The R-F iRacing Shop

Discussion in 'Sim Racing' started by SpeedPagan, Jun 1, 2016.

  1. SpeedPagan

    SpeedPagan The iRacing Guru

    Since the last thread on set-ups got gobbled up by the great server crash of 2016, I thought I'd create a new set-up thread for iRacing.

    So I'm pretty comfortable with setting up the Legends Car. At this point I would have gone to Street Stock, but iRacing no longer has an open set-up Street Stock Series. Which sucks, but it is what it is. So the next car I'm going to tackle is the SK Modified. Season 3 is about 2-3 weeks away and I'm already working on the car, figuring out what does what for the first race of the season.
     
  2. SpeedPagan

    SpeedPagan The iRacing Guru

    As of right now I'm about 98% happy with my set that I tweaked for Concord. However entry into the turn after the apex is too tight for my taste. I'm using 25% braking & it slows down my car too much.

    Any suggestions?
     
  3. LouieLouie

    LouieLouie Team Owner

    I'm not familiar with all the options for adjusting the SK mod, but there are a few things you can do to loosen the car on entry.

    Depends on which end you feel is tight, is it the front end or rear end, and is it more left side or right?
    You can always mess with the tire pressures if you need small adjustments. It changes the ride height so be aware of that.

    I would start with the bump stiffness or rebound stiffness. IF you hold your mouse over the adjust it will tell you which direction to go. If it doesn't tell you in the sk modified setup screen, open the cup car and it explains it in that setup screen. Just take notes and apply the appropriate adjustments to the SK car.

    For front end, you can adjust the front sway bar. Lowering the sway bar a mouse click or two will loosen it up.
    If it doesn't have a sway bar, look for the ARB, it is basically the same thing.

    You can make the same adjustments at the rear end too. i.e. raise or lower the sway bar or ARB.

    If you are getting tight when applying the break, lower the brake bias. It shifts the braking to the rear which will allow you to use less braking and it turns the car into the corner.

    I would definitely try to figure out if it is the front end or rear end that you feel is tight and then only make adjustments to that end. Trying to make adjustments to the front and rear at the same time is really tough and will confuse you moving forward.
     
  4. SpeedPagan

    SpeedPagan The iRacing Guru

    I've done two races last night @ Stafford & in both races, the car tends to get really loose off of turn 4. It would start to get really loose about 25-30 laps in.

    What I did was took the iRacing Stafford set-up, adjusted the fuel & gear ratio. I also lowered the wedge by lowering RF/LR.

    Do I need to raise the wedge or is there another way to tighten up the rear end so the car won't get loose off of turn 4?
     
  5. LouieLouie

    LouieLouie Team Owner

    Raising the wedge would certainly tighten you back up.
    If it is just in turn 4, you might consider lowering the right rear track bar one or two clicks. (Not sure if that is an option in the SK).
    Check your rear camber too. If you lean the tires more toward the center of the car it will tighten up the rear.
    You could also take a half pound out of the RR tire though this affects your entry too.
    Last would be lower the RR spring rate one click, but this would tighten you up mid corner too.

    Be sure to pay attention to your tire wear on the long runs, if you are burning up your tires, you might need to change your line or go easy on the gas getting out of the turns.
     
  6. SpeedPagan

    SpeedPagan The iRacing Guru

    So I actually do have a set-up question. On oval, you want the LF ride height to be the lowest of all the four corners right? That way the car is pointing towards the left turn?
     
  7. LouieLouie

    LouieLouie Team Owner

    It's not that you want the LF to be the lowest to point the car, it just happens to be the lowest because the amount of travel on that wheel is much less than the other wheels. In oval racing on concrete, you are trying to get the front splitter as close to the ground as possible without touching in the corners. This gives you the largest amount of downforce because you are basically sealing off the bottom of the car. The more air allowed under the car the less downforce you have. Since the right side of the car travels up and down more than the left side, the ride hieght on the right side needs to be a little higher than the left so it doesn't hit the track in the corners.

    At the rear of the car, it has much more to do with handling. The rear spoiler creates all the downforce and yaw on the car. So if one side is higher than the other, you will get more downforce on that side of the car. But too much downforce and the spoiler acts like a parachute and slows the car down the straights. Too low of a ride height and the spoiler doesn't create enough downforce and the car won't turn.

    Thanks for asking the questions, explaining it helps me understand it better and gives me a few ideas to try when adjusting my setups.
     
  8. SpeedPagan

    SpeedPagan The iRacing Guru

    @LouieLouie

    I lasted 25 laps at Five Flags Speedway practice session tonight. I was trying out FFB at 50% and it actually helps a lot in term of car control. However, the car is still getting loose off of exit in between 25 to 31 laps into the run. Let me know what you think!

    [​IMG]

    [​IMG]
     
  9. LouieLouie

    LouieLouie Team Owner

    Ok so from what I can tell, this is what is happening. The fuel sits to the rear of the car adding a lot of weight when it is full and the longer you go in the run, the more fuel you burn off and the lighter the rear end becomes which makes you loose.

    btw download the spring tuning chart and setup matrix from this link. They have good general advice.
    http://members.iracing.com/jforum/posts/list/3266211.page#8247732

    There are several things you can try but in the end you will have to just choose one because each option has tradeoffs.
    You could lower the RR spring rate, but this will tighten you up mid corner. Probably not the best option.
    You could lower the RR track bar, which might be your best bet. You will be tight off, the first few laps but should loosen up on the long run.
    You could lower your RR bump stiffness by 1 or 2 clicks but i'm not sure that will help on the long runs.
    You could also lower RR tire pressure but temps look pretty good.
    Same thing for stagger, lower RR stagger but again not sure this is the best thing for you.

    I would try lowering the RR track bar first and see if that makes the car too tight for you.
    If that is too tight, I would put it back and then maybe lower the stagger or RR tire pressure or both. I'm just not familiar enough with how much stagger will tighten up the car.
    If those don't work I would try a combination of some of these, i.e. lower the RR track bar 1 click but raise stagger 1 click. Or Lower the RR spring but raise RR track bar. You are basically trying to find that balance of being too tight and too loose.
    The bottomline is that as you burn off the fuel, the RR becomes light and then your car loosens up.
    The only real remedy is to start the car off being a little tight and letting it loosen up over the long run.
    Good luck!
     
  10. SpeedPagan

    SpeedPagan The iRacing Guru

    @LouieLouie

    Did some testing tonight for this week at Thompson and lowering the RR Track bar was the right call. It gave me much needed stability off of exit without costing me too much speed through the turn. So thank you so very much for that. I found this out by running 50 laps during a practice session.

    I have another question. Do I have to run 50 laps every time I want to see what the car will do on the long run, or can I adjust the fuel tank to where I think it's going to be at the end of the race and build a set around that?
     
  11. LouieLouie

    LouieLouie Team Owner

    Hey glad it worked out for you. I look forward to hearing about your win in your next race!

    Unfortunately, to get the best results you are just going to have to run a full 50 laps. If you lower the fuel, you are getting kind of skewed results since you have fresh tires.
    The whole fuel issue goes away once you move into the C level cars. The cars are a lot heavier so fuel levels don't play into handling nearly as much. But now you know you can adjust the track bar to get the results you want on the long run without having to run the full 50 laps.

    I was fortunate last night to ask for a setup from one of the A level Division 1 guys and he provided it to me. I took a quick look at it and he has a few things that are really different. This guy is on a big team and I'm sure it is not their top setup but it will certainly provide me with some good ideas. I'm looking forward to taking a closer look this weekend. I haven't had a lot of time to race these past 10 days so I'm hoping I can get something in at Kansas this week.
     

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