Volvo T5 250bhp from 2.3 @ 100 bhp/litre, 2.3=230bhp, 250 in not far above
Megane 225, 225 hp from 2.0 @ 100 bhp/litre, 2.0=200bhp, 225 is not far above
etc
i agree that that technology is moving on and maybe this estimate is beginning to fail as a rule, after all it's a while since it was told to me!!! But in its defence it still not bad.
With lots of re-enforcement and expensive parts, it is true that you can get lots more power from a 2.0, but the cost is so high, something like a rover/(Buick) V8 would provide similair power with little modification and be under less load.
Or in the case of the new Dodge Viper you could have a huge 8 liter engine and get only 400bhp from if???!!!!????
As a max for production and reliability, you should use the max
> 100bhp per litre rule, but actual figure are usually less than this.
Actual figures are usually slightly more than this.
Volvo T5, 250bhp from 2.3
Megane 225, 225bhp from 2.0
Mazda 6 MPS, 260bhp from 2.3
Vauxhall VX220/AstraVXR, 220bhp-230bhp from 2.0
Any number of VAG cars, 225bhp from 1.8
etc. etc.
A mere 200bhp from a high-pressure 2.0 Turbo these days, is sub-par - hell there are plenty of normally aspirated engines that can almost match that figure (Honda VTec, Clio 182, 206 GTi180, Toyota VVT, etc. etc.)