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      09-08-2016, 08:21 AM   #23
paradoxical3
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Quote:
Originally Posted by koastal View Post
Your car paradoxical ?

Sounds like you gave it a serious work out and had some fun doing it.


http://www.roadandtrack.com/car-cult...?click=taboola
Yup! Jack was a fun guy to hang out with, and I did almost go off. However, he drove the car in the instructor group for a full session and I took it out immediately in the A group right after. The tires were already 160f when I left the pits, which contributed to the tank slapper in thunder valley (wasn't expecting them to be greasy on the out lap, which I absolutely should have anticipated). RE71R are great tires, but really aren't designed for 1hr stints. So it's probably not valid to compare tire temps given the higher starting point, but for the sake of a good article it makes sense and I agree with the overall point of what he is trying to say.

One thing I am curious about is how the m2 knows what temps the tires are. Is it calculated? If not, is the sensor built into the TPMS? I wonder what it is actually reading, must be either temp of the metal wheel or maybe the air inside the tire.

Last edited by paradoxical3; 09-08-2016 at 08:36 AM..
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      09-09-2016, 07:57 AM   #24
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Quote:
Originally Posted by paradoxical3 View Post
Yup! Jack was a fun guy to hang out with, and I did almost go off. However, he drove the car in the instructor group for a full session and I took it out immediately in the A group right after. The tires were already 160f when I left the pits, which contributed to the tank slapper in thunder valley (wasn't expecting them to be greasy on the out lap, which I absolutely should have anticipated). RE71R are great tires, but really aren't designed for 1hr stints. So it's probably not valid to compare tire temps given the higher starting point, but for the sake of a good article it makes sense and I agree with the overall point of what he is trying to say.

One thing I am curious about is how the m2 knows what temps the tires are. Is it calculated? If not, is the sensor built into the TPMS? I wonder what it is actually reading, must be either temp of the metal wheel or maybe the air inside the tire.
Ideal Gas Law. PV=NRT, just solve for Temp. T=PV/NR, where pressure is known, volume is constant. With Ambient temps and starting pressure, its easy to calculate temperature from the change in pressure. Pressure goes up as the tires get hot, just back calculate temp. Science!

Last edited by Spinnetti; 09-09-2016 at 08:03 AM..
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      09-11-2016, 08:50 AM   #25
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@paradoxical3 Don't forget about those in the right seat as you continue to work ok ways to get more comfortable while tracking the car
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      09-11-2016, 09:28 AM   #26
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Quote:
Originally Posted by koastal
Your car paradoxical ?

Sounds like you gave it a serious work out and had some fun doing it.


http://www.roadandtrack.com/car-cult...?click=taboola
Or, in other words, attend an autocross once in awhile


The two sides of tire mountain are seen at every autocross course at every event. Some drivers are getting the back end around and on the edge of grip and dancing the car around with tire squealing and lots of corrections.

Some drivers will go through the course and not make a single tire squeal and you don't even hear the car go around the course and then they come up with a time that is .2 seconds faster than the driver above and everyone is shocked.


Unfortunately, most HPDE instructors cringe in fear when they hear a student has autocross experience. I LOVE IT. I know the autocrosser likely at least has developed some car control skillz, and also likely can control the car AFTER. The car has gone to the wrong side of "Tire mountain". In other words , an autocrosser isn't going to PANIC where a novice definitely might.

While it can certainly be done on track ,
It's a lot safer to play with the back side of tire mountain at an autocross to start.
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      09-12-2016, 01:02 PM   #27
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Quote:
Originally Posted by M3 Adjuster View Post
Or, in other words, attend an autocross once in awhile


The two sides of tire mountain are seen at every autocross course at every event. Some drivers are getting the back end around and on the edge of grip and dancing the car around with tire squealing and lots of corrections.

Some drivers will go through the course and not make a single tire squeal and you don't even hear the car go around the course and then they come up with a time that is .2 seconds faster than the driver above and everyone is shocked.


