I have s4 n/a rear end can't seem to find any info in the forum on the limits of n/a diff and axles. From what power/torque I should start thinking of upgrading it to TII diff and axles?
If there was a discussion about it that I missed somehow links would be appreciated.

Thanks.

 

Recently talked about
https://www.rx7club.com/2nd-generati...train-1054332/
The diff and halfshafts can stand up to some abuse according to some people, the NA transmission seems to be the weakest link in the driveline. Honestly I would run the NA rear end until it puked its guts out and go from there, but that's just me

 

Not sure you'll find any hard and fast numbers since a lot depends on how the car is driven.
Aaron Cake managed to nurse his NA drivetrain over 300 hp (I think) before some hard launches finally killed it.

That standard forum answer is that you should always be thinking of an upgrade from NA to turbo drivetrain, if only to be safe.

 

ahhh....it'll do fine..just up to the point where it Breaks...

But with that Raw unleashed N/A power..it'll survive.

 

drag racing, drifting, just spirited driving- these are all to be considered

in NA form run it till it breaks

 

it probably wont like redline clutch dumps. mine stripped the planetary gear. As others have said you'll (probably) kill the trans before the rear end. While everyone is buying up T2 drivetrains I'll stockpile the NA stuff for a fraction of the cost

 

I am putting 4cyl turbo (shame on me ) so gearbox is sorted. The only concern is diff that will be welded and axles. I am planning to run something in between 300-350whp.

 

Thanks for the link, it seems I should be fine with my power plans and no drag racing with clutch drops at high rpm.

P.s. sorry for double post, it appears I can't edit previous message to add something.

 

if you are just doing straight line runs and no serious launches you will probably never break the rear end components even up to and beyond 500whp.

but you start shock loading the drivetrain and things can break at substantially lower power levels. non turbo drifters have been breaking the components for years at a fraction of that power level. so you see it all really depends on how harsh you treat the drivetrain.

i have never personally seen anyone break any rearend components but i also tend to explain to people what to expect of them. if you treat the car like a kid who just got the car as a present from your parents and you just watched initial D for the first time, you probably lack appreciation for the car and might understand the level of abuse it might take. trying to clutch kick the rear end out with a welded diff at 50mph is usually quite more than enough, and often where i see people breaking those parts.

the other deal breaker is wheel hop, it is extremely hard on the drivetrain. this comes from improper drag setups, broken diff/trans/engine mounts and welded diffs raking turns. on a drag launch if you want to be easy on the drivetrain it must be preloaded by either dragging the clutch or a driveline brake installed.

 

Car will be used for drifting with welded n/a open diff. Diff and rear subframe will be mounted on solid mounts. I have experience with cars and drifting and have owned s13 for a couple of years. It might see higher speed clutch kicking with welded diff thou... Should I be worried about it then?

 

to some degree yes, but nothing will fix the issue more than ditching the welded diff and running a better LSD choice and heavier duty diff/axles.

most drifters with welded diffs using n/a components usually break something sooner or later. the chattering caused by the welded diff is extremely hard on the half axles, eventually even just easy street driving will fatigue the metal enough that it will simply shear the first time you put the hammer to it.

 

Then I will probably need to install turbo diff and axles to be on the safer side. Thanks for info.

 

or purchase and set them aside for when you do eventually need them. no need to subject them to abuse before necessary unless you are already in the stages of real competition.

it should be more difficult to initate a slide with a stock diff, a 2/3 way LSD would improve upon that and be closer to the welded diff once you apply power to lock it. so it would probably be easier to practice with a welded diff but more difficult to drive casually with.

 

I have been driving with welded diff on a daily basis for quite some time in s13, no big problems except extra attention when parking because everyone thinks your car is broken
As for the diff I might just buy it and wait or just swap in bmw diff and call it a day. More work but I will have bmw zf gearbox anyway and then I would have unlimited options for rear gear ratios.

 

Just snapped driverside stubshaft launching at 5k while slipping the clutch. I had been fine launching at 4k about 5 passes, but I'm on very low boost and about 300whp. I would just upgrade now

 

The thread was like 10 post down...nice job searching

Anyways its not a exact number so many diff. Variables from 100hp to 500hp is what they will hold.