How are people tuning out rwd "snap"-oversteer?

I’m kind of surprised “search” didn’t show this covered before…

Anyways, despite my tuning/engineering knowledge and Worm’s tuning tips, I still can’t fully counter mid-corner from corner entry snap-oversteer when a gear change is necessary.

Sad thing is, even with normal steering, I still can’t fully get rid of it in the following cars in question:

A class C63 AMG Black Series

A class SLK55 AMG

Don’t get me started on the 458 Italia. I won’t bother talking about that one.

I’m a big Mercedes V8/V12 fan and this is driving me nuts! No pun intended, believe me.

I’ve countered some of the problem with softer springs (overall both softer with an understeer/oversteer balance in place), negative toe (-.2 degrees) and more rear downforce. I’ve actually had decent results but still not satisfied.

Any ideas from the more talented tuners out there?

Move up the decel bit by bit. Don’t be afraid to move it to an extreme.

This should be the very first thing you try. If it doesn’t work make sure you have a note beside you telling you what it started at and move it back.

Mercedes aren’t fun to drive and as a generalization most never have been. The same thing goes for the 458 Italia.

Heh, thanks Worm. I know what you’re getting at. I’ll try that next.

Funny thing is, my S class SLR is smooth as silk and very fun to drive. No problems with that one.

I tuned the black series for single player mode, and as worm days, i seem to remember having the diff quite high.

if you like, send me a pm on xbox live, and ill share up the tune. If it works for you, im happy to give it to you open source

Heh, thanks bud. I’m trying to do this myself as tuning is my best Forza skill (well…I think so, anyways. lol).

I’ll let you know if I end up pulling all my hair out. ha ha.

if you want, put up what you got, open sourced or not. We can give you feedback on the tune itself instead of just throwing darts at a board.

Just what I was thinking, Dust. Thanks. I’ll have to do it when I have time as I have to hit the sack. Maybe tomorrow evening, PST.

Currently, my SLK 55 decel is 74%. The C63 is 75% decel (pretty much default). Anything over that for both and my lift-throttle oversteer goes a little haywire.

Of course, these are the only two cars (of mine) that have this issue.

Since I think the numbers “458” and the word “Italia” should be considered profanity on these forums, I won’t count that car (despite doing some decent fixing of that car in S class). lol.

Running a high decel will not create lift throttle oversteer, it will eliminate it.

What about left / right pull during braking? And the margin of error one has in regards to being not perfectly straight when braking?

I bring this up because I actually grabbed your 2005 NSX Tune - Speed B class - last night. It’s a great tune - I just kept getting faster and faster with each lap, realizing how hard I could push it and get away with it - however, there sometimes seemed to be left / right pull on braking. Which would usually throw me into oversteer for the corner - I got used to it and adjusted, and even began using it to my advantage - I should be able to put it in top 50 of road america this weekend. I figured you had simply set the decel LSD very high, but perhaps I am wrong.

Very true Worm - Nice to see/ Chat again ,

as for the Snapping business- try to remember that the Diff has two modes of operation - accel and decel when changing gear the diff switches from accel to decel as the clutch is depressed and then back to accel as the clutch is lifted. having a large difference in the two settings will most definitely cause snap whilst gear changing under cornering, this said having your accel set too high will cost you acceleration rate,

for B class - most of my tunes are about the 35% mark on the decel with the accel not more than 15% away, with the more torque driven engines the gap is usually less.
Hope this helps

Another thing that I’ve found can sometimes help is brake bias. If the car is pitching and bobbing noticeably under braking - or even ploughing its nose - try shifting the bias a notch or so toward the rear - not so much as to make it squirrely, but enough to take a little of the load off the fronts. It will help the car keep a more neutral stance and soften the transition. Also, if the front tyres are working too hard under hard braking they have less grip left for turn in and you will tend to overcompensate on the steering. As soon as you release the brakes, the tyres will get more bite on the turn and you will suddenly find you have too much lock on. This game is noticeably unforgiving of excessive lock.

please answer the following with a yes or no:

  1. When does this occur and do you do the following?
    (a) lift off the throttle when changing gears?
    (b) Are you off the throttle when the rear comes out?
    (c) Are you braking when this occurs?
  2. Are you on the power when the rear comes out?
  3. Does this occur on more than one track?
    (a) If No.3 is true, please specify what track and if you can, please specify the corner.
  4. What type of corner does this occur:
    (a) Low speed corner:
    (b) Medium speed corner:
    (c) High speed corner:

Completing this will allow me to diagnose what the problem is and/or find a solution to your problem.

