Pyrometres...

[Stephen06GT]

The topic of pyrometers came up at the last WNNOTC or was it track day, regardless I found this one from our friends at Longacre:

http://www.longacreracing.com/specialfunctions/serverincludes/showImage.ashx?filepath=e:\Projects\vsm\code\websi te\U\356\\Userfiles\Ecom-Images\Pyros\Dual-Infrared-probe-pyrometer-50620.jpg&nw=750

•Use as Probe type pyro for tires OR a non-contact infrared laser pyrometer
•Accurate, fast response in either mode
•1400º range on IR
•500º range with tire probe
•ºF or ºC switchable
•Includes standard tire probe and silver case


Tire Temps Tell a Story

For optimum performance (and hopefully a trip to Victory Lane) you need to maximize tire grip.

To do so you will need to run the right camber and air pressure.

Purchase a good probe type pyrometer to check tire temps and you are half way to the front.

To get accurate tire temps, it will be necessary to check each tire before the car returns to the pits. You need to do the test quickly, after a full speed practice run before the heat has the opportunity to dissipate.

For speed, you might want to consider having one crew person quickly check for temperatures, while a second crew member records the results. Another option would be to purchase the Longacre Memory Pyrometer (part # 50690) and the unit will do both functions (reading temps and recording them) at the same time. You will want to read the temps in 3 places across the tire face: the outside, center and inside area. For best results always read the tires in the same order (RF, followed by the RR, LR, LF) and each of the 3 readings in the same order.

If the middle of the tread face is hotter than both shoulders, you will want to consider lowering the air pressure. You will want to think about increasing the pressure if the center reading is cooler than both shoulders.

If the inside area of the right front tire is cooler than the outside area, you should look at increasing negative camber. Conversely, you would want to decrease negative camber if the inside area of the tread face is hotter than the outside area.

If the inside area of the left front tire is running cooler than the outside area, you should look at decreasing the positive camber. Conversely, you would increase positive camber if the inside area of the tire is running hotter than the outside tread area.

When racing on a paved oval, the goal would be to make pressure and camber changes that would keep the variance in temps across the face of the tire within 10%.

[ZR]

How much $$

[Stephen06GT]

How much $$

$219.00.

They also have this one for $145.00

http://www.longacreracing.com/specialfunctions/serverincludes/showImage.ashx?filepath=e:\Projects\vsm\code\websi te\U\356\\Userfiles\Ecom-Images\Pyros\Tire-pyrometer-50640.jpg&nw=750
•Accurate, super-fast response electronics
•Can hold highest temp reached
•Compares one temp to another with the push of a button
•Low battery indicator and auto shut-off
•2000º Range (tire probe max 500º)
•ºF or ºC switchable
•Standard coil cord tire probe and carrying case included

[Stephen06GT]

Some good reading on their site:


Tire Temps Tell a Story

For optimum performance (and hopefully a trip to Victory Lane) you need to maximize tire grip.

To do so you will need to run the right camber and air pressure.

Purchase a good probe type pyrometer to check tire temps and you are half way to the front.

To get accurate tire temps, it will be necessary to check each tire before the car returns to the pits. You need to do the test quickly, after a full speed practice run before the heat has the opportunity to dissipate.

For speed, you might want to consider having one crew person quickly check for temperatures, while a second crew member records the results. Another option would be to purchase the Longacre Memory Pyrometer (part # 50690) and the unit will do both functions (reading temps and recording them) at the same time. You will want to read the temps in 3 places across the tire face: the outside, center and inside area. For best results always read the tires in the same order (RF, followed by the RR, LR, LF) and each of the 3 readings in the same order.

If the middle of the tread face is hotter than both shoulders, you will want to consider lowering the air pressure. You will want to think about increasing the pressure if the center reading is cooler than both shoulders.

If the inside area of the right front tire is cooler than the outside area, you should look at increasing negative camber. Conversely, you would want to decrease negative camber if the inside area of the tread face is hotter than the outside area.

If the inside area of the left front tire is running cooler than the outside area, you should look at decreasing the positive camber. Conversely, you would increase positive camber if the inside area of the tire is running hotter than the outside tread area.

