jeremy

I know that with each version of Evo and Impreza they become 100% more rigid etc.

Does anyone actually know which chassis is more rigid?

Thanks

Claudius

The 7 is much more rigid than the 6 from driving both next to each other; the 8 has additionnal weld spots compared to the 7. No idea about the scoobies, but they seem a little less rigid. You can easily add welding spots though. Well, if you take out the engine and a few bits and bops anyway

jeremy

Cladius,
Thanks. One question. My father just bought a 325xi wagon. And comparing this car to the Evo and Impreza its just amazing how much more solid the German car seems. Is this simply just the doors and fit and finish or in truth are the japanese cars just as solid?

Thanks, JL

Claudius

The "solid feeling" of the BMWs comes from the excellent insulation and the good quality interiours. That's not the same as body shell rigidity! Take corners fast, and you can feel the car, the body, flex after the suspension is fully loaded.

I would like to know how the shells compare as well. Anybody know more about this? Are there any absolute measures for body shell rigidity?

jeremy

There most certainly are specific numbers around concerning rigidity.

Actually the Germans do publish them. I'll look. Actually I think the new Audi A8 is the most rigid car now- much more so than the new Jaguar XJ. But the Japanese do not.

Frankly it would seem to me that the issue has more sides then one might think. There is rigidity when new and then rigidity over time. German cars seem to be made of much higher quality and thicker steel then the Japanese. Maybe that is why certain German cars are (and swedish)the ones that have the capacity to last decades and still feel like new. Most japanese cars even if they do run well really begin to feel tired.

Mycroft

FYI, you need to correctly identify parts of the car... Chassis to a 'layman means the car minus the bodywork panels... this is simplified because it is for people who know little aboout Engineering.

To a Motor Designer/Engineer the chassis is any 'fast path' items that transmit info to the driver and can be effected by driver input... this will be the suspension/steering and even the seat mounting and location... the rest, 'the shell' so to speak is the 'Monocoque' everything 'hangs off' of this item and is the 'slow path' for inputs in Engineering terms... a great car is one that gets the balance of these 2 items right, by subtly choosing certain kinematic locations you can impart a large chunk of the 'fast path' inputs to the 'slow path' Monocoque, all road inputs have some element of both slow and fast properties and a Good designer/Engineer can manipulate this 'split'... this is simply the definition of 'Controllability' or in laymans terms 'Chuckability'... drifting is purely the way in which you can see this in real life...

From one of my recent posts on the GTR...

Claudius

Thanks for the input

What would be good or bad ways of mating the fast and the slow parts?

Monocoque design has become pretty standard these last years; do you have any numbers to look for to quantify body shell rigidity or how well the car is designed, particularly for the scooby / Evo as the original poster asked?

Mycroft

Claudius... this is a subject of great complexity and one that has already resulted in me being 'slagged off' on here, so, not wishing another 'free for all' I will take some time and work on a post for the 'other EVO site as there are also some messages there that need my attention... there is also a plus point to that site... the BMW Racing Team man who posts there... although arrogant, he really does know his stuff and his input would interest me greatly...

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[Edited by Mycroft - 5/11/2003 1:13:20 AM]

Claudius

thus me asking YOU!

Seriously? I must have missed that Did you say that your Soarer was more rigid than all the other cars? LOL

Indeed...

BMW and monocoque... LOL that will be funny... but that no anti roll bar story sounded way OTT and would result in wheel bounce from a certain spring rate on, like you said (unless perhaps the BMW chassis flexes so much that you could consider it an additionnal (softer) spring... LOL