Effect of afr on power

In this module Andre was showing effect of lambda on torque etc. In a Nissan 350z he was holding revs at 2000 rpm but said the throttle ws all the way open - how is this possible or am I being dim. Was he perhaps controlling the braking on the dyno to create enough resistance to achieve this -am I on the right track?

Martin Uk

Hey Martin,

Not being dim at all, this place is here to ask questions and not feel judged :)

The way the dyno operates allows you to adjust load applied to the engine (via the wheels). Effectively (when set up correctly) this allows you to set a steady state RPM on the dyno which means the dyno will apply X amount of load to hold the engine at the targeted RPM.

Example, you say Andre was at 2000rpm. Once he had set up the dyno (Diff ratio input, wheel diameter, run rates etc) he would of set the steady state to 2000rpm and the dyno would apply the needed load to the engine via the wheels to hold the engine at 2000rpm, from here he can go anywhere from light throttle (providing it is still enough throttle to have the torque to turn the wheels) to 100% throttle and the engine will not go over 2000rpm. This will work throughout the RPM range i.e 2000rpm, 5000rpm, 9000rpm etc etc

I recommend watching the webinar below which might help you get a good understanding of exactly how the dyno operates.

https://www.hpacademy.com/previous-webinars/053-dyno-operation/

Cheers chris.

https://www.hpacademy.com/previous-webinars/60-effect-of-afr-on-engine-torque/