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ZO6 overheating issues ***MEGA Merge***

 
Old 05-07-2015, 01:05 PM
  #2081  
GP1224
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Originally Posted by kverges View Post
Yup - I bet there are fewer than 20 Z06 owners who can drive truly fast, as in within say 2 sec a lap of Milner or Pobst. They probably lament the lack of cooling. But I think I read that over 8000 Z's were sold for the 2015 model year. That is more than the entire production of Ferrari. Seems like the right call by GM to just sort of fade all the track-worthiness questions.
You dont have to be close to Pobst to have heat issues. The Z was sold as the most track ready Vette ever. This is a new world in the car world and anyone will tell you that far far far more owners of all makes are now hitting track days being so many cars these days are so quick and have the track day potential. 1990s is long gone when very few cars could be track ready off the show room floor. Moral of the story is far more Vette owners are hitting track days than ever before so the issues will come out 10 fold now, so GM should wake up.
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Old 05-07-2015, 01:17 PM
  #2082  
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And I had the audicity or delusion that this thread might get one response from the "genius" with the solution. But this topic appears to be red meat for the masses - eat hardily comrades. Best
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Old 05-07-2015, 01:31 PM
  #2083  
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Originally Posted by kverges View Post
My personal opinion is that it is asking too much for a stock, 3500+ lb, 650 hp, air conditioned car to run at race pace for 20+ minutes in 80+ deg ambient and not overheat. I don't know of a single stock car that can do that. Just the airflow restriction from an A/C condenser is a street compromise that significantly reduces cooling capacity.

.
Not at all ..My bonestock Gen V viper at 3300+ lb with 640 hp, air conditioned etc never gets close to getting hot on the track . It just keeps going lap after lap. Session after session in hot weather temps. Same goes with my bonestock 2010 Viper ACR. At Laguna Seca I am at 2nd and 3rd gear most of the time too. Also ran Buttonwillow track in the heat , no issues.. With that being said. It's an engineering flaw by GM causing these new Z06 overheating on the road course..
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Old 05-07-2015, 02:45 PM
  #2084  
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Originally Posted by kverges View Post
My personal opinion is that it is asking too much for a stock, 3500+ lb, 650 hp, air conditioned car to run at race pace for 20+ minutes in 80+ deg ambient and not overheat. I don't know of a single stock car that can do that. Just the airflow restriction from an A/C condenser is a street compromise that significantly reduces cooling capacity.

At a race pace, you will likely see wide open throttle close to 80% of the time on track. And average speeds are probably in the 80 mph range for most tracks. (e.g. I've run 2:25 at CoTA in a street car, so average 84 mph, despite over 160 mph on the longest straight).

Surely someone can do the thermodynamic calculations to see how much surface area and airflow for heat exchangers is required to dissipate the heat from running 650 hp?

For a purely anecdotal comparison, my Radical SR8 track car has a pair of sidepod mounted radiators that are comparable in size to a normal automotive radiator, that are ducted to enjoy what looks like a lot of air flow and no restrictions like an A/C condenser or even a radiator fan and it makes only about 400 hp. It never overheats, running coolant temps consistently under 100 deg C and oil temps under 125 deg C.

I'd bet that it will take pretty radical surgery to get a Z06 to run cool at race pace, as in lots of mods to improve airflow and much different and more numerous heat exchangers.

The solution is non-trivial.

For example, LG appears to be silent right now. I know Lou and he can drive with real pace and I suspect they are having to do a lot of work to try to make a new Z run cool with him driving it to his potential.

This car was not built for a guy who can run serious pace to track for long periods of time - I felt pretty sure of that when I saw the stats of power, supercharging and weight. It is an awesome GT car, very appealing to the drag racers, and great looking. But a track car it is not.
The issue is though, that some people aren't running a "race pace" and are overheating quickly. Some others feel that simply spirited driving in 90 degree temps is going to be an issue.

Originally Posted by jvp View Post
I wouldn't be so quick to write GM off regarding this topic. While I have no details or specifics yet, I do know they're looking into it. Whether they're able to come up with an explanation or solution or not is another thing entirely. And it may be best to hand this off to the aftermarket (see: DeWitt).
Yet again (I say yet again, referring to the GTR/alignment test debacle), how is GM behind the ball though? They tested this car, what you would think would be extensively so. I have absolutely NO doubt they saw this coming, but understood that damage control was better than a higher msrp. They also calculated that the small cries from the minority would be outshined by the love and affection of the non-track driving masses who buy the car. To me this was a strategic decision that shows the mindset of where the heads of this program are taking this car. Sales are important for any program, but long term Corvette ideology is imperative to survival. The car represents the best, and compromises have been made for a reason. What those reasons are...who knows...maybe you do.

