Pyrometer user feedback for tracked TA and other non adjustable Gen V s

[Bruce H.]

I'm getting serious with my TA's setup for track day performance and tire longevity. A buddy has taken my tire temps with his Longacre unit on a few occasions, but I'll be using my own consistently this summer in an effort to dial in alignment, pressures and my driving. Factory alignment has never been checked, and I'd like to check it first as a good starting point from which to make any adjustments based on temps.

While the temp reading we've taken have not always been immediate after coming in off a hot lap, they generally show that the fronts are considerably hotter than the rears, and the front insides hotter than the outsides. The front tread always starts to peel/delaminate on outside, indicating overheating that the pyro readings don't reflect, likely because of where the readings are made in the pits relative to the corners on the track that are hardest on the fronts. The higher average front temps would be partially reflecting the higher front brake temps immediately following a high speed straightaway brake zone and from engine temps to a lesser degree. I've been running 32-34 psi all around on the Corsas, and if it is still at factory alignment setting then camber should be -2.5 f/-1.5r. My sense is that alignment and pressures aren't far off, and that the peeling from overheating is from too high corner entry speed on two particular corners where the front pushes a fair bit. I try to show restraint there, but hey, when the chase is on.....

So I'm hoping those of you who have used a pyrometer to dial yours in can offer some advise. Differences in driving styles, tracks and other conditions would affect results but there should be at least some consistency in findings and recommendations, particularly since the suspension is otherwise non-adjustable.

Also, monitoring temps has likely been one reason that has led some of you to install a fully adjustable suspension, thereby allowing you to optimize tire temps and handling. How effective did you find that modification for balancing temps? I suspect I'll be upgrading at some point.

I'll be using the Longacre #50690 with memory...
http://www.longacreracing.com/produc...Tire+Pyrometer
There are some good tech articles at the bottom of that link for those that would like to learn more about the value of monitoring tire temps.

Thanks in advance for any feedback.

Bruce

[38D]

A 20 degree spread across the tire is typical. You definitely need to do temps immediately after a hot lap (no cool down at all) as they change rapidly.

The first thing you need to figure out is if the fronts are too hot, or the rears are not hot enough. At bondurant, the instructors definitely spent a lot of time working on doing more trail braking, and getting on the gas later. This reduced understeer, and also was easier on the tires.

[steve911]

That is one heck of a Cadillac pyrometer. there a several others that are much cheaper with a direct contact probe that will work just fine.

I have a single read pyrometer and a small dry erase board that I write everything down on as I check.

Checking temps as soon as you get back to the pits is imperative, other wise your readings will not accurately portray what's happening out on the track.

[Bruce H.]

A 20 degree spread across the tire is typical. You definitely need to do temps immediately after a hot lap (no cool down at all) as they change rapidly.

The first thing you need to figure out is if the fronts are too hot, or the rears are not hot enough. At bondurant, the instructors definitely spent a lot of time working on doing more trail braking, and getting on the gas later. This reduced understeer, and also was easier on the tires.

Good advice. It'll be interesting to see how changing braking in those corners will affect temps. On most corners on my home track I do tend to threshold brake to turn-in and then release, which contributes to heating the fronts as well. It makes me wonder how much impact there is to temps when shifting the factory bias more to the fronts.

That is one heck of a Cadillac pyrometer. there a several others that are much cheaper with a direct contact probe that will work just fine.

I have a single read pyrometer and a small dry erase board that I write everything down on as I check.

Checking temps as soon as you get back to the pits is imperative, other wise your readings will not accurately portray what's happening out on the track.

That's for sure, but I'm hoping by making it easy and quick that I'll do it more often and more accurately. The calculated averages across each tire, and balances front to rear and diagonally will save a lot of work and show at a glance what's happening. I think the probe's insert time is reduced by its ability to predict peak temps before actually measuring it based on the rate of temp increase vs time. Pretty slick datalogging.

[TrackAire]

Bruce,
If you're doing this alone at the track, IMO you'll get readings that will not be accurate enough to formulate a true tire temp reading. By the time you get off the track, into the pits, out of the seat and get the tire pyro ready your temps will be so far off its not going to help much. If you have a helper the track to grab the temps in the hot pit lanes, that would be better.

