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Four-Liter Conversion

CMW Racing offers a new four-liter conversion for late model Porsche automobiles powered by the “flat six”. These conversions are available in six different stages.
These engines are normally asperated, not turbo charged!

  • Stage 1 4.0 Liter Kit 388 H.P. $14,895.00 (US)The 11.5 to 1 compression ratio modification boosts power to 388 hp @ 8000 rpm and raises torque up to 301 lbs. ft. @ 5333 rpm. The CMW four-liter Porsche is designed to run on “pump-grade” gasoline. Included in stage one is a new crankshaft, steel connecting rods, 102MM pistons and cylinders, new camshaft and new rod bearings.
  • Stage 2 4.0 Liter Kit 398 H.P. $18,895.00 (US)Stage two includes all stage one modifications plus a port and polish of factory heads.
  • Stage 3 4.0 Liter Kit 418 H.P. $19,995.00 (US)Stage three includes stage two modifications plus modify factory heads with 56MM intake valves, 43MM exhaust valves, and d-port exhaust inserts.
  • Stage 4 4.0 Liter Kit 448 H.P. $22,095.00 (US)Stage four includes all stage one modifications plus CMW d-port billet heads.
  • Stage 5 4.0 Liter Kit 468 H.P. $34,995.00 (US)Stage five includes new crankshaft, steel connecting rods, 102MM pistons and cylinders, new camshaft, new rod bearings, port and polish factory heads and install 56MM intake valves, install 43MM exhaust valves, d-port exhaust inserts, fuel managemant system (MOTEC), TWM manifolds, plumbing, hardware, etc.
  • Stage 6 4.0 Liter Kit up to 500 H.P. $38,995.00 (US)Stage six includes all of the stage five modifications plus CMW d-port billet heads.

“Since we’re seeing environmental forces limiting our freedom to run at very high speeds, I wanted to offer Porsche owners the feeling of world class torque-to-weight ratio in a streetable automobile,” said CMW’s president Bob Cousimano.

CMW Racing’s unique D-port aluminum billet heads feature a smaller, more efficient exhaust port size (patented by Cousimano).

Intake valves are available in sizes ranging from 52mm to 56mm while exhaust valves are only available in 43mm and are made of heat resistent Incennel. Valve springs, drilled “holey” retainers, and guides are specifically designed by CMW (“factory” seals are retained).

Cylinder bore and stroke are 102mm and 82mm respectively. Connecting rods feature a precise width in order to clear the stock oil pump, thus retaining as many factory internal engine components as possible. Wrist pins are specially designed to sustain high torque.

A special billet crankshaft is also used in this conversion. Its’ knife-edged design is center counter weighted and is eight pounds lighter than a factory 3.6 liter crankshaft (less reciprocating mass=higher throttle response). Camshafts feature a moderate profile very close to production specifications in order to satisfy emissions requirements.

Special 11.5 to 1 compression pistons and piston rings with a low drag coefficient complete the four-liter conversion.

A sequential fuel management system, intake manifold, “winged” intake port inserts and even a cylinder bore size of 104mm are being considered as future conversion options for the “flat-six” engine.

See our complete price list!

E-mail us with your questions, encouragement and suggestions for these ideas.

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Santa Fe Springs, Ca 90670
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