When racing on a paved oval, the goal would be to make pressure and camber changes that would keep the variance in temps across the face of the tire within 10%.



Probe versus Infrared


Choosing a pyrometer? What is better; probe type or Infrared? The answer really depends on the application. Most tire engineers prefer the probe type for tires as the probe gets down to the cord. At the cord, the tire heat is un-affected by out side factors and the surface rubber insulates the heat for long enough for you to take readings. There is also an elastic stretching of the rubber near the cord that creates heat as well. The bottom line is that probe type pyrometers are best for specific applications such as tires.

On the other hand, Infrared pyrometers are versatile and can be used to check just about any kind of surface temperatures. You can find sources of heat which will affect the driver, locate dead engine cylinders, check track temperatures, brakes and just about anything. You can even use them on tires. However, this is a bit of a compromise. You will be getting a surface reading that will be 10-40 degrees cooler than temps taken with a probe type pyrometer. You will also get variances from the engine and brake heat. Further, the track temperature will cool off the surface very quickly. A tire with camber in it will ride on the inside edge when the car is rolling back to the pits. The area that is in contact with the track will cool down at a different rate than the rest of the tire. Your readings will not be as relative as compared to probe readings.

If you accept the limitations, the Infrared pyrometers will work for tires but will not be relative to probe readings nor will the delineation be as good. Using the right tool for the right job always produces better results. Just as the probe type is better for tires, the infrared type is better for most other surface temps. The probe type is designed to be submerged in rubber and does not work well for things like track temperatures. For rubber, probe type is best. For surface measurements, the infrared stands out.

[Stephen06GT]

Pyrometer Tips

Table of Contents

1.Proper Depth and Location
2.Adjustable Tip Probes
3.Getting to the Tires Quickly
4.Camber Adjustments
5.Taking Advantage of New Tires
6.Averaging
7.IR Versus Probe
8.Summary


A. Proper Depth and Location

In order to get consistent and relative tire temperature readings you must be sure to insert the probe as near to the cord as possible. You must also insert the probe to the same depth at all locations at each and every tire. Temperatures should be taken at 3 locations on each tire. Take one reading at the outside approximately 1.5" from the edge, one reading in the middle, and one reading approximately 1.5" from the inside edge. Do every tire the same way at the same depth and location.

As you insert the probe deeper into the tire you will find more heat. If you insert the probe half way in at one location and then all the way in at another location you will get temperature differences due to the different depths. You are trying to see relative numbers based on how the tire is heating due to camber or loading changes. Improper depth can confuse the true issue.

By inserting the probe to a depth down near the cord you will also use the surface rubber to momentarily insulate outside elements such as brake and engine heat away from your true temperatures. Further, by getting down near the cord you will also measure heating that is caused by an elastic stretching of the rubber. If your probe is too shallow you will not see the heat generated by the pulling of rubber from the tire carcass.

Another thing to consider when using a probe type pyrometer is that rubber is a poor conductor of heat. The metal probe will suck the heat out of an insertion hole very quickly as the metal probe transfers heat quicker than the rubber. At the first tire in a temperature session you should pre-heat the probe by inserting it in the rubber a few times before taking your readings. Once the probe is pre-heated you will get faster, more accurate and relative results.

Be careful not to leave the probe inserted too long in any one location. You need to measure the temperature rise at its maximum point and no more. If you wait too long the insertion point will start to cool, giving you inaccurate readings.

Pyrometers with an anticipation feature speed up the temperature taking process and automate the procedure so that your readings are taken as quickly as possible. You simply insert the probe and immediately hit the read button. The pyrometer will calculate the rate of temperature rise and automatically lock in the highest reading. The pyrometer will then prompt you to move to the next location. Pyrometers with anticipation complete all 12 temperatures in nearly half the time of conventional pyrometers.

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B. Adjustable Tip Probes

If you use a pyrometer with an adjustable tip probe you can set the probe to match the rubber gauge (thickness) for the different tracks that you run. The adjustable tip allows you to bury the needle of the probe all the way to the housing to insure that you are at the same depth each time. Repeatability increases dramatically and the relativity is better because you are always down near the cord with your probe tip.

