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Pyrometer readings - too much camber?


turbogrill
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Hi

 

Based on these readings it looks like I have to much camber? Inner is hotter. 

 

The previous owner of the car was much faster than me, I struggle to be fast in this car. I think the car is setup well.

 

Could it just me not pushing it enough in the corners? It feels like if I push more i will just scrub speed.

 

 Car is a 1.6 na miata with 205 falkens rt615

PXL_20201113_173942896.jpg

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Those don’t look too bad.  20 degree spread is normal.  Maybe RF is a bit over inflated. The inside is always a tad hotter because it always has contact with the road.   Down the straights, the outside doesn’t touch (or has less pressure)

If you do a lap or even half a lap “cool down” on the way into the pits it will exaggerate the spread.  You should always drive at race pace and come directly into the pits to get the fastest temp readings that you can. 

 

I'm not familiar with the tire, so not sure if the operating range is optimal or not.

Edited by petawawarace
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5 minutes ago, petawawarace said:

Those don’t look too bad.  20 degree spread is normal.  Maybe RF is a bit over inflated. The inside is always a tad hotter because it always has contact with the road.   Down the straights, the outside doesn’t touch (or has less pressure)

If you do a lap or even half a lap “cool down” on the way into the pits it will exaggerate the spread.  You should always drive at race pace and come directly into the pits to get the fastest temp readings that you can. 

I agree with exactly everything said.

 

However, they are all kinda cold if you were pushing hard.  I usually see at least 10 to 20 degrees warmer everywhere.

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Hi.

40 minutes ago, Burningham said:

What are:

 

hot and cold tire pressures?

camber and toe front and back?
caster?
Coilovers?


Hard to tell much without knowing a bit more. 


Hot is supposed to be 35psi, not sure about cold. 

Car has KYB shocks and Racing Beat springs (OEMish), aftermarket front sway.

Don't know camber or caster, but I assume that they are set to a "race alignment" (as the previous owner raced this car successfully for a while).

 

55 minutes ago, wvumtnbkr said:

I agree with exactly everything said.

 

However, they are all kinda cold if you were pushing hard.  I usually see at least 10 to 20 degrees warmer everywhere.

 

Agree on the temps looking low. No cool down laps and I absolutely violated pit road speed. Jumped out of the car and took temp measures with helmet and hans.

 

Maybe I just need to push more but it feels like the car would go slower and just scrub tires if pushed more.

 

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http://949racing.com/using-a-tire-pyrometer-949-Racing.aspx

 

How old are the tires? Any pictures of the tread faces? If they have a few heat cycles you may have to slide them a bunch to get some heat in them before they'll work. 

 

It takes grip to get temp and it takes temp to get grip, and sometimes you have to help the process.

Edited by mender
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22 minutes ago, mender said:

http://949racing.com/using-a-tire-pyrometer-949-Racing.aspx

 

How old are the tires? Any pictures of the tread faces? If they have a few heat cycles you may have to slide them a bunch to get some heat in them before they'll work. 

 

It takes grip to get temp and it takes temp to get grip, and sometimes you have to help the process.

Plenty of thread but maybe 10 heat cycles, each being 45mins or so.

The rt615 is a long lasting tire.

 

I will redo the measurements and push more, but it doesn't feel like that will help with laptimes. 

 

The junkyard 1.6 has so little power it's hard to get into trouble :)

I guess I need to brake way less, can't really loose grip with the throttle :)

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Drop your tire pressures a couple of pounds each then try again, you might find they feel sloppy initially but start working after a few laps. 

 

How many laps did you do before checking the temps? Which track? How stiff are your suspension bushings?

Edited by mender
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1 hour ago, mender said:

Drop your tire pressures a couple of pounds each then try again, you might find they feel sloppy initially but start working after a few laps. 

 

How many laps did you do before checking the temps? Which track? How stiff are your suspension bushings?

