Tuners, please help another tuner, This is driving me BANANAS!

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First thanks for reading and if you can and are willing to help, please do, PM me, reply here or add me on Xbox (TVRacing331). This is driving me BANANAS. I have been tinkering along with tuning since way back when (previously GT was Alphapd331). Never been crazy active on the forums or posting tunes, but got some good help and info in the past from my PTG guys, GFY guys, TN Eagle, 40oz, Skatemaster, etc. So with Forza 6 I decided to get way more into tuning and to start sharing what I was shown before with others who want to learn just like me! BUT my thinking or should I say the way I have been thinking is just jumbled now.

I probably have way too much info I have gathered over the years about tuning, how to, what you are supposed to do, what not to do, what works, etc. Yeah there are ways many people come up with springs, arbs, rebound, bump, etc. I had been under impression high rebound low bump, cars weight and % somewhat dictate the initial spring etc. Even heard “hey the location of the sliders is how you do it”. I have never been formally told “hey this is how you calculate your initial spring, rebound, bump etc. I just took bits and pieces from everything I read or watched. But I can’t wrap my head around this. I wish I had days and days to tinker, but unfortunately I don’t. I am asking if you can explain, PM me, help me to see how or what is the proper way to start and then what to do, etc.

Example of the EVIL car below, the Mercedes. I have been messing with this car for over 2 weeks and a friend in our party last night decided to grab the car and we both worked on it, just not me driving but him and my brother both driving. They both posted some really, really quick times with the tune below at Bathurst and Road Atlanta. I am the more so tuner and they drive, apparently my driving ability isn’t as great as I would like it to be.

So my thinking was a 3037lb car at what Forza says is 53% Front would be roughly 50% or so of the cars weight for me to set the initial springs at 53% and then 47% (roughly total springs at 1518lbs or so) right, umm nope. Same thing on setting ARB’s (40 max so 53/47 or the 100 other ways I was told how to do them) and rebound and bump, nope wrong again. So now my mind is all kind of BANANAS. Only because my friend went to extremes did we actually tune & tame the rear end on this thing, but the numbers don’t make any sense to me.

The tune ended up being at 39% the overall vehicle weight and 67% Front and 33% rear, with a CRAZY arb setting and even more confusing rebound and bump??? I am sorry for the long read, but I just want to be able enjoy tuning and driving again, but can’t if I have no clue WTH I am doing. Thanks again if you can and are willing to help me out.

Oh and we all drive with No assists, manual w/clutch and most of the time normal steering with controller.

S800 Mercedes #9 E63 AMG V8
3037lbs / 53% Front
630HP / 475 Torque
Tires @ 27.5PSI Front 290/40R18 Rear 320/35R18
ARB - Front 35ish Rear 1.00 (WTH!!)
Camber - Moderate nothing crazy
Toe - 0.2 / -0.2
Caster - 6.5
Springs - Front 796 Rear 389
Ride Height - 4.2 & 5.0
Rebound - 10.8 / 9.5
Bump - 8.1 / 8.0 (WTH!!)
Aero - 260 / 345
Brake - 47% @ 180
Accel - 33 Decel - 50

Thanks again,
Racing

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Check out Stella Stig on youtube

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Very familiar with the Stig, doesnt help atm

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If I have time tomorrow after running the tunes in the Testing Community Tunes thread then I will build this and take a look at it. Keep in mind that my theory on tuning has never matched the “norm” around here. If a car has wacky settings and it runs great times then its a good tune. I may start a fire by saying this but to me, there is no “correct way” to tune. You tune to what makes the car give you the best chance at putting up the quickest time. The only thing that HAS to be correct is the build. Period.

1 Like
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Just a quick glance.

Tires: Front 29 - Rear 28
ARB - Front 1 - Rear 40
Camber -1.0 both
Toe -0.1 both
Springs Both about 1/3 bar
Rebound 6.9/6.0
Bump 3.9/3.1
Aero Max
Brake 54 @ 119% pressure personal pref
Accel 23 Decel 11

That is a basic baseline that I use, then I test and adjust from there

6

I don’t usually venture out of C-Class, so S-Class is far above what I’m used to tuning and driving, but I wanted to try this anyways.

I really don’t like the way the car drives completely stock, and even with the upgrades you have on it, I feel like it just doesn’t have enough grip for how much power it has.

