Engine Coolant Temps With and Without Airdam- Data Inside
Thread Starter
Racer
Joined: Jun 2010
Posts: 457
Likes: 0
From: LaGrange Ga
Engine Coolant Temps With and Without Airdam- Data Inside
All,
When I purchased my 2002 Z06 the previous owner had removed (don't know how or why) the center front airdam from the car. I assumed it was only a piece necessary for high speed stability and since I was driving very carefully home I wasn't going to need it anyway.
After reading on this forum I noticed that many people claimed it was an important piece of the engine cooling system.
This worried me a bit so I purchased a used part from a forum member. While I was waiting for the center airdam to arrive it dawned on me that I should try and determine (though an experiment) what effect the center airdam had on engine coolant temps.
So I pulled out my OBD-II data logger and set up a simple experiment to find out the truth.
The setup was as follows:
Drive the car home from work and park it in my driveway and let it cool down to ambient temperature over night.
The next morning, I would log ECT and vehicle speed on my commute to work I would start the logging before the engine was started, and I would stop the logging after the ECT had reached steady state.
I did this test on 2 consecutive days and lucky for me the starting ECT's were identical! (down to +/- .2 deg F, the resolution of the stock ECT sensor)
I did my best to drive the same way each day, you can see some slight differences in my speed and how long I have to wait at lights etc. But I am still very pleased in the similarity of the velocity plots.
Make your own conclusions, if you have questions please ask!
Tech Contributor
Joined: Jan 2007
Posts: 19,450
Likes: 1,155
From: Dyer, IN
All,
When I purchased my 2002 Z06 the previous owner had removed (don't know how or why) the center front airdam from the car. I assumed it was only a piece necessary for high speed stability and since I was driving very carefully home I wasn't going to need it anyway.
After reading on this forum I noticed that many people claimed it was an important piece of the engine cooling system.
This worried me a bit so I purchased a used part from a forum member. While I was waiting for the center airdam to arrive it dawned on me that I should try and determine (though an experiment) what effect the center airdam had on engine coolant temps.
So I pulled out my OBD-II data logger and set up a simple experiment to find out the truth.
The setup was as follows:
Drive the car home from work and park it in my driveway and let it cool down to ambient temperature over night.
The next morning, I would log ECT and vehicle speed on my commute to work I would start the logging before the engine was started, and I would stop the logging after the ECT had reached steady state.
I did this test on 2 consecutive days and lucky for me the starting ECT's were identical! (down to +/- .2 deg F, the resolution of the stock ECT sensor)
I did my best to drive the same way each day, you can see some slight differences in my speed and how long I have to wait at lights etc. But I am still very pleased in the similarity of the velocity plots.
Make your own conclusions, if you have questions please ask!
Thread Starter
Racer
Joined: Jun 2010
Posts: 457
Likes: 0
From: LaGrange Ga
ECT at the start of the test was 87.8 F for both tests.
HVAC System indicated 85 F for test without airdam and 84 F with the airdam.
Edit: The A/C was "off" for both tests
Last edited by KrispyZ06; Sep 17, 2010 at 01:06 PM. Reason: Addded A/C state information
Tech Contributor
Joined: Jan 2007
Posts: 19,450
Likes: 1,155
From: Dyer, IN
After an overnight (~12 hr) soak the coolant temp should be equal or very close to equal the ambient temp.
ECT at the start of the test was 87.8 F for both tests.
HVAC System indicated 85 F for test without airdam and 84 F with the airdam.
Edit: The A/C was "off" for both tests
ECT at the start of the test was 87.8 F for both tests.
HVAC System indicated 85 F for test without airdam and 84 F with the airdam.
Edit: The A/C was "off" for both tests
Thread Starter
Racer
Joined: Jun 2010
Posts: 457
Likes: 0
From: LaGrange Ga
The big change there is that both fans would be on. I am not so much wanting to know how well the fans do at cooling as I am wanting to know what "scoop" effect the center dam will have.
I didn't want to do that becuase I wasn't sure how the HVAC control would regulate the fans and compressor. Just another variable to mix me up. What do you think?
Tech Contributor
Joined: Jan 2007
Posts: 19,450
Likes: 1,155
From: Dyer, IN
Well I don't know about doing it with the A/C on.
