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...).

[jd74914]

October 2016 Update:

Not much got done this month due to school commitments. I did get time to clean off the car and start organizing parts. Yesterday I also got the intake manifold assembly off of the LGT motor, removed the TGVs and started removing all of their parts in preparation for gutting them. I'm going to be removing the throttling valves and welding up the throttle shaft ports in the coming weeks. Pictures coming soon.

This picture is stolen off the web, but essentially the end goal of the TGV delete.



Additionally, I started designing the mounts and arms for the new sway bar. It's a NASCAR bar from HRP. Before deciding on the final arm length, I wanted to check the effective installed motion ratio to understand at what point further adjustment is useless. Some initial basic calculations indicate that an 8" arm length is enough, but the actual travel math is relatively complicated since the control and bar arms move in different planes. To solve this I added the bar into my suspension kinematics model, but unfortunately the effective motion ratio is a bit harder to pull out than I thought it would be. Results TBD. (IMG:style_emoticons/default/smile.gif)

[914forme]

Additionally, I started designing the mounts and arms for the new sway bar. It's a NASCAR bar from HRP. Before deciding on the final arm length, I wanted to check the effective installed motion ratio to understand at what point further adjustment is useless. Some initial basic calculations indicate that an 8" arm length is enough, but the actual travel math is relatively complicated since the control and bar arms move in different planes. To solve this I added the bar into my suspension kinematics model, but unfortunately the effective motion ratio is a bit harder to pull out than I thought it would be. Results TBD. (IMG:style_emoticons/default/smile.gif)

really love what your doing but over complicating it a bit. The distance front the bar center to the center above the A-Arm is your ideal location since th pivots move in multiple plains. Then you are "stuck" with the number of degrees the amounts will allow your bars to travel with out binding over the range of the suspension. two points in a cad drawing will not tell you that, real world will. This of course is based on the factory U tab on the arms, and a double sheer tab up top running a set of rod ends for the drop links. If you are using a spherical bearing on the arm, or a different high angle mount, then your movement can be greater.

Looking forward to seeing your solution to the Nascar bar mounts. I know I gave lots of thought to mine before I said (IMG:style_emoticons/default/WTF.gif) and just did it! Best solution (IMG:style_emoticons/default/confused24.gif) I do know they do not bind with bar rotation.

[jd74914]

really love what your doing but over complicating it a bit. The distance front the bar center to the center above the A-Arm is your ideal location since th pivots move in multiple plains. Then you are "stuck" with the number of degrees the amounts will allow your bars to travel with out binding over the range of the suspension. two points in a cad drawing will not tell you that, real world will. This of course is based on the factory U tab on the arms, and a double sheer tab up top running a set of rod ends for the drop links. If you are using a spherical bearing on the arm, or a different high angle mount, then your movement can be greater.

Looking forward to seeing your solution to the Nascar bar mounts. I know I gave lots of thought to mine before I said (IMG:style_emoticons/default/WTF.gif) and just did it! Best solution (IMG:style_emoticons/default/confused24.gif) I do know they do not bind with bar rotation.

I'm planning on running a high misalignment rod end on the arm-side to gain a bit more travel. That said, as angle increases the force applied to the arm increases tremendously, so buckling can become a concern. I still haven't gotten a change to measure everything yet so we'll see. (IMG:style_emoticons/default/smile.gif)

The mounts will look similar to OEM mounts. I wanted to keep the mounting geometry the same so I'd be easy to align and let me use the stiffening plates from MADDOG. The big difference is that instead of the OEM bushing, I'm going to use a Frelon-lined flanged sleeve bearing. These are self-lubricating and are supposed to last well in dirty environments but that's something driving will need to validate. The bar certainly spins well in them! (IMG:style_emoticons/default/laugh.gif)

The CAD views are below (drew it up to check some clearances before making chips and buying fasteners). I'm going to machine first thing next week when my metal comes in (6061-T6). They are a bit beefy, but I really didn't want to risk HCF cracking after a few years of use and exposure to sand/salt. The gap you see between the bushing mount and backing plate is ~0.110 to account for inner fender and stiffener thickness.