24 Hours of LeMons (Now Open To The Public!) > General LeMons Talk

LeMons Car Prep

(1/2) > >>

I just saw this article and thought I'd post it up. Sorry if this is a re-post. (Source here)

Car Prep

it ain't rocket science
The 24 Hours of LeMons gives everyone from novices to pros a chance to race on the cheap--and a chance to build a car like they've never built one before. Whether you’re an expert or newbie, it pays to read the rules closely and tackle this stuff step-by-step.

LeMons is all about racing crappy cars—you're not a true gearhead if you don't enjoy watching a rusted-out Volvo dice with a barn-find Fiero. But remember, a crappy car will kill you just as fast, if not faster, than an F1 ride. That's why the bulk of your LeMons build is likely to center on mandatory safety improvements, and why safety stuff doesn't count toward the $500 limit. It's also the reason we make every car go through a full tech inspection before every race: If you cut a corner somewhere, our inspectors are just dying to catch you.

For rookies, the list of mandatory upgrades might seem intimidating, but remember that nobody expects you to do it all by yourself. Just take it a step at a time, ask questions about things that confuse you, and you'll see that it's not all that hard.

If you're just starting out, set aside some time and money for high-quality, professional assistance on big stuff like the rollcage. (If you just rely on your old drinking buddy Jimmy to zap up a cage with his $200 Lincoln home welder, there's a pretty good chance that he'll botch up the job or violate his parole before finishing it.) But remember, here, we said "high-quality" professional help. We've seen cages from "Joe's House of Racin' Stuff" with lousy welds and improper bends too. Use common sense—if you or whoever doing the work is uncertain how to proceed, don't wait until tech inspection to find out you guessed wrong.

There are several key areas LeMons' tech inspectors will be focusing on:

• Roll cage
• Driver's seat
• Racing harness
• Fire extinguisher
• Fuel tank
• Fuel system
• Electrical cut-off switch
• Race number

Keep reading to learn about these one by one. Just remember, this is car racing, not rocket science: A LeMons build isn't that different from any other roadracing series' requirements, and if those dorks can handle it, so can you. Best of all, once you've done it, you'll either be able to re-use the same car again and again, or knock out another one in a quarter the time. We've seen some LeMons machines compete in eight or nine races without major updates. Apparently, some people just like the punishment.

Give yourself plenty of time, familiarize yourself with the rules, and enlist expert help where needed. Next thing you know, you'll be on the grid—and probably wondering why you didn't just take up gardening as a hobby. 


Before you put in a rollcage, you've got a decrepit $500 hooptie. After you put in a rollcage, you've got a thoroughbred competition machine. Really. And hey--as a side benefit, that rollcage might even prevent your heap's rusty scab of a body from collapsing right onto your head. Assuming you built it correctly.

Don't know what "built it correctly" means, exactly? Overwhelmed by the prospect of bending tubes, cutting metal, welding seams, and getting hot flaming sparks up your corn chute? Well then, you've got other options.

1) Use a professional cage builder/installer. Go to your town's local race shop or competition fabricator, drop the car off empty, and pick it up a few days later with a rollcage in place. This can cost a ton, or be shockingly cheap--it pays to shop around and get referrals. There's a huge spread on pricing, and it's not always associated with quality.

If you choose this route, make sure that both you and your builder understand LeMons' cage requirements in advance: A lot of roundy-round and drag-racing series don't build their cages to anything approaching roadracing standards. Whether you're doing the fabrication or handing it off to a pro, it's your butt (and your entry) on the line in the end. Make sure they understand what the LeMons rules dictate.

