Best 60 Foot on Stock 7.5"?
10-22-2014, 09:16 AM
#84
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Thread Starter
The 7.5" is weak in comparison to just about any other rear axle anyone has made for a V-8 RWD car. But, it's strength is greater than people here and other places lead on to believe. Probably why GM used it.
In my honest opinion, based on the data gathered here and else where, the 7.5" axle is more likely to break from wheel hop or improper care than a hard launch. Yes, hard acceleration can (and does) break axles, the 7.5" is more susceptible than the larger axles. But, their leading cause of breakage is likely a cause of something else with or without a combination of the hard acceleration.
The Girdle is invaluable. It really does help a lot. Looking at the list compiled on post 1 shows that none have broken with the Girdle on. And some of these cars are doing decent 60 foots at full weight. Adding the brace tubing only improves further on that.
Running consistent 10's or faster (is possible, it's been done) is not recommended with a 7.5". But 11's certainly isn't impossible, if reasonable. And for 95% of us (enthusiasts) we don't run much faster than 11's with our 400rwhp or less. Mostly on street tires too.
My take away? Girdle, good maintenance, proper suspension geometry, and brace tubes will add a significant amount of strength and life to the axle assembly. But overall it's still limited by the small ring and pinion.
Last edited by hrcslam; 10-22-2014 at 09:34 AM.
10-22-2014, 09:34 PM
#85
Go to post 1.
The 7.5" is weak in comparison to just about any other rear axle anyone has made for a V-8 RWD car. But, it's strength is greater than people here and other places lead on to believe. Probably why GM used it.
In my honest opinion, based on the data gathered here and else where, the 7.5" axle is more likely to break from wheel hop or improper care than a hard launch. Yes, hard acceleration can (and does) break axles, the 7.5" is more susceptible than the larger axles. But, their leading cause of breakage is likely a cause of something else with or without a combination of the hard acceleration.
The Girdle is invaluable. It really does help a lot. Looking at the list compiled on post 1 shows that none have broken with the Girdle on. And some of these cars are doing decent 60 foots at full weight. Adding the brace tubing only improves further on that.
Running consistent 10's or faster (is possible, it's been done) is not recommended with a 7.5". But 11's certainly isn't impossible, if reasonable. And for 95% of us (enthusiasts) we don't run much faster than 11's with our 400rwhp or less. Mostly on street tires too.
My take away? Girdle, good maintenance, proper suspension geometry, and brace tubes will add a significant amount of strength and life to the axle assembly. But overall it's still limited by the small ring and pinion.
The 7.5" is weak in comparison to just about any other rear axle anyone has made for a V-8 RWD car. But, it's strength is greater than people here and other places lead on to believe. Probably why GM used it.
In my honest opinion, based on the data gathered here and else where, the 7.5" axle is more likely to break from wheel hop or improper care than a hard launch. Yes, hard acceleration can (and does) break axles, the 7.5" is more susceptible than the larger axles. But, their leading cause of breakage is likely a cause of something else with or without a combination of the hard acceleration.
The Girdle is invaluable. It really does help a lot. Looking at the list compiled on post 1 shows that none have broken with the Girdle on. And some of these cars are doing decent 60 foots at full weight. Adding the brace tubing only improves further on that.
Running consistent 10's or faster (is possible, it's been done) is not recommended with a 7.5". But 11's certainly isn't impossible, if reasonable. And for 95% of us (enthusiasts) we don't run much faster than 11's with our 400rwhp or less. Mostly on street tires too.
My take away? Girdle, good maintenance, proper suspension geometry, and brace tubes will add a significant amount of strength and life to the axle assembly. But overall it's still limited by the small ring and pinion.
10-22-2014, 09:46 PM
#86
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Thread Starter
Agreed. I will say that no one that used a girdle, A4 or M6, reported any problems with the 7.5".
