How much power will the Rear end hold???

GOAT6SPD · 01-17-2006, 07:00 PM

This questions has been asked before im sure....

I just got my GTO and I was wondering if someone knew how much power a stock rear end will hold.

Sarge...with 600 HP. Is yours still stock....or what kind of rear end did you put in?

Thanks for the info..

**BlueSuperGoat** · 01-18-2006, 04:55 AM

Originally Posted by GOAT6SPD

This questions has been asked before im sure....

I just got my GTO and I was wondering if someone knew how much power a stock rear end will hold.

Sarge...with 600 HP. Is yours still stock....or what kind of rear end did you put in?

Thanks for the info..

Sarge's is an auto...autos can take a lot more than the 6 spds can because the shifts don't shock the drivetrain as much. There is no exact rule of what the rear end can take but it is really a combination of things. I know of a couple of goats making at or around 500rwhp in a 6 spd that have held up as long as they stay off of drag radials. You put that kind of power through the stock driveline on drag radials and it will only be a matter of time before something breaks. I am running 400rwhp on street tires with no problems with the stock driveline in a 6 spd, and it has seen track use on drag radials with no problems. (knock on wood) I would honestly tell you that anything beyond 400 at the wheels and you should keep money set aside to replace what might break. Throw on a harrop diff cover and some poly x-member bushings and that will help with the driveline shock, but I would still be careful launching and shifting hard on sticky tires with anything in excess of 400 at the wheels. JMO.

**Sarge** · 01-18-2006, 05:51 AM

Yup^^^^
Mine is an A4 with 3500 stall.....however I have beefed up the back end....
Harrop Diff cover eliminated the rear end "walking: around by allowing us to bolt the rear end to the frame.....Poly bushings...beefed up sway bar...Pedder Drag Springs and Koni shocks eliminated the squat....with the IRL the squat causes excessive strain on the rear end......that was eliminated....an added bonus of eliminating the "squat" was you do not
launch on the insides of your rear tires..../ \ now you launch | |......
As for where or how much is the magic break line.....well ol BSG (above) is right....who knows......I would recommend the mentioned modifications for sure on a M6 or A4.....but I installed a simple driveshaft safety loop just to cover my ass......

**BlueSuperGoat** · 01-18-2006, 06:03 AM

Originally Posted by Sarge

but I installed a simple driveshaft safety loop just to cover my ass......

Me too.

GOAT6SPD · 01-18-2006, 08:41 AM

Thanks for the info guys...I guess I better get those mods done before a Supercharger.

**BlueSuperGoat** · 01-18-2006, 09:10 AM

Originally Posted by GOAT6SPD

Thanks for the info guys...I guess I better get those mods done before a Supercharger.

Absolutely. Harrop Diff Cover and Poly X-member bushings, bare minimum.

GOAT6SPD · 01-18-2006, 10:30 AM

how much can I expect to spend for those mods and anything else I might need prior to a build up

**BlueSuperGoat** · 01-18-2006, 10:50 AM

Originally Posted by GOAT6SPD

how much can I expect to spend for those mods and anything else I might need prior to a build up

The Harrop diff cover comes from down under, so it will cost you about $400ish to get it to your door. The bushings will be about $150 to your door. Other than that you will need enough (3.something qrts, basically buy 4 quarts) new diff fluid (I recommend royal purple) and some gasket maker...so approx...

$400 - diff cover
$150 - bushings
$5 - tube of gasket maker
$30 - 4 qrts of royal purple diff fluid

About $585.00, but it will be well worth it. When/if you get the diff cover, make sure you are getting one with the new bracket design or with the washer/spacer kit to protect it's internal poly bushings (these are different than the x-member bushings) or else the bracket may start to eat the bushings. It was a design flaw that they have now identified and are taking care of.

I hope this helps, let me know if I can be of further help.

**Sarge** · 01-19-2006, 09:16 AM

I still think that dumbshit HRJ installed his wrong....mine is still rock solid perfect and I GUARANTEE I am putting one helluva lot more to the ground that that yellow POS he drives around in.....

**BlueSuperGoat** · 01-19-2006, 09:24 AM

Originally Posted by Sarge

I still think that dumbshit HRJ installed his wrong....mine is still rock solid perfect and I GUARANTEE I am putting one helluva lot more to the ground that that yellow POS he drives around in.....

Mine is still looking solid as well. But I just wanted to warn GOAT6SPD just in case...making sure you get the updated bracket/bushing set-up can't hurt.

**Sarge** · 01-19-2006, 10:55 AM

Originally Posted by BlueSuperGoat

Mine is still looking solid as well. But I just wanted to warn GOAT6SPD just in case...making sure you get the updated bracket/bushing set-up can't hurt.

Oh hell no...I totally agree.....but you and I are putting down some serious horsepower and you and I drive the crap out of our Goats.....why are ours OK and his broke all to shit....I would "guess" it wasn't aligned properly....

txcosmos · 01-19-2006, 11:26 AM

I would "guess" it was the monkey helping him put it on.

Sorry Shane, but you should have invited me...

**BlueSuperGoat** · 01-19-2006, 11:35 AM

Originally Posted by txcosmos

I would "guess" it was the monkey helping him put it on.

Sorry Shane, but you should have invited me...

**brent eb02** · 02-14-2006, 08:15 AM

i have the harrop cover and bushings

and it holds over 600 rwhp and 700 rwtq 1.54 sixty foots

10.6@132

i have a built a4

**Sarge** · 02-14-2006, 09:30 AM

Yup....I'm not worried about axle stubs and that crap....

**Rob** · 02-18-2006, 12:49 AM

I'm only ~400rwhp and mine is completely stock. So far so good

May try the air bags as I'm now starting to pick up some wheel hop again since the latest go 'round in mods. Guess the Nittos are starting to loose their grip

**05VZ** · 03-01-2006, 09:04 AM

Originally Posted by Sarge

Oh hell no...I totally agree.....but you and I are putting down some serious horsepower and you and I drive the crap out of our Goats.....why are ours OK and his broke all to shit....I would "guess" it wasn't aligned properly....

It would be a guess, for sure.

Shane and I installed mine the same way we installed his. His doesn't have the problem and mine does. Ken @ Harrop Engineering stated to me on the phone when this first came up that he believes the way that some of the cars are strapped down on the transport ship from Australia might cause the subframe to shift slightly. Not sure if he's right, but it does make an interesting case.

**plasterman182** · 03-24-2006, 08:50 PM

Hasn't anyone heard about a technical bulletin put out on the 04 and 05 gto?
i had clicking from my rear end and eventually my right hub bearing blew when i was on the highway. I went back to the dealership cuz my goat is stock and the replacement rearend was on recall. GM wont tell you unless you ask, but if your goat is still covered they have to replace the whole thing all the way to the dif.