Don't sweat the heat...here's some graph data showing..
#1
Race Director
Thread Starter
Don't sweat the heat...here's some graph data showing..
what my 03 Turbo did in Sunday's 111F heat coming back to Livermore from Stanford Concourse.
Look at coolant temperature graph and intake air temperature graph. Even in Palo Alto car's OBC showed 100F and on way east OBC temp climbed to and at one point for several miles was at 111F. Then it got cold. Dropped to 107F.
Sincerely,
Macster.
Look at coolant temperature graph and intake air temperature graph. Even in Palo Alto car's OBC showed 100F and on way east OBC temp climbed to and at one point for several miles was at 111F. Then it got cold. Dropped to 107F.
Sincerely,
Macster.
Last edited by Macster; 04-03-2010 at 09:55 PM.
#4
Three Wheelin'
The only time my coolant temps get up too high for my comfort are when the car is not moving, in bumper to bumper traffic, for a long time (I'm talking real, 2 to 3mph stuff). Otherwise, pretty close to 180 mark.
Moving high volumes of air over the radiators (instead of hot exhaust from the car in front of you) is the key! Even 30 seconds at 60 mph is enough to dramatically reduce temps on a hot car. Opening the engine lid also helps a little
Moving high volumes of air over the radiators (instead of hot exhaust from the car in front of you) is the key! Even 30 seconds at 60 mph is enough to dramatically reduce temps on a hot car. Opening the engine lid also helps a little
#6
Race Director
Thread Starter
Um, about those colored lines... Just keeping up with traffic.
Sincerely,
Macster.
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#8
I have one of these and it's fantastic. I use it for all of my cars. It's been invaluable diagnosing issues on my wife's Accord.
I have no relationship to Macster or Davis engineering. Oddly enough I won my carchip in a contest at autogeek.net but, it's been a great product.
I have no relationship to Macster or Davis engineering. Oddly enough I won my carchip in a contest at autogeek.net but, it's been a great product.
#9
Race Car
Remember, unless you are reading the coolant sensor directly, you are NOT reading the actual coolant temperature. It is extremely unlikely (if not impossible) that your coolant temperature remained in the narrow band indicated. The OBD reading is smoothed by the computer. Additionally, there is substantial lag in the temperature sensor.
#10
Remember, unless you are reading the coolant sensor directly, you are NOT reading the actual coolant temperature. It is extremely unlikely (if not impossible) that your coolant temperature remained in the narrow band indicated. The OBD reading is smoothed by the computer. Additionally, there is substantial lag in the temperature sensor.
I think smoothed not smoothed, lag or no lag, its a clear trend that the temp is stable in a variety of different driving scenarios. Other than that, you're simply splitting hairs for a street driven car.
#11
Race Director
Thread Starter
Well, the sensor emits a voltage which is fed into an A/D converter...
Remember, unless you are reading the coolant sensor directly, you are NOT reading the actual coolant temperature. It is extremely unlikely (if not impossible) that your coolant temperature remained in the narrow band indicated. The OBD reading is smoothed by the computer. Additionally, there is substantial lag in the temperature sensor.
However, I think this value is well valid. I've observed -- used an OBD code reader/data viewer observing OBD data in real time -- many times in the various cars I've owned since OBD II became standard and seen the coolant temperature reach the trigger point when the radiator fans should come on and they do. They go off when the coolant temperature drops below the fan off temperature threshold.
If I run for instance the Boxster with the A/C off in hot weather and in slow traffic conditions, I will see coolant temperature climb to the point the fans come on then the coolant temperature drop as fans remove heat from coolant. When coolant temperature drops below fan off threshold of course the fans shut off. The coolant temperature slowly begins to climb again if the same driving conditions prevail and the process repeats itself.
The coolant temperature data very real time and not smoothed any significant amount if at all.
Other OBD data: ignition timing advance, MAF air flow, O2 sensor voltages, short term/long term fuel trims, etc. all appear reasonable, believeable and up to date, real time, as near as I can tell.
I think the coolant temperature reading obtained from the Ecu is close enough to reality to be very meaningful and useful.
Sincerely,
Macster.
#12
Parts Specialist
Rennlist Member
Rennlist Member
so which years have OBD and when did OBDII replace it ? - I see some of these are not very expensive and might be fun to record certain data for later review.
your rmp was below 3k while traveling at above 70 mph for a long stretch...for me I tend to keep in lower gear to keep the r's up a bit - sometimes I run down the freeway in 4th and as long as I dont go over 75 I just keep it there....I almost never hit 6th gear (unless I am having one of those solid red/blue line moments)
I think these are data "points" not real time rmp logs - if I draw a line at 3k rpm, you only have about 20% of your run above that line. I assume that is either because it doesnt record real time or you just dont rev the motor thru the gears as we would see more spikes from shifting - right ?
your rmp was below 3k while traveling at above 70 mph for a long stretch...for me I tend to keep in lower gear to keep the r's up a bit - sometimes I run down the freeway in 4th and as long as I dont go over 75 I just keep it there....I almost never hit 6th gear (unless I am having one of those solid red/blue line moments)
I think these are data "points" not real time rmp logs - if I draw a line at 3k rpm, you only have about 20% of your run above that line. I assume that is either because it doesnt record real time or you just dont rev the motor thru the gears as we would see more spikes from shifting - right ?
#14
#15
your rmp was below 3k while traveling at above 70 mph for a long stretch...for me I tend to keep in lower gear to keep the r's up a bit - sometimes I run down the freeway in 4th and as long as I dont go over 75 I just keep it there....I almost never hit 6th gear (unless I am having one of those solid red/blue line moments)
I think these are data "points" not real time rmp logs - if I draw a line at 3k rpm, you only have about 20% of your run above that line. I assume that is either because it doesnt record real time or you just dont rev the motor thru the gears as we would see more spikes from shifting - right ?