15,500 lb-ft/degree?

[Daves]

In this month's issue of 5.0 Mustang magazine, an article about the new 2005 Mustang claims that its chassis is about 49% more rigid in bending and 31% more rigid in torsion, resulting in 15,500 lb-ft required to torque the frame 1 degree.

An online article backs this up: http://www.autofieldguide.com/articles/110402.html

Can this be right?

[-]

The head engineer for the newest mustang was an old FSAE student out of Carnegie Mellon if I remember correctly. I am sure you could search around and possibly find out from the source.

[jack]

this was measured at the a-arm mounts on the chassis, not the uprights? that would make it a bit more believable.

[Daves]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>this was measured at the a-arm mounts on the chassis, not the uprights? <HR></BLOCKQUOTE>

I suppose it was measured at the suspension points on the chassis (Mustang has no a-arms), considering the Mustang probably has different front springs and shocks for different engine options. In addition, the rear suspension points are near the centerline of the car because of the live axle. How can this be compared to an FSAE car, though? Is the new Mustang's chassis torsionally stiffer than the best FSAE car's?
http://www.autofieldguide.com/mag_images/110402b.jpg

[Marc Jaxa-Rozen]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Is the new Mustang's chassis torsionally stiffer than the best FSAE car's? <HR></BLOCKQUOTE>

Well I sure hope so, given the difference in size and weight. The Ford GT chassis reaches approximately 20,000 lb-ft/deg and the LX platform (300C, etc.) is about 13,000, so 15,500 would be believable for the Mustang.

[jack]

oh, forgot about silly american cars and their silly solid rear axles. http://fsae.com/groupee_common/emoticons/icon_razz.gif http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

[Daves]

Does anyone have any torsional stiffness data for the 2001-2005 Honda Civic or the 2006 Honda Civic? For example, a value in ft-lbs/deg. or N-m/deg. or a percent improvement relative to any previous model Civic would be greatly appreciated.

[Garlic]

Seems quite believable.

Larger cars are going to be stiffer. I'm sure suspension stiffness is an orde of magnitude higher as well. It's all relative. Don't worry about comparing apples to oranges.

[Mike Flitcraft]

Originally posted by jack:
oh, forgot about silly american cars and their silly solid rear axles. http://fsae.com/groupee_common/emoticons/icon_razz.gif http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

http://i151.photobucket.com/albums/s127/jeep45238/1340812661_s.jpg

Can't beat the solid axle for reliability.

[NetKev92]

There are plenty of cars stiffer than that in torsion. Look here and remember to convert units:
http://forum.miata.net/vb/showthread.php?t=189795&highl...=torsional+stiffness (http://forum.miata.net/vb/showthread.php?t=189795&highlight=torsional+stiffness)

Closed-top cars will have a massive advantage in most cases over open-top cars like convertibles and FSAE ships.

Chevy and Mazda have both picked up on the opportunity to box in the under-floor driveshaft tunnel to push torsional stiffness up. Good odds Mustang has started growing braces down there too.

>
Quick note, I doubt the 350,000 Nm/degree is correct on the BMW 7 series. I'd suspect somebody mis-placed a pesky decimal.

[Mexellent]

Can't beat the solid axle for reliability.

What about unsprung weight?

[Mike Flitcraft]

Street production driving and reliability isn't about unsprung weight, is it? http://fsae.com/groupee_common/emoticons/icon_smile.gif