Rear Axle Failure

[gcmak]

They're going to blame the radials if they're still on there. These axels like to break. I know of axels snapping on drag radials with a modest tune on an 11.5 second car (at the drag strip).

Thanks. I was aware of axle issues when dragging the car on sticky/prepped surfaces. Especially true with more power and radials. Not sure any of that applies to me - as I described.

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[gcmak]

I saw that video, it’s interesting he snapped the bearing cage. If it was just that you can normally pull a cage out of a trashed car and put it in along with the bearings and a new boot but it heavily depends on cost and availability. That’s mildly concerning if the axles can snap on stock power. I’ve been down the track 8 times this season on the last 2 test and tune days on factory tires and wheels and I have major traction issues but no axles yet (knock on wood)

The slip I’m sure is what prevents the snap. I still have slip but it’s not like I used to spin through 1st and 2nd on unprepared surfaces.
Sounds like you’re ready for some built parts soon!

 

[MisterSkiz]

I remember reading that this car uses axles that the previous generation BMW M5 did - i'll have to track back where I found that it post it here.

For the folks reading this, remember that if you upgrade the axles, then you are passing the stress down the line to the differential.

If they do come out with a manual, it will be interesting to see how many more parts will be destroyed with the driveline shock of folks drag racing them.

 

[Mason]

has anyone reinforced the diff yet? At what point is that really needed?

 

[Cptnslo]

Once you solve the major traction issues (a good tire + a good launch) you're cringing as you're building boost while the tree lights up. My best pass of the season (low 11s) I was absolutely terrified. Once I saw my 60' I packed it up for the season until my built axels showed up. STILL WAITING, NORRIS/P2UNED/DSS.

lmao what was your 60` and wheel and tire setup

 

[MisterSkiz]

Here is where i read something about the F90 M5 axles - another member on the forum, which is not saying much (no offense to original poster).

https://www.supramkv.com/threads/a9...-diagrams-all-revealed.1404/page-4#post-27678


I did my own digging:

BMW Z4 M40i rear driveshaft part numbers:
33209896323 z4 left
33209896324 z4 right

Toyota rear driveshaft part numbers:
42330-WAA04 toyota right
42340-WAA04 toyota left

From googling around the BMW part numbers, I see the numbers as being the same as the following cars (assuming that the Toyota and BMW parts are the same)

"Fits 330i, 330iX, 430i, Z4" - the 3 series and 4 series are about 300 and 600 lbs heavier than the Z4/Supra.

 

[zrk]

lmao what was your 60` and wheel and tire setup

1.74 - Titan-7 Drag Pack. MT ET Street R 305/45/17.

 

[Mason]

1.74 - Titan-7 Drag Pack. MT ET Street R 305/45/17.

Can you link the wheels? I haven’t found any 17” that hold a 305 on their website

 

[zrk]

Can you link the wheels? I haven’t found any 17” that hold a 305 on their website

I actually think the Drag Pack i have is discontinued. It's all welds now.

 

[METAL]

Could keeping traction control on prevent stress on the drivetrain?

 

[jchadwell]

1.74 - Titan-7 Drag Pack. MT ET Street R 305/45/17.

Dang, had no idea how brittle our axles are. I only went to the drag strip twice last season for a couple test and tunes. Just wanted to see what it could do. My best run was 11.98 with a 1.74 60'. The car was also damn consistent. All 4 runs when I went in the Fall were between 11.98 and 12.05 and 60' ranged from 1.74 to 1.81. This was on factory wheels and my 200TW 275/35/19 AX tires (Federal R595 Pro). I was very pleased. Last Spring I was learning the car and much less consistent but still had a best of 12.2 I was on the factory Michelins then and I think the best 60' was like 1.9 something. Don't have the slips any longer though so not sure.

Reading this thread, I'm glad I don't really have a desire to go to a drag strip again. I enjoy autocross much more. I just wanted to hit a test and tune or two and see if there was an 11 in the car. Got an 11, no need to go back! Also can't launch nearly as hard on the dusty, unprepared parking lots we autocross on so won't be worrying about breaking an axle!

 

[black_sedan]

Once you solve the major traction issues (a good tire + a good launch) you're cringing as you're building boost while the tree lights up. My best pass of the season (low 11s) I was absolutely terrified. Once I saw my 60' I packed it up for the season until my built axels showed up. STILL WAITING, NORRIS/P2UNED/DSS.

What's even worse. Watching another Mkv break an axle and being pushed off the track right before I had to make a pass.

 

[gcmak]

Here is where i read something about the F90 M5 axles - another member on the forum, which is not saying much (no offense to original poster).

https://www.supramkv.com/threads/a9...-diagrams-all-revealed.1404/page-4#post-27678


I did my own digging:

BMW Z4 M40i rear driveshaft part numbers:
33209896323 z4 left
33209896324 z4 right

Toyota rear driveshaft part numbers:
42330-WAA04 toyota right
42340-WAA04 toyota left

From googling around the BMW part numbers, I see the numbers as being the same as the following cars (assuming that the Toyota and BMW parts are the same)

"Fits 330i, 330iX, 430i, Z4" - the 3 series and 4 series are about 300 and 600 lbs heavier than the Z4/Supra.

Appreciate the share.
My friend who has access to databases did some digging and found similar results. Notably, we're not using the 340i (or equivalent) axles - which would give more headroom for torque.

Unless someone's clear on the rated loads of all the drivetrain components, I can only assume - aside from cost - the Supra comes with the weaker axles to prevent complete drivetrain failure.

 

[John8]

Appreciate the share.
My friend who has access to databases did some digging and found similar results. Notably, we're not using the 340i (or equivalent) axles - which would give more headroom for torque.

Unless someone's clear on the rated loads of all the drivetrain components, I can only assume - aside from cost - the Supra comes with the weaker axles to prevent complete drivetrain failure.

Well that is reassuring. lol Would have been nice if they beefed up the entire driveline. But then maybe the crank would go. :^)

 

[gcmak]

Well that is reassuring. lol Would have been nice if they beefed up the entire driveline. But then maybe the crank would go. :^)

haha, you already know how this goes - Compromise is the name of the game.

Wanted to provide an update to those interested. Toyota has not yet formally approved repairs, but the dealership ordered parts and will proceed with the repair this week. Replacement axle and suspension bolts (torque to yield), and the car needs to be calibrated (requires renting a machine). My next follow-up will likely be after I get my car back, look over the paper work (work completed, etc.), and a few days of driving.

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