thanks for all the replies guys. i guess i should have been a little more specific in what i have and what i plan on doing.

i have an A4 car so i know that will help some. my plans are to get a 3,5k or so stall with 3.73/4.11 gears. i will be spraying a 150 shot right out of the gate.

other than the gears, stall, and juice, the car is mostly stock, as you can tell from sig.

i feel pretty sure about it holding up fine NA, but the gas was what i was wondering about. but from what im hearing here, it sounds like i should be able to do some minor strengthening and be OK for a little while.


anyone else want to add something, feel free to chime in!




jon

 

I have the eaton posi, with girdle/stud kit, and solid spacer. I planned on head cam this year but do to funds I'm thinking about a torque converter and nitrous...


Jason

 

I just had mine built along the same lines as a few of the others, Eaton, new bearings, solid, girdle and GM 3.42s. I've been told that with the A4 it'll probably hold up to about 500HP. Seemed like the thing to do, until last week when I went crazy and decided to add CNC heads and a D-1SC blower... Now I'm going to be sweating bullets with (hopefully) almost 600 at the engine...

 

you are COMPLETELY wasting you money and time, my last rear end was BUILT and i blew it up in 3 months....

 

read above post's. you have a M6.


btw, WASTING MONEY is buying a 12blt/9in for a A4 car that's MAYBE making 400rwhp.



jon

 

"Building" a 7.5 diameter ring gear 10 bolt is like trying to polish a turd into a gold bar IMO. Even with an A4 it will be barely enough. It would make more sense to me to only change to the gear set you want (minimum investment), then when (and if) it fails, junk it in favor of a rear end that was actually designed to back up a V8 engine. But if hopping up 6 banger rear ends is your bag, it is your money, and a gamble that has worked for some and not for others.

BTW, pouring money into cars that have a rapidly declining resale value is a waste of money! Its all about fun factor, not "return on investment".

 

maybe 400rw? 306,heads, everything else + poweradder a little more than 400

as for building a 7.5 rear.. this is my 4th one.. combine all the money i have wasted in my rears.. i would have 9"ed it and be still on my frist set of 9" gears.. to each his own.. but ill take a 9" ANY day over this pinky sized gear

 

after three sets of blown gears

all that money and you can almost have a 9'' if you sell your rear

 

I'd be willing to bet a wager that I could go out and break a "built 10 bolt" (oxymoron, isnt it?) within 3 launches. My last 10 bolt lasted 10 passes at the track. Twisted both axles, broke the ring and pinion. On BFG drag radials.

 

I have broken 1 set of gears in 3 1/2 years of street/track abuse with a 10-bolt. Best 60ft. so far of 1.55. I do have an auto. IMO if you have an auto, you could get away using a 10-bolt with slicks at the track for a while. As always anything can happen. If you have a 6 speed, just save up the money and buy a 12-bolt or 9".

 

Thats the key here, behind an M6 its almost not worth it. Its not the HP that kills them its the shear shock of dumping the clucth and having the tires grip that tears them apart. In an auto you dont have that harsh shock. They can be built to handle a mild car and some fairly hard launches. Even in auto, with the right converter, you will break one with ease.

You can argue all day long about cost. Bottom line is that if you can do it yourself its not worth going to a 12 bolt/9".

example.

-bearings, shims, install kit - $100 new
-new axle seals - $20 new from pepboys
-4.10 motive gears - $100 used off the board
-welding the tubes - FREE with welder from work
-Girdle and stud kit - $125 used off the board (but I already had them)
-Carrier - $100 from SLP (I'm using the carrier that came in the rear I bought for a grand total of $100 used)
-Oil and additive - $30 new from pepboys
-set up of the gears - $200 (or do it yourself for free like me)
-solid spacer - $15

Grand total is $690. I can see why you dont want to have a 10 bolt in a M6, especially if you break it all the time.

If your like me, it cost a total of $100 for the used rear. $100 for a used set of gears. $100 for an install kit, $15 for a spacer. And $30 for oil. Total is $345... and the oil you would have to buy for any rear. And I have my stock rear for spare parts just incase.

I can break my 10 bolt 5 times before i can justify buying a $2000 rear. My stock rear lasted me well over a year and the new used one should be the same. Thats 5 years worth of racing. In an auto it will hold up to more than you think.

If you have a clutch... I agree, dont waste your money on the 10 bolt. But for an auto, you can build one to hold up to a car with 300-400rwhp. Especially if you can do the work youself, its just not worth spending the money for a rear you dont need.

BTW, I know a few people who have gone out and spent the $2000 on a 12 bolt and broke it their first time out in a M6... A clutch is just harsh on the drivetrain... an auto is much more forgiving.

 

please explain what can be done to beef it up. PM me with info or post it..... I would love to know.

 

perfect answer!!!

I have an M6..and have killed 2 stockers, including killing 1 set of Motive 4.10's, and 1 factory carrier.

 

factor in down time, towing bill, and every time you blow them-
you might need a new posi and such if the metal scraps get in there. Like mine, I got metal in there and now its pretty much like having welded axels.

 

With those plans, dont spend a dime on the stocker......you need the 12 bolt or 9in . Go for the sure thing not the maybe....youll save money in the long run.