Weight and weight distribution

[KAlex122]

Hi everybody!
Back to learning tuning.

1.) Do you try to achieve the often mentioned 50:50 weight distribution only for FR cars or MR, RR and 4WD to (often that would mean relatively much mingling with the weight as MR and RR are very bottom heavy and 4WD are typically front heavy)?

2.) Is getting the weight a bit more to the rear (48:52 for example) a viable way for you if you feel the rear is acting out on throttle or are you first doing everything you can to tackle the problem with suspension settings, LSD and aero?

3.) What would you consider a good weight distribution on a 500-600PP FF car so that power gets to the wheels but its not too front heavy? Generally.

4.) Are you mostly using all possible weight reduction stages as one of your first moves as characteristics when accelerating, braking and cornering generally get better or is it only a later resort for you?

Thanks everyone!

Edit: I bought an AMG GT S '15, a 911 RS CS '95 and an Impreza WRX '99 to practice tuning with different drivetrains.

 

[Meythia]

1. No, 50:50 would only be ideal if the car is designed around this weight distribution.
If you change weight distribution from its default position, you may sacrifice acceleration potential or worsen the handling.
You would also need to change suspension accordingly to the change of weight distribution, but it still may propably not be better.

2. If you feel the car with your setup, changing weight distribution absolutely can help, but it also will change your PP rating, whereas LSD and suspension dont.

3. It absolutely depends on the car, there is no rules to strictly follow other than "try and error" or - if you can "factually calculate" which is how race cars usually are designed.

4. Depends on the track, the more topspeed reliant it is, the less reduced weight plays a role.
But the way I created my setups was chose tyres -> take same performance brakes -> check if default suspension is ok otherwise use racing suspension -> racing transmission -> full weight reduction -> power
Only by my preference, I know that full weight reduction will not always be faster than having more power, I just like it more this way.

 

[KAlex122]

Oh, one thing i just discovered (and never thought about) is that different aero parts can give you the same range of motion in the aero setup but don't deliver the same PP.

The AMG GT S '15 has 40 front, 60 back aero points by default. If i ad a diffuser it doesn't give points in the front (normally does, doesn't it?) but the rear gets a range of 60-160. If i use the type A wing instead i get a range of 110-210. If i set both setups to 150 i get a PP of 588,06 with the wing and 590,95 with the diffuser. The only other difference i see is that at the G-levels on the bottom left the 240km/h G is 1,20 with the wing and 1,23 with the diffuser and the 0-1000m acceleration is better with the wing: 21,10 against 21,13.

Also there seems to be a bug in the PP calculation (which you al know). Base PP is 582. When adding aero there is a big jump from 78 to 80 aero points which costs you about 10 PP points (diffuser). Also with the wing, when you go from 190 aero points to 194 you gain about the same 10 PP (from 590 to 580) points.

A bit confusing for me.

Edit: anyone needs screenshots form my explanations?

 

[Meythia]

Also there seems to be a bug in the PP calculation (which you al know). Base PP is 582. When adding aero there is a big jump from 78 to 80 aero points which costs you about 10 PP points (diffuser). Also with the wing, when you go from 190 aero points to 194 you gain about the same 10 PP (from 590 to 580) points.

These bugs are not solely reliant on your aero setting, but include all parts of the car to some extent.
While I dont believe the effect on the car is as huge as the difference of PP would suggest, it then leads to "gamble the system", finding any such jumps to decrease PP to then add more power or use less weight (or add other higher performance parts), but at the same time any such change could propably bring PP back into the "correct" spot.
You can find this kind of jumps for some cars by changing the power restrictor, propably like this
100% 400PP
99% 399PP
98% 401PP
97% 397PP

It can be even more strange when changing certian parts it changes stats that at first glance wouldnt seem related like for example fictional

default brake pad
pp 400, acceleration 0-60mph 10 seconds

sport brake pad
pp 410, acceleration 0-60mph 9.5 seconds

racing brake pad
pp 390, acceleration 0-60mph 10.5 seconds

These bugs happen for some very strange PP simulation reasons, in which the car obviously has some very VERY ultra high specific corners in which it for whatever reasons suddenly gets better and then worse again, be it by the change of the power curve or by changing the weight transfer with different brake pads.

 

[KAlex122]

Only by my preference, I know that full weight reduction will not always be faster than having more power, I just like it more this way.

... and if the standard suspension feels okay it should be even a bit better, a bit harder, a bit less nodding and rolling if you reduce weight, right?

That's what goes through my head driving the stock AMG right now. It feels good for a stock suspension but a bit undertsteery ( maybe due to it's weight and weight distribution). Here i would probably goe with weight reduction plus some kilos to the front instead of a racing suspension.

I jave to try out a lit of things and write them down with values as I won't remember the effects of things.

 

[Meythia]

... and if the standard suspension feels okay it should be even a bit better, a bit harder, a bit less nodding and rolling if you reduce weight, right?

Usually it does, the default settings are often generic enough to provide a better handling on less weight.

Though in the more "performance" categorie of cars it can also be the other way in that the suspension is close to the limits and lower weight will have no positive effect on handling, or even be worse if other parts of the car rely on this specific values (4wheel steering, active aero, or whatever).

In that case, using ballast to increase weight back to its original value or just slightly lower would solve this situation again.

 

[KAlex122]

One more question about the AMG GT S '15. I just saw i can purchase a 4 wheel steering adapter for that although the description says its for 4WD cars only. If i use it, it's set to 100% and doesn't change PP. If i set it to zero PP goes to 589 with a lot of weird PP jumps in-between 100 and 0. Can't make anything of this...

Does it even do anything on such a car?

 

[Meythia]

Never used that part, cant say anything about it.
Though I guess this is a genuine bug as it shouldnt be available to this car.

 

[KAlex122]

Thanks a lot for your time and wisdom!

 

[MrHorsepower]

I can only answer to question one.
I wanted to create a replica of the 09 Abarth EsseEsse kit (180 hp, in real life the kit was sold through dealership in a crate) I upgraded the engine (can't remember the parts, but I changed the exhaust and cams among other stuff and reached the exact 180hp) the brakes, suspension (Fully ajustable, but untouched) and tyres.
When testing at the Nurburgring tourist layout, I found when I first braked before the first right hand bend, that the Abarth's rear axle was soaring and the car rolled longitudinally. I modified the natural frequency of the suspension and installed the rigid chasis, there was a slight improvement, but the car was still extremely tail-happy.
The best solution was installing the level 1 light body and adding ballast to stock curb weight values, placing the ballast all the way back. The car's rear is still a bit nervous when heavy braking, but at least it no longer rolls.
I also built a 50:50 97 Civic type r Spoon tribute, just for fun, it very exciting to drive!