performance upgrades 40.l

[cljxc50]

Hi all, has anyone made any performance upgrades on their 40.l xjs and do they know any companys that can help (chip.induction,exhaust ?) any information would be great,thanks....

[ptjs1]

Don't know if yours is an AJ6 or AJ16 engine. However, general consensus seems to be that 4.0 litre airflow meters are pretty good. If you talk to AJ6 engineering, they would probably suggest the following:

Revised induction manifold to breathe better
Slightly increased size throttle body
Standard ECU - No replacement chips
Straight through pipes to replace centre exhaust boxes

This should give you about 30 bhp+. More importantly, you'll get improved low and mid-range torque.

Give them a ring and see what they say.

Paul