I built scaled down models of 3rd gen chassis' so I could try and objectively measure the effect of certain chassis modifications (particularly SFC's).


Everyday other day someone is asking about which SFC to buy or there is an argument about which is best. So I figured, maybe some objective data and visual results might help.

Here are the pics of the two designs I built. Of course these are models and built somewhat to scale. They are only analogous to the f-body chassis and were never intended to be exact representations. But I think that they will be helpful in showing what effect certain chassis mods might have on torsion. And since is the first time I've seen anything like this here, at least it will be a good place to start.

The methods, measurements, and data are meant to be critiqued. We are seeking truth, yes? But critiques are not helpful UNLESS you provide some information regarding what things you'd change to make the data more relevant.

Above all else, lets keep this professional please.

 

Here is the method I used to inflict torsional forces. Its a 6" rod with a 17mm socket on the end. Wish I had a small scale to measure the socket weight so I could tell you exactly what torque I used.

I used a prop under one of the subframes to isolate torsional forces apart from the weight added to the model form the torque arm.

 

So I just braced the rear of the chassis and took 2 measurements; 1 without any torque and the other with torque (i.e socket added) and measured (by the vertical scale) what the deflection equaled.


Chassis A (on the left in the pic):
baseline (without torque)=798mm
with torque added = 811mm
Total deflection = 13 mm


Chassis B:
Baseline:797mm
With torque: 816mm
Total deflection = 19mm


Discussion:
So it appears that in this study design, Chassis A resists torsional forces better that Chassis B. I'll be adding other components to each chassis design to see what effect they have.

Any suggestions? Comments?

 

we use several modling and stress anaylsis programs at work that i've often thought would be great for proving or disproving some of the ideas that get posted here. trouble is the programs take a very long time to complete, and i don't have them on my puter.

 

See above edited post, ede.

Yeah, computer models would be awesome if we could get them. Looks like you are about to put some overtime in. I wish we could do that. This study is crude, but effective I think.

 

just throwin in an idea, but could you rig something up similar to the kenny brown brace and see what kind of difference it makes?

 

only problem i see, is that you are missing a few key points. the spohn style to tie into the front subframe area (which is not included), they also do tie into the rear, and also into the LCA mount, which is also not included.

you also didn't take into acoutn scale of the SFCs, and the car.

i would agree it is a crude test, but with some refining to get it right, not a bad test.

of course, one of these days, the Crew might have to do a SFC test, since we have Spohns old designt, spohns new design, and alstons, all with 20 miles of each other

 

For chassis B, I did try to do a spohn style setup. I know you could see the bars running along the lateral edges, but not sure if you see the little pieces between the side rails and the front suspension points. Is that what you were talking about? The pictures not very close up, but they are there. As for the rear LCA attachments, I'm not sure what to do.

When I added the torque arm I kept the rear of the chassis stable by sandwiching those rear bars between two heavy books. Maybe I can get a better simulation by tying in the the rearmost part of the siderails to each of those fixed points. I'll let you know when the glue drys.