seedyrom
23-11-2008, 10:10 PM
An impulse buy whilst in Bunnings. The MicroTemp MT-EXP Digital Infrared Thermometer.
I've had Seldo's words from http://www.ls1.com.au/forum/showpost.php?p=1294309&postcount=156 stuck in my head for a while.
You will find that the best way to set tyre pressures for the track is with a pyrometer - tyre temp guage. You go out, do 4 or 5 laps and then come in where your pit-crew stick the pyrometer probe into the tread of the tyre and take the outer edge temp, the middle and the inner edge. You go around the car quickly and do this on all 4 tyres and record the temps and you can see whether your pressures are correct depending on the temps across the tyre.
You simply must keep a record-book where you write down all the info you can about the settings on the car, pressures, old tyres/new tyres, the weather, time of year, sunny, overcast, wet etc. It will save you trying to remember what you used that last time when you went so well/so bad. I used to have a book where we recorded all info such as the temp/weather on the day, track temp, shock settings, sway bars etc, and then had 4 pre-prepared boxes drawn which represented the tyre contact patches on the road ( LHF, RHF, LHR & RHR). Then, as they took the temps they just write them across the subject tyre box always starting from the outside>in.
What you end up with is for example:
LHF: 160, 180, 170
RHF: 155, 165, 180
LHR: 175, 190, 175
RHR: 175, 175, 177
So - what can we learn from this?
LHF: pressure too high, and a fraction too much neg (all the work is being done by the centre and inside of the tyre)
RHF: Way too much neg, and maybe drop a couple of psi.
LHR: Pressure too high (the centre of the tyre is doing all the work)
RHR: about as close as you will get to being perfect. Maybe add .5 psi.
Get yourself a pyrometer - it takes all the guesswork and trial and error out of the game and they aren't expensive - change out of $200
Hope that helps a bit.
So when I saw the gauge, and took a few in store measurements which seemed semi-accurate (full functioning via the "try me" option) I thought why not?
http://www.oz8.org/gallery/albums/album05/1_G.jpg
http://www.oz8.org/gallery/albums/album05/2_G.jpg
http://www.oz8.org/gallery/albums/album05/22_G.jpg
Got it home, aimed the "gun" at the car and pulled the trigger
http://www.oz8.org/gallery/albums/album05/3_G.jpg
That seemed about right for the day.
But I really wanted to test how accurate the gauge was.
I got 3 industrial thermometers.
http://www.oz8.org/gallery/albums/album05/4_G.jpg
http://www.oz8.org/gallery/albums/album05/5_G.jpg
I ran boiling water over a face washer, waited till it was cool enough to wring out, then placed the thermometer in it for a while
http://www.oz8.org/gallery/albums/album05/6_G.jpg
http://www.oz8.org/gallery/albums/album05/7_G.jpg
http://www.oz8.org/gallery/albums/album05/8_G.jpg
http://www.oz8.org/gallery/albums/album05/9_G.jpg
Pretty decent result, though the temperature of the rapidly cooling washer was too hard to measure properly.
Needed something more constant.
I've had Seldo's words from http://www.ls1.com.au/forum/showpost.php?p=1294309&postcount=156 stuck in my head for a while.
You will find that the best way to set tyre pressures for the track is with a pyrometer - tyre temp guage. You go out, do 4 or 5 laps and then come in where your pit-crew stick the pyrometer probe into the tread of the tyre and take the outer edge temp, the middle and the inner edge. You go around the car quickly and do this on all 4 tyres and record the temps and you can see whether your pressures are correct depending on the temps across the tyre.
You simply must keep a record-book where you write down all the info you can about the settings on the car, pressures, old tyres/new tyres, the weather, time of year, sunny, overcast, wet etc. It will save you trying to remember what you used that last time when you went so well/so bad. I used to have a book where we recorded all info such as the temp/weather on the day, track temp, shock settings, sway bars etc, and then had 4 pre-prepared boxes drawn which represented the tyre contact patches on the road ( LHF, RHF, LHR & RHR). Then, as they took the temps they just write them across the subject tyre box always starting from the outside>in.
What you end up with is for example:
LHF: 160, 180, 170
RHF: 155, 165, 180
LHR: 175, 190, 175
RHR: 175, 175, 177
So - what can we learn from this?
LHF: pressure too high, and a fraction too much neg (all the work is being done by the centre and inside of the tyre)
RHF: Way too much neg, and maybe drop a couple of psi.
LHR: Pressure too high (the centre of the tyre is doing all the work)
RHR: about as close as you will get to being perfect. Maybe add .5 psi.
Get yourself a pyrometer - it takes all the guesswork and trial and error out of the game and they aren't expensive - change out of $200
Hope that helps a bit.
So when I saw the gauge, and took a few in store measurements which seemed semi-accurate (full functioning via the "try me" option) I thought why not?
http://www.oz8.org/gallery/albums/album05/1_G.jpg
http://www.oz8.org/gallery/albums/album05/2_G.jpg
http://www.oz8.org/gallery/albums/album05/22_G.jpg
Got it home, aimed the "gun" at the car and pulled the trigger
http://www.oz8.org/gallery/albums/album05/3_G.jpg
That seemed about right for the day.
But I really wanted to test how accurate the gauge was.
I got 3 industrial thermometers.
http://www.oz8.org/gallery/albums/album05/4_G.jpg
http://www.oz8.org/gallery/albums/album05/5_G.jpg
I ran boiling water over a face washer, waited till it was cool enough to wring out, then placed the thermometer in it for a while
http://www.oz8.org/gallery/albums/album05/6_G.jpg
http://www.oz8.org/gallery/albums/album05/7_G.jpg
http://www.oz8.org/gallery/albums/album05/8_G.jpg
http://www.oz8.org/gallery/albums/album05/9_G.jpg
Pretty decent result, though the temperature of the rapidly cooling washer was too hard to measure properly.
Needed something more constant.