Andy Champ wrote:
The Natural Philosopher wrote:

its rare to see more than 70bhp/liter from any normally aspirated road
engine.



Almost any bike.

Or if you want cars - Toyota 3SGE (in the MR2 Mk2 among others), 2
litres, 158BHP from the later UK models, and over 200 if you can get
hold of one of the Japan-only BEAMS engines. Though the last does have
variable valves etc...

Or the BMW 320, 150BHP/ 2 litres from 1991.

Or IIRC the Cavalier GSI, 156 BHP, 2 litres, and that's back a few years.

Thse are pushing 75bhp/liter and are RARE. I did have an astra SRI
wahich was quite a lively injected 1.8 liter engine...otherwise it was
deeply dull.

None exceeds 100bhp/l;iter. You need to be up around 7-8000 RPM AT LEAST
for hose, Bike engines do more than that: Thats how they get those sorts
of power levels.


What a current state of the art F1 engine? 900bhp at 18000 RPM? on 3
liters..Given that they are as torquey as can be made, and run on
special fuel with SOME air boost from te intakes, and tuned exhausts..at
6K RPM you are stuck with about 1bhp per liter absolute MAX.




If you say normally aspirated, *carburettor* engine, then I'll let you
have it.


It's not the carbs that kill you - twin choke webers will do any power
you want: its the valve timing and RPM limit bit. You COULD get about
160bhp out of a race tuned bored out re-headed 1430 mini engine..as long
as you didn't want to use it in traffic and didn't mind the 12mpg
consumption..or the 3000 mile rebuild..


Andy.