Honda Challenge 2 is the most popular class in Honda Challenge. It offers a tight rule structure for close competition among a variety of donor cars from which to choose. Honda Challenge 2 consists of “Limited Preparation” and “Restricted Preparation” vehicles, which are typically later model Hondas and Acuras. There is a lot of variety in the horsepower and weight of the different cars eligible for H2, so you have a lot of freedom to build the kind of car that either you prefer or the kind of car that excels on tracks in your area. Check out this month’s “Class Syllabus” to see if H2 is right for you.

Class Description

“The NASA Honda Challenge Series presented by Honda Performance Development was created to meet the needs of Honda/Acura owners looking for a series specifically tailored to accommodate Honda and Acura vehicles that are modified to a degree, which might be found illegal in other racing series, yet provide a set of rules that would still accommodate existing Honda racecars and provide a “showcase” to unify the field. The following rules are not guidelines for this class but an actual listing of the allowed and the required modifications. These rules and addendums specify the only modifications allowed. If these rules do not expressly state a modification is allowed, it is prohibited. No item, which is allowed, shall also perform a prohibited function.”


Eligible Makes and Models

In “Limited Preparation” vehicles, all Honda and Acura cars with the following engines: D15, D16, B16, B16 CTR, B17, B18A, B18B, B18C1, B18C5, B20B, B20B1, B20Z, H22, H23 (non VTEC), F20b, F22, F23, K20a3, K24a1, K24a4. Parts requirements, maximum compression ratios and vehicle weights apply. In “Restricted Preparation” vehicles, all Acura RSX, 2006-2012 Honda Civic, 2004-2008 Acura TSX, 2015 and up Acura TLX with 8DCT transmission, and 2013 and up Acura ILX with six-speed transmission. In “Factory Preparation” vehicles, all 2000-2009 Honda S2000.

Donor Prices and Availability

Depending on the model you choose as a donor, prices can range from a $500 1988 CRX to a $30,000 2015 Acura TLX.

Engine Specs


140 to 220 depending on model

Compression ratio

9.8:1 to 12.5:1 depending on model



1,900 to 2,900 pounds depending on model



Fuel Required

Any grade of unleaded or leaded fuel obtained from a commercial fuel station that is open to the general public. Also, any grade of unleaded or leaded fuel is allowed that is obtained from the fuel vendor at race track where you are competing. You may not obtain fuel from drums or cans unless that is the fuel vendor’s customary method of dispensing fuel. No more than 20 percent ethanol.

Average Cost to Build Car

$10,000 or less for home builds, including donor, or have a car built for around $15,000, including donor.

Average Cost to Buy Built Car

$10,000 or less to around $20,000 for a front-running car

Typical Modifications

H2 is a suspension-focused class, so you need a good setup and excellent handling to be competitive. A limited-slip differential, whether it’s a Torsen or a metal-plate-style unit also is a must. Any battery permitted, replacement mirrors, wiring harness removal, 3-inch brake ducting holes in front fascia, port-matched intake and cylinder head, half-point compression increase, spherical bearings on suspension, exhaust header, underdrive pulleys, adjustable fuel pressure regulators.



Cost Analysis

Average cost to run a weekend From $750 to $1,000 including fuel and entry fees.

Consumables Prices

Tires, size, brand and prices Toyo Proxes RR, max width of 235 mm From $175 for a 205-50-15 to $222 for a 235-40-17 Maximum wheel width is 7 inches

Brakes, brands and prices

Big brake kits allowed, driver preference on pads, Hawk, Cobalt, Carbotech, etc. $175 to $200 for fronts, which last about three events or more depending on car weight $125 to $150 rears, which last a full season

Available contingencies

Honda Performance Development, Toyo Tires, Hawk Performance, Hasport Engine Mounts, Spec Clutches, Winding Road Racing, AiM Sports, AST Suspension, Neo Motorsport, Frozen Rotors

Factory Participation

Yes. To qualify for any HPD contingency awards, each Honda Challenge competitor is required to be a member of the Honda Racing Line program. As a member, you will be eligible for NASA Championship contingency and have direct connection to HPD with the ability to purchase Honda OE parts at discounted rates with overnight, door-to- door delivery. In addition, Honda Racing Line members will also have the ability to explore Honda’s internet-based library, of electronic service publications. In Service Express, members have access to the same service information available to Honda and Acura dealers: service manuals, service bulletins, newsletters, wiring diagrams, and parts catalogs in one convenient place.



