All-motor
How it works: No forced induction, no spray. The all-motor (also known as naturally-aspirated) method of engine tuning means optimizing all the components already found in the engine. Using the engine-as-air-pump analogy, all-motor tuners concentrate on improving volumetric efficiency - helping the engine to breathe - at normal atmospheric pressures through intake, cylinder head, camshaft, valvetrain and exhaust modifications. Camshafts are typically the biggest contributors to power gains, followed by valvetrain and head work.
All-motor tuners also earn power by increasing engine displacement with stroker kits, cylinder overboring or assembling hybrid "Frankenstein" engines, which is created by pairing a larger-displacement engine block with a cylinder head not offered from the factory. One of the hottest hybrids in the all-motor community right now is the Honda K24/K20, which combines a 2.4L block from a K24 engine found in Accords or CR-Vs with the K20A2 head, the RSX Type S head with VTEC on both the intake and exhaust cams. Combining the 2.4L's torque with the flow characteristics of a Type S head is a potent mix. When we visited Skunk2 Racing, there was a K24/K20-powered street-driven '88 Civic being prepped for a dyno pull that everyone expected would be near, or exceed, the 300-hp level.
One of the biggest knocks against the all-motor tuning route is its cost. The parts themselves are expensive, plus you have to factor in the labor costs for installation as well as any custom work, like head porting. Even the all-motor tuners admit theirs is far from a bang-for-the-buck solution to add power. However, if you're looking for moderate gains - in the neighborhood of 100 hp or so - the same $4,000 to $5,000 you'd spend on a turbo kit will get you there (or close) the all-motor way with a new cam and valvetrain, intake, throttle body, ECU programming, headers and exhaust.
Where it works best:
Street, drag racing, road course
Bang for the Buck rating:
"Maybe a 4. The money becomes more of an issue as you step up."
- Charles Madrid, Skunk2 Racing (see above)
Dope:
"With an all-motor car, the power curve is real broad and flat. Plus, the throttle response is really sharp, and really crisp. The power band has a different feel than a turbo car or a nitrous car. It's just a different beast, and the guys who go all-motor tend to like that beast."
- Tony Shagday, Skunk2 Racing
"I like the way it drives, the way it sounds. The throttle response is razor sharp. In a race, if you have two cars, one turbocharged and the other naturally-aspirated, the latter car could go just as fast, if not faster, with 20 percent less power. Once you come around the corner and put your foot down, the power's ready."
- Doug Macmillin, Hondata
"With the B-series engines, a GSR motor or a Type R motor, we know where our limit's at - how much power this motor can make. Now, the K keeps making power. That motor has so much potential. When we thought we were near the limit, boom, someone jumps it up. It just keeps going faster and faster."
- Charles Madrid, Skunk2 Racing
"The K motor, now that's insane. There's almost a cookie-cutter combo where people are slapping together the K24 bottom end with a K20 head, a 12.5:1 piston and a rod, and they'll put in some company's Stage 3 cam, and you can make 300 to the wheels, daily-driven and all-motor, that's completely reliable. Take those cars to the track and they can run low 11s on slicks."
- Tony Shagday, Skunk2 Racing
Nope:
"I love an all-motor engine that makes big power, but I can tell you from experience that an all-motor engine that makes as much power as a nitrous engine will cost twice as much as a nitrous engine."
- Matt Held, Nitrous Oxide Systems
"If I had a 200hp Honda and I wanted 280, to 290 hp, I might spend, if I wanted to go all-out with a naturally- aspirated engine, $12,000 to $15,000 to build the engine - by sleeving the block, boring and stroking, with bigger valves, that's everything you can do. And I may get 80 to 100 hp out of it. Yet you could do that for $5,000 with a turbo or supercharger kit."
- Doug Macmillin, Hondata
"The naturally-aspirated guys are gluttons for punishment. No offense. I love Pro Stock - for the racing aspect. But to spend $100,000 to get 2 more horsepower baffles me. I don't like hitting myself on the head with a hammer and hoping for a different result. With $4,000 to $5,000, plus a couple of six-packs and wrenches over a weekend, you can double your horsepower with a turbo."
- Tyler Tanaka, Turbonetics
"Stroker assembly and cam setup may sing between 7,000 and 9,000 rpm, but from stoplight to stoplight you are left with a car that refuses to idle south of 1,000. In addition, pulling the motor and installing all of these internals is no cheap proposition. Plus, there's down time for the building, installation and tuning can run into months and even years, all at $95 per hour, plus the cost of your Ford Focus rental to travel to and from work. "When my car comes out of the shop it's gonna scream" is the battle cry of those brave enough to venture down this path."
- Michael Ullrich, Stillen