Nashua_Night_Hawk

From my experience at the drag strip on April, 6th 2002.

That day it was cold and partly sunny with some wind:

Here is the Weather stats: http://www.wunderground.com/history/...lyHistory.html

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Time Temperature Dew Point Humidity Pressure Visibility Wind Speed Gust Speed Precipitation Events Conditions
08:55 39.20 °F / 4.0 °C 19.40 °F / -7.0 °C 45% 30.06 in / 1018.0 hPa 20.0 miles / 32.2 kilometers 11.5 mph / 18.5 km/h N/A N/A Partly Cloudy
09:55 39.20 °F / 4.0 °C 19.40 °F / -7.0 °C 45% 30.06 in / 1018.0 hPa 20.0 miles / 32.2 kilometers 10.4 mph / 16.7 km/h N/A N/A Mostly Cloudy
10:55 42.80 °F / 6.0 °C 19.40 °F / -7.0 °C 39% 30.04 in / 1017.0 hPa 20.0 miles / 32.2 kilometers 9.2 mph / 14.8 km/h N/A N/A Mostly Cloudy
11:55 41.00 °F / 5.0 °C 19.40 °F / -7.0 °C 42% 30.04 in / 1017.0 hPa 20.0 miles / 32.2 kilometers 12.7 mph / 20.4 km/h N/A N/A Mostly Cloudy
12:55 42.80 °F / 6.0 °C 17.60 °F / -8.0 °C 36% 30.04 in / 1017.0 hPa 20.0 miles / 32.2 kilometers 12.7 mph / 20.4 km/h 17.3 mph / 27.8 km/h N/A Mostly Cloudy
13:55 46.40 °F / 8.0 °C 15.80 °F / -9.0 °C 29% 30.01 in / 1016.0 hPa 20.0 miles / 32.2 kilometers 8.1 mph / 13.0 km/h N/A N/A Mostly Cloudy
14:55 44.60 °F / 7.0 °C 12.20 °F / -11.0 °C 27% 30.04 in / 1017.0 hPa 20.0 miles / 32.2 kilometers 13.8 mph / 22.2 km/h N/A N/A Scattered Clouds
15:55 42.80 °F / 6.0 °C 12.20 °F / -11.0 °C 29% 30.04 in / 1017.0 hPa 20.0 miles / 32.2 kilometers 13.8 mph / 22.2 km/h 20.7 mph / 33.3 km/h N/A Scattered Clouds
</pre>



My best run of that day was at 4:13 PM... So:

Temp: 42.80 °F / 6.0 °C
Dew Point: 12.20 °F / -11.0 °C
Hum: 29%
Pressure: 30.04 in

I had only CAI and Spark Plugs and 18" rims... and run 14.6@96.5 MPH.

However, my best runs were the one that were run-after-run....

After Seeing the CLS-6 dyno on Vtec.net showing that the CLS drops like 5-10 WHP due to the rise of engine Coolant Temp to 200+.....

I believe that the normal operating temp of the engine coolant contributes considerably to lower WHP... and since most of us do not push their cars till the normal operating temp of the engine coolant is reached.... The CLS is downgraded from the factory just for this fact alone....

Now the question is why Honda chose the stock normal operating temp of the engine coolant ?

...Emmisions? maybe...
.....Easier Break-in on the Engine?
...less Engine wear?


What's the disadvantage for lowering the normal operating temp of the engine coolant ?

EricL

Emissions probably... The first thing they did in the 70s was increase the thermostat temps to drop emissions.


Possible loss of gas-mileage under certain conditions….
Higher emissions…

Transmission could run cooler (good in certain respects) and depending on the ATF properties could have more fluid losses from thicker ATF (it would depend). There's a range where it probably doesn't make a lot of difference. The lower engine coolant temp is going to translate into lower tranny temps during conditions where the current coolant-to-ATF intercooler isn't being swamped.

Remember, the Temple of VTEC was on a 6-speed (not an auto…).

Someone would have to run a very careful set of before and after dyno runs. From what has been commented on, the transmission (slushy) temp sensor doesn't show up on the scan tools. A small probe can be bought or fashioned to get at the temps on one of the PCM connectors (if required).

YMMV

Wires

The stock temp (usually 195 F in all vehicles), is a balance of power and fuel economy. As the engine get's hotter, fuel vaporizes more easily, so you get better fuel economy. But, the less dense air produces less power. As you cool the engine, the incoming air is more dense, so you get more power, but the fuel doesn't vaporize as well, so you get lower fuel economy.

The 195 F is a balance between power and economy. You can take the temp down to 160 F, and pick up a bunch more power, but then you'll lose some fuel economy. Raise the temp to 212 F, gain some mileage, but have a dog.

Since EPA governs all the fuel stuff, it's in the best interest of the auto maker to make their vehicles more fuel efficient (it's usually a overall fleet economy. For example, GM produces a bunch of fuel burning SUV's and trucks, so they manufacture a bunch of efficient Fireflys to balance out the overall fuel consumed per year by GM vehicles).


:P