Boost conversion with sea level adjustments,

I have been looking around the net to convert Bar to PSI, as i have a bar boost gauge, i know the conversion rate but found this little site which takes into account sea level as well, for boost conversions, and if you don't know the sea level where you are it can be found here, Gary,

Thanks for that, does anyone know what boost a V70R with 18T normally runs at!

On an NA engine, atmospheric pressure affects performance in a linear manner - i.e. 1% drop in pressure gives 1% drop in performance etc. Its more complicated on a turbo as the engine will typically run at constant manifold pressure, i.e. as atmo press drops boost increases to compensate so performance will generally stay the same. However, when this happens the the turbo speed will increase. As atmo press decreases further at high altitudes the turbo speed will reach critcal levels and the engine management system will start to reduce the boost to stop the turbo exploding.

i was actually thinking along the lines of top speed & power needed to reach top speed with pressure changes... i know with my sport(cycling) air pressure can make a huge difference in sustainable top speeds & its as far as i know the reason why many sports will not let you break world records at altitude but obviously these are very low power sports how much differnce would high air pressure to a car the shape of a brick with around 240bhp @ its top end?