Cummins 250 turbo for uprated torque
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:UMMINS has launched a .urbocharged version of its VHC-250 engine which, the ;ompany claims, will give a 10 rer cent improvement in fuel ;conomy over its naturally tspirated counter-part.
With a gross rating of .80kW (240bhp) at 1900rpm, he new engine has the same tominal output as the NHC rersion, but its torque inTeases to 1085Nm (830 lbft).
Much of the turbocharger tackage is derived from the nore powerful E290 engine, ncluding the Holset HC3 tlower, exhaust manifolds and dr crossover duct. It retains he standard 51mm (2in) liameter camshaft of the ■ THC-250 rather than the "Big 7,am" of the E-Series engines.
The 250-Turbo has a lower ;ovemed speed (1900 against 1100rpm) and a torque rise of 10 per cent — twice that of the VHC-250. Turbocharger and )y-pass filter increase engine weight by around 18kg (401b).
Although the new engine is in addition to the Cummins [4-litre (854cuin) range, every )ne of its individual corntonents is already used in .xisting power units. From the ■ IRC cone the cylinder block, ylinder heads, pistons, valves, water pump and oil cooler, while the fully hardened timing gears, fillet-hardened crankshaft journals and improved connecting rod lubrication come from the ESeries engines.
The camshaft of the 250Turbo differs from the NHC 250 component only in the timing disposition of the injector cam lobes.
Although the power output has not been altered over the NHC-250, the improved torque figures makes it directly competitive with the Rolls-Royce 265L at around 1,020/1,090Nm (750/800 lb ft).