Diff (??) gave up at the track, ouch!

[trackratZ]

Not mine thankfully but...

https://www.roadandtrack.com/news/a...-nissan-z-grenade-its-diff-at-the-drag-strip/

 

[rocksandblues]

Same shop that burned one to the ground. Tough luck

 

[Jah_Happy]

Pretty sure it was a sport model so I wonder what diff they had?

 

[rocksandblues]

Pretty sure it was a sport model so I wonder what diff they had?

Good question. I thought the Sports didn't come with a locking diff. which I would think you would need w drag racing?
Unless they just did some old school tricks or mods which in case not Nissan fault at all.

Same shop has a very dubious history building up.

 

[trackratZ]

Both Sport and Performance have the same diff internals, except for the LSD in the latter, correct? I'm curious if it was stock and gave up due to the power mods and repeated runs.

 

[StrikeS30]

That was a hard launch. At some point somethings got to give. Surprised though. Nissan Diffs have been known to take a lot of abuse over the years. It's usually the stub axles that snap before the diff gives up

 

[MHockey17]

There was a FB post about it, sounds like it was a stock Sport diff. Some were claiming the Perf LSD hasn’t had any issues like that so perhaps the base open diff ain’t a good candidate for drag racing on slicks..

 

[rocksandblues]

There was a FB post about it, sounds like it was a stock Sport diff. Some were claiming the Perf LSD hasn’t had any issues like that so perhaps the base open diff ain’t a good candidate for drag racing on slicks..

that is what i don't get? if you try and launch an open diff one wheel is just going to spin. ? right?

that has me wondering if they went cheap and old school and welded the diff and or have some after market lockup?

 

[trackratZ]

You never know what these guys did, and they probably wouldn't say if a questionable part or install. Very curious to know though, if it's OEM weakness. That's a major blow, grenaded that casing.

 

[MHockey17]

that is what i don't get? if you try and launch an open diff one wheel is just going to spin. ? right?

that has me wondering if they went cheap and old school and welded the diff and or have some after market lockup?

That’s the intuitive assumption if launching hard with an open diff. Though the Z has a 4-channel ABS controller so each wheel can be independently braked; I think this is partly how the factory VDC/TC system operates.

From the comments doesn’t seem like they opened up the stock diff at all on this car, so perhaps their flash tune includes custom TC software that uses the ABS controller to prevent one wheel spinning on launches ; For example I’m pretty sure EcuTek offers feature like this for 370Z & other Nissan FM cars. Just my guess tho

 

[takemorepills]

Open diffs, when one-wheel-peeling can spin certain parts of the diff 2x faster because when one side of the wheel isn't spinning, now the spider gears are spinning between the two side gears. If you do this belligerently and in an un-relenting manner, the spider gears can overheat and grenade, destroying the diff.

In a straight-line and with both wheels under same torque, the spider gears hardly spin at all. Only during turns are they usually turning.

https://www.carparts.com/blog/your-...-plus-faqs/#What_Causes_Spider_Gears_to_Break

What Causes Spider Gears to Break?

Free spinning your wheels can cause the spider gears to rotate at an alarming rate and result in metal-to-metal contact.


Once this happens, the cross-shaft and spider gears can melt and damage the entire spider gear and ring and pinion set as well as the differential case.


A worn-out clutch pack can also result in a play in the spider gears, generating a small contact area and causing the spider gears to chip.

 

[BlackHawk77]

I don't think they've torn it down yet but it was a stock sport diff. You can still get both wheels to spin even in a burnout.

There have been a ton of passes on stock performance LSD without a hiccup. This is the first sport I've seen drag raced so either they were really unlucky with a defect from the factory or the open diffs are way weaker than the LSDs.

 

[BlackHawk77]

So they did an update on YouTube, the diff itself didn't break. The rear mounting stud on the rear cover broke off allowing the whole diff housing to twist which then the axle popped off. Also busted the driveshaft because the rear joint was at an extreme angle.

 

[trackratZ]

So they did an update on YouTube, the diff itself didn't break. The rear mounting stud on the rear cover broke off allowing the whole diff housing to twist which then the axle popped off. Also busted the driveshaft because the rear joint was at an extreme angle.

So the weak link was the mounting stud on the rear cover? Hmm

 

[Jah_Happy]

So the weak link was the mounting stud on the rear cover? Hmm