The ISSUE is, yet again Corvette has targeted other markets..it's been stated that was the goal. They've made it clear they want Porsche buyers and they also invested quite obviously in racing and in Nurburgring presence. All this adds up to a track machine, and an increase in buyers who want to track the car...as you see with Porsche owners. I don't care if 90% don't use it there, for the 10% that do, it should show up.

I'm not Tadge...and I've defending the company, the crew, the leaders endlessly, but...these are calculated moves or they are incompetency. The Z06 acts as the HALO car...this simply can't happen. I feel like we are experiencing similar fumbles from the Corvette/GM people that we saw with SRT. The alignment fumbles, the lack of performance, the dealer ball drops, etc...and look at the impact it had on Gen V sales...the Plymouth Prowler was more successful than this Viper, and that problem starts with Gilles.

Last edited by RC000E; 05-07-2015 at 02:54 PM.
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Old 05-07-2015, 02:48 PM
  #2085  
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Originally Posted by LEE427 View Post
Not at all ..My bonestock Gen V viper at 3300+ lb with 640 hp, air conditioned etc never gets close to getting hot on the track . It just keeps going lap after lap. Session after session in hot weather temps. Same goes with my bonestock 2010 Viper ACR. At Laguna Seca I am at 2nd and 3rd gear most of the time too. Also ran Buttonwillow track in the heat , no issues.. With that being said. It's an engineering flaw by GM causing these new Z06 overheating on the road course..
Lap times? Consistently 1:36 or better in that ACR and Gen V? And the couple of hundred fewer pounds the ACR has to haul around is not insignificant nor is the 50 fewer hp. I raced the ACR-X in 2010 and in our experience cooling was marginal and it had no A/C condenser to contend with and quite a bit of extra cooling and air management. I bet I could overheat either of your Vipers on a hot day on track. Maybe not as bad as the Z06, but unless you tell me you can whip off say 12 laps in a row at Laguna Seca under 1:37 on a day with 85 deg + ambient will I believe those cars are immune from overheating in stock configuration. Perhaps you can and I stand corrected.

The anecdotal stories about how well any car does on track are worthless without lap times. For example the TWS story had a best lap time less than 1.5 sec faster than Spec Miata TWS track record. Not exactly wringing max performance out of the Z06 in my mind.

I do agree that GM did not engineer these cars to go fast on track for extended sessions. I also think they had to know that well before production began. Most of the target market simply does not care that much, IMO. We track rats are on the lunatic fringe

Last edited by kverges; 05-07-2015 at 03:05 PM.
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Old 05-07-2015, 02:55 PM
  #2086  
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Originally Posted by kverges View Post
Lap times? Consistently 1:36 or better in that ACR and Gen V? And the couple of hundred fewer pounds the ACR has to haul around is not insignificant nor is the 50 fewer hp.
The anecdotal stories about how well the car does on track or worthless without lap times
Lead and follow with a gen 5 Viper, slow pace:
Z06 oil 264*
Viper oil 200*

That's a difference of 64* doing exactly the same drive at the same exact speed.
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Old 05-07-2015, 02:56 PM
  #2087  
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Originally Posted by LEE427 View Post
Not at all ..My bonestock Gen V viper at 3300+ lb with 640 hp, air conditioned etc never gets close to getting hot on the track . It just keeps going lap after lap. Session after session in hot weather temps. Same goes with my bonestock 2010 Viper ACR. At Laguna Seca I am at 2nd and 3rd gear most of the time too. Also ran Buttonwillow track in the heat , no issues.. With that being said. It's an engineering flaw by GM causing these new Z06 overheating on the road course..
In fairness, I've spoken to more than one GenV owner that have experienced heat issues that were seemingly not as severe as Z06, but regardless still an issue.
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Old 05-07-2015, 03:15 PM
  #2088  
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Originally Posted by RC000E View Post
In fairness, I've spoken to more than one GenV owner that have experienced heat issues that were seemingly not as severe as Z06, but regardless still an issue.
Why does the Hellcat have no overheating issues with all that power?
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Old 05-07-2015, 03:22 PM
  #2089  
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Originally Posted by charliek View Post
Why does the Hellcat have no overheating issues with all that power?
Do hot laps with real pace and I will wager the Hellcat will overheat. It's not a track car, though.
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Old 05-07-2015, 03:27 PM
  #2090  
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Originally Posted by RC000E View Post
In fairness, I've spoken to more than one GenV owner that have experienced heat issues that were seemingly not as severe as Z06, but regardless still an issue.
As have I. It's just very, very hard to run race pace in a high power stock car and not have overheating. I held off on the new Z as soon as I saw 650 hp and 3500+ lbs. First, the power and weight told me consumable costs for brakes and tires would be very high, and second I was immediately worried about cooling, having myself overheated Vipers, Gallardos, C6 Z06, and (marginally) MP4-12C on track.
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Old 05-07-2015, 03:32 PM
  #2091  
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Originally Posted by charliek View Post
Why does the Hellcat have no overheating issues with all that power?
Not used in the same way.
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Old 05-07-2015, 05:09 PM
  #2092  
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Originally Posted by kverges View Post
My personal opinion is that it is asking too much for a stock, 3500+ lb, 650 hp, air conditioned car to run at race pace for 20+ minutes in 80+ deg ambient and not overheat...

