LocostUSA.com

I know the name needs work.

I am Ryan and I'm a year out of engineering school where I was heavily involved in the FSAE team. I designed the suspension and steering, chassis (wrote an Ansys torsional rigidity optimization program with real testing accurate to within 5%), and the pedal box. I can say now, fortunately, I didn't get a racing gig and I'm working a normal higher paying fewer hours type job with time to design my own car.

I plan on designing this car slowly over the next few years in hopes of having a final design before the day I move into a house with ample garage space to start building it. With that said this will be a total theoretical/design log for quite a while so turn away now if you're looking for real life pics!

I actually started last summer with a blog page for my FSAE buddies to track. My original intent was to build a closed roof street legal LMP type BEC with a McLaren style 3 seat interior and a turbocharged dry sumped Busa. It came to a halt quickly though when I selected the wheels I wanted and the company wouldn't give me inside dimensions to base my upright and brake hat design from.

I've since simplified my goals a little bit though this isn't really a low-cost vehicle. It'll be a street legal open cockpit LMP type 2 seat non-turbo with the goal of being a reliable daily cruiser and able to get me from Pittsburgh to Wildwood, NJ and back without any problems. Using E85 will be up in the air for a while.

Basic plans...

Chassis
Tube frame with aluminum and carbon stressed panels
-still undecided on 1020 vs 4130
Likely to send plans out for the tubes to be laser cut
Off the shelf racing seats
Possible removable hard top
Non-stressed engine design
Removable rolling rear subframe
-Possibly removable rolling front subframe (cam lock pin thingys for alignment)
Need to locate jacking and tow points for flat bed tow trucks

Suspension
16x7” Enkei RPF1 wheels
CNC’d Aluminum uprights
Front and rear SLA push or pull rod
Round tube 4130
Penske dampers (possibly externally non-adjustable at first)
Corvette Z06/Z51 wheel natural frequency and total travel starting point
Adjustable camber, toe, caster, and ackermann to start while dialing in

Engine
Near stock Hayabusa most likely
-Considered Honda Fit FF package with a Hewland tranny, not enough power?
-Doubtful but maybe 4G63 or boxer engine
Electric water pump conversion w/swirl pot
Dry sump conversion

Drivetrain
RWD
Need to analyze pros/cons of chain driven vs drive shaft
Electric or mechanical reverse?
Taylor-Race tulip style 1 piece stub axles, hollow half shafts, 84 Rabbit hubs

Brakes and clutch
Floating rotors, custom aluminum brake hats
Wilwood Dynapro 4 piston calipers, 11.75” OD Wilwood rotors (width TBD)
Vertically mounted Tilton 77 master cylinders or standard configuration?
Hand clutch or foot clutch? Can both be done?
Electronic push button shifter with manual back up

PA Legal Issues
Headlight/taillight heights
12” high windshield
Suspension/ride height rule
Bumpers no less than 12” high
More research required.

Utility
Storage compartment in nose?
10-14 gallon gas tank
E85 compatible?
Cup holders
Music options?
Computer fans for possible swamp ass solution?
Oh shiza bars
DAQ?

I'll probably post up any useful info like my brake sizing calcs and assumptions and hopefully some Solidworks drawings will start to flow in. I'm going to actually follow the advice given to me for the first time and place the components first and then fill in the chassis later. This should be interesting.

Initial flow as I see it right now... brake calcs > wheel size determination > suspension and steering design > engine and drivetrain decisions.

Experienced opinions on the above ?'s are certainly welcome!

Welcome Ryan. Sounds like you have one heck of a project planned. Have you checked out Airframefixer's build yet? It sounds a lot like what you are planning.

Which FSAE team were you a member of?

Sounds like you're pretty hung up on brakes and wheels. - IMHO forget about them at this stage. They're interchangeable, engine & drivetrain are not. Narrow down the big stuff first and design out from there.

The one thing I saw conspicuously missing was a budget. - Know that if you design everything up front then every part you go source has to be exactly as it was designed which = big$ and or a big time commitment. The more flexible you are and the more stuff you take directly from a donor the lower cost your build will be. - I'd recommend a donor no matter what route you go. - There's no substitute for having a rash of hardware/wires/relays/clips etc. handy, not to mention the tough stuff like spindles, rack, diff, engine, tranny etc.

