KRPTONT

I am with you ALI!!!
Shannon

OldJedi

I have to admit that I am disappointed after running my Z51 A8 at Palm Beach International Raceway. It was an afternoon HPDE from 6:00 to 10:00PM and my second time at the track and my first night event. The temps were in the upper 80's and 65% humidity. The tranny temps rose pretty quickly and my case they stayed just below redline and the car did not go into limp mode. Another A8 that was on the track with me went went off the track in limp mode when it overheated in the first 30 minute session and did not return.

It would have been a lot better if I was not constantly looking at the transmission temp gauge the whole time. I did not manually shift the car but kept it in drive and let it shift itself while in Sport mode. The other A8 was manually shifting in Track Mode before it overheated which is why I decided to stay in Sport and let it shift itself. I had three gauges on, oil temp, oil pressure on the pocket gauges and transmission temp in the center.

The transmission temp stayed around 270 most of the time. The Z51 A8 is supposed to be "Track Ready" but I do not believe that it is. I drove the Z51 manuals at Spring Mountain without a problem at all and they drive these cars everyday in very hot conditions without overheating. They were just receiving their A8 Z51's while we were there.

My ZL1 manual is truly "Track Ready" having tracked it many times without any overheating or any other problems for that matter. The car is virtually bullet proof the way it was put together. The Z51 A8 is not "Track Ready" in my opinion, certainly not compared to the ZL1. It is a great car for everything that you want to do except take it to a track.

It will be interesting to see what changes were done to the 2016 Z51 A8's and if they actually work on the track. My concern is that Chevy knew that that A8's were really not "Track Ready" but did not tell us or change the cooling system to make them truly ready to take to the track.

SEE7 Z51

Thanks for the info. I think I will try putting it drive / sport mode to see if I can go longer without it going into limp mode next week. However, I think that most folks were defining limp mode as when the car denies the manual shift (up or down) and shifts for you, softly and in strange places like mid corner. Maybe this is happening to you? Mine seems to do it between 265 and 270'F.

OldJedi

That is why it was so frustrating in not being able to just drive the track because every small straight I was checking the temp. I kept expecting the car to slow down into limp mode after every hard straight. Just not as much fun as I hoped it would be and not the track car that the ZL1 is. Because the transmission stayed so close to redline I changed the tranny fluid along with the engine oil and differential fluid. The A8 takes a special transmission fluid at $37.00 per quart and the dealer charged $260.00 for the 7 quarts alone. It would get expensive if you had to change the transmission fluid after each track session.

Dale760

IMO they had to know this problem existed and released the car anyway thinking how many guys will be tracking them. We got the shaft and I hope they come up with a cost effective solution for brand new 2015 Z51 owners, so we can track the car as intended

We will see, but it may take awhile

Thanks for your report

Dale

5thGear

Watch out for your brake pads especially the rear when you drive in sport mode. Stability control will kick in often and will eatup the pads quickly on the track. It's highly recommend to check pad thickness especially the inner (take the wheel off to check). I have tried sport mode before and that didnt help transmission overheating. I am now running an aftermarket transmission cooler. I have listed some details on my other thread in general discussion.

sromley

Just curious what Ron Fellows is doing at Spring Mountain. Must be running those cars pretty hard most of the time. Are there any articles on overheating, and what they did about it?

GM's solution may not be the best or least expensive.

C7Z51

Over the past couple of weeks I have test drove the Porsche 911 GTS, Carrera 911 4S, the Nissan GTR and the Audi R8.

The GTR is an awesome performance vehicle but the interior is dated and a brake job costs $4k, making it a costly track car.

The 911 GTS didn't give me the excitement I thought it would. Although both exterior and interior quality are very nice, the chrono package that comes standard on the GTS requires you to hit the "lap" button every time you pass the finish line to record your times.

The Audi R8 is beautiful in all aspects interior and exterior but I don't think I would track the car if I bought it. (still a possibility though)

All in all, well done Chevrolet. I don't agree with the actions of the makers of the car and how they don't stand behind their product. Even though I want to sell the car based on principle, I can't find a suitable replacement. I think I appreciate the car more now then I ever did before. I have explored all my other options extensively and nothing else even comes close to the amount of excitement I feel every time I drive the C7 and all the features that are included. The PDR, the ventilated seats, the roar when you slam on the gas. I'm still upset that GM isn't even going to at least cover the labor for the fix and I will continue fighting for it. C7 is truly an amazing car and I want to give everyone that worked on the car kudos(other than the transmission cooling guy)

Dale760

Id like to test drive a new Shelby GT 350 someday, but being a first model year it may have some problems also

descartesfool

I have been in contact with operations manager of the Ron Fellows school a few times, starting June 2014 to see if they were having same overheating issues I was having with my Z51 MRC M7. He was kind enough to reply. When students drive the cars, they don't drive fast (they only think they drive fast) and thus no overheating. When instructors drive the cars at full tilt, they overheat. AFM actuators fail like on mine, manual transmission overheats like on mine, rear OEM pads wear out in one day, etc. They had no solution except to avoid using 2nd gear and to do more cool-down laps. Ron Fellows himself apparently said to someone who posted about it on the site that they were working on cooling solutions. My inquiries to them were all about manual trannies.

