Build #2, No huge car progress...but...cool new toys! Options

[jd74914]

Hello all.

I figured I’d throw up a progress thread for my car’s second rebuild. For those who don’t know me my name is James and I’ve been a 914 addict since age 13 (now 26) and used to hang around here a bunch more. It seems like a good start to this thread would be some background information. Its first build took place when I was in high school (age 13) and ended as a freshman in college. When I originally purchased the car it didn’t run and had some pretty serious external rust problems. I rebuilt the motor, fixed tons of electrical issues, replaced all of the rotten metal with new (all hand-formed since I didn’t have the money to pay for reproduction pieces), and repainted. Everything was done in my garage with the exception of turning/balancing the flywheel and I learned how to MIG weld and paint from my dad, some books, and through a lot of practice.

After reassembly, it was my daily driver for 3.5 years during my undergrad degree. I pretty much drove it hard and put it away wet for the entirety of these years and it never saw a garage. Something about getting a mechanical engineering degree, dating a few girls, working throughout the year as a design engineering intern, and finding FSAE cars really limited the amount of time I spend on my own car. By the end of my undergrad degree there were some pretty rough spots, mostly in terms of the suspension/brakes and a pesky ignition switch (replaced 3 or 4 times and it kept failing), which pushed me to taking it off the road and fixing everything correctly. I thought it might take about a year-that was 3.5 years ago! (IMG:style_emoticons/default/wacko.gif)

Just like after the first rebuild, life got in the way and the car sat as I went through a master’s degree, worked full time, continued to play with FSAE cars, and starting working on friend’s real racecars. Now I’ve finally finished my MS (and know way too much about fluid dynamics and heat transfer (IMG:style_emoticons/default/laugh.gif) ), am applying to schools for a Ph.D., still haven’t stopped [advising] FSAE design, and really want to drive her! The play was to start and finish rebuilding the suspension last summer (I saw Chris Foley-Racer Chris in the grocery store one day and told him this), but I got carried away and a bit behind. This thread is to chronicle the build back to the road.

We’ll start with a few pictures from when it was originally completed in 2006/7 (well, it's missing the plates and still has the original windshield but...).

[veekry9]

I missed this thread last year as I was off on other pursuits and have just now discovered this build.
We were/are using the sls technique to create lost foam patterns for small production runs of exotic metal castings.
The FormulaSAE racer is a jewel,well done. The pertinent specification of interest to me was the torsional stiffness of the chassis.
Now the arduous journey begins,the sheetmetal repair of the 914 and the skilled application of lightweight reinforcement.

Q
The longs themselves were redesigned and made taller with slightly different metal thicknesses/layering. This was done to increase the vertical moment of inertial and improve the car's bending stiffness in this area. From a design perspective, the new geometry (more or less 0.5" taller with some strategically sized metal thicknesses) results in a 246% bending stiffness improvement over stock with a stiffness/weight efficiency (in terms of moment of inertia/cross-sectional area) of 4.927e3 mm^4/mm^2 vs the stock efficiency of 4.042e3 mm^4/mm^2. Overall weight increase is about 27 pounds. For reference the Engman kit (best as I can tell since I haven't held one) weights 18 pounds and increases stiffness by 168% assuming an OEM long to start with.
You'll note that it will still be double layered with the corrugated inner. The insulated heater tube was removed and a solid tube put in its place. This might get used as a wire tray later. Anywhere there are butted seams there is also a backer lap joint.
Q

Yeah,this is what I like,the deepening of the cross section of the longs,the use of corrugated rather than flat sheetmetal panels.
That you are placing them internally is brilliant and never occurred to me,looking from the outside of my pristine longs.
I'm going to use that idea as it's a great solution to the flexi flyer characteristics of the floorpan.
A stiff perimeter monocoque ala 904,not outside the box,inside.Terrific.

Some of this may be of interest to you as no doubt you're proficient in the use of cae software.
https://www.rhino3d.com/
http://www.cimsystem.com/
http://www.mastercam.com/en-us/
http://www.caelinux.com/CMS/