2) Buy a Pre-Made kit. One alternative to a scratch-built cage is buying a pre-made kit. These can be great, but all kits are not created equal. Pre-made cages from high-quality builders like Kirk Racing and AutoPower tend to be jigged, bent, welded, and sized precisely to your particular car; expect to pay $500-600 or more for one of these than for a generic, one-size-fits-none cage. And just about everything cheaper ($250-$400 range) turns out to be the latter, unfortunately, even if the company claims that it's specially made for your car. By the time you're done modifying and fixing and re-shaping a one-size-fits-none cheapier cage, you'll have spent more than you would have getting a good one to start with. Also avoid kits sold as "drag cages" or "street cages." These rarely meet the requirements for wheel-to-wheel roadracing.

3) Buy a Tubing Kit. Halfway between a real kit and pure DIY, these offer raw tubes that have been cut to approximate lengths. It's then up to you to bend, weld, and grind stuff accordingly.

4) Go with a known quantity. A couple of cage manufacturers consistently deliver good stuff: Autopower, Kirk Racing, Chase Race (WA), and Full Tilt Fabrication (MA) are all recommended. If you're in the SF Bay Area, Chris Overzet and Mitch Parella (510.526.5003) can build and install custom setups.

Cages should fit the cabin's original contours as closely as possible, but should also contain as few bends as possible. Obviously that means some tradeoffs. Stripping out the interior always gains you more room and more options. Removing the dash makes things even easier.

Use common sense when designing your cage. Bars that are too close to the driver will diminish both safety and comfort; avoid unnecessary curves or bends, since straight tubes are always the strongest; verify that your drivers can still get in and out of the car in a hurry; make sure the tops of your team's helmets are comfortably lower than the top of the cage (at least two inches' clearance is a good rule of thumb). Again, this is car racing, not rocket science.

When visualizing your cage, imagine it made out of dried-out spaghetti. Now picture a fat dude perched right on top, pushing against the sides, or rocking it back and forth. Wherever the spaghetti breaks first is the weakest part of your layout. Return curves and compound curves are especially bad (and virtually always unnecessary). Use straight lines wherever you can, and triangulate wherever you can't.
LeMons' most basic cage requirement calls for at least six major mounting points to the car: two where the front hoop meets the car, two where the main hoop meets the car, and two where the main-hoop backstays (two straight reinforcing tubes connecting the top of the main hoop to stout mounting points at the rear) meet the car.

The windshield hoop and main hoop should be connected with at least a pair of straight tubes running as close to the roof's edges as possible. The door bars should run across the door opening between the front and rear hoops to protect the driver from a side impact. When positioning the door bars, try to balance impact protection and ease of entry/exit--the only thing worse than getting T-boned is not being able to bail out in a fire. Cutting out the stock inner doorskins will get you a lot more room to design safe but accessible door bars. Vertical reinforcing bars that tie the horizontal door bars together, and/or connecting the horizontal door bars to the rocker sill, are also good ideas.

A horizontal harness-mounting bar behind the driver is generally the best (and sometimes the only) place to anchor your shoulder straps. Keep in mind that the shoulder-strap anchors must be even with, or no more than 15 degrees below,the point of seat entry. Position your harness bar accordingly.

Finally, you must have one main-hoop diagonal support--the simplest way to accomplish this is to run a clean, straight tube from the driver's-side top corner of the main hoop to the passenger's side bottom cage-mounting pad at a more-or-less 45-degree angle. This bar will likely intersect your harness bar; you can make either the diagonal or the harness bar from two pieces to deal with that intersection, but the finished two-piece section must still form a very straight, very clean line.

A single, continuous piece of tube, properly bended as needed, should be used for all major cage elements. This means if your main hoop comes up a few inches short, just build a new one that actually fits--don't try to extend it with short bits of tube grafted onto the ends. Spliced tubes, hoops made from multiple intersecting sections, and damaged tubes scavenged from other cages are always a no-no.

Bear in mind, all tubing isn't the same. Purpose-built rollbar tubing (the only thing we allow) is a whole lot stronger than muffler pipe, water pipe, or electrical conduit, and you won't find it at the local hardware store. This is special-order stuff. We highly recommend seamless, drawn-over-mandrel (DOM) mild steel rollbar tubing. A cheaper but much less robust alternative is seamed (commonly called ERW) mild steel rollbar tubing. While LeMons allows either type, we feel the extra cost of DOM tubing is peanuts in light of the additional safety it buys. Want to be smart? Use DOM.

