What really causes the 2015 and 2016 Corvette C7 Z06 to run hot and overheat?

There are three problems experienced by the newest Corvette C7 Z06:  high operating temperatures, overheating and heat soak.  They are not the same and should not be used interchangably.  However, all three can be traced to a common cause.   What is this cause?   There are short and long versions to this question, of course.

The short version, as stated in this blog on multiple occasions is the UNDERSIZED SUPERCHARGER.

Yes, no matter how much +General Motors and +Tadge Juechter try to deny this, the small and fast spinning supercharger is the root of all the problems causing the latest Corvette flagship not only to run hot period but overheat at will as well, testing the limits of the engine durability and exceeding typical recommended operating temperatures by big margin, not to mention the heat stress put on the engine oil and its ability to protect the LT4 motor.

As previously mentioned here, the Roots type compressor has a very limited optimum thermal efficiency range and no matter how much rotor design improvements Eton may be claiming, it still falls short at higher boost and RPM levels.

Unfortunately, morons like Tadge Juechter and his team of "engineers" refuse to conduct any reality check whatsoever and what they come up with, named Corvette C7 Z06 is nothing short of absolute and complete disaster.

So what is happening here and why can be the entire fiasco traced back to the choice of supercharger?  HEAT produced by this little turd is what initiates this chain reaction.   But... but... supposedly the IAT's are low, in fact lower than when compared with the previous flagship, ZR1.

After all, if the IAT's are low, there should not be any problems with the supercharger, as long as the car can dissipate the heat in the supercharger, right?  ABSOLUTELY WRONG!!!.

Here is a funny example of how stupid self proclaimed car experts can be.  Someone calling himself nineball on the internet, conducted  a dyno test, while supposedly monitoring the IAT's of C7 Z06 as follows:

2015 Corvette Z06
Initial Temps:
Intake Mani Temp 133F
IAT1 66F
IAT2 90F
Oil 176F
Coolant 189F

Run 1
HP 552
TQ 560

Run 2
HP 563 (+11)
TQ 562 (+2)

Run 3
HP 563 (+0)
TQ 563 (+1)

Run 4
HP 559 (-4)
TQ 566 (+3)

Final Temps:
Intake Mani Temp 134F (+1)
IAT1 64F (-2)
IAT2 73F (-17)
Oil 201F (+25)
Coolant 208F (+19)

After this "scientific test" this genius proceeds to claim there is no problem with the little supercharger/hair dryer due to those temperatures being low and no significant loss of horsepower, leading naive Corvette sheep into believing the problem must be somewhere else (this wild goose chase continues until today, with not a single numbnut capable of figuring out what is really happening).

Of course, in real life, nothing could be further from the truth than this idiotic test and even dumber "conclusions". 

First of all, as with any other Z06 dyno tests, this numbnut left the hood wide open while running the fans to circulate the air.  As already stated in this blog, in addition to undersized air intake front opening, the newest Corvette has a very flawed air circulation design, literally trapping the heat in the engine compartment, no tests with hood open can be accepted as legitimate due to this flaw.

As already well established, during spirited driving, including track events, coolant temperatures routinely exceed 250 degrees while engine oil exceeds 300.  Want credible test?  Get the car up to the real temperatures and then measure the IAT's and corresponding horsepower and torque values and CLOSE THE FRIGGING HOOD!!!.  Not difficult to tell what happens when the heat is going up from the torque tables.  Where do the tools like this one come from? 

Furthermore, even with the hood wide open and external fans running, these short dyno runs made the coolant and oil temperatures jump by about 20 degrees which is a large jump for the test settings, a big red flag right there because this is where the real trouble starts...

Here is the first problem with all of this heat being generated, with 53% thermal efficiency at WOT, 47% of the power generated to compress the air and create extra horsepower is literally wasted.  What this means is a 650 hp rated engine in reality is a 750 hp engine due to that inefficiency and parasitic loss and this is a lot of extra heat because with any ICE, more power is more heat.