This car was not built for a guy who can run serious pace to track for long periods of time...But a track car it is not.
Respectfully disagree. Check the Ask Tadge forum and you'll find the following which came from TJ in response to a question on track overheating.
"The Z06 Manual is designed to keep engine oil, coolant, transmission and differential fluids below the hot warning targets when driven by a professional on a 30C day (86F) on a "typical" racetrack for an indefinite period of time (effectively the time to burn through a full tank of fuel)."
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Old 05-07-2015, 05:39 PM
  #2093  
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Originally Posted by TKOGTO View Post
Respectfully disagree. Check the Ask Tadge forum and you'll find the following which came from TJ in response to a question on track overheating.
"The Z06 Manual is designed to keep engine oil, coolant, transmission and differential fluids below the hot warning targets when driven by a professional on a 30C day (86F) on a "typical" racetrack for an indefinite period of time (effectively the time to burn through a full tank of fuel)."
I disagree as well. This car offers a Z07 package that features tires that brag that you can drive them from the street to the track, has massive downforce which offers little outside of track conditions, and stiffens the suspension such that the track is where it's most at home. When I "built" the car on the website, it produced high resolution pics of my build on the track. Are you seriously going to try and say that the car was built for the track, but only if you drive it slowly?
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Old 05-07-2015, 05:42 PM
  #2094  
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A thread with one question and takes off like a rocket. I may sit down and right a paragraph and be entertained for weeks. Best

Originally Posted by rob725 View Post
I disagree as well. This car offers a Z07 package that features tires that brag that you can drive them from the street to the track, has massive downforce which offers little outside of track conditions, and stiffens the suspension such that the track is where it's most at home. When I "built" the car on the website, it produced high resolution pics of my build on the track. Are you seriously going to try and say that the car was built for the track, but only if you drive it slowly?
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Old 05-07-2015, 05:44 PM
  #2095  
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Originally Posted by TKOGTO View Post
Respectfully disagree. Check the Ask Tadge forum and you'll find the following which came from TJ in response to a question on track overheating.
"The Z06 Manual is designed to keep engine oil, coolant, transmission and differential fluids below the hot warning targets when driven by a professional on a 30C day (86F) on a "typical" racetrack for an indefinite period of time (effectively the time to burn through a full tank of fuel)."
While not the full quote, this is the bulleted list of his response:
Originally Posted by Tadge
•The Z06 Manual is designed to keep engine oil, coolant, transmission and differential fluids below the hot warning targets when driven by a professional on a 30C day (86F) on a "typical" racetrack for an indefinite period of time (effectively the time to burn through a full tank of fuel). Our team validates the durability of the Z06 cooling systems with a 24hr accumulated track test to simulate the most aggressive track-day usage by our customers.
•We designate our track: the Milford Road Course, as the "typical" standard, but recognize that there are tracks around the world which are easier on a cooling system and some which are harder on a cooling system. Generally speaking, tighter tracks with lower average speed and higher sustained RPM, will drive higher fluid system temperatures.
•Higher temperature ambient conditions affects all car's abilities to run sustained laps at ten-tenths.
•The Z06 Automatic transmission put in "Drive" selects the lowest possible gear ratio for best acceleration, and because it has 8 closely-spaced ratios typically runs higher average RPM than the manual. This optimizes lap time performance, but also taxes the engine oil and coolant more for any given track. So the automatic has the capability to run faster laps than the manual, but thermal limitations are reached more quickly. Customers who are planning to run extended track-day sessions at 'professional' speeds, are advised to go with the manual transmission, or to paddle shift the automatic and select higher gears when conditions warrant it.
•Any time the maximum recommended temperatures are reached in any condition, the DIC will give warnings at the appropriate time for coolant, oil, or transmission fluid. A cool-down lap or two will bring operating temperatures back to a reasonable level and aggressive track driving can be resumed.
Nowhere in that, or in the full response, did I see the statement "by a professional to x% of his or her" or "x% of the car's capability". Taken on its face, this statement can be interpreted differently than insinuated. The statement "to simulate the most aggressive track-day usage by our customers" is non-specific, and may not reflect anywhere near the capabilities of the car or their "professional". Finally, a "professional" what? Driver? Engineer?

