Well I broke my driver side axle 3 weeks ago and replaced it with Level 2 DSS axles. I went back to the track and didnt even get one run I broke on the line! I have been unable to get a look at what broke(buisy with work ect ect.) I did get a chance to drain the rear diff oil and there was no metal shavings like I expected? It sounded like its the rear diff? It will still drive but makes a horrible grinding noise (sounds like from the rear) and the revs jump when I give it gas (similar to a worn out clutch). I sure the big boys that are putting down some power have went through this already. Any thoughts it may be a week before I can start tearing things apart to see for sure so I would like some ideas. Its really starting to keep me up at night thinking what it might be. Thanks in advance for any ideas or similar experences you guys are willing to share.

 

Actually after the axles...there's not much else that will become a problem with any normal boosted power levels. The rear diff is very strong. I have hear of a guy cracking the rear diff cover with wheel hop. but have not heard of any street cars grenading the rear diff. The trans in these cars is very solid aside from the occasional third gear failure due to the engagement gear for third being braised on to the main gear instead of beam welded. It sounds like it could actually be a clutch failure...that or a rear diff. Nothing normal though, the drivetrain on these cars is pretty stout.

 

Thanks for your ideas BriGuy. I thought at first it felt like the clutch but....I have a New Nismo Supper Copper Mix twin plate clutch with less than 1500miles on it. The grinding noise sounds like it comes from the rear of the car as well. Like I said before I will need to tear things apart to find out for sure but I was looking for a few ideas. I was wondering if it might be the VLSD?

 

What kind of power are you putting down? You sure it's not your launching technique?

 

Doesn't everybody drop the clutch at 10GRAND?!

 

No, I drop mine at 12Gand

 

I know the axles are very weak. After that I suspect the differential would be next. I know that the way the diff is mounted in the car is suspect. I plan on reinforcing ours before any trips to the track. Trying to get a 6 spd car into single digits in the 1/4 can be VERY hard on drivetrain parts. If they are going to break, we will break them!!

 

400whp 375ft/lbs on drag radials at the track. When I broke the axle I was launched from 3800-4000rpm. The last time (the time in question) i rolled off the line slowly (it was the first run of the night)and just started to get on the throttle when something let loose.

 

is probably one of the inboard CV joints, it happened to me even with Level 5 axles, here is a pic

 

Wow looks nasty but that is a good possibility it would explain the grinding in the rear and lack of metal in the diff fluid. I will check those prior to cracking open the rear diff. Thanks

 

^^ That's the reason some people recommend sticking with cheap stock axles and replacing those rather than causing the CV joint to fail. I don't believe there is any high performance upgrade for those...

 

you sure you feathering the clutch enough?

 

Our axles are NOT weak.

Our driveshafts and diff's are very stout. Id work on launch technique and play with tire pressures, you shouldnt have issue sat those power levels with those axles. Preload the drivetrain.

 

I remember you saying that before. How do you do that?

 

You do that by holding the clutch at the line right past its engagement point.

Let the clutch out until the car starts to creep-now push the clutch in 1/2". When you let it out the drivetrain wont be "shocked" by the power, that many axles and driveshafts (not in our cars) fail to at the track.

Note-dont preload it too long or too much or you will burn the clutch off the line.

 

+1 I saw Intense's diff after they were going for low 10's in the G.... The Diff cover snapped right off the diff mount to the rear cross-member. I hear there are some things in the works to help prevent this in the future.

 

Yeap, mine also broke the bolt that holds it to the cross-member. If you do a search u could also find a couple that cracked the rear cross-member.
As far as weak links; axles, cv-joint, dif rear bolt, dif cover, and cross-member.
to prevent, drag wheel aligment, preload, and a clutch that will allow some slippage? who knows.

 

our axles are not weak at all. we have some of the fastest quarter mile times on the board on stock axles. we also have two formula d cars with stock axles that have had no issues.


breaking the axles has a lot to do with the driver. preloading the clutch is very important and needs to be done properly. good luck!!

 

I agree...I've beat my car up pretty good the last 3 years with FI...but one thing I DON'T do is shock the drivetrain. I've yet to break any drivetrain part since the turbos went it. On top of that I've been on either DRs or slicks the entire 3 years.

 

Thats what it was! Thanks for the help. My car has over 65,000miles on it things are starting to show wear. Thanks to those that had helpful suggestions.