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Old 08-31-2012, 05:02 PM   #201
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Thanks Alta Racer. I won't be able to make the event on the 22nd, but I'll be at Monday's Time Attack at Stratotech. You?
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Old 08-31-2012, 05:41 PM   #202
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long weekend, I get to work.
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Old 09-10-2012, 05:55 PM   #203
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Quote:
Originally Posted by Alta_Racer View Post
Deer Hunter

After hard days at Statotech (the go cart track) my rotors look similar to the bottom pic, my brakes (94+ and XP10) work flawlessly there. I have yet to have fade, pedal loss, or bubbles bleeding after an event. I use the Prestone 5.1 fluid from CTC. It's cheap and will be upgraded this winter, when I turn up the power. For comparison to your times, I run 70 second laps, I am NA. If you know Grant with the white Mustang or Adelbert with the black GTR, we run quite close, they certainly out power me on the straights.

I think we have openings on the 22 Sept if you want more track time. 8am till noon
70's @strato is not fast enough to require any significant brake mods. I ran that on pbr ultimates (fading ever so slightly after 10min) on 94+ brakes.

Not to mention the speeds at the indy track are much higher then stratotech.
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Old 09-10-2012, 07:35 PM   #204
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Are there any alternatives to these Alcon temp strips or has anyone here used them with success? Has anyone taken caliper temps for reference?

I remember reading a post stating getting them up to temp and it was barely at the minimum indicator, not much resolution. I am interested in taking temperatures pre and post ducting to see how effective I make it so I have a measurement of improvement.
My IR temp gauge maxes out as is, but it only goes up to 230-250 or so. I can get readings in the rear, but fronts it just says "HOT!"

If the Alcons would read one bar from 250F to 340F, I don't think that's much resolution (I don't think my 1.6 brakes are getting above 340F front, but staying below 230F in the rear.

Kit Consists of 14 Temp Indicator Strips with a temperature range of 250F to 536F

Recommended Brake Caliper Temps:

Up to 340F - Too Cool
350F-400F - Ideal
400F-450F - OK
475F plus - Too Hot

Tempature Indicator Strips - Alcon Brake Caliper Kit
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Old 09-10-2012, 07:45 PM   #205
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My infrared gun goes to 1500f. It isn't as accurate as test strips since everything cools some while I am coming off track instead of showing a 'high water' mark. Mainly, I look for temperature differentials front to back and side to side. I keep it in the door pocket of the truck and shoot the trailer's wheel bearings at least once during each long tow. Again, 3 bearings at +/- two degrees of each other and the 4th bearing 40 degrees hotter is all I need to know that trouble is on the horizon.
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Old 09-10-2012, 08:09 PM   #206
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Quote:
Originally Posted by mr_hyde View Post
My infrared gun goes to 1500f. It isn't as accurate as test strips since everything cools some while I am coming off track instead of showing a 'high water' mark. Mainly, I look for temperature differentials front to back and side to side. I keep it in the door pocket of the truck and shoot the trailer's wheel bearings at least once during each long tow. Again, 3 bearings at +/- two degrees of each other and the 4th bearing 40 degrees hotter is all I need to know that trouble is on the horizon.
mr_hyde, do you think an infrared gun would be better instead of a "high water" mark for what I'm looking for? (keeping 1.6L brakes for as long as i can for weight... 1.6L power, on all seasons until I am sure my driving is up to sniff). p.s. all seasons still overheat Hawk HP+

the hotter corner is exactly what i found the night before a track day. i have a small IR meter, which is probably why it's limited to 230-250*. One corner was 50 degree hotter (pax front)-- piston seized i think as i found a hole in the boot. Luckily I had a spare with a good piston boot. It got me to the track the next morning, but was having brake issues all day (on top of heat cycled tires, 80A durometer, but that's another thread). The freshly lubed slider pin probably led to this:



