'14 AGM 1SS/1LE Track build [COTW 11/17/14]

[Dropspeed]

As an FYI...I tried and 18 x 11 APEX wheel on my car. As I suspected it hits the upper part of the front knuckle just above the alignment bolt hole) and maybe even the lips of the strut once that gets cleared up. With some grinding it should work....just not sure I want to do it yet.

[X25]

Originally Posted by Dropspeed

As an FYI...I tried and 18 x 11 APEX wheel on my car. As I suspected it hits the upper part of the front knuckle just above the alignment bolt hole) and maybe even the lips of the strut once that gets cleared up. With some grinding it should work....just not sure I want to do it yet.

I presume the idea is being able to use lighter, cheaper tires? I've heard of some being able to do it, so I'm sure it's possible. You might need coilovers for the clearance, though. Those who had it had full suspension upgrade. We installed a set of BC-ERs with race valving. He might have a better luck with it.

I know the piece of that knuckle that is trimmed, and it should be safe. When I tried to install my StopTech BBK kit on my 2013 Z06, I was horrified to see that the instructions call for trimming the bottom part of the knuckle right where you have a huge bushing. I couldn't believe that they would ask that weakest part of the knuckle trimmed in instructions as if it's such a trivial thing to do. I did, and it never failed, but I had to add that to my list of things to inspect.

[X25]

Originally Posted by Nathan Moreno

We have a carbon version in stock ready to ship if you like

I actually looking into it, but it was quite a bit more pricey, so I ended up ordering the OEM part. It took 3 weeks to get the part, though, so if I knew, I guess would get your part anyway : )

[X25]

The aero is finally finished! I have track days coming up on Monday and Friday; will definitely go to at least one of them with the 1LE : ))

As expected from OEM parts, everything seems to fit together well:


The belly pan and the extension of front splitter provides a smooth bottom:


Here it is with the street wheels/tires"


It now looks pretty mean from the back:


Here with the Z/28 wheels and Michelin Pilot Sport Cup 2 tires:

[X25]

The car is ready for track:

• Changed the oil with Mobil1 5W-30EP for lower temps (from 0W-40). I did not change the filter, though, since it was changed recently.
• Bled the brakes, and put back race pads. Since they still have so much life left, I put back the ST43s up front, and Cobalt XR2s at the rear. Once they're done, I will switch to ST47/45 combo, though I might switch ST45 back to XR2 if they are noisy. For your information, 95% of the noise comes from the rears in this car per my experience, so using a quiet pad at the rear does wonders for street driveability.
• The car now has Z/28 wheels and MPSC 2 tires on.

The night was not without an incident, though. I took my TPMS learning tool with me for the test drive, so I thought I could easily configure it with the Z/28 wheels' TPMS were far away from the street wheels. This turned out to be a huge mistake. I was hearing a weird noise up front, and the suspension was also very rough on the rough surfaces. I drove about 3.2 miles to a parking lot to take pictures and setup TPMS. When I configured the car TPMS, the car was showing 6 PSI on the left front tire, and 9PSI on the right!

The rears were still at their original pressure at 32 PSI. Obviously, all the noise was coming from the tires. During my trip to the parking lot, I drove through roads between 25-40 MPH speed limits. Do you guys think that I might have damaged the tires during that 3.2 miles? Once I put the air in, I continued my test drive, and slowly increased my speed up to 60-70 MPH range, and everything felt fine. I am hoping the stiff sidewalls of the R-compound tire will survive this torture : ( I am still a bit weary, and will drive to around during the weekend, and also to the track venue to gain confidence on the tire.

The tires were mounted a few months ago at 32 PSI, and I did not touch them since until today :(

[Synner]

The only true way to tell is to dismount them and look inside unfortunately. This happened to me after a flat tire, I ended up driving a few miles on it until I could safely stop. Outside looked fine but the inside wall was shredding itself and when I dismounted the tire a ton of rubber fell out from where it was delaminating.

[X25]

Originally Posted by Synner

The only true way to tell is to dismount them and look inside unfortunately. This happened to me after a flat tire, I ended up driving a few miles on it until I could safely stop. Outside looked fine but the inside wall was shredding itself and when I dismounted the tire a ton of rubber fell out from where it was delaminating.

So do you recommend getting it checked out at Discount Tire? I suppose $50-100 is cheap insurance considering what is at stake.

[Synner]

If they're your track tires absolutely. The lateral loads they'll see I wouldn't want a sidewall failure in a turn.

[Burt]

Originally Posted by X25

So do you recommend getting it checked out at Discount Tire? I suppose $50-100 is cheap insurance considering what is at stake.

I doubt it'll even be that much, when I had my quality local shop dismount a tire, and mount/balance a new one, it was around $8 or $12, I believe.

[X25]

What a day!

I stopped by my local Discount Tire shop. They unmounted the front tires: the right front tires (which had 9 PSI) was fine, but the left tire (which had 6 PSI) was damaged!


I quickly went back home and grabbed one of the set of Trofeo Rs, and got them mounted. I will buy a replacement 305/30/19 MPSC 2 later on to make it my backup set for the next time.

Well, they installed my rear wheels up front, and once we moved the car, I immediately knew something was wrong, but it was too late:


The wheel's clear coat is damaged, and there is a bit of surface rash as well, but it doesn't look too bad. I will drive it with this scratch for a while, and get it fixed at Discount Tire's expense when I have some time.

The car now looks very sinister, and it draws so much attention, including my own. I can't stop staring

[Synner]

Aint ya glad you looked. Sucks to see but better now than on track.

[AG1LE]

Looks great! Now that the extensions are installed, do you plan to ever use the OEM 20" wheels?

[X25]

Originally Posted by Synner

Aint ya glad you looked. Sucks to see but better now than on track.

Absolutely; thank you very much for the good advice! At least I will be a lot more confident with the car now that any possible tire damage is ruled out.

Having Trofeo Rs will also make the tire pressure settings very easy. These tires are optimal at around 29-30 PSI hot per Pirelli, but GM states they should never have less than 26 PSI cold due to the weight of the car, so since I can't do the really optimal settings, I'll do 26 PSI cold all around and hope that the car is indeed neutral enough (will watch temps to check on that).

I really missed the car while I waited for the parts and aero install, but after spending so much time in the Miata, I was also shocked to see how high I sit in this car. We'll see how Recaros + Schroth Rallye 3 + HANS will work out.

[STONE SS]

That really sucks about the wheels, but glad you found out the tire issue before hitting the track. Sure wish you we making it to fest next month so I could check this thing out.