1 Like

Whoa, cool! I’m getting help from quite a few top drivers! This is getting interesting.

By the way, Worm, that “thumbs up” was so big a had a nightmare where I thumb wrestled that thing and it broke my entire hand! AHHHHH! ha ha.

Open source tune (or open source handicap, depending on your point of view. lol) coming up later (for the SLK55).

Yeah, if higher Decel is supposed to reduce lift-throttle oversteer then I certainly have another issue! sigh.

Thanks for the tips, Mick. I’ve certainly implemented those tips before.

Anyways…on to the questions…

  1. b) although, it occurs slightly even when on the throttle. a) (on a straight) and c) don’t apply with my driving.

Edit: Sorry, I should clarify that a) does apply when I’m in the middle of the corner, when necessary.

  1. see above, happens both on and off throttle, only in turns.

  2. Yes, all tracks. A perfect example is Road America’s second corner before the second long straight (just as a point of reference for you, if you need it).

  3. All types of corners. The only way to completely prevent it is settle on a corner entry gear, fully lift off the throttle and turn, straighten out, then shift if needed. Hope that makes sense. Thanks RR!

Please can you answer them again with a Yes and No! It’s very annoying looking back and forth! + It’s hard to understand if your answering the right question.
Copy and past this and remove the unnecessary Yes or No.

  1. (a) Yes/No (b) Yes/No (c) Yes/No
  2. Yea/No
  3. Yes/No (a - Answer only if Yes!) Track: / corner:
  4. (a) Yes/No (b) Yes/No (c) Yes/No

Bud, don’t you still have to look back and forth, even when I answer these (looking back at your questions)? lol. Sorry, I’m not trying to be “annoying”. I’ll know how to answer your questions in the future.

I’m in test drive mode now and re-tried simulating the problem so…

…here’s a re-write for you, as requested:

  1. (a) Yes (b) Yes (c) No
  2. No
  3. Yes (all tracks!) Track: / corner: exp: 2nd corner on Road America (before second long straight).
  4. (a) Yes (b) Yes (c) Yes

Right Now with it nicely organised I can help =]
So my answers:
1.(a) The fastest and best way (on this game) to change gear is to not lift off the throttle, press the clutch and and gear (up or down) at the same time to change gear.
(b) So when your off the throttle the rear comes out. This means that you need to adjust your Differential by increasing the Deceleration.
(c) As this problem doesn’t occur when braking, you don’t need to adjust your brake bias
2. Because this is a “No”, DO NOT adjust your springs as they’re fine. However if your getting literally no oversteer when applying the throttle, you may want to make your front springs softer in relation to the rear, this may help with cornering speed.
As 3 and 4 are a “Yes”, and it only occurs when your off the throttle through any type of corner these are your possible problems and areas which may need some tweaking:

  • Alignment: Increase rear and front Toe-in. / Reduce front camber and increase rear camber
  • Damping: Decrease rear rebound, decrease overall front damping (by 1 or 2)
    If this solves your low speed corners but you still get oversteer on the medium and high speed corners, adjust your anti-roll bars making the front stiffer in relation to the rear.

Hopefully this helps and you’ll be able you have some great racing!

Lol Worm! Just a simple way to find out what the problem is =P

I know, just commending your helping of people.

A lower decel creates lift throttle oversteer. You still have it backwards Zippy, that NSX is running a lowish decel (most mid engines need to be a little higher). Using it to your advantage is the reason it does, just takes time getting used to but it’s faster that way. The faster you can turn in without sliding the faster you can get to the apex and the more speed you retain throughout a corner. Just make sure you aren’t sliding.

I guess you’ve noticed that already. Some mistake lift throttle oversteer for barreling into the corner too fast and sliding because they broke too late.