Regardless, I was tuning this on Road Atlanta, no idea what a good S-Class time there is, but with my mediocre driving skills and ABS I was able to run relatively consistent mid 1:24’s

These are the settings I have on the car right now:

Tire Pressure: 27.5/27.5
Gearbox: I just changed 6th gear to 1.00
Alignment: -1.5/-1.0 Camber, 0.0/0.0 Toe, 6.0 Caster
ARB’s: 18/13
Springs: 600/575 Rates, 4.0/4.9 Height
Damping: 7.9/6.7 Rebound, 4.8/4.0 Bump
Aero: 276/386 (Max)
Brakes: 50%/110% but that’s for my preference and ABS
Differential: 70% Accel/20% Decel

Give it a try, see if it’s better or worse than what you have been using.

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Thanks so much for all the replies…I will definitely give a few of these a go…and yeah 1;24 TO 1;25 was what I was running around road Atlanta,I think my friend had it at 2:09 at Bathurst. Again thanks for the replies…I have been tinkering with other cars in C, D, E class experimenting with basic tunes and believe I have found the right medium…at least dialing the car in is a ten minute type thing vs hours, LOL. Ya’ll hit me up if you are on, love to do some racing. Thanks again to Eagle and Knucklehead, its been awhile and to Falcon, those are some good times with the car especially with ABS…lol.

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Notice the rear bump setting in the replies you have received. I suspect that is the key.

Total levels may vary but a low rear bump in comparison to the other damping setitngs is often key if you are going for rear end stability.

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Don’t completely slam the bump though, 1.0/1.0 used to work on FM4 but now it won’t take the bumps or kerbs so you need some decent bump in there relative to your rebound.

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Yeah I have found that also, usually above 2.2 or so on the bump

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I like Knucklehead & F4LCON’s settings; they are something that I would also use. As already stated, the build is very important.

My recommendations:

  1. Springs: Start from the default then lower the power side (in this case rear) by about 5% > for better compliance over bumps. This cannot be calculated purely from mass + wt % of the car because of the suspension geometry on each car is NOT KNOWN. The car’s CoG (centre of gravity) is also needed but info also not available. I suspect only T10’s code/vehicle builders have this information.
  2. ARB: Also start from default; use ARB for mid corner balance, lower the side where you want grip BUT if spring is too high ARB will have reduced effect
  3. Bump: In FM, bump can be used to either control the unsprung mass (wheels) OR the sprung mass (body) but not both. The 1.0 bump is bias toward the unsprung mass damping where higher setting will control the sprung mass. This also cannot be calculated because this parameter has NO unit which leads me to suspect the numbers are RELATIVE to the spring rate, not ABSOLUTE. Bump generally equates to response characteristics: lower for smoother & slower, higher for faster but rougher ride.
  4. Rebound: generally speaking, rebound is for stability (opposite of response): lower for faster response but wobbly ride, higher for stable ride but slower response.

That’s the sequence that I use for set-ups. Ride height, is a function of all of the above but mostly springs; set ride height so the car does not bottom out. Lower side gets more weight loading.

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Interesting thread, i’ll keep an eye on it!

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Ok so after reading this I thought I’d give tuning the Mercedes a try and this is what I’ve come up with. The rear end is planted (it’s quite lively if you over do the throttle but it’s mega grippy and smooth)

Tyres
28.5/26.0

Gearing
Stock (haven’t played with it yet)

Alignment
-0.9/-0.3
0.0/0.1
3.7

ARB
18.93/12.15

Springs
592.9/494.9
3.9/4.6

Damping
5.7/7.8
4.7/2.9

Aero
245/355

Diff
36/24

Give that a try.

Odd one out is damping. Reason for those setting is with the way the rebound is set I’ve set it up to plant the rear more so there’s less sliding about on/off the throttle and less oversteer through the corners. I set the bump up to counter any excessive understeer so it’s very balanced with a planted rear end providing you don’t use the throttle like a light switch.

Feedback would be appreciated.

Edit:
Aero was the last thing added so should behave well without it but you will have less high speed grip without it.

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Rabbit can u elaborate on how u set bump to counter any excessive understeer & your theory behind the damping…thats the area I am very inexperienced on…thanks,
Art

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Ok.

Think of it like this.
You have 3 springs per corner and 1 bump stop.
Spring 1 (main suspension)
Spring 2 (rebound)
Spring 3 (ARB)
Bumpstop

Your bump stop is a solid piece of rubber on the top of the shock absorber which stops your cars suspension bottoming out, you can see it work if you set it to max and run a curb the bar graphs won’t max out.

