Suspension Design 103

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Kohlenstoff
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Re: Suspension Design 103

Postby Kohlenstoff » Wed Mar 18, 2015 9:19 pm

As i said, the suspension is too weak. Especially, when we try to save chassis from collisions. I made for test a ultralight car with maximum useful suspension / part ratio. But even with too much hardness for the weight (becomes jumpy) and a too high center of mass (tends to tip over) and high separation of parts it crashes still its chassis: http://dreamcarracing.com/dcr3-index.html?carid=6094

The more suspension we add, the higher gets the center of mass, the more the car tends to tip over. When we want to prevent chassis crashes, we have even to increase the height of center of mass. I think Car 897 does a real good job! Best thing you can do is to take of mass from the top. This will improve overall performance.

RedRavenRuler
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Re: Suspension Design 103

Postby RedRavenRuler » Wed Mar 18, 2015 11:49 pm

Ok so I've been toying around with some ideas today and I think I've gotten some better results.

This idea is loosely based on a sway arm type of system (very much a hybrid system) and bottoms out a lot less while retaining a large amount of suspension travel. It can tip over fairly easy if you accelerate to quickly but other than that I think it's an improvement.

The car ID # is 6188 or here's a link for you all:

http://dreamcarracing.com/dcr3-index.html?carid=6188

Love to hear what you all think. Any suggestions to improve the design are welcome! I'd love to see what you all do to tweak my ideas that I tweaked from the original post.

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tfaith08
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Re: Suspension Design 103

Postby tfaith08 » Wed Apr 01, 2015 6:23 pm

The issue that I see with car # 6094 is that the leverage ratios decrease with travel. Unfortunately, this game has a very narrow window for leverage ratios, which sucks. Increasing rate ratios and leverage ratios other than about 1:1 aren't gonna fare well.

http://images.off-roadweb.com/features/ ... y_04_z.jpg

That trophy truck uses a shock mounting location that is in about the dead middle of the trailing arm. That would give a ratio of around 2:1. When that happens, your rebound needs to be highly restricted so as to not make the rear end almost jump off of the ground after impact. But King, Fox, and Bilstein have got the issue more than covered. A 2:1 leverage ratio means that for every 1" of shock travel you have, you get about 2" of wheel travel. The other issue is that the shock has to be able to handle twice as much weight. The solution is a stiffer spring and compression damping.

1. http://dreamcarracing.com/dcr3-index.html?carid=18004 (Don't try to race this car. It is useless for racing, I only intended to show a higher leverage ratio.)

I've often wondered what would be possible if we could adjust the rebound and compression damping on some of the cars we make.

2. http://dreamcarracing.com/dcr3-index.html?carid=17991 (Don't try to race this car either. It is useless for racing, I only intended to show a suspension linkage.)

This is an example of a suspension linkage. Linkages were originally incorporated to provide rising rate ratios and leverage ratios without an overly large design. The initial travel was smooth and soft for comfort while the leverage on the shock increased at an exponential rate to provide excellent bottom out resistance. The initial ration may be a 1.5:1 or so and increase to as much as 6:1 as the suspension moved upward.

Unfortunately, dream car racing doesn't include the adjustments required to create a fully functional suspension system with anything other than a static 1:1 leverage ratio. Hopefully the 3D version will.



Car 6188 has a lack of any trailing arms to connect the suspension to the chassis. The rear bounce is likely due to the (yet again) leverage ratio being off, but the number of springs makes it a compromising situation at best. I wouldn't know where to start without completely changing the structure of the car.
OP was drunk. All is forgiven.

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danieldorais
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Re: Suspension Design 103

Postby danieldorais » Fri Apr 03, 2015 4:54 am

Hey tfaith, could you check out there cars. They are modeled after your original car:
http://dreamcarracing.com/dcr3-index.html?carid=929 Simplified rear, modified front suspension to absorb bumps and jumps and a swing arm to roll over if you flip.
http://dreamcarracing.com/dcr3-index.html?carid=6223 Modified both ends, less ground clearance but is designed for rear suspension to snap in place for a second preventing it from pushing the front end down

Nice explanation of leverage ratios. I think another problem with the shocks in general is that it seems like the game is artificially preventing the car from bouncing based only on upgrade level. Now, this game isnt a simulator, but to see what I mean, take the default car, fully upgrade it, and make the springs full hardness. Should be pretty bouncy right? Wrong. Besides constant wheelieing, the car takes all jumps well. It seems like a different force is preventing the car from bouncing up on impact, even though it effectively has no suspension, solely because the shock is fully upgraded. This raises the question of what is being upgraded. It seems like its the shock oil being thickened, but you seem to be the expert, so what do you think. I'm probably just overcomplicating the whole thing :P . Really, though, the way the wheel snaps back down almost instantly makes it seem like there is no oil in there at all (but they could be friction style for all I know...)
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