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What are the truths of adding a 9" to an F-Body?

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Old Aug 7, 2007 | 11:34 AM
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Question What are the truths of adding a 9" to an F-Body?

I'm in the market of buying a new rear end since my stock one is just about shot, makes clicking, popping, grinding sounds when making turns.

I've done a little reading in this forum and it seems that the 9" is not as easy to bolt in as some would say.


Please correct me if these are wrong:

- The rear of the car will sit higher due to the axle tubes being a bigger diameter, how much higher, 1/2" - 1"?

- You must purchase weld-on sway bar brackets or buy large exhaust U clamps to mount the sway bar and hope it works.

- You can't use bolt in LCA relocation brackets, you must get weld in.

- You can't have 3 channel ABS with a 9" unless you custom fab up a reluctor wheel. (Why doesn't Moser have an option of adding a reluctor wheel)

- Not all 9" rears are quiet, some do have noise just like the 12 bolt (why is that?)

Before I drop $2,400+ I want to make sure I understand whats all involved, so if I'm wrong please correct me and explain in great detail.

Bill
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Old Aug 7, 2007 | 11:54 AM
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I think you pretty much covered everything...and the noise of the rear end is directly related to how the gears were set up (unless you went with a race gear, then it is probably because of that).

And a lot of those reasons were why I went with a Strange 12-bolt...sway bar brackets were already welded on, my bolt-in relocation brackets from my 10-bolt fit, 3 and 4 channel options, but the rear should sit a little higher still, there could still be gear noise (I haven't installed it yet), and it won't be as strong as the 9" design.

All that for only $2500-ish

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Old Aug 7, 2007 | 12:48 PM
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i didnt notice my car sitting any higher after the 9in install. Looks normal to me
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Old Aug 7, 2007 | 03:01 PM
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9" pros: Tough as hell

cons: weight, inefficiency, noise, no torsen
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Old Aug 7, 2007 | 04:05 PM
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Originally Posted by Billiumss
I'm in the market of buying a new rear end since my stock one is just about shot, makes clicking, popping, grinding sounds when making turns.

I've done a little reading in this forum and it seems that the 9" is not as easy to bolt in as some would say.


Please correct me if these are wrong:

- The rear of the car will sit higher due to the axle tubes being a bigger diameter, how much higher, 1/2" - 1"?

- You must purchase weld-on sway bar brackets or buy large exhaust U clamps to mount the sway bar and hope it works.

- You can't use bolt in LCA relocation brackets, you must get weld in.

- You can't have 3 channel ABS with a 9" unless you custom fab up a reluctor wheel. (Why doesn't Moser have an option of adding a reluctor wheel)

- Not all 9" rears are quiet, some do have noise just like the 12 bolt (why is that?)

Before I drop $2,400+ I want to make sure I understand whats all involved, so if I'm wrong please correct me and explain in great detail.

Bill

My car is approx. .5 higher in the rear after the moser 9 install.

You can get the Spohn Sway bar mounting kit that comes with new sway bar brackets and U bolts and hardware to bolt up the stock sway bar....really nice no welding.

No 3 channel, I was lucky that my car was 4ch

Weld in LCA reloc brackets are a must, GO WITH UMI...the BMR's took a bit of grinding to make fit...big thumbs down..UMI UMI UMI.

As for noise...I can't help you there my driveshaft is on its way. I'm sure it'll be bit noisey...but then again...my car is noisey

Oh yeah, never have to worry about blowing it up +1000 points....M6'ers still manage to weaken 12 bolts after some hard track use.
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Old Aug 7, 2007 | 08:02 PM
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Your list looks good to me. My car sits almost an inch higher. The tire is also about .75" rearward in the wheel opening. You missed one, there are no provisions for the brake lines so you have to zip tie them or weld on clips.

My UMI brackets I had to cut to fit, but that was because of Moser I think.

I think the noise is more dependent on the gearset and ratio rather than 9" vs 12-bolt.

Brian
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Old Aug 7, 2007 | 08:07 PM
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I think you purty much covered it but its still all worth it.
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Old Aug 7, 2007 | 10:42 PM
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interesting, a Borla PHR.
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Old Aug 8, 2007 | 12:48 AM
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Originally Posted by Jaspirr
interesting, a Borla PHR.
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Old Aug 17, 2007 | 09:03 AM
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Thanks for the info guys....

What brand/type fluid are people putting in the 9" with a Truetrac and how many quarts?

Do you add the GM additive?
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Old Aug 17, 2007 | 12:35 PM
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Originally Posted by Billiumss
Thanks for the info guys....

What brand/type fluid are people putting in the 9" with a Truetrac and how many quarts?

Do you add the GM additive?
2.5 quarts of Coastal 85/140 here. No additive
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Old Aug 17, 2007 | 01:21 PM
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i'd get with Bob at Exotic Performance Plus. i just bought my 9" Moser from there. i love it....yeah it's heavy, yeah the stance is affected.....

but try launching at 6K on a stock 10-bolt all night long and see how many passes you make.

i got the alluminum center chunk, 4.11's, detroit locker, 4 channel with new reluctor wheels pressed on, 35 splines (i ordered 31 ), and i haven't noticed any gear noise, BUT i'm sporting a catless H-pipe with single chambers....

the locker is noisy and weird to DD at first, but i'm used to it. i wish i had got the Trutrac, but i don't really care that much. i bought 3" u-bolt clamps for the sway bar and they work perfect. i had to beat on the factory bracket a bit so it would sit flat againts the clamp, but it was no biggie and works fine.

mine all bolted right in and is working great with about 500 miles on it.
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Old Aug 17, 2007 | 08:55 PM
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I've been using the Quaker state full syn GL5 80-140 with pleasing results. Very quiet lube
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