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  • comments after JZilla fall track day...

    Went to the Jzilla fall track day at Road Atlanta on 9/22. Stu Biggs was my instructor. It’s been over 12 years since my last track day and it showed. Thanks again to Stu for his patience and guidance as I learned the car, track, and how to drive again!!!

    Also many thanks to JZilla for such a well run day. :-)


    Things I learned:


    It’s fun to drive a momentum car like the Miata! My prior track car, 85 Fiero w/ 3800, was a much different beast.


    The stock cooling system was fine in the morning but the car got progressively hotter as the day went on. By the afternoon sessions, the needle was reaching the center of the dreaded H while at WOT between T7 and T10a. I’ve modified the temp gauge to make its response smoother so I don’t know the temperature value at H (may be the same, not sure yet). To compensate during the event, I manually turned on both cooling fans (AC compressor clutch control unplugged) and didn’t run the straights at WOT until braking. This helped some but the gauge was till near the H by the ed of the session.


    The stock sport brakes and pads and 16 year old rubber brake lines are OK but just OK. With Stu in the car, I had to brake at the 300 mark going into T10a. Things got a little sketchy when I tried compressing to the 200 mark as I overcooked the front tires and the pedal grip position became noticeably lower making heel and toe a challenge. For my last session, I added two PSI to all four Dunlop Direzza ii (final value was 31 hot, 27 cold), ran without a passenger, and stayed at part throttle between T7 and T10a to reduce the cooling system load. All of this meant I could easily start braking at 200. I know changing more than one thing at once is best practice but I did it anyway. Either way, it was a better setup, easier on the brakes, and more enjoyable as the car wasn’t at the limit. T10a became smoother and probably faster.


    Which leads to: stay off the curbing, even the inside like T10a. You can kiss it but it gets rough just a few inches in and really upsets the car. Better car control due to not overloading the brakes made T10a smoother.


    Turn 12 is a *blast* and easy to get right once you are over the pucker factor of not seeing the road ahead. Regardless of cooling issues, I stayed at WOT until I was on the front straight then backed off a bit.


    I also tried a wider, arcing line around T6 by putting the car at about 1/3 track (over a patch I noticed in the late day sun) and not touching the curbing at the inside apex. This made it easier to put the car parallel to track edge along the T7 braking zone curbing and made entry T7 much smoother. Felt like the car carried more speed through the entire T6-T7 combination. T6-T7 feels a lot like T11-T12 (Oaktree, sniff) at VIR but T6 @ RA has some camber!


    I need to tighten up the rear view mirror pivot ball, as the mirror would change position after some corners. A smoother driver would probably help here too.


    Lastly, I didn’t use the parking brake until I got back home - and found it at the top of it’s adjustment. The adjustment is really easy and everything’s back to normal. I assume that the adjustment does not change the hydraulic operation of the rear brakes because the car felt balanced during braking for the entire day.






    A larger radiator was moved to the top of my wishlist (CSF #2863 (2 row) ordered yesterday). The rest of the wishlist still includes in no particular order: frame rails, seats & harness, and Wilwood front brakes w/ stainless steel lines on all corners.


    until the next track day…
    '01 BRG #2807 FS: 4 nice black Chaparral's, $400

    Build log: http://forum.miata.net/vb/showthread...02#post7862902

  • #2
    Do you run the splash/belly tray on your car? Without it, you are going to continue to have cooling issues.

    Comment


    • #3
      +1 for an undertray/ducting and the aluminum rad. The hottest temp I saw was 208 while under WOT between 7-10, and temps would cool back down to 204 by the time I would come back around to T7, and back down to 200 while on cooldown laps, and 195 by the time I would pull into my spot. This includes the hottest parts of the days from 3-5:00.

