Wobbly dyno graph

[yes i'm mad]

What would cause this?

[rigga]

Wheelspin

[philmots]

Not enough smoothing on the graph?

[300bhp/ton]

Most/all dyno software should have a setting called graph smoothing. Or does the car actually feel like the graph to drive? If so there is another issue.

[J4CKO]

The Buttery Biscuit Base ?

[yes i'm mad]

J4CKO said:

The Buttery Biscuit Base ?

haha! I am watching that at the moment

[Kitchski]

Traction control.

[anonymous-user]

Incorrect PID tuning on the dyno speed control loop

[PhillipM]

Or buggered coils if it's a rotary.

[AER]

If it's an inertia dyno, then it looks like a drivetrain oscillation, probably caused by too sudden an application of power at the start of the test.

[ivanhoew]

it can also be caused by a run being too fast for the dyno absorber to stabilise , I have seen this sort of pattern on a dyna pack hub dyno .
although in that case it was a reasonable time of run , just (and I may be drivelling here) if I remember correctly it uses a water brake ,and the feed valves can oscillate the load when trying to set the absorber to the right level for the programmed accel rate.

[s m]

Earthquake?

[GVK]

Dyno by 'etch a sketch'

[richwig83]

Probably some sort of ECU intervention. If that were remapped properly youd probably lose that wobbly-nes

[Shadow R1]

Id be interested what that is.
Below 60 for both bhp and torque.
2cv ?

[smiffy180]

Could be 55kw in which case it'd be about 74hp?

[GroundEffect]

The control system in the dyno itself could do that.

[Marvib]

I think he turbo'd an aygo

[yes i'm mad]

Marvib said:

I think he turbo'd an aygo

Supercharged.

View the thread on my profile

[airbrakes]

yes i'm mad said:

Marvib said:

I think he turbo'd an aygo

Supercharged.

View the thread on my profile

most appropriate username win