My VirtualDyno

[Kosta135i]

Did a Pull on my accsessport after my ptf e tune and decided to put it into this virtual dyno program.
How do these number look for my Mods?

Car is a 2008 135i AT
93octane
VRSF DPs,7''FMIC,and Chargepipe with tialq
AA Gen 2 Axleback, Stock Mids, BMS DCI

Also how accurate is this program?

[bmw0bsession]

Put my real dyno sheet next to my virtual dyno and it was off by 3 rwhp and 5rwtq pretty accurate if you ask me

[froop]

Your graph has an interesting shape to it. Can't say I've seen an N54 look like that before.

Normally they have a flat torque curve early on which is pretty steady and then drops gradually around 4k as the power comes up and peaks around 6k.

[mike@x-ph.com]

When using a virtual dyno (or any dyno) you always want to have baseline numbers so you can compare delta which is more important than raw numbers since each dyno reads differently.

[Freon]

Most of these types of things just take vehicle speed and calculate acceleration rate, and you enter the weight (mass) of the car. Or they take RPM and you enter in the gear ratio, tire size, etc., it figures out vehicle speed, then acceleration, and so forth.

A log from the street will not compensate for wind and incline in particular. It doesn't take much of a grade (incline/decline) or much head or tail wind to gain or lose several horsepower. Take your results with grain of salt.

Getting it to consistently line up with a chassis dyno is a crapshoot. If it were accurate it should vary and not always line up well. It would make me worry if it always agreed with your chassis dyno as they are not testing the same thing under the same circumstances. One is measuring the acceleration of the mass of the car with a bunch of outside variables like incline and wind. The other is measuring something like the dissipation power into a water braked drum, acceleration rate of a high mass drum, or dissipation power in an eddy current brake in the floor of a garage, with some fans pointing at the radiator. They should in fact come up with different values.

As above, baselining still can work, but you probably want to pick a specific piece of road to always use, same direction, and try not to test when wind is high or temperature is too extreme. Testing in both direction of the same stretch of road and averaging may help reduce some of these outside factors.