Little tuning tricks, expanding your palette?

[Ske]

Recently I've been tuning a few high powered machines to tackle the last races in career mode, and I've seem to come across a talent wall as far as my tuning abilities go... I was wondering which tricks you'd use to try and iron out very specific issues with otherwise great cars.

The problems mentioned below mainly arose when I was trying to create fast and stable S-class AWD and A-class FWD cars. How would you tackle these issues without compromising other aspects of the car's handling? Aero tuning would of course be a last resort, but I'd generally try and fix it "mechanically" first. I'll give examples of sections where you'd expect to encounter these issues.

- Medium speed turn-in response (e.g. Laguna turns 3 and 4)
- Mid-corner understeer, transitional understeer when applying power (e.g. Mugello turns 1 and 7)
- Stability through high speed chicanes (e.g. Atlanta first crest, Mugello 13-14, Maple top of the hill)
- High speed exit understeer (e.g. Tsukuba Dunlop and final, many corners at Maple)

Any other tricky problem areas? Feel free to post them here, I do know a couple of tricks

[Blooze]

What a great thread!

I don't know that I have any "Little" tuning trix for the items you listed.  Most of those things can/would be fixed with a single manuever - I would bump the Wb about a half a percent.  Say that I started out at 56%... I would set it at 56.5%.  If I had not done so, I would bump the stiff of the ARB and the Springs.  This has a tendency to help the rear end rotate around when turning in under decelleration.

So, like I said.  No little trick - this is a major trick.  Every suspension parameter, almost, is touched.

$

[bimmerlovere39]

Hm... little tricks.  I'll have to think about it, but I would like to agree with Blooze - this is a great thread.

Now if I could just figure out what to post. 

[TheJohnNewton]

So, like I said.  No little trick - this is a major trick.  Every suspension parameter, almost, is touched.

$

Those are the little tuning golden nuggets that can take ones tuning skill one notch higher.  I'm with Bimmer, good thread, but I'll have to be here more to learn than contribute 

Any advice on the damper tuning?  I noticed you (Blooze) mentioning some minor individual adjustments there in another thread.  Currently I just set them up or down as a group based on the standard BT calcs.  I'm totally lost as to how/why to tune them individually.

TJN

[Ske]

I haven't been very successful when departing from my usual damper setup on any car to be honest... any "by the book" changes I've tried to make have only proven worse in A/B testing. It might sound strange, but 7.1/6.5/6.4/4.4 seems to be the sweet spot for just about every car I've tried lately, even mid-engined.

Changing the weight bias or f/r stiffness is an obvious option, but I haven't really had much luck with it to be honest... Even with a severe change of "spring bias" or ARB (to the point where overall balance is upset), I find that quite a few cars retain some annoying traits like the ones I mentioned. Especially FWD/AWD cars seem to need some other treatment besides weight/roll management one you start forcing too much power on the drive wheels...

I think a couple of my problem cars actually have pretty optimal spring and ARB settings, and that alignment and diff is the way to go... but lately I've began to wonder if the settings really do what it says "on the tin".

It might be that I'm just asking too much from the cars, but when the problem areas per car are so narrow and specific I can't help thinking that there's a little alignment trick or something that I just don't know of.

[Blooze]

...It might be that I'm just asking too much from the cars...

LOL - I think we ran into some of that in the GTR thread...

I am in no way as discerning, usually only going after the seriously blatant issues.  Some of the "uncomfortable" things just are.  Sometimes you just have to wait on the car to get turned before you hit the gas.  My current Montegi West record holder is one of them.  The fastest way onto the straight is to lift slightly and let the car rotate toward the apex before pulling the trigger.  I can hit it sooner and I can stay off the outside rumble strip, but the tires squal like a mashed cat.  I have to hold hard against the understeer with the wheel... and the ghost that waited, the one that I shot past trying my power manuever... drives right thru me and away because the tires are hooked up and he has momentum for the shift to third.

Any advice on the damper tuning?  I noticed you (Blooze) mentioning some minor individual adjustments there in another thread.  Currently I just set them up or down as a group based on the standard BT calcs.  I'm totally lost as to how/why to tune them individually.

TJN

The only changes I make to Dampers are regulated by one of the devices on my Car Sheet.  The initial setting is via the Wb.  Tweakage is provided by the Damper Agents.  I'll try to explain them. 

First, I refer to them as agents because more than one damper value is modified with a specific goal in mind.  I created the agents so I didn't have to all the time be remembering the combinations.