I really like the car. They've done a helluva' job with the C7 and the Z06. But the relatively marginal cooling needs to be addressed. If it's a simple fix GM needs to implement it and provide it to existing owners. I don't think the sky is falling, and I don't think that everybody tracking the car is going to have these issues. But if they want to be mentioned in the same breath as "GT3" or "Porsche" it must be done.
S.
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Old 05-07-2015, 05:47 PM
  #2096  
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Originally Posted by BobSWFL View Post
OK, got it. Thanks. (Also, thank you ncrowe for the clarification.)

The A8 has a supplementary trans fluid cooler mounted in the bottom of the radiator inlet area. I wonder if an M7 could add that cooler and use it for engine oil?
Since I have a M7 I was wondering if I could lay my intercooler down like this? This would open up airflow to the radiator, Than a DeWitts might work. Thoughts?
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Old 05-07-2015, 05:51 PM
  #2097  
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Originally Posted by Snorman View Post
While not the full quote, this is the bulleted list of his response:

Nowhere in that, or in the full response, did I see the statement "by a professional to x% of his or her" or "x% of the car's capability". Taken on its face, this statement can be interpreted differently than insinuated. The statement "to simulate the most aggressive track-day usage by our customers" is non-specific, and may not reflect anywhere near the capabilities of the car or their "professional". Finally, a "professional" what? Driver? Engineer?

I really like the car. They've done a helluva' job with the C7 and the Z06. But the relatively marginal cooling needs to be addressed. If it's a simple fix GM needs to implement it and provide it to existing owners. I don't think the sky is falling, and I don't think that everybody tracking the car is going to have these issues. But if they want to be mentioned in the same breath as "GT3" or "Porsche" it must be done.
S.
Agreed.

Even his explanation, though, was delivered after people started having problems in response to this forum. Never was it marketed as only a fair-weather track car for those with manual transmissions and novice trackers who can't go fast enough to really stress it.
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Old 05-07-2015, 06:02 PM
  #2098  
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Originally Posted by Bill Dearborn View Post
Heat soak is a totally different problem than over heating.

Bill
and those thermal plates are grounds for a warranty violation!!!

Something a dual core radiator will not do (at least it should not matter as far as the warranty is concerned)
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Old 05-07-2015, 06:08 PM
  #2099  
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Originally Posted by jvp View Post
I wouldn't be so quick to write GM off regarding this topic. While I have no details or specifics yet, I do know they're looking into it. Whether they're able to come up with an explanation or solution or not is another thing entirely. And it may be best to hand this off to the aftermarket (see: DeWitt).
C2 big blocks were known for overheating in anything but the middle of winter

However, a Dewitt dual core replacement solved my problem without needing any more airflow than the sock GM radiator had
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Old 05-07-2015, 06:21 PM
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I agree that Tadge's comments are sufficiently vague as to not exactly say how hard the car can be driven and not overheat. It sure seems like some of the quicker track drivers are having very high fluid temperatures (I for one never allow one of my race cars over 240 water or 280-90-ish oil) that really shock me. 260 water? Yikes. 300+ oil? From what I have read that really means an oil change every few hours of operation.

I am a huge GM and Corvette fan; I've owned several including the C6Z and my DD is a CTS-V Wagon. But I decided to pay more for "less," by buying a GT3. Why? Well partially I just wanted to try a P car as I've never had a street Porsche, but I also liked the lighter weight and lower power, as I figure it's easier to cool 475 hp and Porsche somehow manages to punch way above its weight in terms of lap times for the power level. I would have been much more impressed if the C7 Z06 went down in weight with a modest increase in power (imagine say 3000 lb and 525-50 hp) with a big emphasis on cooling and brakes.

Problem is, I really think the Corvette demographic would rather have the power than serious track ability, and of course lower price. The car is fantastic looking, can lay down a serious hero lap, and drag race in the 10s. But hard, race-pace track driving is very expensive to design and build for and a complete waste if the driver never really uses the car that hard and I honestly don't think most Corvette owners track their cars with great pace (present company excluded). I can't blame Chevy for building to this market, but that's exactly what I think happened.
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