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On the street it was NEVER an issue. So I suppose you are asking about on the track.
I own a C6Z that I race and a C7Z. I am a track rat, a racer and an instructor. You can overheat almost any car on a race track. The changes GM made (auxiliary radiator, tilted bricks, taller lid etc) made a noticeable and measurable impact to keeping the C7Z cool and mitigating global overheating. I'm at the track (Watkins Glen) pretty much every week, and will be there the next two days. I see literally hundreds of different C7Zs over the course of a season. I drive them, instruct in them and am on the track with them regularly. This year I've seen only two go into limp mode. Both were cars built prior to the changes and one was an A8. The rest (hundreds) run hard and long. All of them though, regardless of year, do run hot. But the changes GM made definitely control the heat better, extend how long the car can be driven in anger and either completely stop or mitigate out of control rising temps.
So in my direct experience, the issue has been addressed. This does not mean "fixed".
Now, if you add power to the car (more heat), put on a set of slicks or Hoosiers, modify the suspension etc, then you can get the car to overheat. But then again, you can get almost any car to overheat. As you add power you almost always must adding cooling. Guys running their cars this hard should consider the LG or GSpeed solution. Most race cars with this much power that are further modified and then abused need to address cooling beyond what the manufacturer installed though.
This is my direct experience, not what I read about on internet forums. If you want to know actual, truthful, real world answers then go down to the race track and watch all of the C7Zs making hot laps.
On the street it was NEVER an issue. So I suppose you are asking about on the track.
I own a C6Z that I race and a C7Z. I am a track rat, a racer and an instructor. You can overheat almost any car on a race track. The changes GM made (auxiliary radiator, tilted bricks, taller lid etc) made a noticeable and measurable impact to keeping the C7Z cool and mitigating global overheating. I'm at the track (Watkins Glen) pretty much every week, and will be there the next two days. I see literally hundreds of different C7Zs over the course of a season. I drive them, instruct in them and am on the track with them regularly. This year I've seen only two go into limp mode. Both were cars built prior to the changes and one was an A8. The rest (hundreds) run hard and long. All of them though, regardless of year, do run hot. But the changes GM made definitely control the heat better, extend how long the car can be driven in anger and either completely stop or mitigate out of control rising temps.
So in my direct experience, the issue has been addressed. This does not mean "fixed".
Now, if you add power to the car (more heat), put on a set of slicks or Hoosiers, modify the suspension etc, then you can get the car to overheat. But then again, you can get almost any car to overheat. As you add power you almost always must adding cooling. Guys running their cars this hard should consider the LG or GSpeed solution. Most race cars with this much power that are further modified and then abused need to address cooling beyond what the manufacturer installed though.
This is my direct experience, not what I read about on internet forums. If you want to know actual, truthful, real world answers then go down to the race track and watch all of the C7Zs making hot laps.
Short answer - Capable drivers that know how to throw a Z around can/will overheat the Z06 of any year, manual or not.
But wait there's more - As the temps climb the car will pull timing and thus power. You see this on tracks like VIR, on the back straight, where coming off Oak Tree we all exit in the 45/50mph range and then bury the throttle. Terminal speed at the end of the straight will be 155 to 165 depending on your braking point. Each subsequent lap will be less as the car pulls timing.
Gspeed and others appear to have solved with their 'cheek coolers'. $4K and you're good to go.
Conclusion - If you're a track guy, get a 2017 or newer so you have the auxiliary cooler and better cooling bricks. Install the Lou Gigliotti or Gspeed cheek coolers to be bullet proof. Of course this assumes you've properly bled the cooling system.
looks like you have chosen to race the c6z you own but you do not mention racing the c7z you own, why is that?
