Splitter fabrication, sheetmetal trimming

This weekend I finally trimmed away the sheet metal fenders to allow for more tire clearance. The trim is pretty modest for now, after the Kevlar fenders are on I'll go back and remove more material. I didn't want to remove too much and not have enough room to mount the flares.


I also began fabricating the front splitter. The construction is a composite aluminum panel...a polymer honeycomb structure skinned with aluminum. The weight is similar to .040 aluminum, but about 50 times stronger. It's pretty cool stuff, amazing strong for the weight. I did consider carbon fiber, but I was worried about destroying it on a speed bump or something. The composite aluminum is simple to duplicate and I can have a couple extra in case I break one.

The splitter isn't pinned to the bumper yet, I still have to make some supports to tie it to the chassis. If this thing actually works, it should generate about 160-200lbs of down force...so I better attach it to the frame properly. Attachment to the bumper cover alone would cause too much distortion for the surface to be effective.

Fenders are rough-trimmed and pinned!

Lots of progress over the weekend- I even cleaned out the garage and chipped some epoxy from the concrete floor...hopefully when I do one of those garage-floor painting kits it'll cover most of the spots. Anyway- the fenders are all pinned on with Cleckos so I can do my final fitting and trim. The car is starting to look pretty good, even though it's 4 different colors.

This time for the rear fenders I used Meguire's mold release paste wax on the male mold and it made a world of difference. The finished parts almost fell off the car...way easier than previous methods. I weighed a rough-trimmed rear fender...exactly 2 pounds! It's remarkably stiff too, at least when it's attached to the car. I may reinforce the backside with a little fabric here and there, in high stress locations.

I also mocked-up a belly pan undertray that will tie in with the fenders. I'm not sure what material to make the undertray out of yet...some sort of composite involving Kevlar for its abrasion resistance. Maybe with a polyurethane foam core? I guess I need to do some testing first.

Below is a Photoshop'd image to see what it might look like with some paint...not too bad so far!

Kevlar on the rears-

I made a lot of progress today, the rear fenders have a few layers of Kevlar on them and should be able to be removed from the "mold" tomorrow. The epoxy cures a lot better at 74 degrees ambient!

The front flares are mocked up using Clecko pins for now, I'll have a little sanding and filling to do before they are done. You can see the Micro in the photo below, it's a mixture of micro-glass balloons and epoxy. It's very strong and can take a beating unlike regular body filler. I still have to do the final trim of both the bumper and fender flares, the I can start removing some of the original steel fender to allow some clearance for the tires.

Rear fenders are taking shape

I finally got around to fleecing the rear fenders now that the fronts have cured and my techniques have been semi-proven. I'm planning on putting a coat of epoxy on the fleece soon, so adding Kevlar should happen this week if all goes well. The cold temperatures have really slowed the cure of my epoxy so the whole process is taking double what it should. We are supposed to have 70 degree weather this weekend, so hopefully I can make some progress.

The fronts came out nice, they only needed a little bit of micro to smooth out a few low spots from the deformed male mold (once again, the cold temp made the epoxy cure too slowly, allowing for deformation of the mold during the cure). The biggest challenge was making matching bumper extensions to match the fender flares. I should've made the whole thing as one piece then cut it to allow removal of the bumper. I believe my solution will work, but it was a lot of extra work that could've been eliminated. I am now doing the rear sections as one piece that I will cut later so I can remove the rear bumper.

Another thing I learned is to reinforce my MDF forms with an adhesive in addition to hot glue. I used heaters to cure the front flares, which melted the hot glue at 150 degrees, which deformed the mold. The rears have additional supports as well as standard adhesive that should hold up under artificial heat.

In other news-- the doors have been prepped for molding as well, I am planning on using a carbon fiber/Kevlar laminate to create some lightweight door skins. I'm just going to pin them on using Dzus fasteners, I can't think of a situation where I would need a hinged door (emergency workers can pull me through the window just as easy as if I had a normal door, since the x-brace is in the way anyway). To prep the doors I cut off all unnecessary sheetmetal and filled in the door handle area. The new skins should be about 12-16oz. each.

More fender work- rough trim to test fit.

The fenders are coming along nicely, I was able to release the Kevlar from the fleece (male mold) without too much drama. The shape gives the fender some rigidity, but it is still a little too flexible with out being securely fastened to the car. I may add some supporting layers of fabric to the back side later on. The photo above shows a quick and dirty trim so that I could test the fit, the finished product will be more refined.

The next step is to add a matching flare to the bumper so that the lines can continue uninterrupted. I would like to make a complete bumper cover, but I think I'll wait until I'm finished with the flares all around. I may start on making some lightweight door skins at the same time, a fixed-position door setup will save about 55lbs over my current setup.

