[Seadog]

Originally Posted by 41Sqn_Banks

This is not correct. In the unmodified condition there was no restriction of the maximum boost when the boost control cut-out was used, thus the boost could be increased to about +17 lbs at full throttle at sea level.

See:
http://forum.1cpublishing.eu/attachm...1&d=1337242614
http://www.spitfireperformance.com/spit1-12lbs.jpg

Thus the boost override could not be used in the unmodded condition since it would cause almost instant engine destruction, which is a very bad thing for pilots to do during combat...It was only after 100 octane was used that the boost override became a useful adjunct to increase low altitude performance.