Operations

Just wanted to follow up with our data we gathered while testing this weekend.
Participating in putting this test together was Adam (SliveradoSS500) he is a Professional Driver for multiple car manufacturers, and
Louis Gigliotti (owner GSpeed), and myself.
Testing was at MSR Cresson TX May 28th & 29th 2016

Our car is a 2015 Z06 Z07 with A8 Automatic.
Programing is stock
Dewitt’s C7 Z06 Kit, 2nd Gen Radiator, Intercooler and Engine Oil Cooler. Installed by GSpeed
Air intake is by Haltech
The X-pipe is by Corsa
World Challenge Rear Wing G2 installed by GSpeed
Front Air Splitter by GSpeed
1” Drop Spindles by LG MotorSports
LG-Spherical A-Arm bearings
LG-Sway bars
Brakes -Stock CCB with OEM Pads
Fuel Texaco 93Octain
Testing was performed at MSR in Cresson TX on May 28th & 29th, both days the high was 91-100deg, 60-70% humidity

May 28th
Goal: 1st Attempt a sub 1:18 lap on cup tires, 2nd compare Conti Race slicks to the cups,
Driver: Adam SilveradoSS500
Tires Michelin Cups that came with the car, no prior track time, about 1,000 easy street miles
Data Acquired from PDR
Session 10:52am, Temp 83deg, 60% humidity
Out lap Max H2O Temp 226
Out lap Max OIL Temp 244
1st lap Max H2O Temp 241
1st lap Max OIL Temp 261
2st lap Max H2O Temp 246
2st lap Max OIL Temp 268
3st lap Max H2O Temp 243
3st lap Max OIL Temp 266

Session 11:30am, Temp 86deg, 60% humidity
Out lap Max H2O Temp 216
Out lap Max OIL Temp 198
1st lap Max H2O Temp 228 Lap Time 1:21.21
1st lap Max OIL Temp 223
2st lap Max H2O Temp 241 Lap Time 1:18.32 (the 241 temp occurred at the end of lap)
2st lap Max OIL Temp 248
3st lap Max H2O Temp 246 Lap Time 1:33.7
3st lap Max OIL Temp 264

Session at 1:06pm, Temp 91, 58% Humidity
More of the same data, nothing improved

Conclusion: Going in to the first day we expected the car to do better then it did. At this point my concern was there was something wrong with my car beyond just temp.

May 29th
Goal: Use HP Tuners to log data points, push the car to heat up, log at what temps timing is pulled, figure out what's going on.

Driver: Me, Operations, Passenger: Louis Gigliotti GSpeed
Tires Continental Race Slicks, 3-4 heat cycles
Fuel Octane raised to 95 by adding VP109

Session 2:36PM Data Acquired from HP Data Logging
Max H2O Temp 264
Max OIL Temp 277
Manifold Air Temp 257deg
Intake Air Temp 108deg
Ambient Air Temp 99deg

Session 3:32PM Data Acquired from HP Data Logging
Removed Engine Hood
Max H2O Temp 248
Max OIL Temp 259
Manifold Air Temp 244deg
Intake Air Temp 108deg
Ambient Air Temp 100deg
Notes: Removing the hood, delayed the inevitable overheating by about 2min, and temps did not rise as high. On this run we added logging engine knock. We were seeing knock through-out the whole session,

Session 4:50PM Data Acquired from HP Data Logging
Removed Engine Hood
Raised Fuel Octane to 98 by adding VP109
Max H2O Temp 246
Max OIL Temp 264
Manifold Air Temp 255deg
Intake Air Temp 108deg
Ambient Air Temp 99deg
Notes: Increasing the Fuel Octane reduced the knock retard by a good margin, remaining knock retard is attributed to high manifold air temp.

Conclusion: As water temps go past 212 timing begins to be pulled and reduced power begins. In the 248+ temp’s logs show timing reduced to only 3deg, if spirited driving continues car will go in to limp mode.

Dewitt’s C7 Cooling kit is an improvement over the factory products. In particular, the Oil cooler has made a major improvement, the highest oil logged was 277deg (265 was high for most laps) and we were intentionally pushing the car to overheat.
The radiator and supercharger intercooler are high quality pieces, but in our testing environment these still could not overcome the limited small opening engineered in the front of the car.
This is not to say this package solution would not work for some who tracks their C7 less aggressively, are equipped with M7, have less aero drag, and (or) are in a cooler climate.

We will be trying LG's solution as soon as we can put our hands on one.

Adding GoPro Video - I have this on anther post, you may have seen it.
Same Lap but from PDR

CGZO6

K B Vettin

are you planning on trying the D3 products specifically the dual spal fan kit?

Operations

It's not in the plans at this time.

HighBeta

I think you are correct that the cramped working area into which your three undoubtedly well engineered coolers are installed is a very large impediment to getting rid of the heat effectively and consistently.

Removing the hood helped, quite a bit, but the cooling units are stacked/arranged single file. Physically separating the coolers in such a way that they each have their own unheated air sources and their own heat exit paths is going to be key to getting our temps down lower than your current efforts already have.

