First Autocross!

This weekend I competed in my first ever autocross!!! A friend invited me to hit the cones with the local Porsche Club of America chapter. Does everyone else know how much fun this autocross thing is?

Seriously, I've never had so much fun driving a car! My hands were shaking after each of my runs, and was pretty winded because I kept forgetting to breathe. Fortunately the course was only 3/4 of a mile or I would have passed out! I have never driven a car so aggressively before.

I'm pretty proud that each of my runs was faster than the previous. That was my goal for the day, to show continuous improvement. I didn't get anything close to FTD, but I was thrilled to get FTJ (Faster than Jeep). I've spent most of the last 24 hours lost in thought of where I left time out on the course. I can see how easily it is to become obsessed with this stuff.

As for my car, she did the job despite having crappy tires and worn-out shocks. I've never been truly at the limit in my car, and I have to say dancing that Miata around the cones was a religious experience. It has always been a major goal for the Spartan to have the same driving qualities as my Miata. I think if I get even close to having the same dynamic qualities it'll be a major victory.

Locosts predominantly race in the D-Modified class in SCCA autcrosses. There are a few details in the regulations regarding construction that I should look into when designing the frame, but otherwise nothing is really different from what I was planning anyway. There are a few tidbits for cars running slicks that I should pay attention to when putting the car together in case I go that direction for competition.

In any case it doesn't look like the Spartan as planned will be competitive in D-mod nationally, and perhaps locally if I'm up against purpose-built hardware. That's not the point of my build, though, and designing to a specific set of rules will probably result in less angst when some stickler techs my car.

Acquiring components for my cockpit mockup

At 5'8" and 225 lbs., I'm not exactly a small guy. With a 44" overall width (42" inside the gunwales of the car), the locost isn't exactly a big car. If at all possible, I hope to avoid the tragedy of building a car I don't fit into.

In the product design world (my day job), we build a prototype to check fit and functionality before committing to manufacturing. I don't see any reason why I shouldn't do the same for this project.

To that end I've been collecting the various components I'll need to construct a plywood mockup of my cockpit (a list of what I need is located in my Specification Sheet). The idea is to simulate the seating position, controls and critical panels so that I can get an idea of how comfortable my finished car will be.

These goodies were delivered yesterday. Those are the brake and clutch pedal assemblies and the clutch master cylinder! These Wilwood parts are quite beefy and light! Perfect. The single master cylinder clutch assembly and the dual cylinder brake assembly are both pretty standard components used in Locost builds.

The dual cylinder brake will allow me to fine-tune the bias between the front and rear brakes. For the record, I matched the Miata clutch master cylinder size by using a 5/8" Wilwood master. I'll figure out the brake master cylinder sizes when I'm farther along in the design.

This is just a tribute...

One of the good things about taking your time with a build is that it gives you plenty of time to consider things before committing to them. In the last few weeks I've made a dramatic shift in my line of thinking concerning how I want the Spartan to turn out.

My line of thinking used to be that I was going to make some kind of F1 inspired rocket. It was going to be super-light, savage and wicked fast. There would only be a token concession to comfort for the occasional long trip. Two things have happened since then.

The first was this post on the LocostUSA forums. It was a discussion on how tough locosts can be on the driver. Shortly afterward, I read of someone who sold his Seven because he just didn't drive it anymore. It really made me think about my priorities. I don't currently autocross, and even though I really want to get into the sport I have to believe that 99% of the Spartan's life is going to be on the street, not the track. Making some kind of cone-killing monster just doesn't translate in to a good street car.

The second event was less rational, but lots more dramatic. I came up to a stoplight near my house and caught a beautiful ivory-colored Bugeye Sprite across the light. The driver was joined by his lovely wife/girlfriend/mistress, and both had huge smiles on their faces.

The Bugeye is one of my favorite cars of all time. It to me is one of the heights of the British roadster era. Simple, light, good-looking and a hoot to drive. The car a classic Anglo jauntiness to it. Plus, with the Sprite you can have a handlebar mustache and wear a tweed jacket while driving around and feel perfectly normal.

That spotting got me thinking. Would my wife really want to ride in some kidney-punching terror? Would I? Was the car I was building really like the Lotus 7 I've loved since I was a kid?

The answer to all these questions was No. That's when I hatched my current plan, to create a Lotus 7 tribute, an homage to all those awesome Healeys, MGs, Morgans, Triumphs, Sunbeams and other greats from the 60s. Sure, under the sheetmetal it'd still be Miata powered and it would still have lots of current technology in the suspension and running gear. But the feel would be more Italian Job (the good one with Michael Caine) and less Bourne Identity. I want it to look and feel like it came from the 60s. When my wife and I are motoring around in it, I want to feel like I'm in a simpler time.