The big change there is that both fans would be on. I am not so much wanting to know how well the fans do at cooling as I am wanting to know what "scoop" effect the center dam will have.
I didn't want to do that becuase I wasn't sure how the HVAC control would regulate the fans and compressor. Just another variable to mix me up. What do you think?
The big change there is that both fans would be on. I am not so much wanting to know how well the fans do at cooling as I am wanting to know what "scoop" effect the center dam will have.
I didn't want to do that becuase I wasn't sure how the HVAC control would regulate the fans and compressor. Just another variable to mix me up. What do you think?
Up to you, but considering the A/C presents a physical load on the engine, and additional heat in front of the radiator, I think it would complete the data nicely.
Also, can you export the raw data to excel?
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Thread Starter
Racer
Joined: Jun 2010
Posts: 457
Likes: 0
From: LaGrange Ga
True, but an unidentified variable all the same. So set the a/c on manual, dial in a temp, make note of the ambient temp, and rock on.
Up to you, but considering the A/C presents a physical load on the engine, and additional heat in front of the radiator, I think it would complete the data nicely.
Also, can you export the raw data to excel?
Up to you, but considering the A/C presents a physical load on the engine, and additional heat in front of the radiator, I think it would complete the data nicely.
Also, can you export the raw data to excel?
I will likely run the test again this time with A/C and see what the changes are, I just need to wait until it looks like I will have some consistant weather to perform the next round.
Also, I am able to log any OBD-II metric, as well as data from an accelerometer and GPS position so if anyone has any specific experiments they would like to see run I wouldn't mind giving it a go...
Melting Slicks
Joined: Sep 2006
Posts: 2,736
Likes: 7
From: Redding CA
I took the air dam off my car, front and sides right before lowering. (5 years ago) The driveway that I have to take to get back into our house would have messed it up anyway(and I prefer the look w/o it).
anyway, I'm not able to data log but I live in Northern CA...we've had 20-30 105+ degree days this summer and every summer. AC on/AC off...zero issues with overheating.
good to know it's not just me.
lol what is that 2-3 degrees different and it was a degree cooler ambient with the air dam?
Just keep the radiator cleaned out from debris and the aluminum block/electric fans seem to do the job fine.
subscribed in case you do the test with the AC just cause it would be good to know
Race Director
Joined: Jun 2009
Posts: 12,331
Likes: 139
Good to know. I took the side air dams off because they kept getting loose at the edges and made the car look ragged and I kept the center because I was told I would kill my engine with no air getting to the radiator. Now I know i can take this thing off and not have it look stupid like it does now lol.
Thanks for the time and effort into this test
Thanks for the time and effort into this test
Drifting
Joined: Dec 1999
Posts: 1,541
Likes: 2
From: Raleigh NC
A track buddy couldn't make it 3 laps around the track without it. He lost his to an off track excursion. He fab'd up a sheet metal air dam and was set for the rest of the day. Spirited driving will tell the tale.
Melting Slicks
Joined: Oct 2007
Posts: 2,464
Likes: 2
From: Cedarburg, WI
I believe your test proved under a certain "drive to work condition". You start pushing and taxing the car more, and I believe it will be a different story.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Steady state driving keeps the engine cool.
But constant stop light to stop light 0-4000 rpms, one right after another ?
or
constant 2000 to redline, 2-3 times every 2 min, with straights of 150 + mph, in there as well. One quickly learns that the stock radiator is just barely enough for cooling
Thread Starter
Racer
Joined: Jun 2010
Posts: 457
Likes: 0
From: LaGrange Ga
I spend 95% of my time on the road driving legal speeds, once a month or so I go to an auto-x, or track day. For the others that are easy on their cars my results may apply to their situation.
Finally my decision has been to leave the air dam on, since I work for an oem I know that the designers have their reasons for their paticular design and they generally have done more research than us on a particular issue.
Remember this is why I asked everyone to draw their own conclusions.
Resident moron
Joined: Jun 2003
Posts: 4,746
Likes: 20
From: Assachusetts
The owner's manual specifically states that the air dams are not for cooling, they are for aero purposes. Now, does the center dam help get air to the radiator? Of course, but that apparently wasn't the original purpose.
It's nice, never scraping on anything anymore.
Dope
