The Chrysler New Hemi : a cost-efficient engine The new Hemi associates well known, proven and cost effective concepts with modern technology. In the spring of 2005, a 6.1-liter / 425 hp version will be available on the Chrysler 300C SRT-8.
The advantage of overhead camshafts due to reduced valvetrain inertia and deflection emerges at high rpm. But soaring revs are of no use nowadays on a street engine, so that a single camshaft-in-block is absolutely adequate, as well as two valves only per cylinder. The hemispherical combustion chamber favorable surface to volume ratio and breathing ability can be exploited without overhead camshafts cost and complexity, making manufacture, servicing and repairs easier and less costly.
Apart of aircraft engines where dual ignition is mandatory for safety reasons, twin spark ignition was largely used on racing engines of the fifties and sixties, especially those of Maserati and Porsche. Alfa-Romeo also fitted it to some production engines such as the GTA and 2-liter "Twin Spark". It allows a faster burn rate, particularly on over-square engines and leaves more space for large valves than a centrally located single spark plug. Furthermore, with a domed piston and a single plug, flame front shrouding may lower the burn rates. This problem is avoided with dual spark ignition.
The New Hemi features both twin spark ignition and single camshaft. Its latest variant develops as much as 425 hp, right out of the factory.
Contents :
Page 1 : Introduction,
Page 2 : Early Hemis,
Page 3 : The Hemi 426,
Page 4 : The New Hemi,
Page 5 : Bottom end,
Page 6 : Heads,
Page 7 : Valvetrain (1/2),
Page 8 : Valvetrain (2/2),
Page 9 : Working on 8 or 4 cylinders: cylinders deactivation,
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With some telephones connected to standards, it is sometimes necessary to compose the 61 in the 1st seconds of connection to have access to this number.
Easy way: you can call several times the AlloPass number to obtain several access codes.