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C. Getting to the Tires Quickly

You should always get to your car as quickly as possible to take tire temperatures. Each time the tires roll across the pavement the cooler pavement is sucking heat from the tires, which can skew your readings. You should even have your car stop at the nearest safe place to the track and have a crewmember waiting to take the readings.

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D. Camber Adjustments

Your pyrometer is a tool to see if you need to make a camber adjustment. I like to see the infield edge of the front tires run 10-15 degrees hot. 10-15 degrees gives you an indication that you are running the maximum amount of camber that will not give you excessive tire wear. You should always monitor the wear in conjunction with your pyrometer readings to insure that you do not wear out the edge of your tires prematurely.

I. Too Much RF Camber

Sometimes teams are running more RF camber than necessary as they are fooled by their pyrometer readings. If you are running an excessive amount of RF camber the pyrometer might only show the inside edge at 20 degrees hot. What you may not see is that if you reduce camber stand the tire up the inside edge may stay 20 degrees hot. Too much of a good thing so to speak.

Start with a proven camber or your car builder's recommendation. Slowly add camber so that you can see the gradual heating of the inside edge. When you run excessive amounts of RF camber the tire is no longer able to stretch the contact surface between the sidewalls. The rubber cups and bunches at the inboard edge due to the excessive camber causing artificial heating, a loss of grip, and premature wear.

II. Too Much LF Camber

Because the LF has less load than the RF, you can sometimes see a visual clue that you have gone too far with the camber. The outside edge starts to show a strange beveled angle that is about 3/4" wide right at the outside edge. Instead of cleanly rolling the rubber off the outside edge the tire gets tipped so much when turned that it chews off the very outer edge.

I would rather have slightly less than optimum LF camber than too much. The tire performance will stay all day as compared to excessive amounts. Excessive amounts of LF camber chews off the outside edge resulting in poor performance after just a few laps. The car will not reach optimum speed and the performance of the LF will fall off very quickly.

You should strive to adjust the camber to the maximum limit without overshooting. Correct adjustments will help the car turn better on both long and short runs.

III. Too Much Stagger

On occasion you can see too much rear stagger in your tire temperatures. Sometimes the infield edges of the rear tires are noticeably hot. Depending on the tire wear characteristics of a given track, I might tone down the rear stagger to even out the edge temperatures to insure that the car is good on a long run. Judgment must prevail, as this is not a hard fast rule. Simply another variable to consider.

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E. Taking Advantage of New Tires

New tires are a big investment. Whenever a new set goes on the car I put more value in the tire temperatures from the sticker tire run and make sure that I get good temperature readings. When the tires are new they will have more friction and generate more heat than at any other time. The additional heat and added friction can provide subtle clues that may not be seen with worn tires.

Further, new tires are not worn down on any part of the contact patch. Therefore, your readings are not skewed by an area on the tire that has already been ground off. New tires have more friction so the tires are less likely to slide or spin. The temperatures more closely reflect the heat generated by tire loading. Looking at the effect tire loading gives you an indication of what the car will do in the future. Hopefully the car is already fast for the main event, but the new tire temperature opportunity might guide you into adding a touch of bite or putting in more stagger based on what you learn from your readings.

Be prepared and insure that you get a good temperature reading when new tires go on the car.

[Stephen06GT]

Continued...

F. Averaging

Temperature averaging is a good tool when your car is fast and only needs fine tuning. Tire temperatures are of little value when your car is in left field. If you car is handling poorly than the front tires will slide early in the turn and the rear tires will slide on exit. The sliding overheats the tires and can make the temperature sheet look balanced.

Temperature readings are more valuable as you get faster and faster. You can use the temperatures to assist you in fine-tuning the chassis. You might see something in the numbers that lets you look into the future allowing you to make a fine adjustment that improves the handling of the car on a long run.

Some memory pyrometers calculate the temperature averages for you. These devices really save a lot of time and allow you to use averages as another tool to fine tune your racecar. You can also use a simple calculator to accomplish the task.

Averaging Tips

By using historical information and common sense you can learn to see potential problems in your tire temperatures. Below are some scenarios based on tire temperatures and some potential cures.