Really this is more of a shift in philosophy than actual design. Fortunately there's plenty of apropriately vintage-y instruments, steering wheels, seats, lights, mirrors, trim, etc. available to the homebuilder.

As a plus, I think the task of researching old British cars for inspiration is going to be a blast! I've already planned a trip to the Lotus Owners Gathering and the Barber Motorsports Museum in Birmingham in May of next year.

I've always loved the Seven because of its purity. I guess I'm learning that purity doesn't just mean leaving everything off in the name of going faster. It's can also be about the single-minded pursuit of the joy of spirited motoring.

Keeping track of things

Being a nerd, I like to keep track of things. Excel and I are on a first-name basis. So it's natural that I'd want to accurately document my build.

Even though the Spartan won't be an absolutely low-cost locost, I still want to keep track. Some have suggested that this is a crazy idea, as it gives my wife real numbers to yell at me about. Fortunately for me my wife is really cool about this obsession of mine, so I feel comfortable keeping a budget spreadsheet with the actual figures for my build.

I'm going to count the full purchase cost of partial items. That means if I use 10% of a $4 tube of grease, it'll be $4. I don't want the pain of tracking how much welding filler wire I've used. The spreadsheet will also break out shipping and tool costs and list sources for each item. I figure that may help someone else understand how I got those figures.

While I've been waiting to start my build I've been reading like a banshee. I've also scoured the internet for anything I can learn about building a car. Along the way I've made lots of decisions about components and specs for my car. I've decided to keep a specification spreadsheet (xls) listing what I plan on incorporating into the Spartan.

Both documents are now on the sidebar, and they'll be constantly updated as I go along. You're free to copy and use them as you see fit.

Comparing Dimensions

I've been reading the excellent Lotus Seven & the Independents, and one thing I'm struck by is how much variation there is in the critical dimensions of various Sevenesque cars.

I've compiled various measurements for the two common Locost platforms as well as for three baseline Sevens and a few lightweight sports cars. I've also thrown in weight and horsepower numbers for reference.

Car	Overall			Track		Wheel base	Ride Height	Weight	HP
	Length	Width	Height	Front	Rear
1962 Lotus Super Seven Series II	131.5	56	39.5	47.5	48.5	88	6	924	85
Haynes Roadster (Gibbs)	129.5	67	46	56	57.5	94	3.9	1309	105 est.
Keith Tanner's CMC Miata-Locost	128	65.5	42.5	51 est.	56.2 est.	92	4 est.	1279	175
FM Westfield	131.5	63.4		55.5	56.2	91.5	5.75 est.	1300	125
2006 Caterham CSR Superlight	129.9	66.3	40.0	59.3	57.7	91.1	3.9	1245	260
1993 Mazda Miata	155.4	65.9	48.2	55.5	56.2	89.2	4	2222	116
1974 MG Midget 1500	141	60	48.3	46.3	44.8	80	4	1631	65
2003 Ariel Atom II	134.3	70.8	47	63	63	92.3	3.5	1005	220
1957 Lotus Eleven LeMans	139	60.5	31	45.5	47	88	4.5	1360	84
2000 Lotus Elise	147	67	45.2	56.7	57.9	90.6	6.3	1574	143
1964 Austin Mini Cooper S	123	55.5	53	52.8	46.9	80	6.3	1250	70

Click on the car's make and model for the sources for my data.

The first thing that jumps out to me is how tiny the original Seven Series II is. The Caterham is nearly 10" wider than the original car. Of course a lot of this is wider modern tires, but it's still significantly smaller than anything on the road.

The other thing is how much longer the wheelbase is on Gibbs' Haynes Roadster vs. every car in the table. If you look in the Haynes book, the front wheels actually stick out past the front of the nose cone! Since my frame design is based on the Haynes Roadster, reducing the wheelbase to 90-95" is going to be one of my design priorities.

I'm going with the stock Miata front and rear track on my Locost (as of right now), so the width of my finished car should be in-tune with the rest of the pack.

Update 6/22/08 - Chris Gibbs has contacted me with corrections to my table. It appears that the figures I had before for the wheelbase were way off, as many have commented. Now with the correct dimensions, it appears that the Haynes Roadster isn't as big as the discussion forums would have suggested. This makes me feel much better about using the design as a starting point!

Update 4/14/09 - It appears the Haynes Roadster wheelbase figures are in dispute again. I've received word from a reader who very adamantly states that the wheelbase is actually 94". The reader states this is what he got in CAD when modeling up the frame. Gibbs himself on his forum states it is 92", so I'll chalk that up to the book not completely representing the actual car.

