What's the max speed x150 5.0 N / A? The catalog is 250 km / h, but mine reached 263 and kept walking but I gave up

 

The official # is based on ecu limited speed when in 6th gear... but apparently if you keep it in 5th the limiter is rev based, not speed. Apparently the front end starts to lift at higher speeds... and if you look at the XKR models with higher limits, there are aero changes to help downforce.

 

I'm wondering out loud here, since the xkr have air vents in the hood is it reasonable to consider that the air that is forced into the engine compartment at speed could contribute to front end lift and that the vents not only help dissipate engine heat but also reduce the air pressure and lift?

wj

 

Actually, Jaguar have done an excellent job of engineering airflow. The bonnet vents along with ducts and under-tray provide a good balance of air flow and aerodynamics. The R-S GT version had larger bonnet venting, from the R version and then further up towards the windscreen, provider improved airflow and aero (along with canards and front splitter). Whilst the X150's capable of higher speed, it's mainly for show as it's original intent's still a GT tourer and not a true sports.