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Old 18th May 2009, 21:50   #60
ROVER 75 2.5 V6 Connoisseur SE Limousine 2004

Join Date: Oct 2006
Location: Welling
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Posted by MacGyver

160 vs 190 - Differences explained

Originally Posted by MacGyver View Post

From the MG Rover Press Site found whilst searching online today.
Two versions of the all-alloy quad-cam KV6 engine are offered in the ZT-T range. For the ZT-T 190 2.5-litre models, several special features have been engineered to achieve the enhanced power output of 190Ps, and increased torque of 245Nm, with reliability and durability. Beginning with the induction system, the air cleaner has an 80mm diameter intake duct in place of a 70mm duct, and a new intake diffuser. This provides a smoother airflow with less than half the usual pressure drop; it has also been tuned for a more sporting induction sound. Internal engine changes include a new inlet cam profile, advancing the inlet valve opening by 4¢ª, and improved porting.

To withstand the higher cylinder pressures, the gudgeon pins have an upgraded material specification similar to that used in the K Series 1.8-litre VVC engine and the big end bearings are also upgraded to AS16 material. For protection at sustained high revs, the oil specification has been raised to ACEA -A3.

A further contribution to the performance boost comes from a new exhaust system, with 60mm diameter pipework in place of 57mm, new low-restriction metal-based starter and main catalysts and a modified rear silencer unit. This silencer has larger-bore internal pipes, twin straight tail pipes and a mechanical valve, which responds to exhaust pressure at around 4500rpm to by-pass the internal baffles.

While still meeting all legal requirements for drive-by noise, the ZT-T 190 and ZT-T+ 190 exhaust system has reduced back pressure and an attractive sporting tone. The 190Ps engine is matched with a lower-geared final drive of 4.4:1 to exploit its free-revving capabilities.

Both the 190Ps and 160Ps engines have specially designed MG throttle cams and engine ECU software to provide the right ¡®sports car¡¯ feeling of responsiveness to the accelerator pedal, with a deliberate reduction of the normal throttle on/off damping. Also common to both ZT-T engines is an enhanced cooling system, with 20% greater cooling intake area, improved-flow radiator and top hose configurations and a new plate-type oil/water oil cooler replacing the oil/air heat exchanger. The Getrag 5-speed gearbox used for ZT-T 160 and ZT-T 190 models has been given distinctively precise MG operating characteristics, with improved detent springs and a shorter gear lever.
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