Macster

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.

Van

Cool - what are you using to record the data?

ivangene

awesome data - yea, how did you capture that and what is with the solid/dotted red and blue lines? Having a spot of fun?

htny

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

Macster

CarChip. My employer makes/sells this.

Sincerely,

Macster.

Macster

CarChip. Connects to car's OBD connector and requests OBD data (speed, rpm, coolant temp, etc.) and logs it to non-volatile memory for later retrieval. My employer makes/sells this device into the consumer and fleet markets.

Um, about those colored lines... Just keeping up with traffic.

Sincerely,

Macster.

Steven B

Veerrrry Cooooooooooool

LJpete

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.

1999Porsche911

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.

SH || NC

So what purpose does the OBD2 coolant temp data serve if it not valid data as you seem to suggest?

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.

Macster

and convertered to temperature. So one is not reading the actual sensor voltage but the temperature the Ecu derived from the voltage.

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.

ivangene

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 ?

Meister Fahrer

Not racing, just qualifying, ha.

Cool tool.

SH || NC

Why is that?

Kevin H. in Atl..

I tend to drive this way as well when moving about town on the interstates. The only time I use 6th is when I'm actually going somewhere. Around town, there are far too many passes to be made to simply cruise in 6th

Macsters car is a 996 Turbo...... boatloads of torque under 3k rpm.......