Reading this thread almost made me vomit, and my stomake is quite gutsie...
The pure amount of generalisation, pessimism and cynnicim is alone a big reason to kill this thread but on the other hand the amount of knowledge some people showed in a fashionable and polite way almost slid the scale to 0.
Don't you think it's wrong to go the same way every time someone is trying to make a point but makes the big mistake of taking "his" knowledge and putting it up against figures?
About free-flow air filters never giving more power, rolling roads are crap, dynos don't work, this and that and so on. I don't now what the word is for this type of communicating so unnecessary repeating will do for now.
A properly cordoned off free-flow air filter will give extra power to some cars.
A, according to engine displacement and configuration correct, free-flow exhaust will give extra power to many but not all cars.
Rolling road shows what power you have at the wheels and that is the only, to me, figure that matters, why quote the engine power if the WBHP is 50 BHP lower?
A dyno is to me the type of device you bolt to the wheel hubs whereas a rolling road is no more than 2/4 rolling tubes, correct? And this gives a more correct reading bla bla bla.
And saying that all commercial dynos are over-reading, isn't that a bit of generalization? Since you(tristancliffe) haven't tested all the cars in the world with all the different dynos available(no time in hell), probably not even the most popular in the UK with the standard dynos(possible but come on?) you can't say for sure that it's always in their interest to make them over-read.
Atleast here in Sweden we want the real power, to a point, getting extra big figures at one dyno when the manufacturer of the after-market parts quoted a 5% (example) lower BHP upgrade you know somethings wrong, you don't get positively surprised.
I'm just mad at everyone always giving these statements, hardly arguments, and getting away with it.
Don't bother to correct any misspells unless they alter the meaning of the sentence, it's 4:40 am and I still spell okay compared to some others whom have english as their native language.