same tires i ran 8 months ago, when it was running 4 seconds faster (in 48-61 gnd temps). when the brakes locked up, the tires were quiet about it until i saw smoke. i think this shot was in the first few laps. i had to ease off the brakes the rest of the day with 90-125F ground temps.
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Old 09-10-2012, 08:36 PM   #207
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My IR gun from Harbor Freight was $29 and goes up to 500+ I think. It shows enough info to be useful, including trans and diff temps. Temp strips would be useful for showing peaks as stated.
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Old 09-11-2012, 04:17 AM   #208
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Measuring rotor temp is best done with paint on the edge.
E.g. https://www.pegasusautoracing.com/gr...upID=TEMPPAINT
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Old 09-11-2012, 08:47 PM   #209
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Quote:
Originally Posted by greeenteeee View Post
mr_hyde, do you think an infrared gun would be better instead of a "high water" mark for what I'm looking for? (keeping 1.6L brakes for as long as i can for weight... 1.6L power, on all seasons until I am sure my driving is up to sniff). p.s. all seasons still overheat Hawk HP+
All seasons are gonna be harder on your brakes than race tires.

--Ian
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Old 09-11-2012, 09:14 PM   #210
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Originally Posted by codrus View Post
All seasons are gonna be harder on your brakes than race tires.

--Ian
Strongly disagree. It's approximately the same amount of kinetic energy being converted to heat, but the conversion happens in a far more compacted amount of time with race tires, resulting in higher peak temperatures.
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Old 09-11-2012, 09:36 PM   #211
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On the other hand. Your corner speed will be WAY lower but your acceleration will be largely unaffected, so you will have to brake more to slow down to that corner speed.
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Old 09-12-2012, 11:08 AM   #212
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The energy needed to accelerate is roughly the same that the brakes need to convert to heat during braking (minus some wind/rolling/transmission resistance). On the stickier tires, the overall speed around the track is higher, which actually leaves less time to build up energy between corners, which the brakes then need to deal with. On the other hand, you can start accelerating earlier out of the corners, which comes more into play on a high speed track with soft curves.

Now, the real issue is the time needed for the heat to move from the brake rotors to the air cooling them. On stickier tires there is simply less time between braking, so the heat will build up faster and generally sit at a higher level than on street tires.

- Tom
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Old 09-12-2012, 01:51 PM   #213
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Quote:
Originally Posted by Savington View Post
Strongly disagree. It's approximately the same amount of kinetic energy being converted to heat, but the conversion happens in a far more compacted amount of time with race tires, resulting in higher peak temperatures.
But is it the higher peak temperature or the amount of time at elevated temp with brakes applied that wears out the brakes.

Higher delta T means a faster heat rejection rate will occur and less distance on the brakes in the braking zone means more percentage of time off the brakes to reject heat and less percentage of the time generating it.

Bob
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Old 09-12-2012, 02:19 PM   #214
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Quote:
Originally Posted by Handy Man View Post
On the other hand. Your corner speed will be WAY lower but your acceleration will be largely unaffected, so you will have to brake more to slow down to that corner speed.
If cornering speeds are higher, straightaway speeds will be higher.

Quote:
Originally Posted by one-niner View Post
Now, the real issue is the time needed for the heat to move from the brake rotors to the air cooling them. On stickier tires there is simply less time between braking, so the heat will build up faster and generally sit at a higher level than on street tires.
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Higher delta T means a faster heat rejection rate will occur and less distance on the brakes in the braking zone means more percentage of time off the brakes to reject heat and less percentage of the time generating it.
Eh, that's debatable. The laps are shorter, but the braking zones are more compacted. You would need to look at actual data to know whether the brakes have the same amount of time to shed the heat or not.

In any case, you also need to look at the force applied - since you're producing (essentially) the same amount of heat, but doing it in a shorter period of time, the force required to make that heat is higher, and this is going to wear on the brakes.

At the end of the day, the difference in heat rejection vs. heat production times is probably negligible, but the race-tire car is going to have brakes that are pushed harder and operated at higher tempeatures than the street car. That's going to cause additional wear.
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Old 09-12-2012, 05:46 PM   #215
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Quote:
Originally Posted by Savington View Post
If cornering speeds are higher, straightaway speeds will be higher.
Of course, but "higher" is a relative term. Say a street tire car corners 10mph slower than a race tire car. The race tire car will exit the corner 10mph faster, however all cars accelerate faster at lower speeds. Therefore at the end of the straight the race tire car will only be going slightly faster than the street tire car, say 3mph faster.