Two British Lightweights

When I started researching for my locost build, I'd never seen a real Seven in the flesh. As of the beginning of this month, the closest I'd ever come was checking out Andrew's build-in progress. Fortunately, in the last month I've gotten to check out my two favorite cars (and biggest inspirations) in the flesh...er, metal. Both experiences were carried out with huge child-like grins!

First up was an honest-to-goodness Lotus Seven Series II that I caught at the 2008 12 Hours of Sebring. Actually, there were two of them - a racing and street version. These cars are owned by Paul Stinson. He races the high-output version in the SVRA and SCCA. The street car is his golf-cart substitute for commuting around Sebring!

He was kind enough to let me sit in the street version, which reaffirmed my need to lose weight or build a larger chassis. I was able to catch the car on video as it went out for a recon lap of the Sebring infield.



The best photos I took of both Sevens are up on my Flickr site.

The other car is the ultimate evolution of the the light-and-agile Seven. The Ariel Atom is my favorite car. If I won the lottery tomorrow, I'd drive to pick up my check in this bad boy. This particular Atom was parked nonchalantly at the 2008 Georgia Tech Auto Show.

I could have stared at this car for hours, but I was taking care of my daughter and had to look fast (fortunately pictures last longer). There are so many fantastic details, so many awesome welds and crafty bits of carbon fiber! Everything clearly had a lot of thought put into it. Even if my Locost doesn't go as fast as the Atom (which it certainly won't), I hope that I can put as much effort into the design and construction of my car as the folks at Ariel do in theirs. It's really a stunning car.

The Atom at the show was for sale for the cool price of $79k. It's tempting to sell our house and buy it, but since there are no body panels and no roof it wouldn't be very good to sleep in.

Both of these cars capture everything that is good and holy about sports cars. They're light, agile, responsive and provide the right medicine to treat the current pandemic of bloated, overweight and overwrought sports cars. I hope my locost comes close to their awesome example.

Starting to lay stuff out

The time has come to start to put things together with the design of the Spartan. I've reached the point where I've got far too many ideas for the frame and layout and it's becoming difficult to keep them coherent in my head.

I work with CAD every day (Pro/ENGINEER to be specific), so I can get quite a lot done during my lunches at work. Fortunately, the software is flexible enough that I can lay out a tremendous amount of detail before actually having the critical components in hand.

The chassis started as a Gibbs chassis, but I've already made several mods, most notably reducing the length 2". I think the Gibbs design is pretty long, and I'd like to get the wheelbase down to 95"-98". I'll post more about the frame once I get the preliminary design done.

The components are rough models based on pictures of the actual components and a few key dimensions. Already I'm pretty concerned by how big the stock Miata intake manifold is.

For right now, though, this will give me enough information to pick components and place them in the car. I'm hoping that I can do an accurate enough job to reasonably predict the CG of the car and do some tweaking. Eventually I'd like to have a very accurate model of the entire car.

Besides, frame development in CAD is cheap and easy. I have access to FEA software, so I intend to model the "stock" Gibbs chassis and compare it to my evolved frame so I can get an idea if my ideas will work or not.

The Spartan 7

Naming my daughter wasn't that hard. Naming my car has proven to require much more thought. I'm not exactly a major manufacturer, but this name will stick with the car throughout the build, and I feel like it needs something a little better than "my locost".

I wanted a name that was serious, without being too stodgy or ridiculous. The "Conway Superturbo AstoCaster XD6" may sound cool to a 6 year old, but it just doesn't fit the car I'm designing and building.

So I'm calling my car the Spartan 7.

The name evokes a certain aggressiveness and purity of spirit. Maybe I've watched 300 way too many times, but I think the name relates the Seven's hard-core philosophy. It also conveys the minimalist ethic so important to this kind of car.

I plan on creating nose and tail badge artwork for the finished car. I'll post them here when they're fleshed out.

Some thoughts on safety

"Do you ride motorcycles because of their proximity to death, or in spite of their proximity to death?"

This was the opening question posed by Matt Chambers, CEO of Confederate Motorcycles, during a recent presentation on American design.

I don't ride motorcycles, but if I did I'd have to answer "in spite". I'm lucky in that I have an abnormally high sense of self-preservation. I usually lift off the throttle well before the limits of my car and I always instinctively slow when rounding a blind corner. That's why I'll probably never be a great racer, and why I pay next to nothing for insurance!

I'm a father and a husband, and I don't particularly want to get killed or maimed for my hobby. Worse, I don't want to take someone out with me. So when a recent discussion with co-workers turned to the subject of the safety of my home-built car, it led me to make a few more decisions on what my car will be about.

