Interpreting Dyno results: RWNM, motive force etc.

[VSCristian]

G'day Gents,

I had a disappointing dyno run today, or so I think: my 5L only pulled 122.8rwkw.

I think there's more to it than that: They did the run in second gear, and rw torque was 567Nm.

Why would they do the run in second? and would the reading be affected? I was of the opinion that runs were done in third on autos.

 

[Immortality]

Power run should be done in 3rd gear been 1:1 in a 4l60 box. Doing a power run in a lower gear means you get torque multiplication through the transmission.

Power wise, depending on condition and mods it's not totally bad. Stock VP put out a stout 160kw, allowing for drivetrain losses (I use .7457 just because..... and yes it's only a rough guide!) so that would suggest 119kw give or take.

There is a big thread about this somewhere with more detailed explanations.

 

[VSCristian]

She has a HSV CAI and K&N Filter, and headers, high-flow kitty, and single 2.5" exhaust.

If she got 567nm in second, which is 1.625:1 that would mean 354nm in third which is 1:1

I don't know why they did it in second.

Am quite disappointed to be honest. I thought she'd be in the 130s

 

[Brisbarnz]

Run the 1/4 then do the math with car weight to get rwhp/kW

 

[Joeseb87]

Some time ago I had a 308 that was rebuilt pretty stock slight cam increase and it made 118 RWKW

 

[lowandslow]

Take it to the track and find out from your timeslip.

 

[delcowizzid]

they are easier to run in 2nd or they allways kick back to 2nd as you start a run but if its programmed in the dyno what gear ratio its in the figures will still be valid

 

[chargedvx6]

The power is about right for the mods. Should definitely be run in 3rd gear to give a true torque reading.

You could get between 110-140rwkw depending which type of dyno you go on and how it's set up so like the other bloke said, hit the 1/4 mile and punch in your full track mph and car weight into Moroso hp calulator and you will knwo the power of the car. Some will even calculate the peak torque but that's a bit inconclusive.

Dyno is a tuning tool only