ITT: We discuss Virtual Dyno settings
 

So I'm trying to get virtual dyno going. And to get good baseline settings I'm using actual dyno runs to compare to the logs.

The issue is, they aren't even close to accurate.

Dyno printout

https://www.miataturbo.net/attachmen...ine=1452624689

Virtual Dyno, weights adjusted to get as close as I can to the right numbers.

https://www.miataturbo.net/attachmen...ine=1452624689

What gives?

(Logs attached)

What inputs does the virtual DYNO use for its calculations?

Megasquirt log

Did you expect it to be accurate? AFAIK Virtual Dyno should only be used to compare against Virtual Dyno. AKA consistency rather than accuracy.

I expected it to be closer than this, at least the way its used around here.

I've compared it to NUMEROUS actual dynojets and it's always really really close. like 2-4hp close

and the curves are also really close. like almost identical. you can check many other forums and see that there's threads like this and all of them match up.

so you're doing something wrong

do you have a 6sp in the car?
why are both car weights you're using so completely off the wall?
don't you have a 3.9 torsen?

Thats why this thread exists. What is it?

5 speed at time of dyno
4.1 at time of dyno
weights are to try and get it to even be close. without weird weights its at like 280hp

STAHP NINJA EDITING

Why is your car weight set to 1300 lbs?

With correct weights:

https://www.miataturbo.net/attachmen...ine=1452627097

so they were that at time of dyno and not that now?

welp.....

Logs are from the dyno runs.

Yikes.

that's weird. I'm too busy and lazy to troubleshoot, will check back when I'z bored

*edit: BUT WAIT

you can't use the logs from the dyno brah

logs are attached to the first post for your pleasure.

motherfucker, thats probably why.

plz delete thread out of embarassment.

cause the VD software calculates drag/resistance, which you don't have on a dyno

it calculates frontal area against wind and some other sort of mumbo jumbo

brain fart

i'll calculate your frontal area.

oh baby

You can adjust coefficient of drag in Virtual Dyno, you should set it to 0 and see how well it matches up.

yeah I was gonna say you can play with that, but I'm not sure how accurate the results will turn out. never done that. try it and report back. or just do a pull on a flat road like the rest of us humans lol

:rofl: :bowrofl: :rofl: :bowrofl: :rofl: :bowrofl: :rofl: :bowrofl:

:noob: :noob: :noob: :noob: :noob:

Thanks for the laugh. I needed this today.

:inout:

That's funny. VD also uses the mass of the car. Dynojet accelerates the drum IIRC.

Use a real road pull, or better one in each direction.

:fawk:

Go to the settings and you can apply custom fields to make boost pressure plot proper, like this for my MS2.

https://www.miataturbo.net/attachmen...ine=1452638635

This is one way, then back. Stock settings for a miata.

https://www.miataturbo.net/attachmen...ine=1452638635

You can't set drag coef to 0.

ITT: aidan learns the laws of nature

just open up the file

and divide by zero

Or, more significantly, it uses the weight of the car to calculate how much work the engine is doing to accelerate the car at the rate shown in the log

Which is why the directions say to do it on a flat surface. You know, on a road...
Whether Dynojet uses a drum mass or eddy current (they make both) is irrelevant :noob:

Directions are for sissies.