FYI- the weight of the new fender is approximately 2.25 lbs :)

Fender progress

I added two layers of Kevlar this morning (with help from my neighbor- thanks again!) The fleece hardened up really well and made a good surface to mold to. I used some liquid poly wax as a release agent and I think it was working a little too well...we had a tough time getting the first layer to stick. The second layer went on easily and laminated thoroughly. The creases aren't super-sharp, but that's what you get using a moldless process. Overall I'm pretty happy and it looks like the technique will work well enough to do the rears as well.

I should be able to release and trim the fenders in the next day or so (the epoxy has a longer cure time due to the cold weather.) Meanwhile I'm prepping the rest of the panels for fleece. The driver's front is done, I just need to cut the MDF for the rears.

Started making the new fenders---

Today I finally got around to starting on the fenders. I'm using a composite technique called "fleece" where you stretch some fabric over a wooden form to get a smooth shape or curve. Fleecing works perfectly for the shape of these fenders. I used 1/4" MDF to cut the wheel shape and the flare. The flare is about 2.5".

Next I stretched some cotton spandex over the forms ( I hot-glued the wood to the body to hold it in place). 3M 77 spray adhesive holds the fabric to the wood and body.

...taking shape!

Here is the fleece with a couple thin coats of epoxy. The epoxy will give the fleece just enough stiffness to add the layers of composite fabric. After the Kevlar is molded, I can release it from the fleece and removed the wood forms.

Doors are for wusses.

I took of the doors today in preparation for making the new fenders. I was pretty surprised to find they weigh 30lbs each, even though they are completely gutted and most of the sheet metal has been removed. I'm going to consider making some new door skins made from composite and just pin them to the car. It's easier to "Dukes of Hazard" in and out of the car anyway. 50lbs off the car would be great, especially since I added about 150lbs from the cage.

Kevlar testing and passenger seat installed

I made a test piece of the Kevlar fabric and wetted it out with epoxy- the Jeffco epoxy seems to work well with the fabric, even in the low temperatures (50 degrees F). I'm using the Jeffco quick-set epoxy, it works a little better in the cold. You can buy it at http://www.aircraftspruce.com/
Two layers of fabric should be enough for the fenders, the sample is pretty rigid, similar to sheet metal. The plan is to mold the new fenders from the existing ones, then cut away as much of the old one as possible to save a little weight.

The passenger seat has also been installed, it is the same as the driver's seat, except it's an inch wider (16") to accommodate a wider range of passengers. I haven't decided if I'll add the halo to the seat yet, I may have to in order to comply with instructor safety rules. Some clubs specify that the instructor or passenger's seat must have identical safety equipment as the driver's.

Wing supports finished, rear firewall added

I finished the wing supports, it is now very rigid. You can easily push the car by the wing, and it's very stiff laterally as well - the whole car rocks back and forth if you push the wing. I had to fabricate a lower brace in the trunk to stiffen up the sheetmetal- it added some weight, but I can use a little weight in the rear anyway.

I also made a new rear firewall since we cut out the original to fit the roll cage. I used 20 gauge sheetmetal and used a cardboard template to finalize the shape. I am going to use epoxy with micro to fill the seams, or a little caulk or something.

My Kevlar fabric arrived, so I'm getting ready to make my new fenders. Kevlar is a pain to cut, but I found a special pair of snips at Home Depot that seem to do the job --- Wiss MPX serrated blade shears. They were about $15 (versus $65 for the special Kevlar shears) and they cut the fabric well, as long as it is under tension. If you don't hold the fabric taut, it is almost impossible to cut.

Wing supports cut to proper height-

Yes, I know my garage is a disaster. I need a 10,000 sq ft workshop. I cut the wing supports down about 8", now it's a little less crazy...maybe even a little DTM style which isn't bad.

Hahaha...this is just a test...

No, I'm not keeping the wing like this...I figured it would be easier to cut the wing down to the right height instead of adding to it to make it higher. I love the photo, funny.

I also fab'd up an X brace out of aluminum tube to add some lateral support. Not the most elegant solution, but I really don't want to use guy wires or anything.

Super-ridiculous wing fabrication begins!

I really want my rear wing to be functional, so that means making my own. Most of the wings on the market are designed for looks, and not much function. One of the most important things for wing efficiency is getting it "clean" air...not the turbulent crap spinning close to the trunk. My solution- raise it as high as I can! In the end it will be almost level with the roof line...should look pretty lame, oh well.

I started with some 1/8" aluminum and plasma cut the shapes using a cardboard template. The wing will mount to the floor of the trunk and tie in to the rear crash rails for extra support. I cut some slots near the license plate to allow the supports to go through uninterrupted.

MIG welding aluminum is possible, but a big pain in the ass. Get a spool gun or a TIG. I got the job done, but I had to fix the spool every 2 minutes due to feed problems.

Ghetto-fabulous wheels arrived!

My new cheapo wheels came in - Sportmax 16x8"s. They aren't my favorite, but they were the right width, bolt pattern and offset. For $99 each, I guess I can't complain. Someday I'll add the $800 (each) custom Kodiak wheels. Anyway- the wheels are 8" wide with 0 offset, so they stick out quite a bit...at least until I fab up my new fenders to cover them. For tires I'm using Sumitomo 16-245-45s...pretty damn wide. I think the section width is almost 11". Tirerack shaved them to 4/32nds for me so they should be pretty grippy. $69 each too, plus $15 each for shaving. I also had to get special tuner lugnuts from Summit Racing, my old lugnuts wouldn't fit in the holes.

