Thread: Virtual Dyno and Smoothing

If your vdyno graphs come out proper with a smoothing of 0, should you use it? It seems the higher I go up into smoothing the less accurate my lower RPM hp figures get and the graph in general compresses quite a bit

Mine usually look like this:



Here's smooth 1:

Looks like "0" will work fine for you

Most need smoothing of about "3", including me. Maybe 2nd gear pulls need more smoothing compared to a 3rd gear pull. Someone should experiment. Might as well be me, still need to get the "after" virtual dyno of my new header

ya the problem is, if the #s are overinflated at 0 smoothing even though the graph looks smooth.

It all depends on your terrain, engine smoothness, and logging smoothness. It's very very very rare that Smoothing of 0 gives you a smooth graph. I think your logging software might be logging possibly too slow?

General rules of thumb when using Virtual Dyno:
- Keep on increasing the smoothing until power stops decreasing by huge numbers. 20whp difference still says that smoothing of 0 is inaccurate.
- Difference between smoothing 1 and 9 should be no more then 10whp, if it is your road is too inconsistent.
- Try to do a virtual dyno run in both directions of the road and verify the numbers, they should be very similar (This makes sure your road is not on an incline).

As Vadim mentioned, after several runs 2 weeks ago using Virtual Dyno, I have realized even a slight gradient can have drastic affects on overall numbers

I did a quick test to see just HOW drastic they were. It read 450WHP on this particular road. My injectors run out at close to 400WHP...........

Bah Vdyno seems too inconsistent. I think I'll stick to reading MAF voltage as a determination of increase in power.

What's "inconsistent" about Virtual Dyno in your case is that you continually refuse to figure out how it works

The only reason it didn't work for me right away is because:

1) 2nd gear had too much wheelspin which significantly inflated the numbers since vehicle speed is used for the HP calculation (after 4K boost hits hard and tires get blown off and the vehicle speed is inaccurately inflated)
2) I did not find a flat surface to do back to back runs
3) The TPS data stream was incorrect

All of which were MY issues, NOT Virtual Dynos! Once I spent a few minutes figuring it all out, it has been extremely consistent. Also, it is within 2-5 HP of what DynoJet and Mustang Dyno reads

Here is a perfect example of Consistency

Know Virtual Dynos parameters and work within them (like you would do with ANY software or car you drive) and you will be fine

Where is the dislike button when I need it.



Incorrect. Virtualy dyno only uses 3 fields from a log file to generate the numbers. Time elapsed, RPM, TPS. The only reason TPS is used, is to only draw dyno on TPS being open above 90%. Which if you want you can easily spoof by replacing all numbers in TPS field with 100 wont affect the accuracy.

I live in the mountains, ask Keo how bad it is out here, we don't have a road that's straight and not inclined. I have a very hard time finding good roads for virtual dyno testing. Usually what I do is just pick one road and base all my testing based on that one road. As long as I'm going on the same exact road in same exact direction, even if numbers are inflated or deflated, I will have good vs numbers.

@Vadim is correct. One unit of the calculation is RPM NOT Vehicle Speed! My mistake. But the concept I mentioned is still the same; wheelspin (just as on a real dyno) will affect numbers drastically (which is a user error and that's why they have the option to dyno in 3rd and 4th gear)

I am not at liberty to divulge where would be a good place to do 3rd gear pulls, as in most states the top of 3rd gear is well into the 70+ MPH region, which is above most state's speed limit.

Wheel spin = instant increase in RPM, to virtual dyno it's seen as a magical increase in power. I've made 500whp before on my T25 B15, with wheelspin of course .



I don't know about you but my 3rd gears end at 90mph, in VA that's instant jail + class 1 misdemeanor with hefty fines. For this reason I do all of my Virtual dyno runs in 2nd gear. It might not be as accurate, but I'm doing 2nd gear vs 2nd gear testing, thus it shows more power, then your mod/tune increased power. I've compared 2nd gear to 3rd gear runs and they were fairly similar, gear ratios help keep the calculations accurate.