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SS Roadster AutoX Setup

Discussion in 'Roadster: Performance' started by Oricle, Oct 10, 2017.

  1. Oricle

    Oricle Member

    Joined:
    Jul 12, 2010
    Messages:
    25
    I've been co-driving and working on setup in a Roadster for 3 seasons now and I feel like I'm finally getting to the point where the car is quick and playful around the cones, so I thought id share my setup and hopefully start a serious discussion about autox setup and driving technique for this car. I've also been petitioning the SCCA Solo Events Board (and failing) to move the Roadster from SS to AS class where I think it'll be more competitive, and to allow the Roadster into the CAM classes so modified Roadsters have a class to compete in.

    2017 setup for Super Street class:
    Roadster 2.0 (Non Sport)
    "Normal" drive mode (not Performance)
    TC Off

    Tires:
    RE-71R
    F: 205/45-16 (34psi hot)
    R: 245/40-17 (43psi hot, +/- 2psi depending on surface grip and rotation)

    Wheels:
    Stock (non-sport)

    Brakes:
    F: EBC Yellow
    R: EBC Yellow (may change to a more aggressive rear pad next season)

    Dampers:
    F: Stock Sport Suspension (7)
    R: Stock Sport Suspension (3)

    Sway Bars:
    F: BWR "Hardcore" (Full Stiff)
    R: Stock Sport Suspension (Full Stiff)

    Alignment:
    (I dont have the alignment print out anymore, but I know what the shims are)
    F: Max Caster (all washers in front)
    Max Camber (No shims)
    0 Toe
    R: Camber (2 shims)
    0 Toe

    Ride Height:
    (No actual height measurements because I'm running at the ends of adjustability)
    F: Min height
    R: Max height
     
    • Informative x 2
  2. RuneTR

    RuneTR Member

    Joined:
    Oct 20, 2017
    Messages:
    5
    Location:
    Norway
    What is the benefit of running in std. drive mode, instead of performance mode in AutoX?
     
  3. Oricle

    Oricle Member

    Joined:
    Jul 12, 2010
    Messages:
    25
    Heat and power. The car will heat up too quickly in Performance mode, and when it's hot out it'll go into reduced power mode. Performance mode also has a narrow temperature operating window, after a few full power corner exits the car goes into "Red" performance mode, which is nearly the same as standard mode.

    On a cold day, you might be able to stay in "White" performance mode for the first lap, but the first lap is usually never your quickest (due to tire temp and unfamiliarity with the course layout), and after the first lap it's just inconsistent power delivery. As a driver, it's easier to push the car hard when you can anticipate the amount of power the car will deliver.
     
    • Informative x 1
  4. DieAbetic

    DieAbetic Member

    Joined:
    Jan 16, 2014
    Messages:
    168
    Location:
    Los Angeles
    Hey there fellow SCCA member! I’m running my Roadster in SS now :)

    Why did you go with 245R 205F? Doesn’t that cause understeer?

    I heard RE71Rs like 28-34 PSI hot. Why go with regular recommended higher PSI?

    Sorry for all the questions - you are the only one i can ask! Lol. As you know at the meets you get lots of advice... I’m just not technically knowledgeable enough to figure out the best setup (yet).

    Thanks for all the research and help!
     
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  5. Oricle

    Oricle Member

    Joined:
    Jul 12, 2010
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    Hey! Nice to see another AutoX'r on here.

    Unfortunately the Roadster has really narrow wheels, add to that the stagger in wheel height and width, and supposedly a finicky regen and ABS when running a different circumference stagger than stock, that makes tire choices is extremely limited.

    For the 2015-2016 season we went with a 205/50r16 235/45r17 setup that worked well. The tire sidewall was quite a bit taller than stock which made the tires a bit squirmy which I didn't care for, and theoretically made it slower to accelerate due to the effective gear ratio change.

    2017 season we switched to the 205/245 setup with shorter sidewalls. My datalogger broke so I can't compare acceleration between the tires, but honestly the difference probably would be negligible. The main improvement is in response, the shorter sidewall with higher pressures makes the car much more precise. Since the tires are quite a bit wider than stock (but still on skinny wheels), they seem to like the higher pressures more. I started out the season at 25psi front 30psi rear, and every time I added more pressure the car felt better and was quicker till I got to 34/43.

