Hey yo,

Being that I'm putting down 431 RWHP and 408 RWTQ, and I'm looking to run a slick/skinny setup at the track this year, I figure its about time I invest in a quality rear-end. I'd also like to maybe come out of the hole with a 150 shot as well, possibly.

I'm an M6 looking to run a 4.10 or 4.11 (brand dependent obviously).

Question is, what is the choice? Yes, I know this has been asked before, but everything I read is different and I can't make up my mind. I don't want something that turns into an annoying whine-trap. I like to be able to drive the car daily minus winter time.

12-bolt = fitiment issues with torque arm? gear whine after a few hard launches? traction control?

9 in. = good differential? ABS options? It's a Ford product?

Thanks for your thoughts, advice and expertise guys

 

From http://members.aol.com/InjuneerZZ/Strange12.htm :

"There are two choices here – the Ford 9" rear and the GM 12-bolt. This is the first choice to make. The Ford 9" has a number of advantages, including:

* Low cost
* A drop-out pumpkin, allowing quick gear changes
* Indestructible.

But it seems to have a few drawbacks too:

* No plug-and-play setups available, all seem to be "some assembly required"
* The pinion is located further below the axle centerline (2.25" vs. 1.50" for the 12-bolt), offering the potential for pinion angle setup problems. This is also contributes to the next problem.
* It has a higher internal friction loss. Published data indicates the GM 12-bolt has an efficiency of 93%, about 3% higher than the Ford 9" which is 90%. In a 500HP setup, this will cost you 15HP. (Ref: National Dragster, 11/10/99, "What’s The Diff?" by Bruce Dillishaw)
* No ABS available.
* It’s made by Ford.

So that got me past the Ford 9". I wanted ABS, I wanted a ready to install unit, I like to keep my car "all GM", I don’t want to lose HP."

That's the gist of it right there. It's all about what you want. But for your application of daily driver, I would say 12-bolt.

 

Why did you rule out the Strange S60 (Dana-60)?

No TA problems with the Strange 12-bolt. Uses the same through bolts the stocker uses. The moser uses separate bolts for the upper and lower TA mount holes and seems to have a problem with the bolts coming loose.

No traction control problem with the 12-bolt. Send Strange your backing plates with the 4-channel sensors in them. Moser may be a bit more D-I-Y in that respect.

The quote in the post above looks like something I posted here many years ago. Do a "search" for recent posts on HP losses, since they appear to be different than the National Dragster article indicastes. The Strange S60 is supposed to be more efficient than the 12-bolt or the 9-inch, but even that is in question based on recent posts.

My Strange has held up to 5-6K (Street Twin) clutch dumps, at 425rwHP + a 125 shot. No whine, no problems. Definitley good for the street or strip.

 

Pinion angle has nothing to do with the location of the pinion as stated above.

The drag numbers can be made better thru the use of ball bearing pinion supports and a few other common trick, it won't be as good but it will be closer than what was published.

I have a 9" that I'm yet to install but if the Dana had lower numerically gears available that would have been my choice.

 

of everything else, the removable center section is selling me on a 9 inch, only to swap one in for drag strip racing and another more mild one for everything else

but i don't like the idea of not having my abs working, anything to fix that?

 

Thanks for all the great information so far guys.

Fred - I ruled out the S60 because of some of the very questions you raised. One being potential power loss, but also I heard that it is a bit heavier and requires a different driveshaft. Also a few people I have heard from with this rear-end have had some problems (inconsistent whine after install). Also, the S60 seems to be the most "heavy duty" of the rear ends. I don't think I'll be putting down the power to really need this setup given the potential negatives.

Although the easy drop gear function is nice, I don't plan on changing them again, less they somehow break.... and I'd rather not part ways with my ABS.

Thanks for your perspective Fred, I feel a bit more comfortable knowing your strange is holding up under a power setup and situation I would probably be at when racing.

Am I thinking on the right track here? Thanks again guys, much appreciated.

 

The 9-inch center-section "quick" swap is made a bit more difficult by the complicated bracket for the torque arm mount. Its an extra piece to remove. But I have seen/helped with a 1-hour swap on a 4th Gen, at the track, so it does accomplish something the 12-bolt can not do.

The "pinion angle" problems with the 9-inch are related to the fact that the pinion centerline is lower (angle obvioulsy needs to be adjusted, and hopefully your TA has the correct range of adjustment) and also offset to one side. There's no "adjustment" on the TA for side-to-side angle, so setup get a bit tricky.

Also note that the common method used to set the pinion angle (pinion shaft angle minus driveshaft angle) is a compromise. Ideally, you have to insure the the centerline of the tranny output shaft is exactly parallel to the centerline of the pinion shaft, under max load. That insures the u-joints function smoothly. If you don't do that, the rotational velocity of the two ends of the DS "attempt" to be different at different points in the rotation of the DS, and its like adding yet another resultant force trying to move the pinion shaft and the rear axle assembly around, wasting energy. The greater the offset on the centerlines of the tranny output shaft and the pinion shaft, the harder the u-joints have to work, and the more important it becomes to get the pinion angle exactly right.

 

how about a 9" with 12bolt gears?
http://www.strangeengineering.net/catalog/index.html page 79

 

yeah i was talking to a buddy last night and he said they are making 9 inch housing with 12 bolt removable center sections, now that would be ****