Words by Brad Littlefield
Whether you gravitate towards the ground-pounding “Big Show” entries driven by John Force or Ron Capps on the NHRA tour or you are more interested in seeing the 1970s-influenced nitro coupes wheeled by Jason Rupert or Kris Krabill from the wooden bleachers in Bakersfield, odds are that most people browsing this web site agree that Funny Cars are cool. For comparison’s sake, we are going to break down what goes into making each type of flip-top-bodied, fire-breathing monster down the drag strip.
Within the span of one week, the quickest passes were recorded in each configuration this past August. Rupert went 5.522 seconds at 262.54 mph in the quarter-mile at the IHRA finale at U.S. 131 Motorsports Park. One week later, Matt Hagan ran 3.822 at 333.82 mph to the 1,000-foot distance at Brainerd International Raceway. (The quickest Nostalgia Funny Car runs reach the 1,000-foot timer in the high-4.6-second range.) What allows each competitor to achieve those speeds? What restricts them from going quicker? Let’s take a look.
The biggest limiting factor in the Nostalgia Funny Car class is the fuel pump. The NHRA Hot Rod Heritage Series allows approved pumps (Enderle 1100, Hilborn-4, Settles Nostalgia Gerotor, Waterman 3209500N, Rage Racing 1400N, and Aeromotive 11936) which are flowed at an approved testing facility (K.J. Crawford) and are lead-sealed when they are certified to flow a maximum of 21 gallons per minute at 8,000 rpm engine speed (4,000 rpm pump speed). Other series take the same spec-pump concept but enforce the rules by measuring the dimensions of the pump rather than putting the pumps on a flow bench.
Entries on the NHRA Mello Yello Drag Racing Series do not have limitations on fuel pump volume. They run dual fuel pumps that churn out upwards of 110-120 gpm to fill the combustion chambers with a big gulp of CH3NO2 that, when pressurized with 65-70 pounds of boost, is in near-solid form when it is compressed.
Competitors in each style of Funny Car can run a maximum cubic-inch displacement of 500. Top Fuel and Funny Car racers all have 4.1875” bore and 4.5000” stroke with blocks made by AJPE, BAE, or JFR. There is a wider variety of engines used in the vintage Funny Car ranks than the aftermarket 426 Hemi design including Big Block Chevy, Arias, and 392 Hemi combinations, and some teams opt for different displacements or bore-stroke combinations.
The motors are topped by Roots-type superchargers. In Nostalgia land, power is added by a 6-71 blower with a maximum overdrive of 18.99. Their modern counterparts are allowed longer 14-71 blowers with the same “standard” amount of twist. The intake manifolds are also different with the Professional teams preferring setback manifolds that position the front outlet of the blower in the center of the intake, a concept popularized by crew chief Austin Coil in the mid-1990s. Nostalgia teams, however, are prohibited from having the back of their blowers extending past the motor plate.
Modern Funny Cars are allowed to run dual MSD Pro Mag 44-amp magnetos compared to the points magnetos and single coil that are allotted in Nostalgia Funny Car racing. Furthermore, crew chiefs on the Professional tour are allowed electronic ignition control. They can draw and adjust timing maps to manipulate the Goodyear slicks at different points of a run, restricting horsepower at critical moments to keep the rubber from breaking loose from the racing surface. In nostalgia racing, any changes to the timing during a run must be a function of the driver without the use of timers; a pneumatic device can turn the mag when the driver pushes an air button.
Teams in the NHRA Mello Yello Drag Racing Series, by rule, are only allowed to run a maximum of 90-percent nitromethane (the rest is cut with methanol) with fuel that is purchased from a single vendor. There is no restriction to the percentage of nitromethane that a team in the Nostalgia ranks can run. With the restrictions to the fuel pump, teams generally try to maximize the amount of fuel volume they can get. A maximum of 24 fuel nozzles allotted further simplifies the fuel system on a Nostalgia Funny Car. Most racers within the category use nitro percentage as a tuning modifier along with ignition timing, blower overdrive, and compression.
Modern Funny Cars use direct drive and a rear end with a fixed 3.20:1 gear ratio. Nostalgia Funny Cars use planetary two-speed transmissions, and their options are open from there in terms of gear ratio for both the third member (3.90:1 minimum, by rule) and the gearbox. NHRA teams use a clutch combination with six discs and five floaters or five discs and four floaters while Nostalgia entries have three discs and two floaters. Most Nostalgia teams have glide-style clutches like their modern counterparts, though some opt to use a pedal-style clutch that is popular in Top Alcohol Funny Car.
NHRA teams employ a clutch canon that is programmed to restrict the amount the clutch levers can move at different points in the run. Clutch management systems are prohibited in the Nostalgia ranks.
Car and body
The greatest advantage a Nostalgia Funny Car has over an NHRA Funny Car is in weight. The minimum weight for a Nostalgia Funny Car, depending on the series, is between 2,250 and 2,300 pounds, while an NHRA Funny Car must weigh at least 2,550 pounds.
The 300-plus-mph entries certainly enjoy a greater aerodynamic advantage than their vintage counterparts. Though rules are implemented to maintain similarities in the Nostalgia ranks to their Funny Car predecessors from the 1960s and 1970s, improvements to the parts on the manufacturing end from design to the quality of the material mean that the most nostalgic quality to a Nostalgia Funny Car often lies in the body style.
While a “Big Show” event may feature Chargers, Camaros, Camrys, and Mustangs that bear little resemblance to the showroom automobiles they are meant to emulate and have narrowed cockpits more likened to an F-16 jet fighter, the staging lanes at a Nostalgia Funny Car race features cars with a variety of different body styles. Mind you, the reason they are called “Funny Cars” to begin with dates back to their A/Factory Experimental origins in which the flip-top bodies were stretched and modified from their stock designs. However, the intent in the rules package is to sway the category from the homogeny of the modern classes and capture the respective imaginations of fans and racers alike.