 

15 laps maybe at Harris hill. Bushings are probably in bad shape, this is a pretty beat up car.

 

Still a great car.

 

Very soft suspension, why?

Edited by turbogrill
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8 hours ago, turbogrill said:

Plenty of thread but maybe 10 heat cycles, each being 45mins or so.

The rt615 is a long lasting tire.

 

I will redo the measurements and push more, but it doesn't feel like that will help with laptimes. 

 

The junkyard 1.6 has so little power it's hard to get into trouble :)

I guess I need to brake way less, can't really loose grip with the throttle :)

 

Try trail braking/sliding it a bit into the turns.  Be a little ham fisted.  I was never a huge fan of the RT61&s on track.  They last yes, but they never seem to match the grip of even an RS4.

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Knowing the alignment specs on the car would help a lot.  Looks like dropping pressures by a pound or so would also be a step in the right direction.  To me, it almost looks like too much camber in LF compared to the rest of the car.  Overall, yes, temps are a bit low.  Be sure you are not just taking a "surface temp", but are getting the probe into the rubber (more heat held there).

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10 hours ago, turbogrill said:

 

15 laps maybe at Harris hill. Bushings are probably in bad shape, this is a pretty beat up car.

 

Still a great car.

 

Very soft suspension, why?

Because that will have an effect on how the car needs to be set up for you. 

 

The bottom line is that if the tires are happy, the car is happy. Keeping the tires happy means keeping the tread (not "thread") face stable and as flat as possible when fully loaded in the corner. Sloppy suspension bushings, narrow rims (what width are yours?), poor suspension geometry with soft suspension all allow the tire to move too much and compromise the grip.

 

You said the suspension seemed to work well for the last owner/driver but not for you.  From the sound of it, you're not getting the tires up to the temp that he was and so the settings that he's using aren't quite right. More load means more flex everywhere, and that means more static camber to compensate in order to get the dynamic camber right for those tires and the way you're driving it.

 

My advice is to sell those tires to someone else and get newer/stickier tires and do some more testing. A fresh set of RE-71Rs would probably transform the car and your tire temps might show that you don't have enough camber for those tires.

 

Having tires that last too long can sometimes be as much a problem as ones that don't last long enough, which is why it's not a good idea to test with old tires. 

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Thanks. 

 

I forgot to mention that this is for a non chumpcar that requires these tires. However next year they are using the rt660

 

Running the RE71r on my NC, it's like it's glued to the ground. Love that tire.

 

I went out today and did a little better, did 1.35 but need to do 1.33. more practice should so it.

 

 

 

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This is just what I have found over the years and I am sure some will disagree, and hopefully we can have a healthy discussion if you do.

 

First thing. Tire pressure does not matter from car to car. Do not ask, what tire temp do you run hot and just run that. Car to car can be very different. We run 32psi hot RS4 on the rear and 31 front right and 30.5 front left at track X. Another team I saw ran 39PSI hot, but different car. Basically what I am saying is that do not focus on tire pressures until the very end as you need to get the alignment right for temperatures first. Do not get stuck on trying to get to a certain pressure and worry about getting the correct temperature across the tire.

 

I have made adjustments on my alignment based on the tire temps and here some things that I see from the numbers I see.

 

The tire temps are far to low. This tells me that the driver did not come in hot and get the temps right away. This would make the tire temps not really worth any real data at this point to me. Example. Assuming the tires were at 160 +/- 15 and now are at 120 is a huge difference. I am sure they did not cool down equally. First thing is come in really hot. When we do this at a race we do tire temps first in a pit stop, fuel up and while fueling up we look at the tire temps and then adjust when fueling is done.

 

For us when we adjusted the alignment and got the tire temps right we added 33-50% more life out of our tires. We have even wear and we also do not have hot spots on the tire that wear out much faster.

 

I like to see 10-15 degrees from outside to inside of each front tire going up or 15 at times and about 6-12 on the rear.  Basically 140-150-160 front 142-150-158 rear.