My guess is that the LG and/or D3 physical arrangements will yield further improvement. My "ideal" scenario is a Gen 2 DeWitt radiator with an outboard oil cooler. The heat exchanger, if it can be moved or shaped in such a way to permit unrestricted airflow to the radiator, is the last item to consider but the radiator needs a clean/cold air supply and good exit path.

Typed on a tablet, forgive any fumble finger typos please.

Subscribed ...

Fitz89

you mentioned that you are running the LG drop spindles, and slicks.
What wheels/tire sizes are you running??
Thanks

Operations

Wheels by Finspeed 18x11, 18x13
In Hoosers R7 345-35/18, 315-30/18
The Conti Slicks I'll have to lookup

SBC_and_a_stick

I'm not surprised at all. My testing shows the same thing. There is no more cooling to get from the stock radiator opening with aftermarket parts.

In all sessions we're talking about 3 to 4 laps of a 1.7 mile course right? That's like 4 minutes of driving. The oil temps look a bit lower than I expected but the coolant seems unusually high, maybe more than stock although I don't drive as hard I'm sure. The increase in oil cooling here may come at the price of higher coolant temps which unfortunately is what shuts the car down.

Neat test with the hood off. I was wondering about that myself. Almost yanked it off one time but I got a check engine light so I gave up on it as cooling become a secondary concern.

Hope to see the LG solution soon. The D3 solution might work a bit better given a different air intake source but I'm curious about how the brakes do for that setup.

GP1224

So after all that the results are still better with the cats being DEI wrapped and cold air snaked in from the front bumper to the oil cooler at a cost of only a few hundred bucks. Its a waste of money with the above mods it would seem when better results have been shown.

https://www.corvetteforum.com/forums...-2015-z06.html

Fitz89

No clearance issues in the rear???

HighBeta

I suggest that we can't draw a good comparison between solutions: different cars, drivers, tracks, ambient temps, etc..

We need to see comparative results with as many variables held constant as possible. Swap out the solutions on the same car, using the same driver on the same track at the same ambient temps and then let's look at the numbers...

GP1224

Sure, there are always different variables to contend with. Regardless, 20 min sessions with a pro driver beating on the car all day at 80 plus and the results were far better with no issues using basic inexpensive mods that take heat away from the cooler by insulating the cats while bringing in direct air at the same time. From a price stand point its well worth it before adding anything else to see results first.

Hopefully others that have used those "exact" mods could show their results. Either way it seems the OP results from those mods added that possibly could affect factory warranty dont seem worth the money much at all.

NemesisC5

Stacked heat exchangers will always be a compromise (even with air gaps). Larger/thicker heat exchangers in a "heat exchanger sandwich" impede airflow and the benefits of larger/thicker unit will be greatly compromised in this arrangement which these tests seem to validate. Volume and temperature of airflow through heat exchangers is absolute paramount in removing btu's.....you can't get around the basic laws of physics.

It seems that GM should have realized this in CFD and wind tunnel testing given absolute values for air temp, airflow, dimensions of heat exchangers and rated values, etc..... The technology is basic science with absolutes tested across different operating conditions, not quantum physics.

0D3PE

Our testing of our oil cooler kit showed to lower the temps just as much with stock radiator with a 4.5" thick intercooler blocking it while making 700whp with a D1SC, imagine what it would do on an oem setup

Operations

No rubbing in the wheel well. With the additional camber with the track alignment on the car, probably helps.

The 18" wheels with drop spindles have rubbing issues with the lower control arms as the wheel articulates up. Mine were notched and welded to address that, were monitoring/watching for stress cracks/bending etc.

Operations

There is no doubt they knew.
Whoever (guy/team or group) who signed off on this should be nut-kicked. (metaphor - not suggesting any physical harm to any person, or farm animal)

I don't think they foresaw the scale of the media and owners outcry, especially the loss of face when magazines test/compare.

We can see from the new ZL1 Camaro, the redesigned mouth the size of a catfish, three radiators, etc. GM does not want a second snafu.

Operations

What your suggesting would provide the clearest data
Reality is, to do this would require someone or group to spend a ton of money, no one is going to do that other then GM.

nhpln

Yes, they knew. Per Tadge himself:

"Some may wonder why don't we design to higher temperatures, say 110 degrees, to accommodate southern tracks in the Summer. We have used the "pro driver at 86 degrees" criteria for generations of Corvettes and for the vast majority of customers, it has resulted in excellent performance for their usage. If we designed to higher temperature criteria, we would have to add a lot of cooling hardware which drives mass up and perhaps more importantly, you have to feed the system with more air which has a huge impact on appearance and aerodynamic drag. Like most aspects of car design, the challenge is in finding the best balance of conflicting requirements."

https://www.corvetteforum.com/forums...-on-track.html

NemesisC5

NemesisC5

I had been looking for where I read that, didn't remember it was here on the forum. Thought that I originally read it somewhere else first but remember like it was yesterday the part you put in bold.