These gain a new, Tier III emissions compliant, 6.7-litre Cummins QSB six-cylinder engine. Retaining a 24-valve cylinder head and a waste-gated turbocharger, the new power plants are fitted with an electronically controlled common-rail fuel-injection system.
This allows injections to be timed to within nanosecond accuracy. Pre-combustion pilot injections before the main fuel delivery result in a much cleaner and quieter burn, says Cummins.
To add to this, the engine auxiliaries’ gear train has been moved to the rear of the stiffened block, which further reduces noise levels. More importantly to the operator, the new fuel set-up is claimed to offer between 12.5% and 16% more low-end torque. JCB says this gives the tractor greater lugging ability and will mean fewer gear changes.
But the company hasn’t gone all out with the Fastrac revamp. The transmission remains the same as previous models – still lacking a clutchless direction shuttle, the same three-range, six-speed manual box with three splits is used.
Styling is brought more into line with the range-topping 8250 Fastrac. Extra vents in the bonnet provide additional airflow for the new high-capacity cooling package and full-length glass cab doors improve visibility.
Tier III legislation governing the noise and exhaust emissions of engines became effective for tractors from 174hp-603hp from January this year. New machines between 100hp and 174hp will have to comply from January 2007 onwards. The next round – Tier IV – will be introduced in 2011.