exhaust bhp v torque

[mickdale]

if an exhaust has a great spread of power and runs on better but has a lower torque on the dyno is it a better exhaust?

bhp will allow to rev
torque will pull the bike

rev loads on the stand but not go well on the road? - or am i looking into this too much?

[mark]

What engine spec have you got

[mickdale]

got a dyno of 4 exhausts but coz its adobe file i cant upload

one has got great bhp and run on but not great torque

[ForemanBob]

F1 teams use the premise that the more revs they can produce, the more air/fuel mixture they can suck into the engine and bangs they can produce and therefore the more power and speed i.e. A car doing twice the revs can suck in and compress the same capacity of air as a car twice its cc doing half the revs.

Revs can therefore provide you much higher power for the same capacity, but it needs to be high revving to produce the speed.

power = torque X rpm

So since power is the rate of work, it can be increase due to two factors. either by increase in work, or the increase in rate.

basically you can produce high power by doing a small work at a heavy rate, as well as by doing a heavy work at a small rate.

So to answer your question on the exhausts.... You pays your money and takes your choice as to what you want. Personally I want high work rate at lower revs; so that I can do 70 at 6k rpm. I chose an ADS3 for that reason.

I'm sure a responsible adult will be along in a moment....

[mickdale]

thanks - it made sense

[lifes a drag]

the only thing that made sence to me was this bit , I chose an ADS3 for that reason

[giankx]

me too!

[Juan]

I'm just wondering what an aerodynamical design with formulated downforce sections has anything to do with the small shed or greenhouse-like qualities of a scooter?

[corrado]

Personally I want high work rate at lower revs; so that I can do 70 at 6k rpm.

That seems to be what 90% of rally goers want. ........ and a 9000 rpm RB for fun.

[sean brady scooters]

relately low revs and max torque is where its at for most road scoots,together with reliability and reasonable fuel consumption...
for race machines or indeed fast road scoots ,its all about max power and so revs...and for these machines really long term reliability and fuel consumption are just secondary considerations ..
sporty scoots are regulary stripped down and checked over as a matter of course at certain intervals and fuel consumption/MPG is not even considered...
how many racers worry about the cost of maintaining their motor or the MPG ?
to those that want and seek some sort of balance between a std scoot and a racer it will always be a balance and compromise ( depending which way they ere )between not only power and torque (drive ability ) but also other factors such as
reliability ,mpg ,and general running /maintanance costs ..horses for courses..hey .