This is the technology you need to get accurate data that matters. I cannot speak if this is the best system, but here is an example of what I'm talking about:

http://www.izzeracing.com/products/i...e-sensors.html

[J TNT]

Bruce,
If you're doing this alone at the track, IMO you'll get readings that will not be accurate enough to formulate a true tire temp reading. By the time you get off the track, into the pits, out of the seat and get the tire pyro ready your temps will be so far off its not going to help much. If you have a helper the track to grab the temps in the hot pit lanes, that would be better.

This is the technology you need to get accurate data that matters. I cannot speak if this is the best system, but here is an example of what I'm talking about:

http://www.izzeracing.com/products/i...e-sensors.html

That's an impressive set up , and the ability to adjust emissivity makes it top tier !

[Bruce H.]

Thanks George. I'm not familiar with this system and will check it out. What system do you or have you used?

[TrackAire]

Thanks George. I'm not familiar with this system and will check it out. What system do you or have you used?

Back when I was pitting for a SCCA GT4 car we didn't have access to this technology but found to get "decent" temps the driver would dive off the track on a hot lap and pull into the hot pits as fast as possible and we'd get readings as fast as possible. We'd start at different corners of the car just to see what differences the temps were from the last session and how much the tires cooled down just in the time it took to get from the first tire to the last. Can you get a baseline and try to work on some sort of temp based camber and pressure data, yes but with the new technology available now you can get much more valuable data from the entire track, not just the last corner. After watching the video in the link, it shows have fast tire temps change.

It would be very interesting to have an IR system on a ACR-E with Kumho's to see what the front tire temps are actually doing.

[Bruce H.]

George, rapid temp changes is certainly a huge challenge, and the pits are often a long ways from the most demanding tire loads. I read an article recently that recommended measuring temps all the way around and then the first tire again after the last in order to see how much the tires had cooled even while measuring them. Then you can factor that into the collected measurements to help interpret them. It also mentioned the difference between measuring faster changing surface temps with IR vs deeper in the tread with a probe where it changes slower, but that was related to measuring in the pits vs instantaneously on the car.

Real time IR measuring with the system you suggested shows surface temps, and I'm not sure whether surface or internal temps are the more critical, or if both are needed to optimize setup to achieve perhaps different goals. My first goal is to avoid the overheating that prematurely destroys the front Corsa tires. Would the surface or internal temp be the critical one, or is one as good as the other? Any info and links would be helpful. I should probably also contact Pirelli. Tricky subject, and I can see I have lots to learn before ordering anything.

The video shows that braking almost consistently heats the tires more than cornering, which didn't surprise me, but none-the-less rather interesting to see. What was hard to tell from the G meter was how much actual trail braking he was doing, which would load and heat the front outside tire more than either braking or cornering. That's been one of my driving considerations in trying not to overheat the fronts.

[38D]

Temp in the carcass is really just a proxy for surface temps. Surface temps change very rapidly (ever seen the IR camera view in F1?). Top pro racing teams use sensors like the ones below, and then log the data for analysis.

https://www.texense.com/en/produits/...sport-_73.html

[Bruce H.]

Very cool, but I don't think those sensors are for me!

So I'm starting to question the benefit of monitoring temps. I seldom see reference to temp monitoring on the forums when discussing set-up or tire wear, and seldom see it done at the track, which seemed odd considering how expensive and frequent tracked tires need to be replaced on a Viper. The Longacre deluxe pyrometer basically costs about the same as one tire...and I'll go through quite a few of those this year.

[Arizona Vipers]

I use that same Longacre pyrometer as you, it's great.
You are probably thinking too much into this at this point unless you are looking to get a couple 10ths faster than you are just by checking/adjusting pressure.
I used to be a fanatic with tire temps, constantly checking after each session. Now I just go by pressures. I have a goal hot temp for all tires, then after a session I will lower the hotter tires down to the coldest tire pressure. The goal is to be able to come off a session with all 4 tires the exact same tire pressure.

[Bruce H.]

That's what I've been doing as well, and since I'm not chasing 10ths then maybe it's enough...

unless you're talking 10th of a minute in which case I'm ordering those fancy F1 sensors

[38D]

I've always found tire temps most useful for dialing in car setup (caster, camber, toe, shock settings, swaybar position, etc). Once you have a good setup for a given track, tire pressure tends to work just as well for 1/10th the effort.