The power of two – “Base” Versus “Triple-4”

There is so much more to a good engine than simply numbers. True car enthusiasts know that focusing on capacity, obsessing over an overall power output figure, or bragging about torque, tells only half the story. A truly excellent engine must first and foremost have spirit and feel, delivering power with finesse across the rev range, proving memorable for its distinctive characteristics rather than its headline numbers.

Following years of development, the KALMAR 7-97 range enjoys the choice of not one such engine, but two. Both engine options share the same goal – to go above and beyond. The first is what we call the “Base” specification unit (though it is far from ordinary), the second is our epic ‘Triple-4’. While the KALMAR 7-97 is not a racing car, the engineering philosophy behind this ultimate bespoke build air-cooled 911 does take inspiration from the track. Classic design meets a modern feel throughout, and that extends to engine dynamics in both instances here.

From the outset KALMAR’s targets were clear. Its engines must start, run and idle smoothly. Catalytic converters and silencers required to satisfy homologation tests should promote a modern-style of power delivery, while reduced resonance at cruising speed was also the order of the day. Easy maintenance was another aim, especially for the “Base”, while the Triple-4 should rev higher and provide crisper throttle response over its alternative. With the help of KALMAR’s experienced engine partner, Lorrtec, these stringent targets were set and well and truly met.

There’s nothing second best about the 3.8-litre Base engine, its development required a lot of hard work and know-how! We balance and retain the original crankshaft. In go new con rods and bespoke pistons, joined by completely reworked cylinder heads. The fitment of hydraulic lifters ensures a quiet, low maintenance valvetrain.

Induction is taken care of by an in-house developed air filter housing. This channels air to a 997 generation GT3 single throttle body and KALMAR intake manifold. The latter boasting highly sophisticated thermal insulation and aluminium runners. Engine management is handled by a Motec M130 unit, inputs via a drive-by-wire system with the option of different driving modes, plus traction control.

Expelling spent gasses is a handmade true equal length exhaust system. The air-based heating system is deleted, its function replaced by a new oil to water heat exchanger. Oil pressure is maintained by a large capacity 911 GT3 system. An enlarged oil-cooler with F1-style air ducting coupled with the original fan, ensure it stays cool when you push on. We are not about the numbers but if you are wondering, it’s generating 355 hp and 409 Nm of torque. It feels lively, and is a highly tractable engine that responds instantly to your inputs.

The KALMAR Triple-4 is our halo engine and no stone has been left unturned in its development. As its name suggests, the specification features the triple; 4-litres, 400 hp and 400 Nm. It shares nothing but its crank case and oil pump with the Base engine – the rest is unique.

Just where do we start with this one? The engine compartment is dominated by custom air scoops that feed air into the large snorkel and filter housing. The bespoke plenum and individual throttle feed air into the state of the art cylinder heads with solid mechanical lifters for the valves. Next come super lightweight pistons. A new 997 4.0-litre crankshaft offers a little more stroke on each cycle.

A large diameter exhaust system maintains the free-flowing ethos. Throttle response is second to none aided by a lightweight, single mass flywheel. Cooling is handled by an enhanced turbo fan and a dual oil-cooler set up. The engine management comes courtesy of a Motec M150 control box. We’ve developed a lightning fast drive-by-wire system with optional traction control and selectable drive modes to put a smile on your face with every press of the pedal. Want to be the nerd who can identify the Triple-4 immediately? Lift the decklid and look for the high-gloss piano black engine ancillaries or just see if the owner has a smile on her or his face. It all amounts to a remarkable and drivable engine, one with 401 hp and 431 Nm, ensuring it is simply on the next level in every way!

Of course, you’ll forgive us for keeping the internal design intricacies for both engines to ourselves, but we hope you get the picture…