A little help please from the experienced track pilots that are running with a recent model Z51. I run fairly hard at VIR in the DE/instructor groups on R rubber with pads and good fluid. I got out of my Carrera S2 but I did like the fact that it was worry-free. Never had a problem with brakes or heat in the Porsche - but I see from this forum that overheating and brakes are a problem which was my experience in my C5 Z06 and C6 Z06 (brakes terrified me).

So, I'd like to think that Chevy has fixed Corvette track behavior but its not sounding that way. Can I track an M7 Z51 on R compound rubber with good pads and fluid and let it ride - worry-free? Or am I going to have problems with brakes and/or overheating this summer?

 

Yes. the Z51 doesn't have the extra 200 Hp worth of heat, plus you don't have the auto, so cooling shouldn't be an issue. Good pads, (properly bedded) and fluid should be fine on the slowdown side.


You may want to change the wheel alignment settings to the track numbers.

 

I have a 16z51 and here are a few experiences I've had.

Xp12 pads and Motul fluid were not good enough.

Hawk dtc 70s and castrol srf gave me a lot more confidence in the brakes.

As far as tires. What rims are you running on. I had a major issue running r comps on a oem wheel.

 

Don't let anyone tell you that overheating is not a problem in the Z51. It is and it has been well documented by people running on various tracks or even just doing spirited driving over winding mountain roads. I can overheat my C7 in less then 10 minutes if driving involves predominantly low gear corners at near red line RPMs.

People who do not overheat on tracks tend to shift well below redline and tend to be in gears higher than ideal for cornering. Even with that they are running water temps near 250F and engine oil temps near 300F. Next week I will be installing the new GM secondary radiator that I hope will fix the the heat issues. I do not have 100 percent confidence in that solution either, I think the car truly needs an external oil cooler to bring those engine oil temps down to around 230-250F levels.

 

Disclaimer. I haven't ran in hotter temps than about 75*

I haven't had issues. But z06s weren't having issues at 65-72* either

 

I run in intermediate (prob could pass for advanced).

Only had my '15 z51 at MidOhio so far.

No problems with Nitto NT01s, carbotechs, torque brake fluid, wrapped rear exhaust.

~145-147mph at end of back straight.

Calipers on C7 are lots better then the oem C6 Gs/z06 setup in my opinion.

 

Thanks for the insights. I am an SRF fan also and glad to hear that one can be confident running with it. Really sorry to hear that heat continues to be a problem. Anyone tried running with 100% distilled water in warm months with water wetter?

 

Yes, it doesn't provide enough difference in cooling.

 

I would suggest replacing the rotors with AP J hooks in the front. $1300 well spent for track only rotors. I like the XP12/XP10 pads, and plan to try Torque fluid next time at COTA. I can boil Morul 600 if I go to 200 meters on back straight braking @ 150 mph. Lap times in the low 2:36's. That is with DBA 1 piece rotors. Coolant temps around 215 and oil at 260 with ambient at 80 degrees with stock Z51 cooling system and wrapped exhaust near trans.

 

I've tracked my Z51 7-speed in the summer heat & humidity at VIR and never had a problem overheating.

 

IMO @ that price point. Go with wilwoods. Better caliper rotor and pad for a couple hundred more

 

Newton - how many years have you been running at VIR? Lap times?

 

Ditto,

Track day at The Ridge Motorsports Park in Shelton, WA State. 2015 Z51. Ambient temp in the 70s. Consistently high RPM near redline, and got the alarm bell for High Oil Temp and oil temp was just at redline. Pulled off the track and it cooled down. Back on the track saw temp rising quickly again so drove home at normal speeds with no problem.

Dealer was initially very unhelpful after they saw no Event Record in the computer, but after insisting several times that they call GM, he came up with a bulletin about this issue applying to the Z06, but told me that GM told him that they now think the bulletin applies to the Stingray also.

Considering an external oil cooler, but not sure if that would really make a significant difference.

 

Well dang. What's a girl to do. Don't want a corvette so it just sits in the driveway. Maybe it's back to Porsche.

 

I should have mentioned that was the only day it happened out of 6 track days last summer. I'll continue to go out this year and see what happens. Hope that Phoenix tow hook I'm getting ready to install doesn't come in handy!