10-23-2014, 08:01 AM
#87
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10-23-2014, 04:20 PM
#88
Id like to add my experience with the 10 bolt. I have a 2002 M6 Trans Am that puts down 450whp and 415wtq NA. Daily drive on 555r drag radials.
My best 60' on drag radials is 1.84 with a very conservative 4k launch... I have the following mods done to the factory 10 bolt:
3.90 orange box Motive gears
Studded bearing caps
solid pinion spacer
Moser Axles
Girdle Cover
185w oil
Stock Torsen Posi
I recently broke the posi during some testing on a local road with tons of rubber from local street racing. I broke the worm gears and the car would make a loud clunk every time I would turn, but would drive fine. Replaced it with another Torsen and will test it out at the track on November 8th. Overall it has served me well with the upgrades I have done... Really wonder how much stronger it would be if I upgraded to an Eaton posi.
My best 60' on drag radials is 1.84 with a very conservative 4k launch... I have the following mods done to the factory 10 bolt:
3.90 orange box Motive gears
Studded bearing caps
solid pinion spacer
Moser Axles
Girdle Cover
185w oil
Stock Torsen Posi
I recently broke the posi during some testing on a local road with tons of rubber from local street racing. I broke the worm gears and the car would make a loud clunk every time I would turn, but would drive fine. Replaced it with another Torsen and will test it out at the track on November 8th. Overall it has served me well with the upgrades I have done... Really wonder how much stronger it would be if I upgraded to an Eaton posi.
Last edited by 455GTO; 10-23-2014 at 04:27 PM.
10-23-2014, 04:57 PM
#89
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Thread Starter
Id like to add my experience with the 10 bolt. I have a 2002 M6 Trans Am that puts down 450whp and 415wtq NA. Daily drive on 555r drag radials.
My best 60' on drag radials is 1.84 with a very conservative 4k launch... I have the following mods done to the factory 10 bolt:
3.90 orange box Motive gears
Studded bearing caps
solid pinion spacer
Moser Axles
Girdle Cover
185w oil
Stock Torsen Posi
I recently broke the posi during some testing on a local road with tons of rubber from local street racing. I broke the worm gears and the car would make a loud clunk every time I would turn, but would drive fine. Replaced it with another Torsen and will test it out at the track on November 8th. Overall it has served me well with the upgrades I have done... Really wonder how much stronger it would be if I upgraded to an Eaton posi.
My best 60' on drag radials is 1.84 with a very conservative 4k launch... I have the following mods done to the factory 10 bolt:
3.90 orange box Motive gears
Studded bearing caps
solid pinion spacer
Moser Axles
Girdle Cover
185w oil
Stock Torsen Posi
I recently broke the posi during some testing on a local road with tons of rubber from local street racing. I broke the worm gears and the car would make a loud clunk every time I would turn, but would drive fine. Replaced it with another Torsen and will test it out at the track on November 8th. Overall it has served me well with the upgrades I have done... Really wonder how much stronger it would be if I upgraded to an Eaton posi.
Is the Torsen the stronger or the weaker of the two units?
Honestly, I'm looking at replacement axle options at my power level, but expendable finances is not a commodity I'll have for a while. So I'm considering putting the studded caps and girdle on to keep the rear living for a while longer until I figure something else out. It's very likely the 8.8 option is in my future.
10-23-2014, 09:25 PM
#90
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Id like to add my experience with the 10 bolt. I have a 2002 M6 Trans Am that puts down 450whp and 415wtq NA. Daily drive on 555r drag radials.
My best 60' on drag radials is 1.84 with a very conservative 4k launch... I have the following mods done to the factory 10 bolt:
3.90 orange box Motive gears
Studded bearing caps
solid pinion spacer
Moser Axles
Girdle Cover
185w oil
Stock Torsen Posi
I recently broke the posi during some testing on a local road with tons of rubber from local street racing. I broke the worm gears and the car would make a loud clunk every time I would turn, but would drive fine. Replaced it with another Torsen and will test it out at the track on November 8th. Overall it has served me well with the upgrades I have done... Really wonder how much stronger it would be if I upgraded to an Eaton posi.