I don't expect this car to be as safe as a real car, period. I plan on using 6-point racing harnesses, but I won't have airbags, ABS or even side-impact door beams. If I get t-boned by an Escalade, it'll probably put me in the hospital (or worse). I take my safety seriously, but I also lament the time where cars weren't loaded down with 1000 lbs. of safety features. I'm starting to get fanatical about weight, and a line has to be drawn between safety and the purpose of the car.

That being said, the primary approach I'm taking with regards to the safety of the vehicle is to prevent a loss of control of the vehicle or dangerous vehicle dynamics while on the road. I'll have to practice "active safety" (aka paying attention and driving defensively) with regards to threats from other vehicles on the road.

To me, loss of control usually falls into 3 areas: structural failure, loss of brakes, and loss of steering. There's also the terrible threat of a fire.

Chassis/Structure

Carroll Smiths "Prepare to Win" is an awesome book, and I think all builders should read it. It outlines his fanatical attention to car preparation to minimize mechanical failures. I won't go over all the details covered, but here are a few "high points" I'll focus on during the design and build:

• Use aircraft grade hardware to secure anything that'll hose you if it fails. Lock washers, nylock nuts and loctite just don't cut it.
  
• Safety wire or cotter pin all hardware that may vibrate loose.
  
• Redesign stress points (like suspension mounts) to maximize weld area and to prevent loading welds in tension. This is a major issue (to me) with the current Locost design.

Additionally, I'm planning on integrating the roll-bar into the frame (like Moti did on the LocostUSA forums). I'm not really impressed with the way the roll bar mounts on the current Locost design.

Finally, I just need to pay attention when designing and building the suspension. I don't plan on cutting corners with the structural integrity of the suspension bits and mounting points.

Brakes

Mark Rivera's crash at Mid-Ohio really opened my eyes to what could happen in my car. In his case, a fastener worked free on his brake pedal and he lost brake control.

Thankfully again he was on a track with enough run-off to contain the accident. My worry is that my car will careen out of control on the street. I've made a few decisions regarding the brake system.

• I'm going to use a commercial pedal set w/dual cylinders. I don't want to make my own when so many proven systems are out there.
  
• I intend to run brake lines away from heat and sources of puncture. The brake lines to the rear will have to run past the driveshaft, so I'll have to think of a way to protect them.
• I'm going to run hanging pedals, if possible. As one commenter on the LocostUSA forums pointed out, hanging pedals are less vulnerable to debris clogging the works.
  

Steering

There have been many posts on the forums concerning steering rack modifications to reduce bump steer. I get the willies when I think about welding my steering rack. Especially because once welded and reinstalled, there's almost no way to quickly inspect the welded area over the life of the car. If at all possible, I'd like a professional solution, either an off-the-shelf rack or something modified by a pro.

I'm considering using a removable steering wheel, but I need to do some research regarding the safety of these on the street.

Fire

This really scares me, and it should scare everyone else, too. It's going to be friggin expensive, but I want to use a real fuel cell for my car. I intend to mount the cell in the rear above the differential to give as much crumple room as possible in the event of a rear impact.

I'm going to have a fire extinguisher in the passenger compartment and battery cutoffs on the dash. I intend to run fuel lines in the same "protected" zone as the brake lines.

In closing, safety isn't just a punch list of features, it's a design approach. As I design and build this car I'm just going to have to be diligent about building something fun and light, but not dangerous.

Why?

I've been talking about building this car for months now, and the first question everyone seems to ask is "Why?"

This question really should be 3 questions:

1. Why build a car?

I spend most of my life hacking away at a computer. Building a locost caters to my intense desire to make something with my hands (an obsession that drove my previous blog for 2 years). I want to learn to weld, to shape sheet metal, and to work on cars. I've been tooling around with my daily drivers for several years now, and I'd love to have another project to work on.

I've spent the entirety of my engineering career working under the burdens of schedule and budget. By necessity, I've had to stop work on several projects before I felt the work was as good as it could have been. With this project, I run the schedule and budget. Here's a chance to do engineering on my own terms. That's why we have hobbies, isn't it?

I don't have a budget for this car. I'm a natural cheapskate, so I think the car will cost somewhere between $5000 and $10,000. But if it costs more, then so be it.

One of the best chunks of wisdom I've read so far came from the book Kimini, Kurt Bilinski's build guide. He said this was a hobby, and as a result he didn't feel the need to create artificial deadlines for his hobby. Sage advice!

2. Why build a Lotus Seven clone?

This question starts when I was 12. I started getting into cars and reading Road&Track regularly. The articles on various new cars came and went, but the "Side Glances" columns written by Peter Egan stuck with me. He's been my biggest automotive influence, and his love for British cars wore off on me in a big, big way.

