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- - Chassis stiffness (http://986forum.com/forums/performance-technical-chat/55008-chassis-stiffness.html)

Quote:

Originally Posted by The Radium King (Post 651259)

given the mechanism of the flex - twist - i'd suggest you would be testing the strength of your epoxy more than the stiffness of the CF?

I really don't know, maybe so.

On the carbon route, this one is interresting https://youtu.be/yUu4yqtCheg

However I'm starting to wonder if the best way would not be just to utilize the doors, make them stick better to the door jamb. The Miata guys seem to be on that path
https://forum.miata.net/vb/showthread.php?t=580463

so, recap - trying to prevent chassis twist. ie, lift one front corner of the car and watch the door gaps change as the front axle twists relative to the rear axle. sometimes called 'cowl rattle' on convertibles. best case - alignment changes under load. worst case - your Z-top disintegrates from the flexing. probable case - some rattles over speed bumps.

if just racing best solution is a full cage - this ties front and rear axles together.

otherwise get a cayman - the metal roof serves the same function.

then anything that can stiffen the middle of the car and/or tie front and rear together.

like springs, any stiffening is additive to current rigidity - ie will improve the situation. so presume fastening stiff things to the car can only improve the situation, whether it is gluing in cabon/kevlar, welding in door bars, or bolting in chassis stiffeners. where does it all sit on the scale of diminishing returns? dunno; the miata and jdm stuff doesn't provide any quantifiable data on outcomes. but hey, at least CF doesn't add a lot of weight,

Speaking of miatas, I think a popular track mod was too put a diagonal brace just inside the door that ran from the A pillar back toward the rear of the frame, and supposedly this was quite effective when reducing body torquing. Something like this (fat red line)... https://uploads.tapatalk-cdn.com/202...6a696d696d.jpg

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i think i'd want to run that bar to the lower green steel in the front as this is what picks up the front strut towers. in the back tie in to the blue steel roll bar as this is about as close as you are going to get to the rear strut towers.

Quote:

Originally Posted by The Radium King (Post 651495)

Who will be the first to try it out ? :cheers:

saw this recently:

https://www.driftshop.com/cybul-mx5-nc-roll-bar-rear-extension.html

makes me think of two bars that bolt to the roll hoop at the back and the top mounting points on the windscreen in the front in some manner for a stiffness improvement. remove them and drive home at the end of the track day.

Wow, that's a new approach.. Would be cool if it could be adapted to the 986.