Unfortunately, most HPDE instructors cringe in fear when they hear a student has autocross experience. I LOVE IT. I know the autocrosser likely at least has developed some car control skillz, and also likely can control the car AFTER. The car has gone to the wrong side of "Tire mountain". In other words , an autocrosser isn't going to PANIC where a novice definitely might.

While it can certainly be done on track ,
It's a lot safer to play with the back side of tire mountain at an autocross to start.
2nd that! When I first went road racing, I was .2 off the track record on my first time in a race car on a race track, and won the first race I entered too - they thought I had previous experience, but only Auto-x... great for car control, though a lot of auto-x guys risk being too fast on the hands in race traffic which is like slo-mo in comparison; more about rythym and strategy than quick thinking...
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      09-12-2016, 01:05 PM   #28
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Quote:
Originally Posted by M3 Adjuster View Post
Some drivers will go through the course and not make a single tire squeal and you don't even hear the car go around the course and then they come up with a time that is .2 seconds faster than the driver above and everyone is shocked.
With autox perhaps, but on the track that's not necessarily true when it comes to actually setting a fast lap on street tires. If they don't have any slip angle than they aren't at their maximum grip. Going over optimal slip angle is bad, but even on the safe side they will squeal like crazy. There is a difference between squealing tires and scrubbing them. If a driver isn't squealing their street tires, they aren't driving very hard.

Last edited by paradoxical3; 09-12-2016 at 01:13 PM..
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      09-12-2016, 02:22 PM   #29
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Quote:
Originally Posted by paradoxical3
Quote:
Originally Posted by M3 Adjuster View Post
Some drivers will go through the course and not make a single tire squeal and you don't even hear the car go around the course and then they come up with a time that is .2 seconds faster than the driver above and everyone is shocked.
With autox perhaps, but on the track that's not necessarily true when it comes to actually setting a fast lap on street tires. If they don't have any slip angle than they aren't at their maximum grip. Going over optimal slip angle is bad, but even on the safe side they will squeal like crazy. There is a difference between squealing tires and scrubbing them. If a driver isn't squealing their street tires, they aren't driving very hard.
I have to agree with this. I was there that day driving mine as well. On the stock tires. About 7 of those corners at least, if your not scrubbing tire on the verge of squeal or squealing your not going fast enough. At least on my street tires. Slicks are different. My temps stayed about 15-20 degrees lower than that but I'm also not experienced and was running upper 1:40's.

I am guilty of going very sideways through thunder valley as well. It wasn't a tank slapper but it's not hard to do there. Uphill over a crest of sorts, little too much trail braking into it got me overly unsettled very quickly.

That silver c6 Z06 on slicks was basically jump hucking itself into grip/"after the mountain" in the instructor group. Crazy to watch.
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      09-12-2016, 02:31 PM   #30
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Quote:
Originally Posted by M3 Adjuster View Post
Or, in other words, attend an autocross once in awhile


The two sides of tire mountain are seen at every autocross course at every event. Some drivers are getting the back end around and on the edge of grip and dancing the car around with tire squealing and lots of corrections.

Some drivers will go through the course and not make a single tire squeal and you don't even hear the car go around the course and then they come up with a time that is .2 seconds faster than the driver above and everyone is shocked.


Unfortunately, most HPDE instructors cringe in fear when they hear a student has autocross experience. I LOVE IT. I know the autocrosser likely at least has developed some car control skillz, and also likely can control the car AFTER. The car has gone to the wrong side of "Tire mountain". In other words , an autocrosser isn't going to PANIC where a novice definitely might.

While it can certainly be done on track ,
It's a lot safer to play with the back side of tire mountain at an autocross to start.
2nd that! When I first went road racing, I was .2 off the track record on my first time in a race car on a race track, and won the first race I entered too - they thought I had previous experience, but only Auto-x... great for car control, though a lot of auto-x guys risk being too fast on the hands in race traffic which is like slo-mo in comparison; more about rythym and strategy than quick thinking...
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