Left Average is abnormally cooler than Right Average

1.Lower the panhard bar
2.Smaller sway bar or less sway bar load
3.Softer right side springs or stiffer left side springs
4.Less stagger
5.More left side air pressure or less right side air pressure
6.Less left side shock rebound


Rear Average is hotter than Front Average

1.More front spring rate if car is unstable in
2.Less rear spring rate unless car pushes on exit
3.More sway bar or more sway bar load if loose in the middle and on exit
4.Lower panhard bar
5.More front air pressure if center of tire is cool
6.Less rear weight if loose on entry and not loose on exit


Front Average is hotter than Rear Average

1.Less front spring rate if car is stable on entry
2.More rear spring rate unless car is unstable on entry
3.Less sway bar or less sway bar load if car is tight in the middle and on exit
4.Raise panhard bar
5.Less front air pressure if center of tire shows hot
6.More rear weight unless car is loose on entry or in the middle


Cross LR to RF is Hotter than LF to RR

1.Less diagonal weight
2.More stagger
3.Smaller sway bar or less load
4.Raise panhard bar
5.Less LR spring rate unless car is loose on exit
6.Less RF spring rate unless car is loose on entry
7.More LF spring rate
8.More RR spring rate unless car is loose


Cross RR to LF is Hotter than LR to RF

1.More diagonal weight
2.Less stagger
3.Bigger sway bar or more load
4.Lower panhard bar
5.Less RR spring
6.More RF spring
7.Less LF spring unless car is unstable on entry
8.More LR spring will help hook up on exit


The temperature averaging suggestions are merely a starting point intended to provoke thought. There are more variables than listed above. Driver feedback, track conditions, racecar type are all factors that can cause variances in the suggestions listed. Real racetrack specifics need to out way generalities.

G. IR Versus Probe

Probe type pyrometers are better for use on tires if used properly. Infrared type pyrometers measure only the tire surface and do not get inside the rubber to find the true results. The rubber down at the cord is insulated away from the outside elements providing for more accurate readings. Rubber at the cord is also heated due to elastic stretching of the rubber. Probes can reach in and see this heat.

Infrared pyrometers measure only the surface. The surface will be cooler as heat is dissipated off the surface very quickly due to the outside air cooling and simply rolling across the cooler track temperature. Typically the surface temperature is 20-40 degrees cooler than temperatures taken with a probe. Infrared temperatures will also be affected by artificial brake heat and engine heat.

You can use the infrared pyrometer for tire temperatures but it is a compromise. Your camber temperature curves will not be shown with as much clarity. Temperature differentials will be more dramatic with a probe allowing you to be more precise in your camber adjustments.

Infrared pyrometers do work well for surface temperatures such as track temperature, cockpit temps, header temps, brake temps, and the like. Probe type pyrometers do not work well for surface temperatures.

H. Summary

Used properly tire temperatures will allow you to see what the racecar is going to do on a long run as the tires heat and wear. You will be able to see through what might be covered up by the extra grip from your new tires as racecars always feel better when the tires are fresh.

You can learn to anticipate what the car is going to do on long runs by using temperature averaging as a tool. Temperature averaging is of little benefit if the balance of the car is dramatically off. Remember your readings have more meaning as the car approaches optimum handling. Temperature averaging is of most benefit when your car is already very fast and you are looking for that final edge.

[ZR]

Wanna split on the killer one?

[Tailites]

will it make ya go faster on street tyerz?...:)

[fast Ed]

I can tell you with out the pyrometer that you need caster / camber plates if you want to run on track and not overwork the outsides of the front tires! LOL

My suggestion would be one of the infrared pyrometers from Canadian Tire when they go on sale. I've got one that I use occasionally (when I remember to), and IMO unless you're competing and looking for absolute best lap times, the money for a fancy probe pyrometer is better spent elsewhere ... like on a set of MM caster plates.


cheers
Ed

[Tailites]

awesome on tube headers to diagnose hot cylinders or miss firing cylinders

[NickD]

For those interested I was at Canadian tire last night and saw the master craft one was on sale for $40 if I remember right

Sent from my HTC One_M8 using Tapatalk

[ZR]

You get me one buddy?

[CON VERT]

^^^^ You can have mine Rick, never use it !