Iker

https://www.corvetteforum.com/forums...t-r-nismo.html

JackTripper

Great News!

Steve Snake Driver

His answer, I think, explains the presence of the M7 Z06 alongside the A8 in the teaser photo from Pobst/Motor Trend on upcoming comparison test.

URBAN LEGEND

My thoughts:

The team responsible for media vehicles should be reprimanded and fired next time a car they prepped isn't ready for the media. Magazines tests is the time for these vehicles to show up ripped, dry and muscular. Not showing up misaligned, fat and out of shape, etc.

Last but not least please update this car yearly as Nissan does with the GT-R. Tweak and update yearly, not every 3 years. Learn, update, learn, update, improve, update, etc.

WA 2 FST

Well said.

lawdogg149

Not to defend.

We just rechecked my track alignment and my settings have moved from what we set them at last month. This response had me interested so i had my race shop check mine. Seems the cam bolts may not be holding. We used loctite this time around.

I have ran 3 track days so far.

WA 2 FST

Good info.

Here's the thing... if you had been asked to take/drive your car for a test of this nature, I guarantee that you would have taken the time to have checked it all, regardless of whether you assumed it was still in spec or not.

Redc8z06

GM has had a policy since at least the C5 where they will make changes to the Corvette throughout the production year not just wait until the next production year begins.

URBAN LEGEND

Ok. Cool. I accept that.
To team Vette <---Learn, update, fix. Easy!

lawdogg149

I would of never of checked it had it not been for his response. I usually have it checked while changing tires.

We wonder if the car settling has anything to do with it. I had the alignment done around 1000 miles on the car.

Anyone planning on tracking may need to keep a eye on this.

jvp

The accursed eccentric bolts continue to plague the Corvette to this day. I understand why they're used, and to some extent agree with it: alignment jobs are much easier with them. But they move, specially with uber-sticky tires and lots of G-forces. The shop manual lists a certain torque setting for those bolts. I don't recall what it is currently, but it's best to just ignore that. Make sure they're MFT. Use a big ratchet and a breaker bar to help apply even more torque to them.

3 Z06ZR1

It's called "cheating"

Snorman

With the bad press Dodge got by sending a bad Viper to a comparison, you'd think GM would be more diligent with this stuff.

Regarding Nissan using "octane booster", or race gas, or whatever...is anybody really surprised? This is a screen shot from their own video re: the Nismo running a 7:08 at the Nurburgring:

Last I checked, 100-octane is not "unleaded premium" in the US. And even if that's RON, it's 96-octane R+M/2, which is still not "unleaded premium" in the US. It's not unreasonable to suspect that they tweaked the fuel and timing curves to take advantage of much better fuel.
I would guess the recent tests using "octane booster", are a result of comments like this from MT's Carlos Lagos subsequent to early tests of the Nismo:

Car & Driver also commented in their July '14 test of the Nismo that it basically ran the same acceleration times as a Track model GT-R. Of note, in the C&D April '15 comparison between the Z06, Nismo and 911 TT the Z06 "Fuel Rating" is 91-octane while both the Nismo and 911 TT are 93-octane. These cars were tested in California. How did they get "93-octane" into the Nismo and 911 TT?
It was well known in the early years of the DBA GT-R's that they were octane-sensitive. The DBA's have a dynamic timing advance using feedback from a knock sensor that provides more timing with low noise conditions (i.e. higher octane, no knock). Early in the DBA cycle, tuners identified that DBA's were sensitive when running 91-octane or getting hot. Initially, the DBA's dynamic timing advance was causing issues by allowing too much timing advance. Nissan updated the DBA factory calibration to allow 3-degrees at WOT, from the original 7-degrees.

https://cobbtuning.zendesk.com/hc/en...ance-Explained

Obviously Nissan knows this, so they are likely not allowing cars to be tested with 91-octane.
I'm a big GT-R fan, it is a great car! But this isn't really kosher IMO. Cars should be tested apples-to-apples.
S.

lawdogg149

We marked the washers when we set the car up last month. Notice the lines are now moved.

This sucks and can get expensive if we have to keep resetting the alignment.

red2012

I don't know much about racing but your post makes perfectly good sense to me. My '13 GS had FIVE wheel alignments in it's first 10K miles. I don't drive the car hard and I don't hit potholes. The dealer did every one under warranty and sometimes it would go out of alignment within one week. I later bought it to a good indy shop who must have really tightened them because after 8 months all is still good. So I guess those bolts do have a tendency to come loose frequently.

URBAN LEGEND

Let me ask you this then. Whats the fix or solution for this situation?

jvp

The fix is a camber kit, but you're never going to see that OEM unfortunately. A camber plate in place of that eccentric will basically prevent the LCA from ever moving again. The issue with camber kits (the plates, specifically) is that they require the alignment tech to add or remove washers to the bolts of the UCAs, which will increase alignment complexity (the first time) dramatically. However, once aligned, it won't move.

Most of us that heavily track our cars have already added camber kits to them. I'm sure the usual suspects will have Stingray and Z06-based camber kits available soon, if they don't already.

jvp

Here's the idea, mounted on my ZR1 (but since removed and replaced with a far better one). The other side of that bolt has an identical plate that slides into the same slot on the subframe. It can't move.



The slots in the C7's subframe are a slightly different shape, it looks like (from lawdogg's pic). That means a C7-specific set of plates would need to be developed by the aftermarket.

blkbrd69

Would lay odds Vansteel is going to have kits out soon to lock it out like a C5 or C6.

Tik

Has anyone developed a camber kit for the C7Z yet? My eccentrics slipped as well and I can sense this is going to be a real pain this season...