The cage is 95% done, I just have to finish a few welds on the A and B pillar ties ( I ran out of welding gas). I'm very pleased with how it came out, very strong and it stiffened the chassis 1000%. I may add a few more gussets in the future, but for now I think it is in good shape, and according to the rules if meets or exceeds all the regulations. I had to pop out the windscreen to get to a few welds, and of course I broke it in doing so. Luckily a replacement is only about $200, and it's always nice to have a brand new non-pitted windscreen.

I also removed the HVAC system. I was going to keep the heater, but my goal of low weight and simplicity overrode the convenience of heat. I guess we'll see if I made a good decision the first time I drive out to the track at 6am on an Autumn day. Removing the HVAC system allows for a lot of simplification of the wiring harness too, and simpler is better on a race car, especially when tracing a bad ground or other electrical gremlin.

Wheels and tires are on order- I bought an inexpensive setup for this year until I decide to drop the $2700 on custom Kodiak wheels.

Cage progress

We took the car over to another friend's shop to do most of the cage fabrication since it is about triple the size of my garage, and he has all the proper tools too. Thanks again! The main hoop fits very snug, which is great. Looks like the whole cage will fit very well, tight against the A and B pillars. A few things are tacked into place and we are fitting more tubes day by day. It's a slow process because the fit of each pipe has to be close to perfect, and the tube junctions can be pretty complex in a few spots. My friend that's helping me is doing a great job though, he has a lot more patience than I do. It's also nice that he can work on it all day everyday since he's out of work right now :)

Prep for the Cage

The cage kit came a few days ago from Kirk Racing. It's basically the main hoop with a few pieces tacked together, then the rest is just a bunch of tubes (about 150lbs worth). We'll have to notch all of them ourselves, oh well. I thought I would get a little more for close to $800. I bought a tube notcher at Harbor Freight for about $40, so it shouldn't be too bad.

My buddy and I ripped out the dashboard in preparation for the dash bar install. I can pretty much guarantee that the dash won't ever be inside the car again...I think it would be a huge pain to try and fit it back in. I will plan on making a new dash after I buy an aftermarket gauge cluster.

Next we have to remove all the paint where the cage points will mount and plan the layout of each piece. I'm really glad i already cut the roof off, I have no idea how we could fully weld the cage otherwise.

Lexan windows installed

The rear lexan windows are finally in, it was a lot more work than I tough it would be. I first had to weld on a bunch of "anchor nuts" (thanks www.aircraftspruce.com !) to the window channel which proved difficult. The nuts have tabs on them, but the steel was very thin and hard to weld correctly. I bought a 4x8 sheet of 1/8" Lexan from Silver State plastics for about $100. 4x8 is plenty to do all 4 windows. After making a template out of cardboard, I used a router to cut the Lexan and a belt sander to smooth out the cuts. A little black paint around the edges finished up the project nicely.

I'm a little burnt out on doing the windows for now, but the fronts will have to be done as well, just for some shred of comfort when driving to the track in cold weather. Since I used anchor nuts, I can unscrew a few bolts and remove the window completely for track days if the club doesn't allow fixed windows.

Fuel Cell halfway installed

I bought a used 15 gallon fuel cell from my neighbor and got it halfway in the car. It's no "Fuel Safe" cell, but it will do the job well without costing $700. I first used the plasma cutter to get rid of the spare tire well, then I cut a circle of 20 gauge steel to cover the hole. I used a spot-weld method to attach it to the car, which worked much better than I thought it was going to. Now there is a ton of room under the car for a diffuser...if I ever get around to making one.

I cut a hole in the new steel to make room for the sump on the bottom of the tank. I am planning on routing the lines into the trunk to a fuel pump, then back under the car to the fuel rail. The removal of the old tank will hopefully shed some more weight as well as make some room for my side-exit exhaust I'm planning.

Kirkey Race Seat Installed

The Kirkey race seat finally arrived...it took about 4 weeks to get a 15" size, I guess they aren't that popular. I just wanted the thing to fit as perfect as possible, and 16" was too loose. It is the intermediate road race version, and I added the Halo head restraint. To attach the seat to the car, I welded some aircraft-spec bolts to the chassis and lined up the brackets.

I decided to not buy the seat cover, I'm going to place some fire-proof foam in a few key areas instead. The seat is about 6" lover than the other one, and I can barely see over the dash! This is great for center of gravity, but bad for visibility. A little foam on the bottom should help a bit. The halo is a nice touch, hopefully it will help limit lateral head movement in a side impact. The seat also feels like it will work with a HANS nicely. Overall, I think it's a great seat for the price. After I add a seat-back brace, it should be a very safe solution.