Agent 1 - Front Grip on Exit: A setting of 1 increases the FR by .1 and RB by .1; a setting of 2 increases by .2 and so on.  Increasing the front rebound will slow the weight transfer to the rear, as will increasing the rear bump - the weight tends to stay over the drive wheels a little longer when you accellerate.  The idea is that you shouldn't need it there after a bit because the turn is straightening out as you leave the corner.  If you have hit the gas too soon, then the weight will go to the back no matter how you have your shocks set.  Note: I have this value set to 2 on all my Civics.

Agent 2 -Transitional Oversteer: This increases the RR and RB.  Consider a car that is having trouble holding the line on the 2nd turn on MV2.  I would increase this value by 1, perhaps 2.  This will slow the weight transfer to the outside on the rear of the car, allowing it to come around a little sooner.

Agent 3 - Transitional Understeer: This increases the FR and FB.  Use this on a car that is getting loose in the backend in chicanes and places like that.

Other than that, I leave the dampers alone.  I noticed that the game does not modify the damper values for changes in spring rate, so I stopped doing that as well.

Should I notice another combination of Damper changes that cures a problem - I would just add another agent.

Get a holt of Newt's Blooze Tooner, or my Car Sheet and set it up for a car at 56%  Note the ARB, Spring, and Rebound values.  Then change it to 56.5%  This change is minimal.  But analyse how it changed.  There is a little more weight on the front wheels now, a little less on the rear.  The ARB is softer in front and stiffer in the rear.  Then be adding the agents, the initial shock of a weight transition is less disruptive.

That's pretty much how I go about it... the types of things I am considering.

I hope it helps some...

$

[Blooze]

I mentioned this a bit, but maybe not enough.  Remember that things that you do with the dampers only have very temporary affect.  If you increase the RR and RB, then the accelleration of the weight toward the rear of the car is slowed, but the weight it going back there eventually.  So when you are thinking about the Dampers as a cure, consider the duration of their affect. 

Part of the reason I don't have push issues is that I also have the Front Toe set to .1 and the Castor at 5.0.  These are fixed modifications, their influence is constant.

$

[Ske]

I might just be overcompensating, as I tend to adjust dampers in bigger chunks (.5's)

However, I noticed something today that I haven't before. I approached my A-class Altima at Mugello, which was a bit of a pain to drive because of the front wheels screeching all the way through the corners.

- Stiffening the rear ARB 5 clicks, not much change in front end grip or laptimes but the car seemed a bit more alive.
- Drastically lowering downforce actually made the car quicker in the corners. Maybe DF can overload the tires?
- Rear toe from 0.0 to +0.2 was where it really happened. The car tucks in and holds the line much easier, and the front end seems to track much better. The result? Much less whiny tires and a whopping 0.45 off my lap time. I now average faster than my previous best lap, even with obvious mistakes.

This definitely hints at the "hidden" potential of alignment tuning... I've previously found it hard to get coherent results from tweaking toe and camber, but both this car and the FCT E-type were drastically improved by a basic change in this area. What makes it interesting is that the same tweaks can seemingly make other cars worse to drive (e.g. the GTR doesn't seem to like rear toe-out or high front camber)

[JG4tr]

I agree with Blooze regarding the dampers. The more damping you have, the longer it takes to 'get to' the springs but, you do eventually get there so, in my opinion, they need to be right before you look anywhere else.
If I'm understeering mid-corner, I start by shifting the weight bias rearward. I see Blooze in his first post used an example of going from 56% to 56.5%. I'm not sure if his example was not situation specific or a difference in philosophy but, I'll leave that for him to answer.

For corner entry understeer, I usually work with diff rear decel and toe. I lower the decel until the rear starts to break loose when tossed into a medium/slow corner and then add about 5 points back in to secure it. For toe, I usually start by adding front and once I get to .2, then start with the rear as well. ( .3F.1R s a pretty common setting for my tunes). Other tweaks may come in the form of small increases to toe or caster and a reduction to rear rebound.

For corner exit understeer, I generally work with diff rear accel and front rebound. Lowering accel allows my tune's rear tires to rotate at the differing rates needed when the tires travel the separate arcs of the inside and outside wheel. Increasing the stiffness of the front rebound delays lift that would reduce nose weight and allow the front wheels to begin losing traction.

The AWD car adds another level to the situation. I have a few that I have tuned to an almost 50/50 torque split which can provide a very even and stable on/off throttle character. I also have a few tuned with a definite rear torque bias that I can utilize to induce a slight corner exit oversteer to help the car rotate, much like a RWD feel.

As always, your mileage may vary

[Blooze]

...
If I'm understeering mid-corner, I start by shifting the weight bias rearward. I see Blooze in his first post used an example of going from 56% to 56.5%. I'm not sure if his example was not situation specific or a difference in philosophy but, I'll leave that for him to answer.
...

