Boss 302 Advance Road Race Tire setup thread

Discussion in 'Brakes, Wheels and Tires' started by steveespo, Sep 11, 2013.

  1. blacksheep-1

    blacksheep-1 TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    If you don't or can't use nitrogen then buy a couple (or 3) of these and hook them inline from your air compressor (segregate the tire hose from the usual stuff) and use it to fill up your air tanks for the races.

    [​IMG]
     
  2. PeteInCT

    PeteInCT #LS-378 - So many Porsche's, so little time.... Moderator

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    Re: Boss 302 Advance Road Race setup thread

    The temps will be about 40 F as long as its dry. Its gonna be cold.
     
  3. blacksheep-1

    blacksheep-1 TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    If he keeps notes he'll be able to put the pressures right on the money
     
  4. 2012YellowBoss

    2012YellowBoss TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    Getting back to running without a rear sway bar, I was at the track this weekend and talked for a while about this with some great techs that support multiple cars at events here. What they said is how I was thinking the issue, the smaller you make the rear bar the more push or under-steer you get. Then once you remove it completely it goes the opposite way and adds lots of over-steer. The easy way they explained this to me was that with no bar the wheels are working independently and that does make for a wild ride.

    While I still may look to a smaller rear bar in the future I still have no plans to remove it. Even with coilovers it sounds like something I don't yet have the skills for.
     
  5. blacksheep-1

    blacksheep-1 TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    IMO it depends on what you call "lots" the idea here is to continually go down on the bar size, make shock adjustments and sort of "sneak up" on what you're trying to do. To go from one extreme to no bar would not be a good idea, but to go from a "micro" bar to none is really not that big of a step because you'll be following the change with shock/spring adjustments.
     
  6. 2012YellowBoss

    2012YellowBoss TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    Thanks for this, I am not an expert and have not actually tried running without the rear bar. You forgot one thing, the piles of expensive bars and springs in the storage room. I would like to experiment more but there are other things I need first, like a wing.

    Right now the car hooks up well with the 18MM bar and the springs work at very different tracks here. I am sure there is a better combo for Sebring vs. Daytona but honestly the driver mod is needed more before fine tuning. Still, I will be interested to see what the Bosses will be running this year at these tracks.
     
  7. 2012YellowBoss

    2012YellowBoss TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    Rob, forgot to mention that I tried different settings with the front bar this weekend. I had the bar in the middle and full soft with the Rolex 285's. I also ran the Conti's 275 squared with the bar on full firm and in the middle. So the only settings I did not try was full soft squared and full firm on the staggered but there is not need to even try that one.

    Once again just like PBIR I felt little difference. I was expecting to fell a difference at least in the full soft setting but did not even notice the change. I do plan to try out a full soft with the 275's all around and hope to feel it. I am guessing it will be a tad loose but very controllable.
     
  8. blacksheep-1

    blacksheep-1 TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    OK, let me think about this..it's been my experience when you make a change and nothing is happening then it's being cancelled out by something else..say for example the sway bar change is being negated by a too stiff front suspension. that's just an example. I don't remember, do you have coil overs on the front? You can try to soften the front shocks to let the bar work..just a thought.
    Back in the day (1970s) there were 2 schools of thought on this one (Guldstrand) felt that all the parts should work together, shocks, springs, bars. The other (Mitchell) thought that you should run the softest spring /shock setting possible (stiffer on smooth track, softer on bumpy) and then use the bars to control the roll. In truth, I think most guys start out with the Mitchell method and as they dial the car in end up with the Guldstrand style.
     
  9. 2012YellowBoss

    2012YellowBoss TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    Yes on the coilovers, Koni's all around weighed and balanced. It does need to be re-weighed as some changes were made, AC delete etc and the fronts had to be adjusted since they were hitting the control arms. I think I have some ability to fell changes made to the car, like the smaller rear bar, but I am not driving on the edge all the time and may not be able to feel smaller changes like the front bar.
     
  10. blacksheep-1

    blacksheep-1 TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    I wonder, and this is just a shot in the dark, if the front end is bottoming out and this is negating any chassis adjustments?
     
  11. blacksheep-1

    blacksheep-1 TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    OK, back to the top, anyone ready for some test questions?
     
  12. 2012YellowBoss

    2012YellowBoss TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    Rob, this did happen, I wrote about it here but I don't think I worded it well. The sway bar was making contact with the control arm and we need to adjust the coilover a little. This messed with the corner weight but I have not had it on the scales again to see how much. This is one of those things I keep forgetting to do but I need to repaint the marks on the control arm to see if it is still happening.
     
  13. 2012YellowBoss

    2012YellowBoss TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    Rob
    I just unloaded my car from this weekend a few hours ago and did not check the control arm to see if the sway bar was hitting it. I can say I felt the car was a little too loose at the turn exits and felt unstable in the long sweepers (turn 1, 17, Big Bend, Bischops Bend and worst of all the right and left high speed turns fter exiting the Hairpin) so we set the bar to the middle from the rear setting. Was running front 275's non GT-I for two sessions then GT-I's after that, rears were GT-O day 1 and day 2 the new G6000 285's from the GTD class.

