Rolling road

[pickmaster Andy Lowe]

I love it

I'm from a bike background years ago and to get that level of information on how your engine is running under all driving conditions as it happens must be magic :)

We could increase timing 2 degs then run again and overlay the results

Drop the needles a notch and check mid range under load and coasting

To set an engine up to that degree would be impossible with the plug chop method I used to use on my bikes

I know that their are lots of variables in dynos but its probably the best way of assessing what sort of power you can expect from which engine carb or injection set up, without this sort of information we'd all have Lister single cylinder diesels in our cars for economy LOL

[Hammy]

You should have resisted Hammy!

In steady state the dyno measures the torque that is being applied to hold the vehicle in steady state - it can therefore calculate the HP because it knows the torque and the rate of the work (RPM) to spit out the power figure.

You can not measure HP - it is the rate of doing work.

If you take the speed transducer of a dyno it will still produce a torque curve in relation to time but can not produce a power curve as it has no speed measurement.

You are right ! I had thought from a measurement point of view the absorbed power was the "easy " measurement to make and dyno makers would have gone this route and derived torque from it , - apparently not then !

Been an interesting thread - Thanks for the discussion , I'll get my coat .....

[Hammy]

Btw a google of "home made dyno" is worth it!

[Dave Eastwood (Gadgetman) - Club Chairman]

Talking of home made dyno's, one of the Practical Performance Car writers has been busy building one, (using the big arrestor units found in coaches) to do some work on his Merlin(?) (tank as opposed to plane) engined Rover SD1!