My best 60' on drag radials is 1.84 with a very conservative 4k launch... I have the following mods done to the factory 10 bolt:
3.90 orange box Motive gears
Studded bearing caps
solid pinion spacer
Moser Axles
Girdle Cover
185w oil
Stock Torsen Posi
I recently broke the posi during some testing on a local road with tons of rubber from local street racing. I broke the worm gears and the car would make a loud clunk every time I would turn, but would drive fine. Replaced it with another Torsen and will test it out at the track on November 8th. Overall it has served me well with the upgrades I have done... Really wonder how much stronger it would be if I upgraded to an Eaton posi.
10-24-2014, 10:29 AM
#93
Thanks for this, it's good to have contrast. So the Girdle does have it's limits. 450rwhp is a lot though, to be fair. I've added you to the list on post 1.
Is the Torsen the stronger or the weaker of the two units?
Honestly, I'm looking at replacement axle options at my power level, but expendable finances is not a commodity I'll have for a while. So I'm considering putting the studded caps and girdle on to keep the rear living for a while longer until I figure something else out. It's very likely the 8.8 option is in my future.
Is the Torsen the stronger or the weaker of the two units?
Honestly, I'm looking at replacement axle options at my power level, but expendable finances is not a commodity I'll have for a while. So I'm considering putting the studded caps and girdle on to keep the rear living for a while longer until I figure something else out. It's very likely the 8.8 option is in my future.
So in my case the weak link has not been the ring and pinion but rather the posi and stock axles... Its my hope to make it back unbroken from the track in 2 weeks...
10-24-2014, 12:10 PM
#94
I was thinking though, I have a series 2 carrier and put 4.10's in so I had to go with the thicker ring gear set. I wonder if this adds any strength.
10-24-2014, 07:13 PM
#95
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Thread Starter
From my reaearch it seems as of the Torsen and Auburn are about the same strength wise in regards to drag racing. Dofference being is that the Auburn can be rebuilt... I upgraded to the Moser axles out of necessity because when the driveline shop was installing my 3.90 gears, he said the axles were so twisted they wont last another launch with the new gears...
So in my case the weak link has not been the ring and pinion but rather the posi and stock axles... Its my hope to make it back unbroken from the track in 2 weeks...
So in my case the weak link has not been the ring and pinion but rather the posi and stock axles... Its my hope to make it back unbroken from the track in 2 weeks...
Personally (and I'm approaching your power level), I'd swap the rear end to something capable of making my car stand up and not worry about it but every 10 years or so for a posi rebuild. Money is an issue though. 8.8 is the likely option for me.
10-26-2014, 02:29 PM
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10-27-2014, 05:02 PM
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Just started by 10 bolt build today. The initial build is going to consist of the following:
-Motive 3.90 gears
-Motive rebuild kit with new bearings, seals, and gaskets.
-LPW girdle cover
-Welded axle tubes
NOT going to go easy on it. Hoping to cut 1.8x 60fts first time out which shouldn't be a problem. If it holds up well to a couple track visits, my girdle has provisions on it for the LPW brace kit, which I will add at that time along with possibly a solid pinion spacer, and see just how much I can get out of this thing. Goal it to get it to survive 1.6x-1.7x 60fts. If I can achieve that then I'll continue pushing it from there, but 1.6x with a M6 would be awesome.
My current best so far is a pathetic 2.1 60ft on completely untouched M6 rear with pathetic driving on my part. 3k dumps but falling on its face bogging hard off the line. No noises or issues since then. I will also be dropping a bit of weight from the car, not sure if that makes things easier on the rear end.
Will update when the build is done and will post 60fts and ETs once I get out to the track.
-Motive 3.90 gears
-Motive rebuild kit with new bearings, seals, and gaskets.