    Saturday slower laps - first with last year's CTSCC compound front 275 and GTO 285 rear that I was told to run at 28 hot but started higher to be safe. Aiming at 39 hot front and 31 hot rear. Started lf 27 rf 27.5 lr 22 rr 22
    LF RF
    39 39
    LF 158 156 156 RF 154 148 144
    LR RR
    31 31
    160 164 168 RR 168 173 167

    session 2 Sat

    LF RF
    39 39

    LR RR
    31 31

    SESSION 3 CHANGED TO CTSCC 275 GT-I compound in front - same rears
    LF RF
    40 40 REDUCED BY 1 POUND

    LR RR
    32 33 REDUCED BUT DON'T REMEMBER HOW MUCH

    SESSION 4
    LF RF
    36 36.5 WAS TAKEN IN PADDOCK SO LOWER NUMBER AFTER COOLING OFF

    LR RR
    28.5 28 LR was corded or better said was worn passed the wear holes, which added to a bad turn in on 15 lead to a spin

    DAY TWO After the first session I started running better Ran GT-I front 275's and the new TUDOR 285 G6000 compound on rear all day

    Session 1
    LF RF
    39 39 Left front tire completely corded inside and out, changed both fronts to same compound but increased the pressure to am at 40-41 because of the cording

    LR RR
    29 29.5 WAS AIMING FOR 28 IN REAR REDUCED PRESSURE

    SESSION 2
    LF RF
    42.5 41 REDUCED BOTH FRONT PRESURES, looking for 40

    LR RR
    29 29
    LR 149 154 154 RR 149 159 158 Taken after cool down lap.

    SESSION 3
    LF RF
    40 40

    LR RR
    29 29 Very close to the pressure we aimed for and left alone for the last session. No data last session.

    So again my apologizes to John, Gary and others running the Rolex tires as the pressure is way different then I had thought. Here is the 275 GT-I that corded in one session, I was running hard and fast, beat my all time low at Sebring by more then 4 seconds.

    [​IMG]
    [​IMG]

    New G6000 compound wear marks, hard to see but nice even wear:
    [​IMG]

    the starting pressure was so low it wore the paint lettering off just driving to the pits and not from rollover. The tires looked as if they were flat.
    [​IMG]

    and the 275's wear day two at 40 psi
    [​IMG]
     
  14. blacksheep-1

    blacksheep-1 TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    I've seen that before when using lots of camber or when inflation is too low, it's where the tire tread is bonded to the tire carcass.
    I'll get back to you guys on the rest..
    Also found a great article on nitrogen vs air

    http://www.vscda.org/cars/expert__racetireinflation.php
     
  15. 2012YellowBoss

    2012YellowBoss TMO Addict

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    Re: Boss 302 Advance Road Race setup thread

    I was concerned about how the rubber seemed to be pealing off on the inside. Spoke with Jon and he assured me it was normal. He has expressed concern about how long I use them but also said since my car is heavier then the GA Boss and I have been pushing a littler harder so this will happen. This is the first time I have corded a 275 in a long while, from before I learned proper inflation on these tires.

    Below is the lest set of GT-I fronts used from the picture above except cleaned up the Blacksheep way.

    FWIW if anyone is following this these are cold pressures when I got home, you can compare them to the notes above and where the hot pressure were taken off. First listing below if the last set used:

    LF RF CTSCC GT-I
    27 28
    LR RR TUTOR G6000
    18 20

    LF RF
    27 27
    LR RR ROLEX GT
    17 18

    LF RF
    26 28 CTSCC NON GT-I (one day since use)

    Although teams have not seen a difference in wear I have noticed the older non GT-I's last a lot longer.

    [​IMG]
    [​IMG]
     
  16. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    Re: Boss 302 Advance Road Race setup thread

    Wanted to bump this back up again for a little more discussion about front suspension setups. I want to do what I can with the macpherson strut suspension despite its limitations - especially with regard to camber gain.

    First, I want to ask about any individual setups that have been changed or adjusted with the intent to modify camber gain rates.

    Second, I'd like ask any of the guys who have pictures of or access to any of the professionally raced cars about what they have modified in the front geometry wise.

    On the front, I currently have P springs, MM CC plates, Eibach camber bolts and LS struts. I have the strut angle of inclination and caster set to maximum positions on the CC plates and use the camber bolts to reduce the static negative camber to -1.5*. My goal is to make more use of the inside front tire than I was without the CC plates and -2.5* of static camber with only the camber bolts. So in theory, I'm getting a bit more compression camber gain with the increased strut angle, plus some from steering input camber from both the increased caster and strut angle. Front grip has been way better in low speed turns at Streets of Willow, and should be better in higher speed sweepers. Tire wear was good despite the reduced static camber. Was hoping to test that at Chuckwalla this weekend, but the whole family has colds at the moment. :( Anyway, my only other planned geometry changes are tall ball joints for more camber gain and higher roll center, but am considering adjustable front LCAs for a bit more caster.

    Comments or criticism on the direction I'm going?
     
  17. blacksheep-1

    blacksheep-1 TMO Addict

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    Keep in mind when I talk suspensions it's from the CTSCC point of view, and their rules are very restrictive, that being said IMO you won't need those extra tall ball joints and the amount of camber you have sounds close. (-2.5) Run the Ford blue bar in the center setting, 18mm or no rear bar about 550-625 in fronts with coil overs and 275 -350 in the rear. The camber sounds about right do all the rest with shock adjustments. That's as close as I'm going to tell you, and a lot of that depends on the track.
     
  18. lbp

    lbp TMO Race

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    check out cortex racing
    they have a setup to run 315 x18 square
    Filip is very knowledgable & a great guy
    www.cortexracing.com
     

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