During the past couple months I haven't worked on the Firebird itself as much as I'd have liked to. I've been busy with the Lab-14 stuff and got involved in replacing the trunk pan, trunk drop offs, inner splash pan, frame rails, and torque boxes in my 67 Camaro that started with the intention of a much smaller project replacing the rear springs. However I did do some deflection testing of the 2nd gen sub frame using various parts from PTFB and Lab-14. I also did some baseline tuft testing on the highway for aerodynamics using a customers car with the same body, ride height etc. as my car (with the owners permission of course).
Pic below was taken during deflection testing. The front foot wells and cowl area were filled with a few hundred lbs of weight while the body was supported on wood cribs. A piece of right angle was bolted to the pinch weld on the body and an indicator bolted to the front of the frame horn to note deflection. Solid body mounts were used and I've boxed the rear body mount area of the subframe. I could get almost 3/4" vertical deflection of the sub frame alone when using a floor jack to apply pressure straight up under the frame horns until the body started to lift off the wood cribs. Not sure if more weight in the body would allow even more deflection but I was surprised to see how much frame deflection there was. I would expect similar deflection in the opposite direction would be possible and may test for that when I do some torsional testing. With a combination of the PTFB G-braces and Lab-14 parts vertical deflection was reduced to less than 1/8 " which appeared to be caused by the deflection of the floor pan where the rear body mounts on the sub frame attach under the front seats.
The availability of a car with the same body, ride height, and tire size as a baseline test mule prompted me to do some tuft testing at highway speeds to get a good look at whats going on with the stock body configuration I started this project with. I'll do similar testing after my car's back on the road to see if I can note any differences due to all the aero changes and modifications. I'll post a couple still pics here and if anyone's interested there's some 360 degree VR videos we made I'll put links for . Those with certain phones or other devices may be able to pan around 360 but you'll need a headset to see full 360 3D VR. Sound is mostly wind noise since the 360 camera was out on a stick held out the window at 60-70 MPH so just turn it down.
https://www.youtube.com/watch?v=6KQA9BzpN50 https://www.youtube.com/watch?v=h6pxo5eh7Zw
By being able to put the videos up on the big screen with the projector I can watch small areas or even individual tufts. So for those who always wondered if there is a ram air effect influencing the air for a 2nd gen TA shaker scoop created by the high pressure area at the base of the windshield, the answer is no at up to 70 MPH. I'll test that again with my own car at much higher speeds on track but I doubt there will be any noticeable air being forced into the scoop. If anything there's a possibility air may actually be getting pulled out at high speeds.
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
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