-LPW girdle cover
-Welded axle tubes
NOT going to go easy on it. Hoping to cut 1.8x 60fts first time out which shouldn't be a problem. If it holds up well to a couple track visits, my girdle has provisions on it for the LPW brace kit, which I will add at that time along with possibly a solid pinion spacer, and see just how much I can get out of this thing. Goal it to get it to survive 1.6x-1.7x 60fts. If I can achieve that then I'll continue pushing it from there, but 1.6x with a M6 would be awesome.
My current best so far is a pathetic 2.1 60ft on completely untouched M6 rear with pathetic driving on my part. 3k dumps but falling on its face bogging hard off the line. No noises or issues since then. I will also be dropping a bit of weight from the car, not sure if that makes things easier on the rear end.
Will update when the build is done and will post 60fts and ETs once I get out to the track.
10-28-2014, 04:30 PM
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Many on here do not understand this, and try for crazy 60 foots/E.T.s with their "full weight"/loaded up with audio and other crap f bodies (I'm guessing for 'bragging rights'), and then wonder why they are breaking even very strong rear axles and such when they attempt their 1.5 or quicker 60 foots on wrinkle walls, with 500+ to the wheels in a 3900 pound car before their weight is added in.
10-28-2014, 04:32 PM
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Go to post 1.
The 7.5" is weak in comparison to just about any other rear axle anyone has made for a V-8 RWD car. But, it's strength is greater than people here and other places lead on to believe. Probably why GM used it.
In my honest opinion, based on the data gathered here and else where, the 7.5" axle is more likely to break from wheel hop or improper care than a hard launch. Yes, hard acceleration can (and does) break axles, the 7.5" is more susceptible than the larger axles. But, their leading cause of breakage is likely a cause of something else with or without a combination of the hard acceleration.
The Girdle is invaluable. It really does help a lot. Looking at the list compiled on post 1 shows that none have broken with the Girdle on. And some of these cars are doing decent 60 foots at full weight. Adding the brace tubing only improves further on that.
Running consistent 10's or faster (is possible, it's been done) is not recommended with a 7.5". But 11's certainly isn't impossible, if reasonable. And for 95% of us (enthusiasts) we don't run much faster than 11's with our 400rwhp or less. Mostly on street tires too.
My take away? Girdle, good maintenance, proper suspension geometry, and brace tubes will add a significant amount of strength and life to the axle assembly. But overall it's still limited by the small ring and pinion.
The 7.5" is weak in comparison to just about any other rear axle anyone has made for a V-8 RWD car. But, it's strength is greater than people here and other places lead on to believe. Probably why GM used it.
In my honest opinion, based on the data gathered here and else where, the 7.5" axle is more likely to break from wheel hop or improper care than a hard launch. Yes, hard acceleration can (and does) break axles, the 7.5" is more susceptible than the larger axles. But, their leading cause of breakage is likely a cause of something else with or without a combination of the hard acceleration.
The Girdle is invaluable. It really does help a lot. Looking at the list compiled on post 1 shows that none have broken with the Girdle on. And some of these cars are doing decent 60 foots at full weight. Adding the brace tubing only improves further on that.
Running consistent 10's or faster (is possible, it's been done) is not recommended with a 7.5". But 11's certainly isn't impossible, if reasonable. And for 95% of us (enthusiasts) we don't run much faster than 11's with our 400rwhp or less. Mostly on street tires too.
My take away? Girdle, good maintenance, proper suspension geometry, and brace tubes will add a significant amount of strength and life to the axle assembly. But overall it's still limited by the small ring and pinion.
My takeaway from the info gathered here is a lot of false hope and a lot of people dumping money into an inadequate rear end. If you plan on taking your car to the strip the 10 bolt will fail or become abnoxiously noisy. Matter of only time.
I recommend getting a girdle and leaving the stock gear in there and save your money. When it breaks, upgrade to 9" or s60.