For the following reasons:
1) I only desire one race car that sucks my bank account dry. Other than owning/flying airplanes, it is the most expensive hobby I've ever done (and money is typically no object for me)
2) To build a racecar (not a DE track car) you need to replace pretty much every single part on the car and make it basically unstreetable. Ask me how I know. I didn't want to hack up my C7Z as I enjoy driving it to work, through the mountains, out to dinner and occasionally on the track when I'm working on my C6Z
3) I had already started building my C6Z race car when I purchased my C7Z
4) C6Z is well understood, with over a decade of testing and countless aftermarket suppliers/raceshops that have developed the platform
5) I love my C6Z more, and this bizarre infatuation is not quantifiable. Doesn't mean I don't also love my C7Z. If I didn't love it I would sell it, regardless of $$ invested or $$ lost.
Can you expand on the "best practices" to avoid the overheating?
Hi,
Aha, Mordeth and cvp both seem to have actual experience! I have intermediate level track experience and a 2016 Z06 that I want to track on a monthly basis but still want to enjoy in the mountains/weekends. I found that the management of my shifting made a big difference in avoiding overheating at my first track weekend with this car this weekend, but I'd like to have a larger safety margin (i.e. keep the engine cooler in general and be able to go the full 20 minutes of driving hard instead of 20 with careful shift management or 17-18 with more aggressive rpms at lower speeds). I'm tracking it next weekend at Pueblo and the end of the month at Pueblo again. SO:
This week, what could I do to make improvements before the next event? I've been told that switching to 15W-50 oil could help and can be done immediately?
This month or season, what can I do to make longer-term improvement? Is the larger intercooler block with the tilted bricks a good choice? I've heard "add a second radiator" and don't know what that entails- any experience with that?
I am less interested in cheap solutions and am more interested in proven solutions that do not change the exterior of the car (i.e. I don't want the extra vents cut out on either side of the front grille). Can either of you tell me what you'd recommend based on your experience???
If it's the manual no you won't overheat on the street nor the track.
It's not the manual (my fiance doesn't drive stick and wanted to be able to drive it too). Trying to figure out what I can do for the automatic transmission to help improve the cooling beyond driving it in manual mode (for which it will still overheat if I keep the rpms high at low speeds).
I got the "Engine Overheating Idle Engine" message in three out of eight sessions at ~80 F ambient temperature at High Plains raceway in Colorado this weekend.
Last edited by Kaitlin007; 09-03-2018 at 04:25 PM.
It's not the manual (my fiance doesn't drive stick and wanted to be able to drive it too). Trying to figure out what I can do for the automatic transmission to help improve the cooling beyond driving it in manual mode (for which it will still overheat if I keep the rpms high at low speeds).
I got the "Engine Overheating Idle Engine" message in three out of eight sessions at ~80 F ambient temperature at High Plains raceway in Colorado this weekend.
Either BS or something wrong with your cooling system.
Either BS or something wrong with your cooling system.
I was in the car driving it, so not sure what you mean by BS... I thought the overheating was a common issue at the track in track mode for the automatic Z06, so I wasn't surprised, but want to know how to manage it. Have you been tracking yours in track mode and not had this issue? Willing to share more if so? A fellow at the track who'd never had an issue said he always shifted at 5500 rpms, which was consistent with my sessions with no overheating, so it seems like the high rpms are the culprit, but I'd love to confirm with others.
Hi Kaitlyn. I believe you. Don't waste your time arguing or explaining yourself here. I'm sorry you are dealing with this, but very happy that you track your car! I sent you a pm.
I was in the car driving it, so not sure what you mean by BS... I thought the overheating was a common issue at the track in track mode for the automatic Z06, so I wasn't surprised, but want to know how to manage it. Have you been tracking yours in track mode and not had this issue? Willing to share more if so? A fellow at the track who'd never had an issue said he always shifted at 5500 rpms, which was consistent with my sessions with no overheating, so it seems like the high rpms are the culprit, but I'd love to confirm with others.