I owned a black 1977 MGB in high school, but what I always wanted was a Lotus Seven. This was a real sports car - light, agile and dripping with British charm. I didn't care that their tops were a joke or that it was based on an ancient car. It was elemental and pure. A racer for the road.

Fast forward to now. Original Sevens are far too rare, and Caterhams are WAY too expensive for someone of my means. I don't know how, but I found Kieth Tanner's web site about a year ago and I was hooked instantly! I read his entire build diary that day which is not easy when there are over 1400 entries.

Project started out as a cheap way to get a Seven, is now a way to get my dream car. It won't be perfect, but it will be uniquely mine.

3. Why use a Miata as a donor?

There's a saying in cooking - a meal is only as good as the quality of the ingredients that go into it. This project is exactly the same.

Despite its reputation as a hairdresser's car, the Miata is a true sports car. I drive one daily, and I think it's the most wonderful car I've ever owned.

As a donor, it's nearly a one-stop shop. It's got a great engine and all the requisite rear wheel drive bits. I can pick up a beaten and abused Miata and have nearly everything I need to build the car. The parts I won't use are also still pretty valuable, so hopefully I can recoup most of the cost of the donor by selling the bodywork and interior on Ebay.

There's also a huge aftermarket community providing performance parts for the brakes, engine and transmission. That means I'll be able to increase performance as much as I'd like down the road by bolting on parts. There's also an awesome community supporting the Miata that I can go to for help.

Here's another reason to build a Seven. Few cars are awesome enough to require sub-titles during their test drive.

Locost Personality

So the second order of business is to start to define what my car is and isn't. Here's a brief summary of what I view my locost to be:

It's a cliche to say that locosts are like bikes, but the analogy is perfect. They're light, fun, powerful and generally not used for any kind of serious daily use. I'll be a little more specific.

This is a BMW F800 ST, Bimmer's most "sporting" sport-tourer. It's a sport bike with a few concessions to long trips and the occasional slog through traffic. My car will share the same purpose and spirit.

First off, it means the car has to be as lean as possible. It's a Seven after all! In my case I'll certainly forgo a stereo, power steering and power brakes.

I expect my car to be a sunny-day only car. If it's going to rain, it's either in the garage or under a tarp. That allows me to ditch the roof and side curtains. Ditto the AC and heater (I'll drive faster or bundle up).

I want to be able to drive my car to work. The car will be street legal and registered in my home state. That means turn signals, headlights, a windshield, exhaust stuff and all that jazz. This requirement also calls for a radiator big enough to cool the engine when stopped, some kind of reverse gear (no motorcycle engines), springs soft enough to handle open road faults, and it has to have a pretty loud horn.

I want to be able to take the car on the annual long trip to somewhere. This means it'll have to have some storage space and a spare tire and jack (just say no to fix-a-flat). It'll be an interesting challenge to get both without losing too much sporting character. A glove box would be nice, too.

This car will definitely be autocrossed, but not raced wheel-to-wheel. This means adjustable camber and toe, but I'll only have a roll bar and not a full cage. I also intend to fit 4 point harnesses in both positions. As an added concession to my vanity, want a camera mount on the roll bar for the occasional race video. I'm still debating adjustable brake bias...

Anyway, this seems to be a good start. When you start making decisions like this, things seem to fall into place quickly.

First things first...

So I find myself sitting here with a blank slate. My locost only exists in my head, and I'm finally ready to start the research, concepting and design process. It's only logical that I start with the most important details, namely, what colors to paint the car.

Sure, things like engine and suspension details are important. But this is what really matters. Casual onlookers, curious friends and ambivalent wives only care about how the car looks.

Lotus/Caterham Sevens often sport a "lipstick" and stripe paint scheme as shown on this Caterham Classic. I love this look, and I think that's the direction I'm going in. As far as the actual color scheme is concerned, I've got other ideas...

You can't swing your arms nowadays without hitting a Red Bull sponsored race car. They're everywhere. And as much as I'd rather drink gasoline than a Red Bull, I think that they're the coolest looking cars in the racing world.

I don't think it's the graphics so much as it is the basic color palette that makes the scheme work over a variety of cars. Doing some web research, I've found that the colors break down like this:

On a locost, he dark blue would make a great base color, the mustard-gold-yellow is a great stripe color, and that crimson red is perfect for accents or additional striping.

I don't know exactly how these translate into real colors, but for right now this seems like a pretty good plan of attack. Perhaps when I get better at Photoshop, I can do a cool rendering of the final product.