Rollbar tubing also comes in various sizes. The measurements that matter for our purposes are outside diameter (O.D.) and wall thickness. This is usually expressed as [O.D. in inches] x [wall thickness in inches]. For cars under 3000 pounds as raced, LeMons requires a minimum of 1.50" x .120" or 1.75" x .095" cage tubing. For cars over 3000 pounds, the spec grows to 1.75" x .120" or better.

Cages can be bolted or welded to the car. Welding is stronger, and all welds should be clean, deep, and as close to fully continuous as possible. If you're using bolts, they need to be Grade 8 or better and big enough to handle the job. You'll also need equally sturdy backing plates on the opposite sides of the mounting pads.

Bolted or welded, sturdy mounting methods are required at every junction between rollcage and car. Usually, this means creating robust mounting plates where the tubes join the body or frame; you might even have to reinforce the area around the mounting plates to guarantee suitably sturdy attachment. And remember, as the tubes travel down toward their attachment points, they should be kept as straight as possible—any bends near the attachment points can significantly compromise strength. Under no circumstances should reverse bends be used under the dash--either run the tube straight down and accept the cramped access, or take out the dash (ie, do it right).

All bends should be smooth and consistent and show zero abnormal crimping, crushing, stretching, narrowing, or other weirdness. These visual markers point to improper materials or handling, and will get you rejected in tech. The typical Harbor Freight bottle-jack bender isn't nearly strong enough to properly bend rollbar tube of LeMons' required diameters. A good, professional-grade hydraulic bender using the correct dies and reasonable radii is the least that you'll get away with. If you've got access to a professional mandrel bender, so much the better.

Wherever any part of the driver's body might contact the cage during a crash, that area must be securely covered with high-density, purpose-built rollbar padding. You'll have to find this stuff from a speed shop—the pipe padding they sell at Home Depot won't do bupkis.

Once you've got the basic cage in place, we recommend adding extra diagonals and gusseting to increase overall strength. You can't really go wrong adding more strength, and nothing makes Friday tech inspection more pleasant than not having to scramble to find cage tubes and welders at 6:30 pm.


The seat isn't just a convenient place to store loose change and hair-covered Lifesavers. Seats really are  lifesavers, or rather they should be. During the race, a comfortable, supportive seat helps you stay in control of the car; in an accident, a loose or busted seat can contribute to serious injuries.

LeMons's specific seat requirements can be found under Rule 3.2. But more generally, the key here is actually seatbelts, because your seatbelts are only as good as the seat that they're holding you into. If the seat gets loose, you're no longer strapped against anything--which is like having no seatbelts on at all.

LeMons allows both--and both need to meet the same standards. Purpose-built race seats are usually lighter and more compact than OE units, and they tend to be better at holding you in place. They usually come with holes for your harnesses already cut. Racing seats aren't always terribly comfy, however, and the ones with huge side bolsters can be diabolically hard to get out of in an emergency.

Many racing seats also aren't always that strong--lightweight aluminum, plastic, and tube-and-stick units should generally be fit with a positive, hard-bolted brace on the seatback to protect against seat failure in an accident. (Just because LeMons gives you the choice of a hard-bolted brace or a retaining bar doesn't mean that the hard-bolted brace isn't safer--it is.) SFI or FIA certification speaks to reasonable levels of fire resistance and strength; look for it. Racing seats also force you to figure out some kind of safe, solid mounting system of your own. Many seat makers sell mounting kits and/or slider kits, but there's no guarantee you can easily graft Seat A to Car B.

OE seats, meanwhile, have the distinct advantage of already being there. Other than that, well.... Perhaps the biggest concern with OE seats is the reclining mechanism, which frequently fails in a crash. Another concern is the general lack of support with most OE seats, and the overly puffy nature of the seat squab. What's delightful to the buttocks during the morning commute can feel tippy and sloppy on the racetrack.