Mine is 2018 M7, still overheat....:-(
alot better than my "old" 2016 A8, but it start loosing power fairly quickly...... . and after 3 15 minute session it did go limp mode....
frustrating, and i am uncertain what to do.... either buy cooling upgrades or sell it and go Grand Sport with LPE or Katech engine.....
Good te see you track the car...... enjoy and hope we figure this out
Short answer - Capable drivers that know how to throw a Z around can/will overheat the Z06 of any year, manual or not.
But wait there's more - As the temps climb the car will pull timing and thus power. You see this on tracks like VIR, on the back straight, where coming off Oak Tree we all exit in the 45/50mph range and then bury the throttle. Terminal speed at the end of the straight will be 155 to 165 depending on your braking point. Each subsequent lap will be less as the car pulls timing.
That is incorrect (at least from my experience).
My 2018 M7 now has ~10 - 12 instructor events.
On VIR Full, I'm turning 2:06's on Cup 2 tires & a mostly bone-stock car, which is pretty respectable. I drive the snot out of it with full NLS at or just below redline.
Just got back from instructing for Potomac PCA at VIR. No reduced engine power, despite temps being well into the 90's with brutal humidity. I even forgot to turn off the AC on a few sessions.
I have never had an overheat issue (knock on wood).
Fastest cars were racers in Porsche Cup Series cars turning 1:58's on slicks, which is on par with Sean's lap times & is hauling butt.
TV at the end of the straights may be an indicator of timing being pulled (or simply a poor drive out of T12/T17, but without question, my best lap times are not those with the highest TV..
My student had a C5 Z06 with an aux oil cooler that was running about as hot as my Z...
I was in the car driving it, so not sure what you mean by BS... I thought the overheating was a common issue at the track in track mode for the automatic Z06, so I wasn't surprised, but want to know how to manage it. Have you been tracking yours in track mode and not had this issue? Willing to share more if so? A fellow at the track who'd never had an issue said he always shifted at 5500 rpms, which was consistent with my sessions with no overheating, so it seems like the high rpms are the culprit, but I'd love to confirm with others.
No I'm just saying that it is not normal. You must have a problem. I track my car in Florida at 90-95 degrees and have no problem. Your cooling system is not functioning normally. There is no way a 2017 + will over heat in 80 degree temps. I am saying either you have a problem or it is not true. Which means to you, you must have a problem. I am not doubting you.
No I'm just saying that it is not normal. You must have a problem. I track my car in Florida at 90-95 degrees and have no problem. Your cooling system is not functioning normally. There is no way a 2017 + will over heat in 80 degree temps. I am saying either you have a problem or it is not true. Which means to you, you must have a problem. I am not doubting you.
Ah, I see- I didn't read the title of the thread correctly, I have a 2016 C7 Z06 A8, the automatic transmission. Yes, I hear the 2017+ M7s are a different story. At any rate, I've gotten good info from a few sources and am going to have a lot of fun short shifting and working to improve within the capabilities of my car. Thanks!
Ah, I see- I didn't read the title of the thread correctly, I have a 2016 C7 Z06 A8, the automatic transmission. Yes, I hear the 2017+ M7s are a different story. At any rate, I've gotten good info from a few sources and am going to have a lot of fun short shifting and working to improve within the capabilities of my car. Thanks!
You have the auto which is basically 95% guarantee overheat lol.
The M7's don't have this problem as much. It's very rare. Even pre 2017. 17+ models come with the secondary radiator which helps. But even 15-16 M7 guys aren't overheating as bad/quickly as the auto guys.
I think saying what others have experienced as incorrect is not doing justice to the problem. Even manuals get hot. If you get hot the car pulls timing. If you pull timing, lap times go up. I didn’t say limp mode or C/E light. I said hot = pulled timing. Glad others can pedal the car to reduce issues and agree M7’s have less of an issue, however Gspeed is selling a lot of kits to others who don’t post because they’re tired of arguing with the ignorant. It’s safe to say that there are several M7 owners who know how to drive their cars that are having issues. $4K is an easy investment to make and no one will argue the car will run cooler with them than without. If your car doesn’t get hot or pull timing congratulations.
