It's not hard to understand really, underbonnet temps are rarely the same as the external environment temps, you do after all have an engine running at over 90 degree water temps, an exhaust at 8-900 degrees, charge temps of 30-40 degrees etc etc.
A difference of 10-15 degrees is perfectly normal if you have ever monitored these temps in the manner we do.
Yes the difference between the two will affect the figures, however the most interesting thing of note is the Correction Factor listed on the top of the dyno in the BAR SCREEN (Doesn't get spoken about enough and I may start adding them to the final graphs), which on this day was around 0.96 or 4% power being removed by the dynos correction factor.

 

I think the main reason correction factors dont get spoken about very often martyn is because they are not shown on the actual dyno printout only on the dyno monitor screen.Because 99% of people tend to focus on the end bhp/ftlbs results the actual way the figures were achieved are overlooked and pushed into the background,the last two tweeks on my car were both achieved with dyno corrected losses of 4.8% and 4% on the last one.maybe an in depth explination of how and why the dyno corrects the figures plus or minus is in order as most of us me included havnt got a clue why this happens and what it actually means to the man on the street,in layman`s terms please martyn if you would.

 

cheers martyn for the reply makes more sense and +1 for the above please

 

http://wahiduddin.net/calc/cf.htm

 

http://www.dynamometer-info.co.uk/au...on-factors.htm

 

Thanks