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

[X25]

Originally Posted by Stephen12ZL1

this journal is a great read! I went through all 16 pages and enjoyed your progression through the many facets of tires, wheels, suspension bits, performance, oil/water temps, etc., etc. I too had issues fitting the Dewitts radiator in my ZL1 and had to modify the fan assembly plastic dowels to make it fit. The A/C condensor did not bolt up to the radiator and I ended up rigging a metal tie strap in a similar fashion as you rigged your fan assembly. It was good for a 10 degree drop at VIR. Water temps were in the low 240s with the stock radiator and around 230 with the Dewitts unit. Of course, the boosted ZL1 was mostly to blame and ultimately reducing the boost to around 10-11 psi proved to make the most difference in temps. Thanks for this member journal as it provides valuable information that will help many people in the future!

I'm glad you enjoyed reading it! This has also become a great place for reference for me, since I started forgetting what I've done : )

For an SS, radiator is not absolutely necessary, but that said, a 10 degree drop would help the engine keep its aggressive timing longer at the track. I wish I could log the temps with and without the radiator, so I could show the impact on an SS car.

[X25]

Originally Posted by White_SS/RS

ya mines a tight fit on my trailer as well. I'll be missing you at ORP by a week, I'm headed there next Monday to run it CCW. From what I hear it's supposed to have better flow in that direction. We'll see I guess.

I tried CCW as well; I usually end up doing the same lap times, but CCW seems to have more potential; let us know how it goes!

The club determines the direction the morning of the track day, so who knows, I might be doing CCW this time, too : )

[White_SS/RS]

Originally Posted by X25

I tried CCW as well; I usually end up doing the same lap times, but CCW seems to have more potential; let us know how it goes!

The club determines the direction the morning of the track day, so who knows, I might be doing CCW this time, too : )

Sounds good, I've been there only a couple times so was hoping to get another chance to whittle some time off my laps but changing it up is cool too.

[Stephen12ZL1]

did you ever review the Trofeo R vs the Michelin Pilot Sport Cup tires?

[X25]

Originally Posted by Stephen12ZL1

did you ever review the Trofeo R vs the Michelin Pilot Sport Cup tires?

As a matter of fact, I'll get to try the Cup 2 tires. I think I will get to try them on September 26th. The Trofeo Rs were finished in just 3 track days. More on that in next post (track update).

I don't expect miracles from Cup 2 tires. In fact, judging from what I've read, I expect overheating issues (like PSS), and reduced traction after the first few laps. In fact, due to this issue, Car and Driver had to try their best laps during their first 2 laps with the new C7 Z06 during their lightning lap trials, since after that, the tire's performance was dropping. It's not all bad, though. I expect that tire to have much longer life. Once I'm done with the Cup 2s, I will switch to my good-old NT01s

[X25]

Track update

Trailer:

• Wow, I know Camaro is heavier than my MX5, but I'd hope my 2014 7000K trailer would not visibly 'flex' for a load still under its rating. Anyhow, I put it on sale over the weekend, and it sold in only 2 days! Check out how the frame bends down. It has 4"x2" channels.
  
• I finalized the details of my custom new trailer. It will be a tilt-bed 7x18.6 ft with 5"x2" channels and 10"x30" approach plates, 4" drop axles, hinged fenders, and radial tires. I'm hoping I won't need my race ramps; we'll see!

Differential:

• The night before the track day, I went out and drove the car a bit. As I was entering the gas station sideways, I put one of the rear tires up in the air, and guess what? I HAD NO TRACTION! This would happen if I had an open diff or a helical unit, but not with a clutch type. Alas, I think my differential fluid or the differential itself is toast! This might also explain why I can't improve my times anymore.
• I have three options for diff upgrade:
  • Eaton TrueTrac 912A686: I can get this differential for about $510, so it's pretty cheap. The problem with it is that Eaton asks you to use non-synthetic diff fluid. Those kinds of fluids don't last at high temps, so it's a no go for me. I asked Eaton again, and asked if I can use Redline 75W90 NS which does not have any friction modifier whatsoever. The reply was that it would work with synthetics, but would not perform optimal. I am weary about this.
  • Z/28 diff: Part # 23172755 costs $1960, and is the whole pumpkin that comes with the Torsen-type Z/28 differential. In order for it to work, though, you'd need to get the diff cooler lines, etc. You can also get the internals of the differential itself for about $1000, but considering a few hours labor the shop asks to put it into the pumpkin plus 5.5 hours of R&R, not to mention worries for labor quality, I'd rather just get the pumpkin.
  • OSGiken diff: I think this might be the best unit available for our cars. It comprises of 20+ clutches, yet is claimed to never need rebuilds, and it can provide lockup in small steps up to 100%. It also keeps working even if you raise one of the tires, unlike the Torsen unit. In such a situation, Torsen unit would have complete power loss.
• Cooler: Z/28 diff cooler kit, at around $500, is very attractive choice. If I got the Z/28 pumpkin, though, the diff lid would already be included.

Trofeo R:

• I had three track days with the Trofeo Rs, and they are now done. It was the front left tire that quit before the others. More importantly, it was the sidewalls that quit, and I actually still have thread left.
• I think there are a few reasons for this: The tire needs lower pressure to work. The recommended 28 PSI is just too high for it to have optimal traction. 26 PSI that I've tried is better, but it actually makes the soft sidewall issue worse. It is also still too high for this tire, but I did not go below that.
• Judging from uneven wear, for those who track their cars with Trofeo Rs, I highly recommend that you hit -3 camber (especially at the front). I am not sure if using at 28 PSI vs. 26 PSI would make any difference.

It actually corded as well.

[X25]

I just ordered The Eaton TruTrac and Z/28 diff cooler kit. I just couldn't convince myself to pay 3x (including labor) just to get the OSGiken. We'll see how it works!

I really want to use this with Redline 75W90 NS. I asked Eaton support again. We'll see.

[STONE SS]

Originally Posted by X25

I just ordered The Eaton TruTrac and Z/28 diff cooler kit. I just couldn't convince myself to pay 3x (including labor) just to get the OSGiken. We'll see how it works!

I really want to use this with Redline 75W90 NS. I asked Eaton support again. We'll see.

Where did you find the TruTrac for that price?

[White_SS/RS]

Originally Posted by X25

I just ordered The Eaton TruTrac and Z/28 diff cooler kit. I just couldn't convince myself to pay 3x (including labor) just to get the OSGiken. We'll see how it works!

I really want to use this with Redline 75W90 NS. I asked Eaton support again. We'll see.

Since your going to run the cooler the temp may not be that high for a conventional oil. I've never had a trans temp above 200 so even with the additional thermal load I wouldn't think it would be over 220. 240 max which a conventional would endure with regular fluid changes. I'd say change twice as often, even then you'll probably come out about even in fluid cost.

[Synner]

I've had no issues with mine and the cooler. Fluid looks fine coming out and unit is working properly.

[CurtiSSWatson]

LOVE THIS CAR!

[X25]

Originally Posted by Synner

I've had no issues with mine and the cooler. Fluid looks fine coming out and unit is working properly.

So, which fluid are you using?

Originally Posted by CurtiSSWatson

LOVE THIS CAR!

Me, too : ))

[X25]

Originally Posted by STONE SS

Where did you find the TruTrac for that price?

http://www.summitracing.com/parts/dtl-912a686

$561 before $50 mail-in rebate, and free shipping.

[Synner]

Lucas conventional