You're going to be $5k at least for a junk yard parts sourced by-the-book car. $10k for something a little more custom and tailored to your flavor (ask me how I know...) and $15k + if you're going to be custom fabbing lots of parts to match what you dreamed up in CAD.

Yes there are several guys on this forum who have designed and built their own uprights, spindles, hats etc and done a nice job, but it's FAR more labor intensive.

- Figure out now where your cut-off point is for design vs. adapt.

I for example opted to design my own rear suspension set-up for the miata running gear which was a considerable cost and time impact while others have opted to just bolt/weld in the miata rear subframe. It was worth it for me. - You may want the control of designing everything right down to your own brake rotors (did that in college...) - I'm curious to hear how your progress on it.

I hear E85 cures cancer.

a.moore - some other forum linked me to airframe's build which is how I discovered this site. I'm watching his body construction very closely as that is something I have zero experience in and will take a lot of time for me. I went to Drexel U.

rust-bucket - I respectfully disagree in the order in which I'm starting because you can start with either as neither of them really affect the other when I know I'm designing for around a 45/55 weight distribution. The engine, diff, and people can be placed accordingly to meet that spec without affecting geometry. If you have another reason I'm all ears. Besides, I'm really looking for someone else to convince me not to go with a Busa at this point, it is pretty much decided and I already have a CAD model of it.

I have a budget to work with, I created the budgets for a few years on the FSAE team so I have a very good idea what everything costs. Our cars typically ran between $40-60k depending on sponsorship levels but I won't be buying a number of big ticket items we budgeted for every year.

cheapracer - I heard that too.

$40-$60k? Even if your budget is 10k less than that I gotta ask with such deep pockets why build your own? Why not save up a few more weeks, save yourself a few years of work and just buy a used Radical SR3?

I'm not spending that much, more like under $20k with the resources I have but I'm designing and building over the course of years so saving for this won't be difficult. Keep in mind I can go back to the FSAE team and CNC a number of items myself. If I had to rate my interests in this anyways, it would be 70% an engineering exercise and 30% for the end product.

It scary how close my design dream matches yours! haha I can't wait to see this progress. Also re trying to design from the wheels(tyres) up i found my tyre manufactures national (new zealand) office couldn't give me the technical data i asked for Also as you, know the design process is such a round-about! Sure you want to do brake calc's first but to do so you need to make some assumption about the drive train as thats going to dictate your COG and total mass etc. Ah fun times
Grant

Tire manufacturers don't ever give up much info. If I'm lucky and I even want to go that small, I at least have tire data for 13" slicks due to my FSAE involvement.

Agreed on the roundabout, I'm starting with the suspension and probably ending with it too. I won't be done the suspension until I've gone out and bought the wheels I want so many years from now just because I won't have the right dimensions or offset until then. I have no idea why wheel manufacturers wouldn't give that up.

RBBugBitMe,

What will you be using for wheels? What is your scrub radius? Are you planning on using bolt on wheel/hub assemblies? Would you share Solidworks models of your uprights?

Mike Lydon

I don't have the answers to those questions yet. Share pics of the models or share the models for you to make? I'm sure there are liability issues if I shared the models so I don't know about that.

Good to see some more FSAE guys here... good luck on the build

-Jerry
(Oakland University FSAE '10 drivetrain lead)

Thanks and good luck this year. I don't think you'll have much competition from my alma mater.

Well i can agree that our year previous to '10 would hold the same record then. Last year was a huge success as we hope this year will be again (basically the same team, but better structured)

Ryan,

Looks like you have some good experience to start your project with. Most important advice I can give you is to take everyone else's advice with a grain of salt. The mantra here is "It's your car, do it the way you want to."

That said, MY advice is to re-write your goals (what you want to achieve, how you will use it) clearly and set them in front of you. Then review your technical choices and make sure they match your goals. Just off hand, it seems like there might be some disparity when the following items are considered for the same car:

- Reliable daily cruiser
- Mostly stock engine
- Carbon fiber
- Custom fab'd spindles and other parts typically sourced from donors.

On the other hand, some might have said my goals were a mess and counseled
me that building a car from scratch doesn't make sense to begin with. But I did it
anyway because that's just what I wanted to do.

If you like doing custom fab work with an eye toward high tech, sounds like a great project. Go for it!

John