      You're going to love those willwoods. Even while using the provided pads that come with the kit(which I've been told are meh) I could still stay WOT till 200ft to slam them home. Swap to a MUCH higher temp brake fluid though, by the 4/5th session I could feel I had lost a ton of petal feel using DOT 4 fluid(500° boiling point IIRC).
      '00 Black NB, Track/Street car.
      It seems like the most powerful weapon in the universe is speed. Move something fast enough and it will obliterate anything

      Comment


      • #4
        David, where did you end up lap time wise? Wondering what NC vs NB/NA looks like.
        David Luney - Suwanee GA
        [email protected]
        04 RX-8, 10 Black MS3, 08 Red MS3, 06 550i, 05 325i 92 Spec Miata and a parts car or two.

        Comment


        • #5
          Curious about real world same driver NB vs NC stats. Having driven two very different calibe NB and Nc cars I suspect the NC is 1.5-2 seconds quicker.

          What does the data say?
          sigpic
          Current: 1994 Merlot (Turbo) Sold: Red '02 Turbo | 2010 - 2015 ~~~ 987 Boxster | 2012-2014 ~~~ Z4 ///M Roadster | 2015 - 2015 ~~~ Z4 3.0i (18k miles!)| 2018-2018 ~~~ 2006 Miata (Laci) | one track day ~~~ Exocet (Turbo!) | 2015-2019

          Comment


          • #6
            Yes - I have the undertray in place. But no hood vents like Wingman703. Pretty sure I got past 208F yikes.

            I've converted a car to Wilwood dynalites before. Really a game changer and pad swaps become a non-issue. But it will take a while to save $700 on my allowance.... Right now, I have my eyes on the SuperMiata Wilwood 11" Front Big Brake kit, rear SS lines, and portioning valve all form 949. Any comments pro or con appreciated.

            And unlike the radiator which seems required to continue and not harm the car, I don't HAVE to have Wilwoods to have a great time.

            Regarding measurements, I almost never time myself. With today's phone apps, there is no reason not to as it's very easy and inexpensive. For me, I truly enjoy the overall drive and the instant gratification of a turn or downshift well executed. I focus on the feeling, the synchronicity of man and machine, the experience of the day, and the people I meet.

            One other thing I learned, I don't see that a top is important. I was wondering how things would be at 100+mph with no top but didn't find that an issue.
            '01 BRG #2807 FS: 4 nice black Chaparral's, $400

            Build log: http://forum.miata.net/vb/showthread...02#post7862902

            Comment


            • #7
              I'm not 100% sure the big brake upgrade is worth it at this time. No offense, but braking issues on a Miata often comes down to usage and technique. A top will help at higher speeds.

              I might consider a coolant reroute as well.

              Comment


              • #8
                Had an awesome time instructing you David! You are a great student!

                As far as the car goes your Sport brakes are more than adequate and the wilwood kits while nice can also add some complexity. You will be having to upsize your brake master for best results among other things. I highly recommend you look at Performance Friction 11 pads for the sport brakes. They work street and track but can be noisy. Their .mu doesn't change much over the temperature range giving you a reliable pedal.

                If you are deadset on wilwoods look at the Trackspeed Engineering 11.75" kit with Dynapro calipers and directional rotors. It's slightly more expensive than the 949 kit, but will give you much better life on the rotors due to the cooling (and better ferrite material) and the hardware can be safety wired which is a huge benefit.

                For cooling I would first check your coolant mix. On track it's generally best to run minimal (most say none) to no coolant with a cooling booster like water wetter.

                Can't wait to see you back out there.
                '00 Silver Miata

                Comment


                • #9
                  Friday was a blast! Sounds like you had a good time! I am currently still going through all my photos from the event, but found this one of you!

                  sigpic

                  Comment


                  • #10
                    Originally posted by theothersawyer View Post
                    Friday was a blast! Sounds like you had a good time! I am currently still going through all my photos from the event, but found this one of you!

