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2015 Stock Cars Now Available

Discussion in 'rFactor 2' started by Blkout, Sep 25, 2015.

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  1. Gijs van Elderen

    Gijs van Elderen
    Premium Member


    Stock cars, undoubtedly the most popular form of motor racing in the United States, is often seen as primitive by Europeans and much of the rest of the world. It is our hope to change this perception by giving all our customers access to what is, our neck of the woods.

    Download: 282MB
    Profile: Link (much of the same info as below)
    NSCRS15 rFM (for vMods with rules, recommended for server hosts)
    These cars and the rules for racing them are closely aligned with many of the changes in Build 1008. Highly recommended to read the B1008 release post.


    Stock cars are dictated by rather restrictive rules. However, the technology and development programs are as sophisticated as just about any other form of motorsport. Extensive wind tunnel testing, CFD programs, 7-post rigs are standard in developing the most competitive cars.

    Stock cars are large and relatively heavy steel-chassis racing cars, a combination of factors that somewhat prohibits maneuverability and handling. Given they tend to run almost exclusively on ovals, which generally feature large radius corners, this has minimal impact on performance. Despite all this, errors at these very high loads can be brutal on tires, and small mistakes can create big consequences. Stock cars have neutral handling, but do rely heavily on setup to be competitive. If you don’t like tinkering with setups, you likely won’t be competitive outside a fixed-setup environment.

    Unlike circuit racing, the majority of downforce is not created aerodynamically, but via banking in the corners. It might surprise some to know these cars produce up to 2600lbs ~(1200kg) of aerodynamic downforce, which is very nearly on par with what GT3 cars would produce were they be able to reach similar top speeds, but stock cars do it without large wings or diffusers. The majority of downforce is created through ground effects, via the front splitter and side skirts, and of course some help from the rear spoiler.

    The nature of ground effects means that you must aim to keep the splitter very close to the ground at all times. As the underside is not smooth, drag is also lowered by blocking airflow under the car. This approach requires running on bump-stops, or very stiff springs to prevent the car raising too much down the straights. Unique damping properties are also used in stock cars for the same purpose. The effect of this is to make the cars somewhat sensitive and edgy, but in finding the right setup and driving style, the car will just ‘work’.


    The car, though always fundamentally the same, is tailored to several circuits types. Our stock cars also feature three main brake packages (which are selected automatically on ISI tracks).

    Short Track
    Similar to other speedway configurations, the brakes tend to be larger, tyres a bit softer. This refers to tracks under 1.0 mile and no inner lines are run. Pressures are also generally much lower and the loads tend to be much lower. Downforce levels are similar to normal speedways, though.

    Setup to provide maximum left cornering potential, the car will pull left in a straight line. Inner liners are required in the tyres, which add unsprung mass. (Intended for use at tracks under 2 miles).

    Speedway II
    Similar to speedway, but has reduced downforce as a testbed for 2016 regulations.

    Speedway III
    Setup to provide maximum left cornering potential, the car will pull left in a straight line. Inner liners are required in the tyres, which add unsprung mass. (Intended for use at tracks over 2 miles).

    The main differences are that it has a symmertical setup, but is otherwise similar to Short Track and Speedway configurations. The ratios are less restrictive as you can run whatever 3rd gear ratio you want. The radiator is opened up and brake cooling is essential.

    Plate Tracks
    These are tracks which are full throttle all the time (under normal circumstances). The power is reduced, and the overall downforce and drag much lower. The cars also tend to be setup to absolutely minimise drag, usually achieved by lowering the rear. The brakes are also much smaller.


    Due to the extreme loads seen in the corners, you must be very careful with your steering lock application; Aim to have the car in the narrowest of slides, getting near peak grip without exceeding this limit, and trying to hold this for the entire corner.

    A light trail brake into the corner, transferring weight in a controlled manner, and building throttle as you exit the corner, is the normal technique. Keep in mind that the tires are designed to fall-off significantly in performance, especially after the first couple laps, you will need to ease off the gas sooner and sooner on every lap thereafter, also being more careful on the throttle so as not to overheat the tires.

    Setup wise, and driving style likewise, the main difficulty is getting the car to be consistent and balanced through an entire stint. Making a qualifying setup is relatively easy, but it will be in your interest to balance the outside tire wear front to rear through both setup and driving technique.

    The engine is a large 5.8L V8 with around 740hp. Peak power is produced somewhere around 9000RPM, and redline at about 9500RPM. The torque curve is quite vast, having only a 4-speed transmission. Short shifting is necessary only to curtail wheelspin, or save fuel.

