom line -- I think you picked the right axles. A swap doesn't get any better.

82transam

iTrader: (18)

Yeah 1/4" in about right for me too, would keep me from having to roll my fenders too much if it at all.

Not sure if you saw this thread or not: https://www.rx7club.com/build-threads-293/finally-my-build-thread-some-weird-crap-here-938042/
He actually uses a Toyota rear in there and it seems to fit perfectly. He mentiones model year 86+ as being the ones to find, my biggest question would be, what year did they change them? I assume sometime in the mid 90's (when everything started getting built supersized...), but I admit I am not up on my Toyota pickup models lol

It would be handy to come up with a year/model list of trucks to look for at the junkyard so you don't have to spend all day measuring rear axles lol. Really interested to see how this works out

82transam

iTrader: (18)

I answered my own question. Found a good site with lots of info on the Toyota 4x4 parts here: http://www.4x4wire.com/toyota/faq/parts/

Looks like 86-95 is what we're looking for and can be either 58" wide or 58.5" wide in the case of coil sprung 4runners

In case that site goes down, here is a copy of the info:


Year: 1986-1995

Gearing: 4.10, 4.30, 4.56, 4.88

Width: 58"-58 1/2"

Ring Gear Size: 8"

Shaft Size: 1 5/16"

Spline Count: 30


Notes: 10" rear drums, V6 and turbo applications used stronger third member with larger bearings and bigger third member, coil sprung 4Runner axles are 1/2" wider than pickup axles, factory 4.88s available in vehicles equipped with automatic transmissions starting in 1992, but the pinion is moved closer to the ring gear than on all the other 3rds. This makes it so they can use a standard thickness ring gear instead of an extra thick one. This "thin" 4.88 gear is only made by Toyotas.

dream36realms

iTrader: (4)

I have the 8.8 with 3.73 as well. I agree with directfreak that it appears to have major loss. I also would like to comment that my entire assembled rear (brakes and all) came in at 315lbs when I shoved it in there. the stocker could be lifted by me alone but I struggled when dragging it to the dumpster that day. so considering I added a bit of weight to the engine I think this evens out my 50/50 everyone harps about.

elwood

iTrader: (1)

Nice find -- nice thread. I like the pics and the mounting for the brake calipers.

I'm about 75% ready to do this. I have two reservations:

1. Like was done in that thread, I plan to drill the Toyota axles to my 4 X 4 1/2 bolt pattern and machine the flange to pilot my GSL-SE rear rotors. I would also like a pilot for my wheels, like factory. Don't know if there's a good way to do that.

2. I'll have to find a way to make my panhard clear the rear of the larger pumpkin (it's currently extremely close on the original, which is smaller). I may have to move the vehicle-mounted anchor aft.

82transam

iTrader: (18)

Yeah that thread shows how similar the Toyota rear end is. Once all the 4runner brackets are cut off its almost the same - crazy.

At this point I've got a few other projects in the works on my turbo FB, specifically a megasqurt ecu, and a repaint, so honestly I wouldn't actually get to upgrading the rear end until later this year at the earliest. Definatly want to do it though, my GSL rear is getting pretty worn, and worn parts are always good excuses to upgrade

A quick search on www.car-part.com shows there are a bunch of these in junkyards nearby, so shouldn't be a problem to find one once I'm ready to roll. My biggest issue would be finding a competent machine shop to redrill the axles and machine them to fit the T2 rotors - basically the sme concern you have. I imagine as long as the axle is machined to fit tightly inside the rotor like a stock hub, everything should be fine, and the wheel will stay centered and, more importantly, on the car lol.

I'm still running the watts, but a tri-link/panhard setup would be nice. I had the G-Force setup and wasn't happy with the amount of road noise, if I were to go with a tri link and panhard again it would have to use poly bushings, not heim joints... I guess I'll have to re-read that "1st gen rear suspension problems/solutions" thread again and get some ideas on what to design when I actually go to do this.

What tri link and panhard setup are you running?

elwood

iTrader: (1)

I'm using the G-Force setup, but my car's pretty noisy so it doesn't bother me; I haven't had any clunking issues since I switched to kevlar-lined heim joints. I'm going to modify the 3-link, however, to eliminate the bent upper link. The plan is to build a "dog house" that runs from the rear load floor to the "waterfall" behind the rear seats. It will be structural and include mounting for the upper link. The plan is to use the same (larger) heim joints I use in my lower trailing arms and get improved geometry by moving the front pivot point higher in vehicle. I'll post more info as I progress.


As for the rear axle, I'm now leaning towards the T100/Tundra/Tacoma version. Based on a few comments from drag racers, the 30-spline axles are stronger than the center section. Toyota corrected this by adding the rear trusses. This axle housing doesn't come in the right width from the factory, but I'm told I can get one with a factory LSD, which would more than offset the added cost of having the housing narrowed. And since I want my wheels to be piloted, I'm looking at aftermarket axles, anyway.

82transam

iTrader: (18)

^You and I think alike apparently lol. My plan for a tri-link is basically identical to yours. Building a boxed in section that allows for a straight upper link, and honestly the whole thing would probably stiffen up that section of the body quite a bit if made correctly. I think with some modifications to the bin frame you could even keep the interior all in tact and it would be totally hidden.

Seems like you will be a good 6 months ahead of me on this project at least, so I'll definatly follow your progress. Good luck.

elwood

iTrader: (1)

I'm moving ahead with the Toyota 8 -- thanks to aws140 for suggesting it and 82transam for the helpful links. I'm creating another thread called "Toyota 8 in FB", since carrying on with this one would be misleading.

Corn

Do I really need a 8.8, for hard canyon and light, light to light driving, In an FB 5.0?

clubber

I'm not sure anyone is really qualified to answer that but I'd guess you will be fine with the yota rear.

Corn

Thanks, just wanted a second opinion, I am more of a canyon carver than dragger.

elwood

iTrader: (1)

Your question is a difficult one to answer. I think many of us feel comfortable with the extrememes -- i.e. saying that if you have 600 RWHP that the OEM rear end probably won't last very long. The in-betweens are more difficult, because none of us really has much data, and there are a lof of important variables:

- Engine speed and torque level when you drop the clutch
- Traction of your rear tires
- Weight of the car
- Amount of backlash in the drivetrain when you drop the clutch
- Amount of stress and number of cycles the components have already seen
- Rear end ratio (affects the pysical design of the ring & pinion)
- Overall gear ratio
- Temperatures

I've heard a lot of positivie comments regarding the strength of the Ford 8.8 . . . but I've also heard a lot of positive comments about the Toyota 8.

Maztang5.0

iTrader: (1)

I an upgrading to the 8.8 as we speak. I have one issue, what do I do about the rear u joint to flange. The flange on the explorer uses a bigger u joint. Is the stock u joint a 1310 cause if so I can get a conversion u joint. Btw. I have a 5.0 w/t5.

elwood

iTrader: (1)

Contact Granny's.