 

From your data

108-120-131  111-120-109

108-122-123  128-125-118

 

I am assuming zero front toe and maybe 1/32 toe in the rear.

Tire temps in the middle are high so the pressure is to high on all tires, but front left. This tells me you were going for tire pressures and not temperature, but easy fix.

Not enough camber on on the front.

Front left has some good camber, but might need another.3 to .5 degrees

Front right needs like 1 degree more of camber

Rear left camber looks close, .2 degree more

Right rear camber looks close .2 degree more

 

This is also track dependent. Once you keep track of the data over 4-5 tracks and keep track of the number of turns, left and right. This way when you go to a new track you will know what to do. We know what the alignments should be now and make fine adjustments at the track if needed. 

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5 minutes ago, MR2 Biohazard said:

This is just what I have found over the years and I am sure some will disagree, and hopefully we can have a healthy discussion if you do.

 

First thing. Tire pressure does not matter from car to car. Do not ask, what tire temp do you run hot and just run that. Car to car can be very different. We run 32psi hot RS4 on the rear and 31 front right and 30.5 front left at track X. Another team I saw ran 39PSI hot, but different car. Basically what I am saying is that do not focus on tire pressures until the very end as you need to get the alignment right for temperatures first. Do not get stuck on trying to get to a certain pressure and worry about getting the correct temperature across the tire.

 

I have made adjustments on my alignment based on the tire temps and here some things that I see from the numbers I see.

 

The tire temps are far to low. This tells me that the driver did not come in hot and get the temps right away. This would make the tire temps not really worth any real data at this point to me. Example. Assuming the tires were at 160 +/- 15 and now are at 120 is a huge difference. I am sure they did not cool down equally. First thing is come in really hot. When we do this at a race we do tire temps first in a pit stop, fuel up and while fueling up we look at the tire temps and then adjust when fueling is done.

 

For us when we adjusted the alignment and got the tire temps right we added 33-50% more life out of our tires. We have even wear and we also do not have hot spots on the tire that wear out much faster.

 

I like to see 10-15 degrees from outside to inside of each front tire going up or 15 at times and about 6-12 on the rear.  Basically 140-150-160 front 142-150-158 rear.

 

From your data

108-120-131  111-120-109

108-122-123  128-125-118

 

I am assuming zero front toe and maybe 1/32 toe in the rear.

Tire temps in the middle are high so the pressure is to high on all tires, but front left. This tells me you were going for tire pressures and not temperature, but easy fix.

Not enough camber on on the front.

Front left has some good camber, but might need another.3 to .5 degrees

Front right needs like 1 degree more of camber

Rear left camber looks close, .2 degree more

Right rear camber looks close .2 degree more

 

This is also track dependent. Once you keep track of the data over 4-5 tracks and keep track of the number of turns, left and right. This way when you go to a new track you will know what to do. We know what the alignments should be now and make fine adjustments at the track if needed. 

Nice analysis.  

 

That all sounds about right to me!

 

Question for you Troy: did you take a guess on the toe setting or are you somehow seeing that in these temps?

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9 minutes ago, MR2 Biohazard said:

I am assuming zero front toe and maybe 1/32 toe in the rear.

 

I think until he gets good recent alignment data this is too liberal of an assumption.  It's an important piece of the puzzle.

 

And agree with Rob, good assessment.

Edited by Burningham
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39 minutes ago, mender said:

Might want to check the corner weights as well, there might be some wedge in the car.

To start that, corner balance with person in the car and 50% fuel

Adjust caster

Adjust camber

recheck corner balance

adjust toe

tire tempature

adjust pressure

use data to make alignment changes

start over again

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24 minutes ago, mender said:

Slight change to the order: set your tire pressures to your usual hot psi, set your ride height then set your corner weights. 

I am going to try that and see if there is a measurable difference between hot and cold pressure. I could see winter being a bigger difference.

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