5thGear

It's obvious all the C7 Z51/Z06 needs better cooling for powertrain (engine, transmission, rear differential) and also needs some improvements for components such as AFM actuators. Other than that, the car is really awesome.

C7Z51

I finally bit the bullet and traded my car for this yesterday.

Dale760

Very Trick Congrats >> bye bye GM / Chevy

Hope it works out well for you, and it wont be the last unless GM steps up to take care of the customer when a problem arise

Dale

5thGear

Congrats to you. Too bad for GM. Few others will eventually do the same if GM doesnt take action so the car can do 20 to 30 minutes sessions on the track. I will be keeping my C7 for now since I just spent $8,000 on cooling and front AP big brake kit. If any issues come up again within the next few track days then I will be looking at other options.

harvey1228

What does a standard 2015 Z51 have for a differential/transmission cooler? I thought that a Z51 was supposed to be a track ready model and shouldn't require cooling modifications.

5thGear

That's what we thought too but the C7 cooling in general is under engineered (I guess this was the case for C5 and C6 as well). Don't get caught up with GM sales talk.
The Z51 is definitely not track ready out of the showroom. The engine, transmission, rear differential, chassis,....etc are all great. Overheating is a problem for anyone that would drive on the track at an intermediate pace plus. If you are willing to spend few thousands to upgrade cooling (at the risk of voiding warranty) and also upgrade the brakes then it should be a decent track car.

descartesfool

Like he said, while Z51 option on a C7 is supposed to be the track option, with dry sump oil tank and pump for better oiling under high G's, and with differential and transmission cooler for track driving, it is not up to the task. My manual transmission pins the temperature gauge every single session and takes forever to cool back down, and as for engine cooling, the Z51 and even Z06 all use the same radiator. I either get an " Engine overheat - Idle Engine" warning on track even in sub 86 degree outdoor temps, or the engine temperature gauges gets very close to the red zone, climbing all the time.


Tadge Juchter said they design the car such that a pro driver can run the car indefinitely on track in temperatures up to 86 degrees ambient. That is just not true. I am not a pro driver, and in sub 86 degrees my car overheats on track. And did I mention my AFM actuators have failed 5 times so far. Yes it's true, 5 days on track, and 5 AFM actuator failures. Just too much heat from the exhaust pipes onto those plastic cased electronic modules.

SublimeZ06

A couple of months ago, I was literally ready to cash purchase a C7 Z51 or Z06. However, the more I read about the multitude of problems with the C7 the more I believe that Tadge is full of $hit. Seems like they sacrificed the soul of the Corvette just to be able to sell more cars to the sheep.

harvey1228

I understand that the C6 Grand Sports Automatics had tranny coolers. Why not C7 Z51's and Z06's. This a design flaw unless Chevy notified buyers that Z51 and Z06 automatics should not be run on tracks without modification.
I say disappointed again because the '15 infotainment system very poorly accesses USB music files. At Laguna Seca Tadge told me my alternative was to get a new corvette!
Additionally, my automatic '11 Grand Sport didn't have the dry sump I thought it would have. I know this was stated in the small print but it was not made clear by the dealer.
Because of the failure to notify, if Chevy doesn't step up and pay for a fix my inclination is to run the car on the track, kill the tranny and give it to Chevy enough times to qualify under the lemon law and switch brands.

JerriVette

All I can say is that at the various cars and coffee events c7 z06 and z51 owners are talking up a storm about NOT being able to use the car on the track because of the lack of cooling issues.

I don't have a dog in this discussion but it would be smart of gm to come out with a gm performance parts solution sooner rather than later.

Being a c6 owner it saddens me to see the reputation of corvette get so damaged by the continuous discussions on how the z51 and z06 can NOT be driven on the track without overheating warnings from the transmission. These c7 z51 owners and z06 owners tracking their cars are working within the design parameters, following all of gm s protocols for track prep....etc and are still having massive cooling issues.

A lot of guys don't want to go aftermarket because it voids their warranties.

I'm a huge corvette enthusiast but this is embarrassing.