Go Karts and Karting: Cheap Track Day Alternative

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The kart has a micron dash just like a race car.  The dash monitors RPM, temperature and lap times.  The steering column height is adjustable for driver preference and the flex can be tuned.

The front of the kart is adjustable for toe, camber, caster, ride height, track width, kingpin inclination and Ackerman.  A lot of tuning with a kart involves controlling the amount of front lift the geometry provides.  This helps tune the amount of rear axle lift and scrub, a big factor in acceleration off turns.  Caster, track width and Ackerman have a large impact on lift.  A lot of rear balance issues are solved at the front.  A lot of kart chassis tuning is counter intuitive to car chassis tuning.

Some of the costs of karting are contained by the rules, usually there are several classes with different price points, the air cooled clutch classes are the cheapest, followed by the more exotic TAG and shifter kart classes.  We have found that even the cheap classes are quite fun.  In the individual classes the engines are restricted to just blueprinting and are usually sealed.  This reduces engine costs and holds down the price of competing.  Most classes have spec tires of medium softness that also reduce costs.

Most karts have highly adjustable pedal assemblies.  Things can be moved by several inches and the leverage ratio to the hydraulic cylinders can be adjusted to change the brake feel.

The back of the kart has a blade type adjustable torsion bar to help with chassis tuning.  The bar can be run with the blade vertical for max stiffness or flat for maximum softness.  Drivers under 170 lbs often prefer to leave the bar off completely.  Stiffening the bar means more rear traction.  Too stiff and the car will bind on corner exit and or get wheelhop in the corner.  Often the rear bumper is used to tune the chassis but we used a floating mount to take it out of the equation and tune solely with the torsion bar.

Ackerman angle can be adjusted at the spindles and on the steering column.  Karts run more Ackerman than any other racing vehicle due to the fact that they rely on chassis flex and wheel lift to facilitate cornering.  A front torsion bar is used to tune the chassis flex.  Stiffer and tighter means more front grip, too much means hop.  The floor pan and front bumper are also used to tune the chassis.  The floor bolts can be bolted solid for more front grip or floated using plastic bushings.  Same goes for the front bumper.  Tuning the flex is a black art for the kart chassis guy.  The carbon panel is used to retain ballast but we are fat enough not to require it.

The 2010 bodywork is actually designed in a wind tunnel for minimum drag and maximum cooling.  The bodywork has to be FIA certified for wheel coverage and impact resistance.  The kart has superlight low void magnesium wheels and Bridgestone medium compound spec slicks which last a really long time.

The bodywork is also designed to prevent karts from touching wheels and getting airborne and have greatly improved safety.  The bodywork is made out of a soft plastic and is designed to absorb impact.  All bodywork has to have a molded in FIA certification to pass tech.

Karting is very family oriented as well; there are many classes for young people from 5 years old onwards. Karting has a safety record better than many traditional ball sports.  There are many families out having fun at your local track.  Track day expenses are much lower.  Typically a track’s fees range from $25-45 dollars for a whole day of driving.  In our Sothern California area, there are more tracks and they are closer than race tracks.  All of our race tracks like Cal Speedway, Willow Springs and Buttonwillow also have kart tracks so your kids can have something to do if you haul them out to one of your races.

The ugly rear bumper is FIA approved and required in 2010 for racing.  It really helps prevent wheel touching and absorbs impacts as well as allows the chassis to flex more freely.  I think the new bumpers give racing karts a sort of lame rental kart look but if it helps safety, I guess it’s a good thing!  The Tillet seat is also a tuning element for the chassis.  You can run as many as three stays per side for stiffness and either bolt the seat solidly or have it float on nylon bushings for more flex.  We run one stay per side and bushings.  We run the torsion bars solidly bolted in the floor pan and front bumper but we allow the seat to float.  This makes the chassis more sensitive to torsion bar adjustment which is the easiest to quickly adjust balance at the track.

Christa has quickly adapted to her bigger more powerful Cadet kart.  A Cadet is a 7/8 scale racing kart for older kids and preteenagers. She seems to be the fastest kid on open track practice sessions and has practiced with the race group on race days where she seems to be up to speed with experienced kids.  She also drives during open practices with adults. She will be racing soon.  Christa’s kart was powdercoated by Embee performance and all hardware was replaced with maintenance free metric stainless by Baller Bolts.

My daughter Christa got her start with a hand me down 50cc Kids Class Emick kart that I had gotten from a friend.  As she quickly progressed and wanted to race, we found that as a 9 year old, she was too old to start racing in Kids class which is for 5-8 year olds, we obtained a used Top Kart Cadet class kart with a 100cc HPV 1 air cooled engine. This was a pretty serious racing kart and a big step up from her Kids kart. As a father daughter project, we went about rebuilding it and as she started to drive it, we changed components to tune the chassis to her driving style.

Christa’s kart uses an HPV engine made by Parilla.  The HPV is a workhorse in kart racing.  In Christa’s case it is restricted in HPV-1 configuration with a smaller carb, an inlet restrictor and an exhaust restrictor.  The air box also has twin inlet restrictors. Her engine is race blueprinted whichh usually is about a 10% advantage over unprepared engines.  It makes about 9 hp on the dyno. It is also internally WPC treated.  Christa runs on VP98 fuel and Motul synthetic oil mixed at 30:1.  Motul runs very cleanly and lubes well. An unrestricted HPV-4 engine that adults run makes about 20 hp.  We feel that HPV karts are a fun bargain.  Used ones can be found for as little as 800-900 dollars and nice ones are typically around $1500-2000 due to the popularity of the more expensive TAG classes.  The HPV-1 Cadet uses a spec Clutch which also simplifies set up.

The expansion chamber is Embee thermo coated for a broader powerband.  It also looks better than the rusty thing it was!

Christa is very light for this class so her kart had difficulty turning in and scrubbed speed.  We switched axles to an ultra soft but springy heat treated centerless ground 30mm chrome molly PKT axle from Noonan Racing.  Noonan specializes in setting up karts for smaller drivers.  Everything on the kart is set to maximize chassis flex.  The rear of the Top Kart Cadet is adjustable for ride height and track width.

A Noonan racing ultralight CNC machined billet sprocket carrier is used to reduce reciprocating weight.  A lightweight brake assembly is also used to cut weight to a minimum.

Noonan racing supplied the carbon chain deflector.  We used a standard DID chain to minimize drag on the engine.  Shielded instead of sealed axle bearings with oil instead of grease are also used to reduce drag.  We use triflow on the chain and bearings for the lowest friction.  This is common practice in kids and cadet classes.  For bodywork we used Password JDM fender washers for a nice touch.