                    Do you post your pictures somewhere? I had a black NB(#72) out there and I think I was in your rungroup(blue) although I don't recall seeing your car.
                    '00 Black NB, Track/Street car.
                    It seems like the most powerful weapon in the universe is speed. Move something fast enough and it will obliterate anything

                    Comment


                    • #11
                      Originally posted by wingman703 View Post
                      Do you post your pictures somewhere? I had a black NB(#72) out there and I think I was in your rungroup(blue) although I don't recall seeing your car.
                      They all get posted to my flickr, but I've barely started to go through the pictures from this event, so I will try to get them all posted by next week but we shall see! https://www.flickr.com/photos/[email protected]/albums
                      I just looked real quick and found two of you for now! Clean car!



                      sigpic

                      Comment


                      • #12
                        Originally posted by Sierra_Bravo View Post
                        Had an awesome time instructing you David! You are a great student!

                        As far as the car goes your Sport brakes are more than adequate and the wilwood kits while nice can also add some complexity. You will be having to upsize your brake master for best results among other things. I highly recommend you look at Performance Friction 11 pads for the sport brakes. They work street and track but can be noisy. Their .mu doesn't change much over the temperature range giving you a reliable pedal.

                        If you are deadset on wilwoods look at the Trackspeed Engineering 11.75" kit with Dynapro calipers and directional rotors. It's slightly more expensive than the 949 kit, but will give you much better life on the rotors due to the cooling (and better ferrite material) and the hardware can be safety wired which is a huge benefit.

                        For cooling I would first check your coolant mix. On track it's generally best to run minimal (most say none) to no coolant with a cooling booster like water wetter.

                        Can't wait to see you back out there.
                        Thanks for these tips! I'll admit a strong bias against the sliding pin caliper design. Opposing pistons are the way to go. +1 for Trackspeed. I had not seen them before - lots to explore! Their 11.75 kit is comparable to the 949 11". The 11.75 from 949 was a big price jump.

                        Any other recommended brands besides Performance Friction? They are not a good company to work for, and I'd rather not put my money in their pockets.

                        I have a bit of a bias towards the Dynalite in part because I still have a set or two of NIB pads. Plus, they never let me down. I'll be looking into the differences between them and the Dynapro model.

                        Then again, my skinny 15x7 & 15x6.5 wheels might be a hurdle regarding any 4 pot brakes.

                        Good note on the coolant. I am probably a little high on glycol in my current mix. I've used water wetter before with good results. I'll also consider a 70/30 mix - I don't really need protection to -34F. Now I am rethinking my quick purchase of the radiator.... sigh.




                        Originally posted by theothersawyer View Post
                        Friday was a blast! Sounds like you had a good time! I am currently still going through all my photos from the event, but found this one of you!
                        Thanks for posting this!!! I'd like to use it elsewhere probably with some crop and post processing. Are you OK with that? Glad to give you credit, let me know.
                        Last edited by DavidC; 09-26-2017, 06:42 AM.
                        '01 BRG #2807 FS: 4 nice black Chaparral's, $400

                        Build log: http://forum.miata.net/vb/showthread...02#post7862902

                        Comment


                        • #13
                          Lot's of guys have great success with Carbotech and G-Loc. They require new or clean rotors because they work on the transfer layer principle rather than rotor friction and are finicky with the bed in procedure. If you don't get it right they won't work.

                          The Dynapro is a stiffer version of the Dynalite and uses the nice W retaining pin rather than the single use cotter pins. Otherwise they are very similar.

                          You might have issue fitting your wheels over the 11.75", but luckily there is a solution. I run a 25mm spacer on my street/wet wheels that are 15x7 to fit them over the Dynapro 6s. Have had no issue with that setup.
                          '00 Silver Miata

                          Comment


                          • #14
                            David- if your not recording lap times I suppose it doesn't matter but staying off the curbs= a slow lap time. A decent set of dampers will allow you to be aggressive on the curbing without upsetting the car....
                            Sean O
                            2017 Ford Raptor, 1998 Wrangler, 2013 PRHT Club Edition 2.5/ Fab9/ Ohlins, KTM 1190 Adventure

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                            • #15
                              Originally posted by DavidC View Post
                              Thanks for posting this!!! I'd like to use it elsewhere probably with some crop and post processing. Are you OK with that? Glad to give you credit, let me know.
                              You can do whatever you want with it!
                              sigpic

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