[Tonyt3]

After market BHP quotes are a minefield of inaccurate information. The only accurate bhp quote can be at the engine, which is what manufacturers quote. Any quote from a dyno is measured at the wheels and then converted using 'scientific algorithms' (someone sticks a finger in the air) by the tuning company.

What must also be remembered is that claims of BHP increase from after market products are NOT cumalative. For instance, 'Airbox + 10bhp, catback + 8bhp' does not mean an 18bhp increase.

If BMW quote 200bhp, they mean at the engine. If another tuning company quote 250bhp, they mean at the engine, but measured at the wheels and then converted using some kind of allowance for drive train loss etc. Not overly accurate.

Big pinches of salt.

 

[Tonyt3]

Not all aftermarket companies do this, BBR for example did their work on an engine dyno (they had an Aston Martin engine on there when I went down), and I'm fairly sure Hartge would originally have done this, to name a couple.

It's a confusing situation for sure.

There is obviously some level of differing professionalism here then, which should probably be recognised.

Certainly, you would think that there should be a 'British standards' type approach to these claims, something you could quote and refer to.

Interesting how JCW/BMW quote BHP, rather than PS now.... I thought it was all going 'the other way'....