On VIR Full, I'm turning 2:06's on Cup 2 tires & a mostly bone-stock car, which is pretty respectable. I drive the snot out of it with full NLS at or just below redline.
Just got back from instructing for Potomac PCA at VIR. No reduced engine power, despite temps being well into the 90's with brutal humidity. I even forgot to turn off the AC on a few sessions.
I have never had an overheat issue (knock on wood).
Fastest cars were racers in Porsche Cup Series cars turning 1:58's on slicks, which is on par with Sean's lap times & is hauling butt.
TV at the end of the straights may be an indicator of timing being pulled (or simply a poor drive out of T12/T17, but without question, my best lap times are not those with the highest TV..
My student had a C5 Z06 with an aux oil cooler that was running about as hot as my Z...
Short answer is, I believe you, and there is most likely nothing wrong with your car, other than the altitude that you are at. Less cooling occurs from less pressurized air, and your ambient air is less pressurized.
The long answer is...
heat is absorbed essentially on a molecule to molecule instance. A molecule/atom that is excited and very hot, has a lot of energy, and when it is forced against a molecule/atom that has less energy, the less energized molecule/atom absorbs some of the more excited molecules energy.
The bigger the gap in energies, the more heat absorption that is possible. So if we have one atom/molecule at 300 degrees F (your car's fluid temps when it is overheating) and we have another molecule that is only 250, we can determine there is no way the 300 degree atom/molecule is going to drop below 250, and more likely it will be they both go to the 275 F range as they exchange energy.
Thus, why the other people who chimed in, said IF you are in 80 degrees ambient, you SHOULD be able to keep your car cool as the 80 degree ambient molecules flowing through the heat exchangers should be able to absorb more heat and keep your temps down.
What these people are failing to recognize is that for every 5 air molecules their radiator's molecules come in contact with at 60mph in X amount of time, you in colorado are coming in contact with 4 air molecules as your air is less dense. Thus, there is less heat energy absorption in X amount of time, even though you are at a slightly lower ambient temp.
10 or 15 degree ambient negative swing from sea level florida for its racers, is not enough to offset the lesser percentage of air molecules your heat exchangers come in contact with, as you are driving at an equivalent speed.
In addition, less PRESSURE means less PROXIMITY, as pressure literally equates to how many air atoms/molecules are forced into an area as they try to repel each other, and how close they are forced to come in contact with solids and their molecules (your metal HX). Put you hand on a hot stove lightly, and you wont be burnt as bad as if you push your hand down hard on a hot stove for the same amount of time. Greater Pressure equals faster rate of heat transfer from atom to atom, molecule to molecule.
This is due to atom/molecule's proximity to each other. Florida cars have more force/pressure pushing the air atoms against the HX molecules/atoms, so they will exchange heat at a faster rate, at an apples to apples speed and ambient temp, vs a car in colorado at 6000 ft.
Either way, make sure you check your res tank for your blower, and make sure there is almost no air inside. Bill D and I have addressed this in several threads, as have others. The below photo is too much air, you want to get as much air out as possible, i will try to find the link to the thread that explains this and the videos of how you can do it yourself if you don't want to pay the dealer... and even paying the dealer wont have perfect results as most have no clue how to perform the procedure, the car's nose has to be titled up. The tank in the photo below is in the passenger side front, down from the headlight, while the hood is open. Too much air in the blower fluid res tank and the entire fluid loop in general, causes the blower cooling water pump to shut down for 3 min at a time when it senses the air/cavitation in the pump, and during these 3 min shutdowns is when your car overheats. Gspeed discovered this 3 min shutdown, however, one does not have to buy their kit to prevent the 3 min shutdown of the pump. One only needs to get the air out of the system, which is no easy chore. Goodluck
09-02-2018, 08:46 AM