    Corner entry is easily the most difficult part of racing the Roadster. The ABS system comes in too early and strong, and is biased too far to the front (in my opinion). The trick to getting the car slowed down is a light initial pedal application (to get the weight shifted to the front), then gradually roll into the pedal firmly but stay out of the ABS as much as possible. If you jump into the pedal full force, the ABS locks out the rear brakes, overpowers front grip, and the car comes to a worryingly gradual and understeery stop (you can test this on the street to see what I mean). So, best way to enter a corner is by getting on the brakes early and soft initially, then roll into the pedal without getting into ABS in as straight of a line as possible, trail brake on turn-in to get a little rotation/minimise understeer. Steady state cornering is pretty neutral with the current setup, I can tighten a line easily by letting off the accelerator. Corner exit will probably always understeer, unless you are really aggressive with it (lift off, quick turn in, stab the accelerator) but that's not very fast. Typical corner exits are fastest when you get the car pointed as quickly as possible, roll on the accelerator as you straighten out the steering expecting the line to loosen and track out wide. Finding that balance takes practice. Getting on the accelerator too early unloads the front tires and understeers bad. Too late and too abruptly spins the inside rear and the car won't accelerate as quick.
     
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  6. DieAbetic

    DieAbetic Member

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    Messages:
    168
    Location:
    Los Angeles
    Thank you again for all the tips. Had a nice weekend at autocross school and getting some good times. Definitely agree on the early brake, release, and then punch it when lined up. I really need to get new tires and a front sway bar.

    I'm tempted to get the RE71-Rs, but I also know the new Rival S 1.5s are very popular this year. They only come in 215/45 R16s - do you think that will fit the car?

    I've also seen recommended on some posts here to get these pads: Carbotech AX6 Brake Pads LOTUS ELISE

    Let me know what you think. Cheers!
     
  7. Tesla 940

    Tesla 940 Member

    Joined:
    Nov 2, 2011
    Messages:
    271
    Location:
    Long Beach, CA & Taos, NM
    I've never done autox but have raced Willow Springs - Streets and Big Willow, and 3 days at Laguna Seca. It's fun but scary putting a valuable car into some of those turns.
     
    • Like x 1
  8. Oricle

    Oricle Member

    Joined:
    Jul 12, 2010
    Messages:
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    Good to hear you're getting some seat time.

    Tires make the most difference, hands down. I'd probably stay away from the 215s, they are just too wide for the skinny wheels even though the compound is slightly quicker.

    We went with the EBC pads because they were cheap and we weren't sure how competitive the car would be. Now that we have a setup that is doing well locally, I plan to change out to the AX6's in the rear in an effort to move the brake bias rearward.

    Front sway would be the last mod i'd do to the car. I feel it's the highest cost to performance gain. You can make the car plenty quick without it.
     
    • Like x 1
  9. Oricle

    Oricle Member

    Joined:
    Jul 12, 2010
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    Agreed, I've done 2 of the early Refuel races at Laguna Seca in the Roadster. Had an off track experience on turn 3, and an unexpected power oversteer on 11 which sent me towards the pit wall. That was about the time I decided AutoX was the better sport for the Roadster, and if I wanted to do track days id use my old Miata instead.
     
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  10. DieAbetic

    DieAbetic Member

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    Jan 16, 2014
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    Location:
    Los Angeles
    Yeah I freaked out a little bit on my first spin. And I'm nervous about PEM/Battery already, but oh well.

    Ok I'll stick with your 205 recommendations and the RE71Rs. AX6s in the back - are you going to keep EBCs up front?

    I sold my 2004 MazdaSpeed Miata after buying this Roadster... but I still miss it. Those are fun cars, and E-Street is a huge class with lots of competition. I have a lot of friends still in E-Street, so I can always drive their Miatas and MR2s

    Thanks all for the advice!
     
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  11. Oricle

    Oricle Member

    Joined:
    Jul 12, 2010
    Messages:
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    Yeah, I'll try the EBC/AX6 combo for a season before I decide to try something else
     
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