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 XD3 V8 engine The original engine was a Meugen Honda V10, but the engines and components are now obsolete, so the customer approached us to see what we could offer on a limited budget. |
Protechs XD3 is very popular with driving school owners due to the reliability and forgiving nature of the engine. Protech Engines can also be found in hillclimb cars in the UK and Europe. |
Component Manufacture Cosworth YB 2WD and 4WD high pressure oil pumps, RS500 throttle bodies, WRC inlet plenums, 8 injector inlet manifolds, Remanufacture of Bosch 803 “Green” fuel injectors. |
Protech Motorsport XD3
The Cosworth XD was introduced in 1996 and ran through 1999. It was replaced by the XF (and in 2003 XF-E). It is a 2.65 litre V8 running on methanol and producing approximately 850 horsepower at 14,700 RPM and 40" of boost. For reference, boost is measured in inches of mercury absolute pressure. Standard atmospheric pressure is 30" (14.7 psi) and thus 40" equates to 19.6 psi or 4.9 psi of boost over ambient pressure. Although they were run to 14,700 RPM in their day, we limit them to 13,500 RPM to reduce stress on the rotating assembly, reduce damaging vibration and generally increase service life. Note: When looking at early XD cars, be aware that the first XD engines used dual round exhaust ports as opposed to the "squished oval” used in the later specification engines.
Performance: The XD produced in excess of 302 horsepower per litre of displacement. For comparison, a very well built normally aspirated Hayabusa engine with nearly the same displacement per cylinder produces 188 horsepower per litre on pump fuel while its predecessor the XB produced 283. Increases in horsepower over the XB are due in great part to improved head design, reduced internal friction and higher operating speeds. A quick comparison of the XB exhaust port to that of the XD exhaust shows a move towards reduced cross section to improve gas velocity. In addition, there was a dramatic improvement in the short side radius on both the intake and exhaust ports.
Construction: The XD, like the XB before and the XF after, is based on a wet lined alloy block with nicasil aluminum liners. Unlike the XB, the four overhead cams are driven from the rear of the engine by a spur gear set which drives two chains, one to each head. The move from driving the cams from the front to the rear of the engine was done to reduce torsional vibration input to the cam drive.
Conversion: Our engine conversions take the standard engine and remove the turbocharger and all related ancillaries. We alter the compression ratio dependant on spec between 12:1 to 13:1. Add custom fuel rails, different fuel injectors, modified plenum or bespoke airbox. Motec or Pectel (Cosworth) are our ECU’s of choice, although EFI and DTA are also candidates. Custom crankshaft with a 56.3mm stroke, and bespoke connecting rods with our own designed rod bolts increase capacity to 3 litre. Our development engine made 618.8bhp @ 12,700 rpm. We are currently working on new camshafts to our own design to move the power band down the rev range and increase mid range torque.
Current Projects: For a customer racing in Euroboss we have developed a 3.2 litre version of the XD engine. With further modifications and the additional increase in capacity, the engine made 680bhp @ 12,500 rpm. Due to the nature of the cams, the engine was still making power, so we will manufacture new camshafts and longer intake trumpets to shift the power band lower down the rev range and increase mid range torque.
Future Projects.
Increasingly we are being asked if we can produce an “Endurance” spec XD engine. The answer is YES, in any configuration of engine capacity upto 3.2 litre. With redesigned pistons, bespoke camshafts, valve springs and valves. Modified inlet system and a reduced maximum engine speed of 10,500 rpm. We can achieve a lifetime between rebuilds of 3,500 MILES or 5,600KM !! This engine specification is ideal for endurance racing or school cars.
Bespoke engine builds.
We can tailor every engine to suit your needs. For example, a hillclimb or sprint engine will need an even spread of torque at relatively low engine speeds. Therefore we fit new camshafts to our own design. This reduces the power band from circa 9000 rpm to circa 6000 rpm. Maximum engine speed remains at 13,000 but mid range torque is vastly improved.