 

Overheating at high RPM use is why GM came out with their secondary coolant radiator for the SCCA T1 class C7s. I will be installing mine next week. That should help with the coolant temps mostly and, indirectly with the oil temps. If I had to pick only one, it would be the external oil cooler. From my own experience the fast rising oil temps are driving the coolant temps high.

Your dealer was unhelpful because up to this new radiator release, GM provided no solution, denying the overheating issues. The car does NOT overheat when driven on streets and highways at normal LOW RPMs. It will, however, overheat under high RPM, low gear public winding road driving, at temps over 80F.

If you read the ZO6 forum there are threads there regarding ongoing development of an external oil cooler, as well as pictures of installed secondary radiators. Between those two solutions, the heat issues will be fixed.

 

Chevy is offering Z06 parts for the Stingray including the Z51, supposedly to make it more track capable. (I could have sworn that's why I bought the Z51.) This includes a secondary radiator kit and a higher wattage fan. The press release says 25 deg lower coolant temp, and 15 deg lower oil temp. I don't see 15 deg lower oil temp as really solving much of my previous problem with oil temp hitting red line. (The coolant temp never became a problem.)

http://media.gm.com/media/us/en/chev...-stingray.html

However, if the Z06 is also having overheat problems (and contrary to popular opinion, I don't believe it's all a blower problem) then what's really the point of spending multiple $Gs on these upgrade parts + installation?

I agree with you, hopefully a good sized aftermarket oil cooler with a thermostat to prevent excessive cooling at street speeds will be an answer, but I'd have to see reports of others' track experience before I do this. It's all a bit frustrating as I'm a dedicated (very amateur) track day guy.

Maybe I need to pick up a 650cc track bike, as I bent my rims on my expensive Kawasaki on a track day last summer.

 

I have owned 2015 Z51 which I have tracked in advance level before switching to 2016 Z06. This is what the Z51 needs:
Brakes, yes they are bad. Warped the front rotors in 3 session. You need front AP Essex BBK and better rear pads.
Overheating, get Ron Davis radiator and you will be fine. Swap to Z06 grille to allow more air flow to the radiator.
M7 transmission, swap to Z06 transmission cooler and Z06 rear fender intake.
With the above, you will enjoy the car and not worry about overheating or brake issues.

 

I understand some overheating from constantly riding near the red line at the track but there should be no issues in mountain roads. I ran three 20 minute sessions in 100 degree temperature and my transmission temperatures is the only one that got close to heating. Another track day I ran three more 20 minute sessions at 85 degree temperatures, this time running harder but no issues. Mind you, on the 100 degree day almost every 400+ hp car on the track that day overheated except my z51 (only c7 vette there). Maybe my sessions were not long enough but I was definitely pushing it for at least 5-6 1.5 mile laps consecutively. 100% stock 2015 z51 manual

 

I don't know why you would state that, "there should be no issues on mountain roads".

Have you truly tried running in canyon roads, hot weather, near redline in 2nd and 3rd gears? I have, since I live in such environment. In 80F+ ambient I can reach 290F oil in less than 10 minutes. If I kept going I would, no doubt, be over 300F and in limp mode. As it seems, I don't think that there are too many people who experience such hard road driving in a C7.

During their initial testing of the C7, two (2) different editors from Edmunds both ran the Z51 into limp mode under exactly the same mountain road driving, mostly in the same 2nd and 3rd gears. That ridiculously ineffective oil/water heat exchanger is totally insufficient for the task. The oil temps go up so fast that I never had any issues with my A8 or the coolant temps as by the time they would reach very high values I long had to shut it down because of the high oil temperatures.

As long as one keeps the RPMs down, all is fine. But, having owned and raced many fast cars, street and dedicated racing cars, sorry to say that I never had one that overheated so quickly under the same driving routine. The been counters at GM obviously built these cars for the coffee & wax crowds and not for the truly enthusiast drivers. Too bad, because if they only spent a couple of hundred dollars more on extra cooling they would have a world beater. Now, it is going to cost at least $2000 with the after market to fix it. (plus, the potential loss of warranty)