Axles, diffs and shaft for 1500hp gtr

[khezz]

Hello. 

My build is progressing slower then expected, but its progressing. I would like to get opinions on what axles, diffs and driveshaft are recommended for a projected 1500hp at the flywheel. 

Car will be running on much lower hp tune for its day to day duties (yes, this will be daily driven and will even have a baby seat) but will see dragstrip and rolling racing work from time to time.

I hear that rear diffs are very strong but front diff, axles and driveshaft will become consumables if not upgraded properly.

would love peoples suggestions on brands to go for and places to contact.

Thank you

 

Edited October 26, 2020 by khezz

[Ben C34]

Is this real or just talking shit?

[khezz]

No its real. Car will be running a nityo 3.2L built by JHH. Boosted by a G42-1450. Block is darton sleeved and half grout filled. Transmission wise im leaning towards an OS88. 

[khezz]

Im getting so many conflicting stories from suppliers. I just want advice from the end user.

[BK]

Driveshaft shop in the USA. Rear 31 spline stub axles and 108mm CV driveshafts modelled on the Porsche design from them is about as serious as it gets. It's at least a $4k exercise though.

[GTSBoy]

As to diffs.... For proper drag, you want a good mechanical diff in the rear. Only needs to be 1-way for drag, which will also make it more livable on the street. 1.5-way if you want a bit more clunk and bang.

The nicest diff in the front is a Torsen/helical. The Quaife is the obvious (and probably only) choice.

[BK]

The Quaife in the rear is also awesome.

[khezz]

High octane sell billet axles. Rated at 1000hp. Car will never launch with all 1500hp and by the time it reaches max power, load will be distributed 50/50 front to rear. Or am I way off?

So 1 way is drivable on the street? Cool.

Driveshaft shop has some great gear. Just worried about transport right now and would love to keep my money in Australia.

[BK]

4 hours ago, khezz said:

High octane sell billet axles. Rated at 1000hp. Car will never launch with all 1500hp and by the time it reaches max power, load will be distributed 50/50 front to rear. Or am I way off?

You are way off. The car launches at 50/50 and progressively reduces the front wheel torque up the track. It's the launch that breaks the shafts, especially with sticky tires like ET streets or slicks.

The reason I mentioned the driveshaft shop gear is they are the only ones selling uprated stub axles, and this is also what the big big power GTRs are breaking. Downside is they only suit their driveshafts and CVs. It's a big step up from the billet hi octane shaft only replacement as their CVs are much bigger, hence why I said it's about as serious as it gets.

Don't know if you know or not, but trying to obtain 31 spline stub axles is almost getting to the impossible stage, where if you break one, the driveshaft shop may become the only option soon.

[khezz]

Thank you. I have heard that previously. Thats why I was hoping to stay local.

Might go for a torque split controller. 

I keep watching the motive video about JUNII setup and how simple it is. Yes its lighter but produces nearly double the power of my goal. The only thing that's not mentioned is how often the components get replaced.

Fairly settled on Quaife ATB centres and might go driveshaft shop for actual drive shaft. Still not sold on Axles though.

[BK]

3 hours ago, khezz said:

Fairly settled on Quaife ATB centres and might go driveshaft shop for actual drive shaft. Still not sold on Axles though.

According to your build thread you got a 90 GTR right ? Your existing rear stub axle half shafts into your diff will be 30 spline. Nismo GT and Cusco have 30 spline centres, but OS giken and Quaife rears are only designed for 31 spline. Don't know of any 30 spline stub upgrades and they too are discontinued.

See where this is going ?

[khezz]

I did not know that. So when you look up axles and diffs and the spill says "direct fit to R32 gtr". It really isn't?

Sorry, I really don't know. That why I ask.

[BK]

Depends on your existing diff centre and shafts, as the centres fit in the housings and is direct fit IF you have late R32 or R33 non vspec half shafts which are 31 spline. Driveshaft shop only makes 31 spline stub axle half shafts, because I guess they assume any serious GTR will be running a 31 spline rear centre, which is what all the good centres are.

31 spline stock half shafts are as mentioned almost impossible to get now, and the Driveshaft shop 31 spline half shaft stub axles only suit their 108mm cv driveshaft axles, not stock GTR driveshaft cv axles.

Long story short is 30 spline only suits Nismo GT and Cusco diff centres, but if you break a 30 spline half shaft they are now no longer available to replace, and there is no aftermarket replacement option. If you want a Quaife, ATS or Giken rear they only take 31 spline half shafts, which are also now discontinued and the only 31 spline half shaft option off the shelf doesn't support stock driveshaft cv axles.

It really is getting to a point if driveshaft axle or stub axle breakage is at all a possibility the Driveshaft shop is the only supported option to know you can replace something if it does break, which it probably won't as that's the reason their gear was used in the first place.

[khezz]

Fair enough. Looks like its an email to the driveshaft shop.

[BK]

I'm waiting on a response from them regarding making 31 spline stub axles to suit the factory cv. If they do this, it takes away a fair bit of future uncertainty.

It means 31 spline diff centre options will never be a problem, half shafts are readily available for breakages, driveshaft cv axle choices mean you can use a standard cv type shafts with stock shafts or billet ones, and because your already running a 31 spline diff the choice is there to go the super dooper 108mm cv down the track.

At the moment if you break a stub axle its way worse than breaking a driveshaft axle because of what potentially you have to upgrade.

Again, FK you Nissan constantly discontinuing important things that aren't available from the Nismo heritage program.