Rally Car 101: The Teardown

"Tachyon Racing" (tachyonracing)
01/28/2016 at 15:18 • Filed to: None

This is the fourth post in our Rally 101 series.

You’ve picked out a car, brought your new baby home, and now It’s time to toss all the extra comfort features out. The extent of the teardown depends on how deeply you want to get into things like seam welding and media blasting.

Before you begin, consult the rules for the organizing body and class for which you plan to compete. Some rules require that the car retains certain factory interior parts, so you shouldn’t attack your door cards with a hammer before confirming this.

General recommendations

Here are some [semi-obvious] tips we’ve learned -

Put everything into labeled ziploc bags and tupperware containers, so you know which bolts, clips go back where. Label even the ones you won’t reuse, so when you have bolts left over, you know they are for the airbags and not brake calipers.

Label all of the wiring connectors. Masking tape and a sharpie works great for this. Label even the ones you don’t reuse, so when you see unplugged connectors under the dash you know that they are not an issue

Don’t cut any wiring before confirming that the car will work without it

Take pictures of what things looked like before you took them apart

Don’t be afraid to cut/break things, like ball joints, you plan on replacing anyway

Have a plan and stick to it. Don’t take things off/apart if you don’t have to

What to remove

At a bare minimum you will have to remove the following, as it will be replaced with rally-car specific equipment, or is needed to make space for cage installation -

The stock seats - you can’t use them in a race car

Carpet, headliner, and plastic pillar trim

Dashboard - you will be reusing most of this, but (for most cars) you will have to remove it in order to properly install a cage

Seatbelts and airbags - these won’t be going back in

Sun/moonroof - this will have need to be replaced with something solid

Sound deadening material

The scope of our project involved some stitch welding, underbody HDPE mount welding, and a complete repaint of the underbody, engine bay, and interior. To do this effectively, and to use the “rolltisserie”, we needed to completely strip the shell down. Keep in mind that all of the things mentioned are in the “nice to have” category, so if this is your first rally car, and you’re looking to get onto the stages quicker (as you should!), skip this and go with the minimum above. That said, we did the following additional teardown -

Engine and drivetrain were already missing from the shell we bought, but we would have removed them if they were not

The wiring - this prevents it from being damaged by all of the welding that we were planning to do. A fried wiring harness is a huge pain, but many cages get built with the majority of the wiring in place, so work with your cage fabricator on a strategy to ensure it doesn’t get damaged.

The brake lines - we’re running our own custom lines to facilitate an aftermarket proportioning valve and a slightly better layout. Subarus have a pretty good layout from the factory, but if you have a car that has lines running outside of the car (i.e. under the floorboards), you may want to consider doing this.

The fuel system (lines, tank, filler...etc) - we’re reusing the stock components, but welding is significantly less dangerous without gasoline around.

Doors, trunk, fenders, and lights were removed from the car

The glass and roof panel - this makes cage installation a lot easier and prevents the glass from getting damaged. Impreza specific side note: I found that not having a windshield makes it way easier to get the dashboard back in place once the cage is in.

The suspension and subframes - these stay in place for the cage installation, since a rolling car is easier to work on. Once that is done, we remove them for “rolltisserie” and paint purposes.

Sound deadening removal

While not strictly necessary, it is good to get rid of the sound deadening to reduce weight and prevent it from coming loose and flying around during a rally. The effort will vary greatly depending on the car, but I found that 50-60% of the insulation comes right off by simply hitting it a few times with a rubber mallet. A hammer and metal putty knife used as a chisel takes care of the rest. Dry ice seems to work well for some folks and is pretty cool to play with, but we haven’t had much luck with it.

Windshield and rear window removal

This is something we had never done before. After watching a couple YouTube videos, I went to Harbor Freight and picked up the piano string-type tool to give it a try. The glass is held in place by a ” - Ľ” thick bead of urethane adhesive, so the general concept is to use the wire to cut the adhesive and remove the glass. We started with the windshield, since we figured it’s the cheaper one to have to replace. I removed the rubber trim, and used the provided tool to get the piano wire through the urethane. It took quite a bit of pressure to cut through the tough urethane while making sure I didn’t bump up against the metal. Once the wire was through, you can begin sawing. I had the wire break a few times, and while it seems to be unavoidable, going too quickly seems to make it break quicker due to heat generated.

Once the urethane is cut all the way around, the windshield could be lifted right out. Having the suction cups (also available from Harbor Freight) is useful, but not necessary for removing the glass, as you can just grab it by hand. They do, however, become significantly more important when putting the glass back in place.

Roof removal

The big advantage to removing the roof panel is that it gives the cage fabricator good access to the top of the cage, enabling a consistent weld all the way around the joints. The big disadvantage is that it is a pretty big pain. I can’t speak to all cars, but on Subarus, the panel is a stamped sheet of metal that is spot welded in place. In order to remove it, grab a drill bit that is a bit bigger than the size of the spot welds and start drilling them out. You can get special bits that are a bit less likely to go all the way through, or just be extra careful. I found that there were a lot of spot welds that were not obvious, especially in the B-pillar area, so going slowly was key. Once the welds were removed, I simply picked a spot and started prying up, hitting any missed spots with the drill.

Tachyon Racing is comprised of a Michigan- based driver Dmitriy Martynov and co-driver Molly Disend blasting their way through the motorsports scene. Dmitriy is a veteran driver who enjoys rallyX, autoX, and ice racing in addition to dirt biking and motorcycling. His passion and competitive drive lured Molly to join him in both TSD and stage rallies. Stay tuned for updates as we develop our team, build a rally car, and post occasional pictures of our lovable rally dog, Gogi. !!!error: Indecipherable SUB-paragraph formatting!!!

DISCUSSION (3)

MonkeePuzzle > Tachyon Racing
01/28/2016 at 15:28

I LURVE build threads, and I LURVE rally. Keep us updated, looks like you’re doing it right! The bugeye (which I THINK this is) is my 2nd favourite subaru, so you’re doing well in the looks department too :D

RallyWrench > Tachyon Racing
01/28/2016 at 15:33

Hey, I’ve done just that, with a silver Evo VIII. I had to rewire the car to take out the ABS without disabling the ACD. There’s a picture somewhere of me draped in the relevant harnesses, piecing together what I needed to do from diagrams. That was fun. Interestingly, we found the Evo highly conducive to roll cage fitment, because it already has holes in the interior structure in some key places. Unfortunately our car got written off at OTR due to bad note, was repaired, then yard saled again at Olympus near the end while in a top-5 position, and is now a sorry shell somewhere. It was good while it lasted though.

Great writeup, looking forward to your progress!

Spoon II > Tachyon Racing
01/29/2016 at 00:54

The top picture looks like Ultron is trying to take over your car