[seanblurr]

Interesting day yesterday at Sonoma Raceway with the ZL1 1LE. I was fighting for rear grip the entire day, the car was handling very odd compared to my last event (Few weeks ago at Sonoma). I wasn't able to get grip on corner exit, especially the tighter corners. I swapped tires, changed pressures etc but could not figure out why the car was acting differently.

I generally drive the car in PTM:Race, it hardly ever intrudes on my driving, and as it is a street car, I like to have that buffer. One thing stood out yesterday though, the PTM was kicking in way more than it usually did, nearly every corner.

I decided to turn TC completely off the last session to see what the car was doing, as the PTM seemed to be masking an issue. On nearly every corner, as I got on power, I was getting wheel spin from the unweighted wheel. Enough wheel spin that the RPM's would jump a few hundred and my speeds wouldn't follow. It's as if I didn't even have an LSD.

To add to the confusion, my HUD stopped working that last session. I have no idea if they are related, but it makes me think it was some sort of electrical issue. No odd sounds, no warning lights, just an LSD not functioning as it should.


Side note: The car still won, and set a new lap record in class for the mini time attack series this organization does with a wonky diff

[seanblurr]

Quick update: I unplugged the battery for 5 minutes in an attempt to reset, the HUD now works again. Harder to test the eLSD, though.

[Markoz28]

I hate reading post like this. It makes me wanna stay from voiding my warranty and going more power. I think I’m going to wait on that until I can put down some serious miles.

[Try2paz]

how often are you flushing the eLSD? Is this on slicks or goodyears?

[FNxR3DNECK]

Originally Posted by seanblurr

Quick update: I unplugged the battery for 5 minutes in an attempt to reset, the HUD now works again. Harder to test the eLSD, though.

Yea Sean I think/hope this was just some weird electrical gremlin and disconnecting the battery solved it. Hopefully at least.

[seanblurr]

So if I am reading this data correctly, this may be proof of what I was talking about. This is a snap shot of the RR and LR individual wheel speeds at the exit of Turn 3A, which is an "over-crest" slightly off camber turn which really unweights the inside wheel, in this case the RR. RR wheel speed 98.1 vs LR 70.6. Compared to the front wheel speeds about 68.9.

If you look a tad bit to the left on the graph, you will see the car doing the same thing at the exit of Turn 2.

Is this not literal proof in data of the LSD not functioning?

[waterman]

Congrats on the win.

Following for resolution of diff issues.

[Ryephile]

Originally Posted by seanblurr

...Is this not literal proof in data of the LSD not functioning?

Looks like it, that's a big speed delta. Is there a line item for LSD lock request or similar?

[TRZ06]

Originally Posted by seanblurr

So if I am reading this data correctly, this may be proof of what I was talking about. This is a snap shot of the RR and LR individual wheel speeds at the exit of Turn 3A, which is an "over-crest" slightly off camber turn which really unweights the inside wheel, in this case the RR. RR wheel speed 98.1 vs LR 70.6. Compared to the front wheel speeds about 68.9.

If you look a tad bit to the left on the graph, you will see the car doing the same thing at the exit of Turn 2.

Is this not literal proof in data of the LSD not functioning?

Wouldn't you received a E-diff. error or some sort of light or warning if there was any sort of malfunction?

You would think there would be warnings of some sort

[seanblurr]

Originally Posted by Ryephile

Looks like it, that's a big speed delta. Is there a line item for LSD lock request or similar?

Doesn't appear to be through AIM.

Originally Posted by TRZ06

Wouldn't you received a E-diff. error or some sort of light or warning if there was any sort of malfunction?

You would think there would be warnings of some sort

You would certainly think so... but it was very obviously not working as it should.

[Can'tHave2MuchHP]

Very interesting. Following to see the resolve.

We all know how cooperative dealers and sometimes GM are with warrantying a car that's been tracked...Or only exhibits the error on track. Hopefully you have a good dealer/know the general manager/owner if you do want to see about getting it replaced...

[Krowser]

Originally Posted by Try2paz

how often are you flushing the eLSD? Is this on slicks or goodyears?

This is an excellent question for the eLSD. OP, are you changing the diff oil after EACH of your track days? I believe the owner's manual recommends this...

[Ryephile]

Originally Posted by Krowser

This is an excellent question for the eLSD. OP, are you changing the diff oil after EACH of your track days? I believe the owner's manual recommends this...

No, it doesn't. Owners Manual calls for 45,000 mile rear axle fluid intervals. The Performance Supplement explains the eLSD's different modes, but no mention of fluid change. The Track Prep Guide doesn't mention it at all.

[Ricco]

Originally Posted by seanblurr

So if I am reading this data correctly, this may be proof of what I was talking about. This is a snap shot of the RR and LR individual wheel speeds at the exit of Turn 3A, which is an "over-crest" slightly off camber turn which really unweights the inside wheel, in this case the RR. RR wheel speed 98.1 vs LR 70.6. Compared to the front wheel speeds about 68.9.

If you look a tad bit to the left on the graph, you will see the car doing the same thing at the exit of Turn 2.

Is this not literal proof in data of the LSD not functioning?

Is this from a Solo2 DL? I guess I didnt realise that data went into Race Studio too. I'm used to using a Mychron 5 with Race Studio, would be cool to get all that info from the car