Not sure if it's been mentioned but has anybody tried water injection system? I know new bmw m4 GTS was using it to keep motor cool and seemed to work very well from my understanding. Lot of people add them to forced induction high compression motors and swear by them. FYI I don't own a z06 because of the talk of not being able to drive it long without detonation and overheating. Just thought this could be a future fix potentially or help Chevy gm possibly

 

Thanks for sharing. I read that about the BMW.
2 things.

1. Don't let all of the talk about overheating sway you away from getting a Z06. While it can occur it is fairly rare. By rare I mean if you don't track the car you will never see it. If you track the car if you are capable of working the car really hard you might see it if its above 80ish degrees outside. Other wise you will never know the problem exist.

2. The overheating in the Z06 isn't the engine over heating it is the transmission or engine oil temps reaching their limit. Water injection would do little to help this.


That being said water injection has been used for years in aviation (since WWII) and in cars (in the 60s Oldsmobile's f85) to suppress detonation. I used it in the 80's with both water and alcohol to run additional boost in a 300zx turbo. It certainly works.

I am sure it could help the Z06 as well. If anyone ventures down this path just make sure to use a quality system that's well thought out for this application. Back in the day when I was playing with it, a good reliable system was hard to find and fairly expensive. With todays technology it should be a piece of cake. Otherwise WI/AI can be a headache.

 

If you are going to the track there are solutions available although some drivers don't seem to have an overheating problem. GMPP has developed the secondary radiator which provides further cooling of the coolant coming out of the oil to coolant oil cooler. This reduces both oil and coolant temps.

DeWitts has several things they are offering including replacing the oil cooler with an oil to air cooler, replacing the radiator with a larger radiator and a larger intercooler.

If you don't track the car none of this is your concern. The cars do not overheat on the street or highway and they do not lose their performance although it is doubtful anybody would ever know based on seat of the pants experience.

If you want a Z06 for the street there is no reason other than lack of money not to buy one. Overheating isn't even a consideration.

If you want to track it you need to observe the oil temps and make sure you keep them under control. However, some people run the hell out of the cars for a half hour and never see an oil temp warning.

The C7 Z is one bad a$$ car and it has the performance to back it. Two weekends ago I was at an HPDE at VIR where they had a Ferrari Challenge Race. The lead Ferrari's were running 1:57 lap times. These are full race cars with cages, stripped and lightened as much as rules would allow. A guy who had recently purchased a used C7 Z06/Z07 came to the event on Saturday. He didn't know how to set the car for the track and was complaining because he was turning 2:05 lap times and the traction control was holding him back. I told him how to get into track mode and about the 5 settings. He chose Sport 1 which has some stability control at the edge and PTM. After the next session he told me he was turning 2:01s with just that one change. The car was completely stock, it didn't even have race harnesses.

There is a member on this board that gets 1:59s on his basically stock car. Not bad when compared to a full out race prepped F430 that turns 1:57s.

Bill

 

As mentioned above, on a street application there should be no concern of "overheating" on the cars. This is most noticed by the guys spending 20 minutes + on track that see temperature issues. That being said, we are in the final steps of development on the "end all" cooling solution for the Z06. See below for a Facebook update from our Vengeance Road Racing division on our test day at Road Atlanta with one of our customer's cars that has the prototype system installed:

 

I'm interested to see the solution here. Doubt I will do much tracking but still just want peace of mind.

 

You have a vendor who seems to be on the verge of offering a solution telling you you don't really need to worry about overheating with your usage of the car.

It is your choice to add extra cooling capacity but you should base the decision on how you plan on using the car. Have you ever participated in an HPDE? When you say you doubt you will do much tracking do you really mean you will not do it?

There are a bunch of solutions being offered by GM and aftermarket vendors. Some are lower cost than others some require a lot of labor to install and some don't. All involve at least a minor mod to the car and maybe some risk from a warranty standpoint if you have a failure that is attributable to the mod or to the installation of the mod.

For instance, Tadge has said if you install the GM Secondary Radiator it will not impact the warranty but he didn't say anything about what would happen if the installation of the secondary radiator was screwed up and caused a problem. Leaving the car stock for street driving means even if the engine melts down to a molten block of aluminum under normal driving circumstances in the US and you didn't abuse it the warranty will cover the replacement.

Once you install any mods or open the engine in any way you raise questions. If an issue isn't going to affect you in any way because you never see the conditions that raise the issue do you really want to spend money to assume added risk you don't need to assume?

Bill

 

Interstting

 

Forgot the mention M7 runs cooler and will over heat much less than the A8.
I think it is chore to over heat the M7.

 

Looking forward to seeing what you guys came up with. Considering a 670 rwhp car had no issues and low temps, a stock car will probably do better.

 

Plastic front fender spats.

I'm kinda holding out to see if they offer real front fenders in the next year or two.

 

You DO love your M7, don't you! But you're correct - in a sense.

It depends how you shift it. If you shifted the M7 as aggressively as the computer shifts the A8, you'd heat up the exact same.

It's not the trans that's making the problematic heat, it's the engine being held at higher RPMs that is doing it.

Similarly, if you shift the A8 like an M7 driver, which is what GM suggests if you're facing heat issues, it cools down. I know, because I've done it in 88F air once, and it did work.

The A8 really holds high rpm gears much longer than I would with an M7 and even more than feels comfortable, like down the straight at 5500rpm without a shift. You keep thinking "Really? Ok, computer, you know best..." and then you find out maybe it didn't in this case.

 

I read there is a fix coming for it but they're going to charge anyone with a defective older z06/07 for the fix. I was sold a defective product and not have to pay to fix it.

WTF

Jimmy

 

Your car has overheated? Do you have PDR video or Cosworth data showing this?

 

I have PDR video of the temps. The oil gets to 300. I come in.

 

I AGREE Jimmy , GM sold it(push it out fast when they new there was this issue) GM sold it this way & should take care of it. But ???

 

I disagree with the statement that they would heat up the "exact same". The design of the A8 uses a torque convertor which is a heat generator when not running in "locked" mode (it is a very reasonable to assume you will not be triggering a TC lock at a HPDE). Automatic transmissions of this design will generate more heat than a manual transmission. You are correct that you can minimize the heat buildup by manually shifting and keeping RPM lower however it will still generate more heat than a manual operated at the same RPM band.

Just my .02, Chris

 

There are reports here of the MT7 running some pretty high temps at the end of HPDE run sessions, but not enough to send the car into limp mode. The A8 temps, whilst potentially higher due to it being a TC transmission, are in fact better controlled than those of the M7 due no doubt to the secondary cooler in the nose. In fact I think highest temps on the A8 are reported around 250dF whereas iirc the temps on the M7 when driven hard get close to 300dF.

So even though an 'auto' by its design may run 'hotter' than a pure manual transmission, GM controlled the temps in the A8 well enough that it actually runs cooler on track than the M7.

Bish

 

Good info, it does make sense that with the additional cooling they could run lower temps, but why would the manual trans temp not put the car in limp mode? 300F is pretty darn hot for Dextron III.

Thanks, Chris

 

You're right, the A8 will make more heat while slipping the converter. But I don't think that's the predominant cause of the overheating - I think that's lack of frontal cooling, high RPM programming for the A8 shift modes, and sub-optimal timing because it really needs more octane (tgo what extent I make no wager).

My point was merely that if you shifted the M7 the way the computer shifts the A8, it'd -probably- heat up similarly. But not exact, granted.

 

If I had a nickel for every overheating thread...