Better/more effecient engine cooling
08-09-2007, 07:23 PM
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Better/more effecient engine cooling
Some clarification and thoughts for better/more efficient cooling for the LSJ 2.0L. , L61 2.2L. , and LE5 2.4 L.
First, there are two fan speeds, low and high. The Low Speed Fans are commanded ON by the PCM under the following conditions:
Engine coolant temperature (ECT) exceeds approximately 106* C (223* F).
A/C refrigerant pressure exceeds 1310kPa (190psi).
After the vehicle is shut off, the ECT at key-off is greater than 140* C (284* F) and system voltage is more than 12 volts. The fans will stay of for approximately 3 minutes.
The PCM commands High Speed Fans ON under the following conditions:
ECT reaches 110* C (230* F).
A/C refrigerant pressure exceeds 1655 kPa (240psi).
When certain DCT’s set.
That being said, those who have noticed better performance when the LSJ 2.0 L. engine is cooler, are absolutely correct. I live in the Northwest and during the fall, especially winter, and also the spring, my 2006 SS S/C with Stage II, 2.8 pulley, CAI, Performance exhaust system w/ Extrude honed exhaust manifold runs like a scalded cat. It also has approximately 1.5 # more boost in the cooler/cold months.
We had more 100+degree, down to upper and mid 90-degree days in July than ever in the history of my state. I did not like my Cobalt SS S/C running the high temperatures many have noticed their cars running – 197* up into the well over 200* range. We could debate the potential for harm to our aluminum engines at these temperatures, but let me just say, I have had over 30 years NHRA drag racing experience, and excessive heat can be very destructive to an engine. I do not like any of my engines running over between 180*/190* period.
I recently did two things which so far have seem to have helped a great deal with keeping my engine’s temperatures down, especially on these hot summer days. One will cost you a few dollars. I added Redline Water Wetter to both my radiator surge tank and the Intercooler system. The other is free, and is a trick I used when I was racing a 1984 Hurst Olds. I removed the rear hood seal. It is at the rear of your hood, and just snaps on to a plastic lip that runs along your firewall under your wiper blades. What removing the rear hood seal does is basically enable the under hood engine heat to flow through and out of the engine area, by allowing the cooler outside air to flow in pushing the hot air out. Much like hoods you see with heat extractors, the 2007 Shelby GT500, for example.
So far I have observed consistent 10* to 15* lower engine operating temperatures, and that is on 90 + degree days
In colder climates in the Winter, it might be a good idea to replace the rear hood seal, so your engine can warm up faster, as it takes longer for the engine to warm up with the rear hood seal removed.
I haven’t noticed anything detrimental when running without the rear hood seal. The plastic lip I described pretty much keeps water out of the engine area.
When you shut the car off and stick your hand by the rear hood in front of the windshield, you can feel the hot under hood engine air flowing out, and the engine also cools off much faster after you shut it off than it does with the rear hood seal on. You can imagine how much heat escapes when it is being pushed out by the cool outside air as you are driving.
Doc
First, there are two fan speeds, low and high. The Low Speed Fans are commanded ON by the PCM under the following conditions:
Engine coolant temperature (ECT) exceeds approximately 106* C (223* F).
A/C refrigerant pressure exceeds 1310kPa (190psi).
After the vehicle is shut off, the ECT at key-off is greater than 140* C (284* F) and system voltage is more than 12 volts. The fans will stay of for approximately 3 minutes.
The PCM commands High Speed Fans ON under the following conditions:
ECT reaches 110* C (230* F).
A/C refrigerant pressure exceeds 1655 kPa (240psi).
When certain DCT’s set.
That being said, those who have noticed better performance when the LSJ 2.0 L. engine is cooler, are absolutely correct. I live in the Northwest and during the fall, especially winter, and also the spring, my 2006 SS S/C with Stage II, 2.8 pulley, CAI, Performance exhaust system w/ Extrude honed exhaust manifold runs like a scalded cat. It also has approximately 1.5 # more boost in the cooler/cold months.
We had more 100+degree, down to upper and mid 90-degree days in July than ever in the history of my state. I did not like my Cobalt SS S/C running the high temperatures many have noticed their cars running – 197* up into the well over 200* range. We could debate the potential for harm to our aluminum engines at these temperatures, but let me just say, I have had over 30 years NHRA drag racing experience, and excessive heat can be very destructive to an engine. I do not like any of my engines running over between 180*/190* period.
I recently did two things which so far have seem to have helped a great deal with keeping my engine’s temperatures down, especially on these hot summer days. One will cost you a few dollars. I added Redline Water Wetter to both my radiator surge tank and the Intercooler system. The other is free, and is a trick I used when I was racing a 1984 Hurst Olds. I removed the rear hood seal. It is at the rear of your hood, and just snaps on to a plastic lip that runs along your firewall under your wiper blades. What removing the rear hood seal does is basically enable the under hood engine heat to flow through and out of the engine area, by allowing the cooler outside air to flow in pushing the hot air out. Much like hoods you see with heat extractors, the 2007 Shelby GT500, for example.
So far I have observed consistent 10* to 15* lower engine operating temperatures, and that is on 90 + degree days
In colder climates in the Winter, it might be a good idea to replace the rear hood seal, so your engine can warm up faster, as it takes longer for the engine to warm up with the rear hood seal removed.
I haven’t noticed anything detrimental when running without the rear hood seal. The plastic lip I described pretty much keeps water out of the engine area.
When you shut the car off and stick your hand by the rear hood in front of the windshield, you can feel the hot under hood engine air flowing out, and the engine also cools off much faster after you shut it off than it does with the rear hood seal on. You can imagine how much heat escapes when it is being pushed out by the cool outside air as you are driving.
Doc
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