10mph > 3mph

Of course this all depends on the track. The longer the straight the more pronounced the effect, and whether or not this effect is greater than the other effects you mentioned is beyond anyone's guesstimating ability.

A simple way to think about it would be a track in which the car reaches its top speed on every straight (something like Indy's oval with an under geared car). Obviously in that scenario race tires would always be easier on your brakes.
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Old 09-13-2012, 12:16 AM   #216
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Quote:
Originally Posted by Savington View Post
If cornering speeds are higher, straightaway speeds will be higher.

Eh, that's debatable. The laps are shorter, but the braking zones are more compacted.
For what it's worth, here's what I noticed btwn mine and others at BW 13CW I average about 90-95s at the top of the straights (stock 1.6L + exh), for a 2:21 on all seasons (2:21, more time on table, messed up on sunset before the lap even started). The Street Class Miata is a 1.8L on 225 RS-3s that sees about 105s in the corners for a 2:08. A friend's S2000 hits about 105s in the straights but is obv slower overall with merely 2:14-2:16 (255 advans), and he and I corner at similar speeds in my Miata. I have to scrub speed and brake earlier to hit a slower corner speed which inevitably kills top speed.

I was planning on staying with 1.6L brakes for weight, have 1.8L brackets ready and waiting, and I know they'll have better heat capacity overall, but whether I need it yet or not is TBD on pad and tire (currently Hawk HP+ which have lasted pretty long that I started dailying them). I planned on doing some ducts before slapping the 1.8L rotors on, mainly so I can gauge how effective the ducts are. I know the cooler the brakes are the longer pads will last etc, but so far with all seasons and HP+, it hasn't been an issue. I sure would like some Wilwoods for many reasons but it's just not in the cards. Please let me know if I'm going about this all wrong and that I should toss the 1.8s on ASAP regardless of if I've ducted the brakes yet or not.
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Old 09-13-2012, 12:51 AM   #217
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Quote:
Originally Posted by Handy Man View Post
Of course, but "higher" is a relative term. Say a street tire car corners 10mph slower than a race tire car. The race tire car will exit the corner 10mph faster, however all cars accelerate faster at lower speeds. Therefore at the end of the straight the race tire car will only be going slightly faster than the street tire car, say 3mph faster.
It's not a 7mph delta. Try 1-2mph. I only know this because it's one of the most obvious things when you compare data between two drivers - a driver who carries 3mph off a corner will typically still be traveling 2 or 2.5mph faster at the end of a long straightaway than a driver who can't carry that extra 3mph.

In the end, cars do accelerate slower at higher speeds, but it's not nearly that large of a difference.
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Old 09-21-2012, 03:32 PM   #218
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Joined the manly brakes club last night after ending Hallett with a slight taper up front on Hawk Blues. Holy **** does the car stop. Need to tweak bias valve a bit, the rear blues don't stand a chance against DTCs on a 11.75" rotor.

Big thanks to Andrew, had a tracking number not an hour after ordering. Getting threads started on the front line coupler was the hardest part of the entire install.

Anybody want to sell their rear 1.8 brackets?
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Old 09-24-2012, 02:25 PM   #219
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I recently did a track day weekend at CMP with freshly rebuilt Na 1.8 on XP10/XP8 pads and noticed slight taper on the front pads, nothing like earlier pictures in this thread. I was not expecting this on factory power. The rotors looked like the snotty picture on post #197. I started with fresh rotors and after the first session I had the snotty rotor surface again.
What causes the snotty surface? Does it cause you to use more pedal pressure and greater force on the pad that then flexes the stock caliper more and result in the pad taper?
The funds for the awesome 11.75" BBK will not be avaliable any time soon, so that isn't really an option at this time.
How long do the XP10/8 pads last on NA power levels? Looks like I will only get 5 track days out of the ones I am running.
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Old 09-24-2012, 03:08 PM   #220
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Quote:
Originally Posted by relte View Post
How long do the XP10/8 pads last on NA power levels? Looks like I will only get 5 track days out of the ones I am running.
About 5 hours would be what I'd expect, not more (rears will last longer, almost twice).
Add cooling and you will get a lot more time out of them.
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