Thus, right from the start, the alleged supercar, sporting the same base Stingray radiator and the same water pump while being responsible for 750 hp.  Honestly, does +Tadge Juechter have shit for brains?

Then, there is this part:  the front mounted intercooler.  According to the GM specifications, this intercooler is very efficient (unlike the turd of a blower) and certainly, there is no reason not to believe GM this one time.

The heat exchanger has 15 fins per centimeter—that’s 50 percent higher density than on the LS9. So even though it’s 24 percent smaller, the intercooler rejects 10 percent more heat than the LS9. Juechter does not like to advertise this part but on a typical 68-degree day, the discharge air from the TVS1740 supercharger can reach 248 degrees. By the time it passes the heat exchanger, those charge air temps are cut in over half to less than 120 degrees  (as demonstrated by that genius mentioned above).

Strangely enough, that blower temperature coincides with the engine coolant temperatures (engine, not blower coolant).  Coincidence?  Only to Juechter and tools buying this great new Corvette.

The reason why this is not a coincidence is the fact that the intercooler is mounted IN FRONT of the radiator and happens to take up the area in the air intake opening (the undersized opening that is...).

So what happens when the heat expelled from the intercooler passes through the radiator?  Does it cool off magically before flowing through the radiator fins?  Of course it does not, as a matter of fact, it is superhot in any weather as long as the car is under WOT.  When combined with the higher density of the intercooler fins, this is a guaranteed recipe for disaster.

The fact that the not only the air intake opening is larger on the ZR1 but the density of intercooler fins is smaller is the real explanation why ZR1 experiences lower operating temperatures and is less prone to overheating, especially since it uses a larger Eton supercharger that also happens to produce less heat because it spins slower.

So... here it is, a very efficient but dense intercooler, undersized air intake and radiator and lots of heat being transferred from the intercooler to the radiator, rendering any attempts at improvements fully futile.  Are we getting warm yet?

There is still more to it, including the engine and supercharger oiling system that happens to use coolant to oil design, with the engine coolant already being very hot but still forced to transfer heat from the engine while using a truly pathetic cooler that is more of an oil heater than a real oil cooler, good in winter but totally worthless otherwise, especially on the track.

One cannot help but wonder, how could anyone be so stupid to design such a flawed system?  Certainly, this has to be the worst design engine cooling and supercharger systems ever, I personally cannot think of one that is worse, at least not in the last thirty years.

Here is how this could be fixed: larger supercharger as step one and not Roots but Whipple instead, it runs cooler, it is more efficient at higher RPMs and it does not run out of breath at WOT like Roots does, especially when it is so severely undersized.

Second step would involve a larger engine radiator surface area along with a larger air intake (active shutter system would be the way to go).

Third step would involve relocating the front intercooler, ideally splitting it up and supply air through dedicated air intakes, there is no question this is mandatory.

Fourth step must include a relocated engine oil cooler, two stage with air to oil and coolant to oil, with a thermostat regulated bypass sufficient air flow to support a heat sink equipped with cooling fins.

Fifth step requires an actual engine compartment heat extraction system involving adequate venting (good for downforce as well) in the hood and fenders, including functional side vents.

EDIT: I forgot step six... Replace factory dash plaque disclosing occasional horsepower and torque adverisements with a replacement plaque clearly stating DO NOT ATTEMPT TO DRIVE COMPETITIVELY AT ANY TIME!!!

There is considerably more to this but this brief description shows very well why this latest flagship is such a failure. 

Will Juechter's team attempt to rectify this quintessential cluster fuck?  NOT A CHANCE!!! Did this guy eat one paint chip too many as a kid?

Ironically enough, none of this would happen if the latest Corvette was configured as a real mid engine car but this is another story.

In the meantime, BUYER BEWARE, the car is as flawed as it could get and it should never be used for any track activities, except for drag strip and cars and coffee runs.  Any attempt to fix this piece of shit relying on aftermarket claims will result in even bigger disaster since the  Corvette aftermarket, except for Katech offering NA 427 engine replacement is either intentionally or unintentionally clueless on the subject.