As always, your mileage may vary

That is a specific situation (all them Civics) so I 'spose it's filosoffacle...

My idea, what I am figuring on, is that by moving the weight forward I am creating better traction for the front tires, more grip.  If I am trying to throttle up, then more grip to spread between steering and accelleration.  Also, the rear becomes lighter (and the ARB is stiffer) so its tendency to want to rotate around the car's center will increase.  Now, I could be all wet with this, but it seems to work.

Remember, I am working off the idea that I am actually moving the weight when I set the springs and stuff with the Blooze Toon Wb business.

$

[bimmerlovere39]

If I have mid-corner understeer, I soften the front bar (RWD cars) or stiffen the rear bar (FWD cars)

[JG4tr]

As Artie Johnson would have said..."Very interestink"
We seem to have two opposite tuning theories but, both of them work.

 

My idea, what I am figuring on, is that by moving the weight forward I am creating better traction for the front tires, more grip.  If I am trying to throttle up, then more grip to spread between steering and accelleration.  Also, the rear becomes lighter (and the ARB is stiffer) so its tendency to want to rotate around the car's center will increase.  Now, I could be all wet with this, but it seems to work.

Remember, I am working off the idea that I am actually moving the weight when I set the springs and stuff with the Blooze Toon Wb business.

$

I see what you're saying here about the traction so, here is my thought process...

 My theory comes, in part, from the observation that, generally speaking of course, a car with a 50/50 Wb would tend to be balanced neutral. Cars that have a rear Wb, tend to oversteer and cars with a front Wb tend to understeer.  Why would this be the case?
I imagine a car driving down the road sideways ( rear on the left and front on the right) and the left (rear) of the car was heavier than the right (front).
 
If the vehicle began to decel, wouldn't the heavier side, due to the inertia of it's higher mass, tend to move to the front and the lighter side then trail behind?

If we are indeed influencing the "weight" of the vehicle in the Forza mathematical car model when we change spring values as we seem to be doing, then shouldn't the 'heavier' front end of a front Wbiased car be more difficult to exhibit a change in direction due to the added inertia of it's higher 'mass' ?

Does the added 'traction' offset the higher 'mass' to overcome the change in inertia??

What would be the change to the handling characteristics if you only shift the Wb forward and do not adjust the ARBs to compensate??

Who would've thought that a degree in physics ( which I do not have ) would be desirable for playing video games!!

 

[TheTechnobear]

theres alot of discussion here about F/R balance of springs/arbs/dampers
(which i understand, as it helps balance between overstreer/understeer)

but does anyone adjust the total stiffness of ARB and springs?
or more particular, the perceived wisdom appears to be to stiffen , to reduce weight transfer...
but arent there cases where softening might help?

my belief is that with the cobra softening helped, and that perhaps this is the case with either a) light cars b)cars with high PW ratio .. hmm might be the same thing

also ive heard stiff springs with soft arbs, or soft springs with stiff arbs - thoughts?

[Ske]

theres alot of discussion here about F/R balance of springs/arbs/dampers

There is

I was really hoping that there would be some more insight into other areas to be honest... Those settings can be pretty effective up to a point, but I think the science of it is pretty well documented by Blooze and others elsewhere.

What I was initially after were some discussion on the workings of tire pressure, alignment and diff tuning... which seem  more "surgical" when it comes to tuning - and also much less explored. I definitely believe that diffs and camber behave quite a bit differently in Forza than we might think...

[TheTechnobear]

What I was initially after were some discussion on the workings of tire pressure, alignment and diff tuning... which seem  more "surgical" when it comes to tuning - and also much less explored. I definitely believe that diffs and camber behave quite a bit differently in Forza than we might think...

yeah, i think i understand what you mean, and in similar boat...

diff settings i understand (i.e know the theory) BUT find hard to put into practice
tyre pressures & camber, i set purely by tyre temp in telemetry (well documented again) - but is this optimal?

toe in/out - an area, which is a bit black magic for me, again understand theory, and know the black box solutions i.e. +0.1 from for turn in, -0.2 rear back end stability.
JG4tr points are interesting on this...

caster, an area i also just play with, heard the supermarket trolley example ... but my eyes start glazing over when others start talking about dynamic camber

brake bias, i try to use telemetry for 4 wheel lockup, and knock down pressure about 10% (im using wheel)

also of course, some of these settings can be worked on to be good for a general setup,
but are some really more track (type) specific  (e.g. camber?) ... i guess a bit like gearing and downforce.
e.g. if we go on a twisty circuit, perhaps a good idea (example only ) would be - up FD, inc d/f , inc camber, inc tyre pressure