hiltsy855

iTrader: (35)

If the axles are made of the same materials a 31-spline connection is 38% stronger than 28-spline, 35-spline is 47% stronger than 31-spline, and 35-spline is over twice as strong as 28-spline.

Rise of the Phoenix

iTrader: (27)

I think an 8.8 with 31 spline axles will work good for what my car will be.

SCott5

iTrader: (40)

I have seen stick Foxbodies and sn95 cars break 31 spline 8.8s at less than the 700-750 level your looking at then again these were cars at the track launching hard but they also weighed less than Your car

hiltsy855

iTrader: (35)

I wonder if the busted 8.8's in those cars had stock or aftermarket axles? I'm sure aftermarket axles are made from different / better materials than stock. For a bullet-proof setup in a 700hp stick-shift car that sees slick launches at the track I think you need 35-splines. Then you're looking at an aftermarket carrier. Here's the kicker: The more aftermarket stuff you have to put into an 8.8 rear (axles & carrier), the easier it is to make the decision to use a 12-bolt, S60, or 9" instead.

MidwestChassis2

iTrader: (1)

The cost to build a rear end is almost identical, where cost separates is in the core itself or starting with something new versus old.. Spools, posi's, trutracs, S-Tracs, all cost similar money no matter what the housing is, axles cost the same no matter the housing, bearings cost the same and so on and so forth.. Of course a 9" has more bearing to add to the cost..

8.8 is a good rear end but it is like any other rear end it isn't going to last with out taking the proper measurements in doing so, such as braces, good diff unit, and axles.. The guys that use them in a drag race situation are constantly replacing ring gears.. Either from knocking teeth off of them or case flex.

There is a rear end for every need, we build a ton of 8.8's for local customers with Mustangs, or leaf spring vehicles..

codyvette

iTrader: (24)

I think this is key. I have set up several ten bolts with good luck. Attention to detail is important in any axle. I have a Moser 12 bolt ($$$$) that is in need of new gears to get rid of the howl and it hardly has any miles and only a few drag strip launches on it. Don't skimp on a rear end build no matter the direction you go. Buy good parts and have them set up by someone with the tools and know how to do it right the first time.

SCott5

iTrader: (40)

I know one or two were Ford 31 spline out of a ranger? I think that's what they were and a couple were mosers.. they are all 35 spline now.

MidwestChassis2

iTrader: (1)

The 12-bolt making noise in a F-body application has always been that way and to be honest I don't see an 8.8 not having the same problem.. I'd imagine more people would talk about it if it was a more common option..

codyvette

iTrader: (24)

I have read this in several threads as well but I have read several times where people that actually know how to set up gears rebuilt their Moser 12 bolts and ended up with quiet operation. Several have said Moser's parts are top notch but there setups turn out well off spec. I am not 100% about this but I will be pulling mine out and measuring tolerances and setting up new gears. 12 bolts have been in tons of different vehicles from the factory and they did not howl. If the rebuild is a failure, I will build a 9" and move on. When that happens( a while from now) I will report my findings here on tech.

MidwestChassis2

iTrader: (1)

The difference is the torque arm and not the vehicle, a leaf spring vehicle or four link 12-bolt vehicle doesn't have the added abuse the torque arm delivers. Of course certain manufactures gear sets will be noisier than others..

When this first took off years ago 12-bolt was probably the most common rear end sold probably because it was so cheap, we have sold many rear ends to customers that with-in years gave up their 12-bolts to get rid of the noise and constant gear swaps alone..

12-bolt is an amazing rear end in the right application and the same goes for the 8.8..

dailydriver

Abuse, or noise/vibration transmission (OR BOTH)??

Is the 'abuse' MUCH less so in a road race/autocross scenario with less power vs. a drag race launch on a sticky track, with wrinkle walls and BIG power????

(And even less so yet with a decoupled torque arm?)

MidwestChassis2

iTrader: (1)

As long as the Torque Arm is attached to the center like it is every time you hit the go button it is creating flex.. I've talked to customers that have a bone stock F-Body break a 10-bolt.. It has nothing to do with power it's simply the design..

SparkyJJO

iTrader: (11)

I'm trying to understand the physics behind it. I would think that you'd have less flex in the system with a torque arm as it is attached closest to the "twist point" so to speak from the drive shaft along with on the ends of axle tubes with the two control arms, vs only out on the ends of the axle tubes like a 4 link does.

Could you explain the forces behind it? Inquiring minds want to know

MidwestChassis2

iTrader: (1)

If mounted like our fabricated rear end is you are correct and that's one of the reason fabricated rear ends have the mounting points like they do.. Attached like it is from the factory out front and to the side it is pushing one side up and back.. Ever noticed once people change from a factory arm to a stronger after market one they break rear ends and no longer torque arms..

These are "my" own theories because I'm not sure anyone has done any true testing to why..

Rise of the Phoenix

iTrader: (27)

I appreciate all the feedback from everyone. I'd like to do this right the first time and not have to ever worry about if my car is making too much power for the rear end to handle.

SCott5

iTrader: (40)

Then just go S60 if weight isn't an option or FAB 9.

Rise of the Phoenix

iTrader: (27)

What's the price for each of those options, 100% complete and ready to bolt in?

MidwestChassis2

iTrader: (1)

That end all decision is a fabricated 9" because there is no where else to go and leaves no regrets in the back of your head wishing you had this or that..

As for 100% bolt in our fabricated 9" is the only true rear end that bolts back in just how the factory one unbolted.. The true fabricated rearend housing features components such as a drain plug, 4 hole relocator style lca brackets, stock style anti-sway bar mounts, brake line clips, and chassis brake hose mounting bracket. 98-02 applications also include brake hose mounts and e-brake cable brackets. These features are all standard equipment at no extra charge. Other manufacturers don't even offer some of these items that make it a true bolt-in.

The chromoly double adjustable torque arm is included with the package and is exclusive to this housing. Short (tunnel mounted) and long (trans crossmember mounted) versions available. Both are the same cost, the short arm crossmembers come with a driveshaft loop installed (available with dual exhaust), the long arm comes with a new trans crossmember, but no loop. We do have a tunnel form-fitting driveshaft loop available for the long arms or any other configuration. It is profiled to the floor pan and does not interfere with exhaust or ground clearance.

SwampWS6

iTrader: (7)

Im in the same boat. i know the fab 9 is pretty high. But a very good quality piece. The S60 is more cost effective for me and offers a lot of strength. So thats the route that im going. If I had more disposable income, I would do the MWC fab 9 in a heart beat!

dailydriver

Does your Fab 9 accept Unbalanced Engineering's decoupled torque arm, or have you, or anyone else never tried to make one work with this setup??