RFactor 2 Advanced Car Set up Guide

Discussion in 'General Discussion' started by davidporeilly, Sep 13, 2015.

  1. tommy737

    tommy737 Registered

    May 1, 2019
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    Hi All/David

    First of all please let me thank you for your guide, as I'm a complete newbie of this world, the guide was exactly what I needed to undestand the principles of car setup.

    Don't know if this comes against the rules of the community, but I'll try to post amessage coming from a different internet site as I'm honestly getting confusing regarding diff lock setting so I really hope somebody else could help me to understand my doubts....

    Other site statement
    Power-diff: High values=over-steer behaviour, Low values=under-steer behaviour.
    Coast-diff: High values=Under-steer behaviour, Low values=Over-steer behaviour.

    To complete this:

    Well, as a poor driver, I'm trying to chase the truth by myself making test and different run (SPA, using Formula Renault 3.5 as it comes on the sim). Closing the diff power (100%) car does not oversteer so quickly but tyre wear highly increases and this should confirm what David explains on the guide, but my question is...

    how is that possible such a video on youtube explaining exactly the opposite? Any possibilities the other sim uses opposite scale? I do believe lock means lock (100%) so an increase on diff power should bring the car towards Understeer, and not oversteer as stated just above.

    I have been also checking at the beginning of this topic some topic related to this, so do we have (as a magic number of setup does not exist) which is the right direction on setting up a car with diff?

    Hope it makes sense
  2. davidporeilly

    davidporeilly Registered

    Jun 12, 2012
    Likes Received:
    In my view the other site statement
    "Other site statement
    Power-diff: High values=over-steer behaviour, Low values=under-steer behaviour.
    Coast-diff: High values=Under-steer behaviour, Low values=Over-steer behaviour."

    Is a bit confusing, do they mean to deal with oversteer behaviour or to create oversteer behaviour?
    They also maintain that more diff lock or less diff lock does the opposite thing on power vs coast.

    My view is explained completely in the guide but to "ad lib" some reply here.
    Increasing diff lock makes the car go straighter in corners, as the freedom of the wheels to rotate at different speeds is reduced and that freedom is what lets the car turn more. There are some very good video links in the guide explaining this by starting at the fundamental function of a diff.
    Making the car go straighter is reducing oversteer. So increasing diff lock reduces oversteer.
    On power side it does it on throttle (mid corner and corner exit on throttle).
    On coast side it does it off throttle (so under brakes).
    Pre-load does it all the time.

    If you ever saw a car in the days before limited slip diffs were available (another name for a diff that locks a bit) you would see the loaded outside wheel gripping and the unloaded inside wheel spinning. This created oversteer.

    That video is a bit long and slow moving for me to watch 18 mins on that one topic-sorry. But I smiled as I raced Snetterton IRL 2 weeks ago and that's where the opening sequences were.

    As a rule of thumb you need to set diff lock as low as possible to reduce front wear. More lock means the fronts are fighting the diff as they try to turn the car.
    So first get the chassis balance right (springs-dampers) for mid corner. Then play with diff in the transitional parts (entry -Coast and exit-Power). Start with none. Only add to solve oversteer that is occurring.
    Lars likes this.
  3. Phoentje

    Phoentje Registered

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    Hi David. Send you a request trough PayPal. Forgot to mention my email address. Did ya receive it?

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