Rebound controls how quickly the wheels return to the ground. If you drop the rebound right down you have a very smooth ride using much more of the suspension travel meaning the car doesn’t crash around as much and doesn’t skate over bumpy surfaces.

Forget the ARB and main Spring stiffness for the time being.

So what you want to do is set up the Bump Stop to control the squat under load. You’re going to want a longer more progressive bump in the area the larger distribution of the cars weight in the case above in the front. That’ll control how the front behaves on the brakes and how it behaves when you hit a curb or bumps in the track. The higher the value the longer, stiffer and more progressive and less likely you are to bottom out, the downside is the car can become skittish.

With the rebound you adjust that after the bump stop NEVER before hand. If you have a stiffer bump in the front and a high rebound you’re creating understeer because the rear is softer than the front allowing the rear to generate more grip because the rear will have a more controlled ride.
So to counter that you decrease the front rebound to allow the front suspension to work more efficiently using more travel, creating more grip thereby eliminating the understeer.

To counter excessive oversteer reduce the rear bump and increase the rebound.

Stiff bumpstop need soft rebound = controlled ride
Soft bumpstop needs a stiff rebound = controlled ride

Soft suspension need a stiff bump stop, stiffer rebound to maintain low ride height.

Stiff suspension needs a shorter bumpstop and softer rebound.

Soft bump and rebound needs stiffer ARBs

Stiff bump and rebound need softer ARBs

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Interesting thread this. May have to try out some of these suggestions myself to see why people set some things the way they do.

Like the sound of the damping setup posted above, not sure if it will work properly with the forza world physics, but certainly worth a try =)

As others have pointed out, getting your springs, damping, ride height and ARB’s working in harmony along with good geometry is the key - and to remember that setups are always a compromise as when you try to fix a problem you will often cause another somewhere else. It’s all about moving any problems to an area of the car you can deal with best if that makes sense.

For example, I was playing around with a P1 this morning before work and was having issues with it locking up on the brakes occasionally whilst hard on the brakes into one turn in particular. Car felt like it was possibly bottoming out (confirmed by the telemetry) while hard on the brakes over bumpy sections - was fine 99% of the time using almost the full stroke but every now and again it would hit a bump while at almost full stroke causing a lock up (not what you need braking from nearly 200mph!).

The car felt fine everywhere else, really nice power delivery out of the corners, great turn in to corners, loads of pace on the straight bits and a really nice balance between under and oversteer so I didn’t really want to change the way it was feeling much except my brake issue. This meant I was trying to avoid stiffening the front springs only as that would change the balance of the car, I tried increasing both front and rear as well to keep the overall feel which did help somewhat but didn’t feel the same elsewhere. Increasing front ride height would also help the brakes, but again this changed the overall feel of the car. Eventually increased all damping settings slightly in ratio together (as looking at the telemetry it was using a good range of suspension stroke - just using it a bit fast), this helped out massively and kept the car feeling pretty much the same.

By this point I was actually running late for work so had to leave it there, but the car was showing a lot of promise - can’t wait to finish it off when I get home actually. As much as I love my '76 Ferrari 312 T2, they always get some hater in the lobby telling you that it’s a proper race car so it’s not fair etc - heads up guys - Forza is a racing game lol. Anyway with the P1 at least I’ll be able to keep the moaners quiet and have a car for the speed tracks too - double win! =)

17

^^
This is tricky because race cars and road cars are in a same category. Road cars will not be competitive with race cars obviously, but what are you supposed to do? Use race cars only on career? On the other hand, if you do use them it isn’t fair to players who want to use road cars. It’s a lose lose situation until they put race cars in different categories i.e. R class road cars and R class race cars. Idk maybe i’m just the only one having a problem with the way this is set up in the game, but I doubt it.

Anyway, i’m steering off subject. I’d like to know how the telemetry tells you when the car is bottoming out? Can anybody enlighten me?

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Look at your compression graphs (4 white bars that Bob up and down) that’s your spring compression. Basically if you are bottoming out the bars will turn fully white or red if it’s caused by your springs. If your ride height is too low you’ll see sparks coming from the car on the brakes or throttle which you can stop by raising the ride height a little and stiffening bump settings.

You’re not strictly correct about the race cars vs road cars, that’s track and tune dependant. You won’t catch them on a tick and twisty track but you’ll smoke them on a power hungry track.