Whether OE or aftermarket, the first thing to examine here is your seat mounting. Grab the seatback and shake back and forth vigorously. How solid is it, really? Loose hardware, flimsy floorpans, damaged bolt holes, weak sliders, or anything else that lets the seat flail is a danger, both to your neck and your chances of passing inspection. The seat-to-bracket joints, bracket-to-floor joints, and (if needed) under-floor load spreaders should all be 100% tight and beefy. In extreme cases, it's easier just to build spurs off the rollcage to bolt the seat to than to fight with a flimsy floor-mounted design.

If you can make it work, we recommend eliminating the adjustable sliders and hard-mounting the seat in one place. This might not be possible if you've got drivers of varying sizes, but if you can make it work, do it: Eliminating the sliders just eliminates one more potential failure point.

Finally, all racecar seats, whether OE or competition type, must be prevented from failing backward. The best method is using a positively located seatback brace (many of these are adjustable). Second-best is a simple retaining bar within half a foot or so of the seatback--a harness bar can happily do double duty here.


Every racecar needs at least a five-point harness--that means two lap belts, two shoulder harnesses, and one central, nard-squashing "anti-submarine" belt running between the driver's legs. Six-point designs, which eliminate that one central nard-squasher for two slightly less soprano-izing straps across the thighs, are also accepted. All belts must be SFI or FIA rated and fewer than four years old. All SFI belts have punchout tags showing their manufacturing date. Most FIA belts show a five-year expiration date instead. That's great, but remember that LeMons' standard is four years, not five--a "good through 2011" tag on an FIA belt means it's only good for LeMons through 2010.

Out-of-date or improperly mounted harnesses are one of the most common reasons for cars failing tech. With lap belts, we recommend using the OE holes and hardware wherever practical. If you must drill through the sheetmetal to get the correct angle, anchor the belts using three-inch steel plates or competition-grade load washers, along with competition-grade hardware and Grade 8 or better fasteners.

Most belt manufacturers recommend mounting the lap belts at a 45-degree angle between the driver's hip and the floor, while keeping the distance from the hip to the mounting point as short as possible. The angle of the lap belts should never exceed 60 degrees.

The anti-submarine belt should be mounted as close to the driver as possible. The mounting point should be directly below the seat hole or further back--some manufacturers even recommend mounting the strap behind the line of the driver's chest. Under no circumstances should the bottom mount of the fifth belt be forward of the seat hole. (If you're not using a racing seat, you'll probably have to cut your own hole in the seat squab. Get it right in there close to the driver's nuggets, and make sure not to route the strap next to anything like a spring that might cut or fray it. When anchoring the strap to the floor, use steel plates or three-inch load washers and Grade 8 or better fasteners.

The anchor points of the shoulder harnesses should be between zero degrees and 15 degrees below the entry points through the seat. The harness mounts should never be located above the seat-entries, since that can cause dangerous spinal compression during a crash. The distance between the seat and the anchors should also be kept to a minimum to prevent excess stretching in a crash.

The ideal spot to mount shoulder harnesses is an (aptly named) harness bar--a horizontal bar running from one side of the main hoop to the other at the proper height relative to the seat. Most pre-fab cages will already have one, but they're easy to add--just keep the relative angle to the seat in mind while you're doing it. Harness bars should be made of the same tubing as the rest of the cage.

Most important of all, wear your harnesses correctly. First, take your time strapping yourself in: If you get out there and something's not right, you'll have to--make that you damn well better--come back in to do it again. Next, have a teammate tighten your lap belt, then your shoulder harnesses, and finally the crotch belt(s). It's impossible to tighten your own belts securely enough to be safe--this is a two-man operation every time. If it feels tight, don't worry--the second you get on the track you won't feel it, we promise. If you're running arm restraints, a cooling system, an intercom, or a window net, do that stuff last.