Affordable and reliable, even junkyard engines are competitive in Honda Challenge 2, great availability of parts, lots of aftermarket and factory support, any chassis is a potential racecar, virtually unlimited choices in engine swaps are permitted.


Body parts for older CRXs are getting more difficult to find

Rulebook Highlights

  • Engines may be balanced and/or blueprinted. Lightening of moving parts beyond what is necessary to balance is prohibited. Engine bearings may be replaced with aftermarket replacements and engine clearances (piston to wall, valve lash, etc) are unrestricted and are considered blueprinting.
  • Cylinder head intake ports, exhaust ports, and intake manifold may be port matched but cannot be machined beyond one (1) inch into the head or intake.
  • Compression may be increased one half (.5) a point greater than OEM number.
  • Timing gears must remain OEM. Cars equipped from the factory with plastic timing gears may use replacement metal gears so long as cam timing remains stock. OEM crank timing gear may be adjusted with an offset key back to stock position. Offset keys may be used with cam gears on SOHC engines only.
  • Polyurethane or hard rubber motor mounts and/or inserts may be used.
  • The flywheel may be replaced with others of unrestricted origin, provided it is the same diameter as stock and would accommodate a stock clutch and pressure plate.The clutch and pressure plate may be replaced with others of unrestricted origin so long as the pressure plate would bolt to an unmodified OEM flywheel.
  • Suspension bushings of unrestricted origin are allowed.
  • Camber adjustment devices (plates/shims/eccentric, etc.) are unrestricted but are limited to one per wheel. Front and rear upper control arms may be modified or replaced with items that allow camber and/or caster adjustment only.
  • All suspension parts must retain their original attachment points at the chassis, and the suspension must maintain its original design and function.
  • Remote reservoir shocks are permitted with a 25-pound weight penalty. Note: any shock with an external reservoir is considered “remote.” If shocks with both high and low speed compression or high and low speed rebound adjustability are utilized, the weight penalty will increase to 75 pounds during competition.


What Racers Say

Sam Myers, National Director, Honda Challenge, NASA Great Lakes

NASA Midwest/Great Lakes @ Mid-Ohio and Awards Banquet

“The great thing about Honda Challenge is for the most part, if the car is built right and maintained right and you keep your nose clean on track, you’re going check your fluids before every session, set your tire pressures and torque your wheels, you’re going to put gas in the car and you’re going to go race and you’re going to repeat that all weekend long. You shouldn’t have to fix anything else. Most of the cars run on 93-octane pump gas, so it’s very affordable and, for the most part, very reliable.”

Jeremy Croiset, NASA SoCal


“What drew me to the class was an inexpensive racecar that had the potential to swap different Honda engines into it that would drastically alter the performance capabilities of the car. They’re relatively inexpensive, and Honda engines are plentiful, and we have a lot of options available to us in Honda Challenge 2.”

Robert Casella, NASA Northeast


“My parents bought two Acura Integra Type R’s, old Speedvision Challenge cars, and that’s what I started in. I guess my father set us all up in those cars, but I stuck with the class because the Honda Challenge group in the Northeast is like a big family. Everybody knows each other. We lend each other a hand, even at a national level. I think the family aspect from the Northeast is why we’re still in Honda Challenge. The cars are really easy to work on. Parts are easy to find. I grew up working on them for my brother before I could even drive, and that’s basically the only car I know inside and out, the Acura Integra Type R. Mostly, everyone’s car is exactly the same, so if anyone needs a hand, you can go and work on somebody else’s car, too. They’re front-wheel drive, so the whole geometry aspect of it is ‘what the heck is going on’ compared to a rear-wheel drive cars, but they’re fun to drive.”

Lapping Videos

Images courtesy of Brett Becker, and Tom Hitzeman/F-51 GT Photography