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The best course is to post the data as is but point out things like starting temps. What really matters is the stabilizing temperature. If you have enough data there should be an obvious tapering off as run time increases.
^agree. I'd guess the difference would be negated after just a lap or two. Clearly car 1 was just getting going and I bet it didn't take long to heat up.
Last edited by spearfish25; May 7, 2016 at 10:39 PM.
Can you post and graph the deltas between laps? IE Lap 2 minus Lap 1 temp, Lap 3 minus Lap 2, etc for each. Was the same driver in each car at different times or different drivers at the same time? All hot laps or were some cool down? I think we need the lap time for each value to make sure we're comparing apples to apples.
Last edited by spearfish25; May 7, 2016 at 10:48 PM.
In the above test both cars failed into the fifth lap. Then the cars did a cool down lap and finished. You can see the DeWitts radiator recovered much faster.
I feel the adjusted curve is a more accurate interpretation of what would take place. Nine gallons of oil at 40 degrees higher is a significant amount of heat.
Last edited by Tom@Dewitt; May 7, 2016 at 11:05 PM.
For the adjusted plot, it seems more sensible to shift the OEM plot to the left until the two graphs intersect at 217. Or move your radiator's plot to the right.
Shifting up or down like you've done here changes the stabilizing temperature. I don't think either stabilized. They both built heat until they overheated.
Cooling this car is pain. The struggle is real.
EDIT: the reason why the starting temps are higher is important too. Say both cars had the same run time but the Dewitts built up more heat idling in the grid. In that case no adjustment should be made.
Last edited by SBC_and_a_stick; May 7, 2016 at 11:14 PM.
SBC is right. Shift the graph right to adjust the temp start point to be equal. The slopes look rather similar to me meaning they build heat at similar rates. The Dewitts is slightly less steep but the improvement looks small.
Last edited by spearfish25; May 7, 2016 at 11:18 PM.
Why was the Dewitts car hotter to start? Was it out lapping before the stock car? Just want to understand the circumstance to improve interpretation.
I do not know the answer to that question but my assumption was that it was run hard and not allowed to fully cool down. The radiator brought the coolant down close, but not enough to drop the oil.
The 20 minutes between sessions is more than enough to bring the ECTs down to 200. So unless the recording of the data started mid session it's hard to see why the starting temps are 217*. Unless my timing app screws up and fails to record the first few laps my ECTS always start between 190 and 200.
Anyway, the stabilizing temp is what is most important.
Tom,
You need more data. Who drove both cars? What were the lap times that went with those temperature levels? I think you also need the time duration from start to finish. The data as they say has to be normalized. SBC suggests shifting the stock cooling data until it closely matches the DeWitt data. I assume each measurement is taken from the Cosworth Software and is on a lap basis. So lining up the DeWitt ECT at 217 and the stock at 214 looks good but the EOTs don't cooperate, they are far different for the two similar coolant temps.
One thing I think has to be done is to plot both ECT and EOT and study the slope of the increase in temp Vs time. However, you need to have some time and performance data to do that. Comparing the rate of change is probably more important than individual temps per lap.
The Cosworth data also includes lap time, max speed per lap, time on throttle and time on brake. That would provide some of the background data needed to see how closely the cars were performing to each other.
Bill
Last edited by Bill Dearborn; May 8, 2016 at 12:18 AM.
From the test data numbers, both the stock and DeWitt equipped car are getting coolant temps above 260F. Stock one gets to 263, then 264 F, while the DeWitt one gets to 261, then 262 F. Statistically that is the same temperature as the sensors for coolant temp must easily have 1-2 degrees F variation between them. So it looks like a wash between the two cars in terms of coolant temperature.
In terms of oil temperature, the stock car gets to 293 F, and then 293 F on the next lap. The Dewitt car looks like it is getting hotter than the stock one as it runs up to 298 F and then again 298 F, then up to 300 F on the last lap while the stock one goes up to 280 F. A 5 degree difference in EOT is not much, and likely also a wash between the 2 cars.
With temperature differences of 1-2 degrees for ECT and 5 degrees for EOT, it is hard to say if there is any improvement since one would have to use identically calibrated temperature sensors in both cars to know if there is an actual difference. If the temperature change was something like 20 degrees, then that would not be simply due to possible sensor variations.
Like George says, Z06 is obviously very resistant to cooling improvement efforts from just a radiator change.
Agree with Bill's comments. You're looking at the ability to remove heat from the system while essentially assuming the amount of heat introduced into the system is the same. Lap times, percent throttle, and precise fuel consumption would be good to know.
Tom,
You need more data. Who drove both cars? What were the lap times that went with those temperature levels? I think you also need the time duration from start to finish. The data as they say has to be normalized. SBC suggests shifting the stock cooling data until it closely matches the DeWitt data. I assume each measurement is taken from the Cosworth Software and is on a lap basis. So lining up the DeWitt ECT at 217 and the stock at 214 looks good but the EOTs don't cooperate, they are far different for the two similar coolant temps. Bill
You are right. This test was not what I was hoping for in terms of data or results. Obviously it does not put us in a good light for just the radiator change but I posted it because that is what they gave me.
I have found that a very small percentage of what a vendor claims on the forum is actually accepted by readers and my hope is that you will see I post only facts as I know them. Good or bad.
There are several things that concern me about these results but one of them stands out. How is it possible the coolant was slightly lowered but the oil was increased? Nothing was done to the oil system.
I'm not sure if the correct adjustment is to slide the data horizontally or vertical, or if an adjustment works at all. What I do know is that our radiator works better than this. In fact, this is the worst data I have received and we have over 70 units out there. We have three five star ratings from customers from the website. I have numerous people tell me they can no longer get the car to fault.
My understanding is they have added our EOC package to this car and will be testing that. BTW, the instructors at the track have limited knowledge of this research going on and the results are confidential until I release them. Some people are asking the instructors for data and they will not provide that to the public.
Dont beat yourself up just yet. Im positive we have a batch of good cars and bad. My prediction its in the intercooler pump wiring. I have personally seen cars ran same day same track fail while others complete the session. I have personally never had a failure of over heating even with my full tank of fuel run at road atlanta last year which equalled 38 minutes of straight track time.
I have seen 2 cars so far that had overheating issues have the intercooler pump and wiring harness replaced and both came back tracking with no issues.
This explains why some are better cooling than others.
GM had been made aware of this through the Tac call center.
DeWitts Test Data
