DIY Brake Ducts for a Series II - Page 2 - RX8Club.com



Series II DIY DIY projects specific for Series II RX-8s

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Old 06-27-2017, 10:12 AM   #26
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When I bought my Miata last summer, I said to myself, "Self, if you have 2 sports cars, 1 will always be ready to go to the track. This idea is brilliant!"

The reality is, that 2 sports cars are always on jack stands, instead of just 1. RX-8 still has no hubs. Broke an end link on the Miata and heat cycled the tires out of service last Saturday. No cars ready to go to the track.
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Old 06-27-2017, 11:01 AM   #27
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I still have the ducts that are made to go in the S1 bumper if anyone is interested, I was going to use them for something else but never installed them.
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Old 06-28-2017, 08:33 AM   #28
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Minor update to this thread.

1. Hubs finally came in, car is back on the ground on its stock wheels.

2. No signs of rubbing during the drive to work this morning. I'll visually inspect it tonight.

3. The sound of wiffel ***** tells me the rotors are receiving air pressure.

4. I believe my track wheels (255s on 17x9s) will rub at full lock. I have that "problem" with my Miata, too.
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Old 06-28-2017, 10:42 PM   #29
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Minor-er update.

Pulled the front wheels tonight. No signs of rubbing with the stock wheels, and I tried to make it happen.

I'm still pretty sure my track setup will rub under full lock, but #supernicegrandtouingfivepercenterracecar.
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Old 07-09-2017, 05:30 PM   #30
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I have some data. Unfortunately, I do not have good comparison data against the Miata photo above, because I ran a different track configuration this morning, and the session times were different.

Let's talk about that track configuration. I ran the 1.3 mile track on the left side of this photo. You'll notice it has no long straights. It also has mostly low speed corners. Those two things together make it absolutely brutal on brakes. I normally dry boil fresh 600 fluid after about 15 minutes on this track. The Miata temperatures were shot after a session on the 1.7 mile track on the right side, with its long straights and sweeping, high speed turns. Totally different animal. This morning's sessions were 30 minutes long, and the Miata sessions were 20 minutes long.




Here's a video of me driving that track last year.



I shot brake pads temps after sessions 2 and 3. I was able to run a full cool-down lap at the end of session 2. I managed only half a cool-down lap at the end of session 3.

These photos are of the right side brake pads, which get the hottest on a CCW track.

Session 2:




Session 3:




So, low 500s. I was hoping for a little better cooling performance, but this certainly is not terrible. Previously, my pyrometer would not even measure this, as it maxes out at 800F, and my pad temps were higher than that on every track configuration. This is definite improvement. I am not displeased.

The other consideration has to do with robbing air from the radiator to cool the brakes. That seems to be OK. I don't have any new data for very high ambient temps to compare to my old data (see radiator thread linked above), as the ambient temps for session 2 and 3 this morning were 86F and 90F, respectively. No idea what a 95F or 100F session would look like, and I no longer care to find out.

These charts don't look too far out of line. I may have lost a few degrees of cooling capacity, but the difference is not dramatic.

Session 2:




Session 3:





Wait. What happened there in session 3? The answer is, I ran up on a Miata that would not let me pass. So, I backed off to give him half a lap of space. Then I caught him again. Then the session ended. Some people.

.

Last edited by Steve Dallas; 07-10-2017 at 07:29 AM.
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Old 07-10-2017, 06:02 PM   #31
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800F+ down to 490-510 is pretty amazing. The coolant temps are fine compared to a lot of your older charts. It might not be the fairest of comparisons, but it would seem like the smaller slower track would exacerbate these problems if anything.

Last edited by Reoze; 07-11-2017 at 09:12 AM.
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Old 07-11-2017, 07:11 AM   #32
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Agreed on all points. I tried to stress that the track drives up brake and coolant temps due to its layout.

I take turns 1 and 2 in 4th gear. The rest of the track consists of bouncing off the rev limiter in 2nd and 3rd, so RPMs are unusually high nearly all the way around. Otherwise, there is lots of hard braking with little opportunity to cool the brakes back down. This track is basically a torture test. Not displeased at all.
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