    On most oval circuits, due to the 3rd gear ratio rule (which must be 1.28:1 or lower), you will be restricted to 4th gear in normal running. Choose your final drive ratio carefully to ensure maximum performance over the lap, and that you won’t hit the limiter in draft.

    On road courses (and also leaving the pits), you do need to be wary of the torque in 1st and 2nd gears, you usually won’t even be able to use full throttle in these gears even with the car in a straight line. 3rd gear may also be difficult to apply full throttle, so sometimes you should remain reserved until in a straight line.

    For speedways, the difficulty is accelerating with an asymmetrical setup as the car will be constantly be trying to pull in one direction. You just have to know your limits here.

    At restrictor plate tracks, the engine is de-tuned to about 470hp. The air restrictor drops the peak RPM’s and this usually makes the car a little easier to drive, but the low end torque is still quite abundant.

    Braking – Roadcourses
    Having a high capacity engine, you will typically feel a strong engine braking effect, this has a habit of changing the effective brake balance of the car in each gear. As such, the engine braking on the rear wheels can be very strong in 1st gear at high RPM’s, probably a combination best avoided. Be smooth and late with down shifts, you will also need to blip the throttle to avoid rear lockups. This effect is amplified by the fact it only has 4 gears, so the gap between each shift tends to be quite high. If it helps, move the brake bias forward.

    Apply much of your braking in a straight line, as locking inside wheels is easy due to the stiff front anti-roll bar. Near top speed, the downforce adds about 60% to the cars’ weight, so you should be able to apply more braking torque at higher speeds. With the car being relatively heavy, you may need to ease into braking initially to allow the car to settle, and relax the pedal later into braking zones, light trail braking is possible.

    Braking – Speedways
    Using roadcourse techniques on speedways would sacrifice too much speed, and trail braking is a must. While braking systems are typically similar on speedways, the higher speeds allow the brakes to cool, and braking distances are usually shorter due to high corner speeds. The disc sizes available are different, and maximum torques usually a little bit less.

    Keep in mind pitting will be tricky with the asymmetrical setup on ovals, and the smaller discs can be a little easier to overheat. For tracks where little braking is required, a weaker (lighter) brake system may be used.

    Tire Management
    At the speeds and loads these kind of cars produce, applying just slightly too much lock, or sliding the rear tires a tiny bit, will very quickly produce detrimental results for the tires.

    In many ways, tire management over the entire length of a fuel stint is exactly what stock car racing is all about. Setup and driving style are everything.
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  2. Gijs van Elderen

    Gijs van Elderen
    Premium Member

    @Daiman Patel :

    NSCRS15 rFM (for vMods with rules, recommended for server hosts)
    These cars and the rules for racing them are closely aligned with many of the changes in Build 1008. Highly recommended to read the B1008 release post.
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  3. excuse me where I find the template to make a custom skin .... many thanks...
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  4. Daiman Patel

    Daiman Patel
    RedShift Racing Staff Premium Member

    That's brilliant! Thank you very much Gijs. I'll get on to setting up the server using this rFM once they have been updated to the latest build. :thumbsup: It would be nice if ISI could forewarn us about game updates so that we can be prepared; they might do already, but I can't find anything. :whistling:
  5. Bez

    All the gear, no idea... Premium Member

    I tried the stock cars last night and was suffering terrible rubber banding on the Ai cars, is this a known problem at all, any fix?
  6. AI Limiter = 0 is no rubber banding. It's in the options somewhere, can't remember if race difficulty or somewhere else
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  7. JoelGL

    Premium Member

    How is AI Limiter supposed to function, what does it mean?
  8. jimortality

    Premium Member

    I couldn't find this anywhere
  9. Stenne

    Premium Member

    "AI Limiter="0.25000" // Range: 0.0 (no limiting) - 1.0 (limiting used to make racing closer but also make more driver differences on flat-out tracks)
    Does as it says, makes racing closer between the entire field of cars or more spread out. To try it out set it to 0.0 and watch an AI race - time accelerate is handy, do NOT just 'Finish Session' as this could have variable results - then note/screenshot the finishing times, exit game and change it to 1.0 and repeat then compare finishing times. Longer tracks/more laps have a greater spread obviously!"

    Picked from this thread

    Some useful AI-reading also in the Legends League Wiki

    Don't have the rF2 UI in front of me but as I remember it should be in the "OPTIONS->DIFFICULTY or OPTIONS->CONTROLS" tab in the main menue. It is also available from one of the tabs in Garage.

    Hope this is some help