Once you're strapped in and secured, check your ability to reach all the controls and switches, including the fire extinguisher and main kill switch. All clear? Then go for it.


Though LeMons applauds most manners of hillbilly engineering, one thing we're serious about is your fuel system. While we try to keep costs down by not making every car run a roadracing-style fuel cell, our tech guys will still turn a very hard eye toward your fuel setup. In a nutshell, we're looking for potential sources of fuel leakage in the event of an off-track excursion, an impact, or a rollover. When evaluating your existing fuel system or designing a new one, keep those circumstances in mind.

Though full-race fuel cells aren't required by LeMons, they're a pretty good idea if you can fit one into your budget. High-end, FIA-certified roadracing cells like those made by ATL and Fuel Safe typically consist of a sturdy metal box with a deformable bladder on the inside and, as a final defense, absorbent foam inside the bladder. These legitimate fuel cells are remarkably resistant to impact, leakage, and fuel spray when bad juju happens on track.

On the other hand, any idiot with a roto-molding machine can whip up some big plastic jugs and call them "fuel cells" in an advertisement. If it doesn't have a sturdy case, an internal bladder, and foam, it's not a legitimate fuel cell--it's a custom fuel tank with a fancy-pants name. Worse yet, it's probably no safer than what your car came with, and maybe even less safe. At least OE tanks usually fit well and don't drag on the ground. The moral is, make sure you have a clear understanding of a cell's features before buying it.

If you decide to stick with your car's factory fuel tank, make sure it's in good physical shape. All tanks should be carefully inspected for corrosion, leaks, and external damage. All lines and fittings must also be in good condition. Finally, even if your tank and lines appear to be in good shape, think about how it's assembled and mounted: If something looks dicey, such as a sharp bolt or frame corner pointed right at the fuel filter, deal with it before reaching the racetrack.

Weird marques and older cars are particularly susceptible to unsafe fuel-system layouts. In those romantic days of chrome and carburetors, a lot of relatively unprotected fuel tanks made it down the assembly line. If the first line of defense between you and some guy's bumper is your fuel tank, think about upgrading the system.

No matter where you position your tank, unless it's a full roadracing cell with a current FIA certification, it needs to be completely separated from the driver compartment by a continuous metal bulkhead or doghouse. Many OEM fuel tanks are mounted underneath the trunk/rear cargo floor or under the rear seat. If there are any access holes or open areas in those structures, you need to seal those holes up with a sturdy metal that's bolted, riveted, or welded in place. For cars with trunk-mounted tanks, the backseat bulkhead is an acceptable barrier if it's solid; pass-throughs and lightening holes must be sealed with metal. If you can't or don't want to completely isolate your tank from the driver compartment with metal, a full-blown, metal-encased, FIA-compliant fuel cell with all of the proper component fittings must be used.

If you do choose to swap out or relocate your tank, put plenty of thought into your brilliant new mounting place. Tanks must be kept out of harm's way as much as possible--keep them away from the car's corners, don't mount them too high (a rollover risk) or too low (an off-track dragging and puncture risk). Finally, place the tank so that it won't be punctured by nearby components, and use proper, purpose-built brackets and fasteners—some home-built tank brackets can present a puncture risk on their own.

If your tank installation necessitates custom fuel lines, make sure the new lines are sturdy and well-protected. If you car has factory steel lines, try to reuse them where you can. Where flexible hoses are needed, use braided-steel lines with threaded fittings wherever possible. If any non-metal fuel lines pass through the cockpit, they must be contained in a metal enclosure or conduit. Fuel pumps and filters should also be solidly mounted and out of harm's way, with all lines and wiring securely routed.

The bottom line with the fuel system is that if it looks hokey in any way, the tech inspectors won't be sympathetic. Stick to the rulebook, don't cut corners, and use common sense, assuming you have any left.


[0] Message Index

[#] Next page

Go to full version