vDyno is a cool tool, it gives you a ROUGH, and I mean EXTREMELY rough estimate on power. It is cool to see progression but shouldn't be used to compare cars to one another in my opinion. Same thing can be said for dyno's as well. If you want a good comparison on how fast your car is, hit the track see how fast you can get it to go!
If the eybrow-raiser was in regards to sharing datalogs, I wish it wasn't the case but some people make it so you can't have nice things.
Eyebrow-raiser to everything.
I definitely agree that it shouldn't be used to compare cars, at least cars that are not literally using the same road at basically the same time, but it is a solid performance measurement if used by the same person to evaluate gains locally for free. Yes, garbage in is garbage out, but I've seen more ruined 'professional' 'real' dynos than I can count, so it still comes back to having solid inputs-regardless of the medium used. I would rather have a shitty V-Dyno that I did for free than a shitty 'real' dyno that I spent a bill on.
Want to know if your intake made all of the horsepowers you were told? Datalog a few runs before, go do your swap, datalog a few runs immediately after (on the same tune with your car at the same operating temps without disconnecting the battery...yada, yada, yada) and throw them into V-Dyno for comparison. Want to know if your tune revision made progress? Compare your previous datalogs to your post-tune datalogs and throw them into V-Dyno for comparison. If you're actively trying to control your variables and have done a proper evaluation of your datalogging road and procedures then you should not have any issue getting very similar numbers to what the 'real' dyno would put out, and most every other community is well aware of that and advocates it as such.
Want to know what your 'real' numbers are? Go shell out your hard-earned cash for a piece of paper and post it for everyone to see (even if you use a Mustang dyno and cry a little afterwards) and throw it in your signature. Want to know what your car does in comparison to your buddies? Invite him to the local dyno and schedule some runs for the same time of day. Post your sheets, get your sick brag, and go back to whatever you were doing before you bought that $100 (ish) piece of paper.
As for not sharing datalogs,
and let me clarify that this is strictly my opinion, I disagree with the concept. If I choose a tuner to change ECU data on my $20k (+/-) form of transportation, which is generally the second-most expensive purchase people will ever make and is something that most people rely on being road-worthy daily or hope for a degree of longevity out of, I want the reassurance that the tuner is comfortable enough with his decisions that I could post a log for peer-review if I have questions. And I don't feel that way strictly about tuners, that is applicable in all facets of modification. If I post a datalog of before/after with a certain DP and the manufacturer chimed-in saying that sharing datalogs was not allowed, I would rip that part off of my car and throw it in the trash-I wouldn't even try selling it.
I'm not knocking-you for your decision, that is your prerogative. I don't think I've seen that advertised anywhere though, so I would consider making sure (if it isn't already) that it's very clear to any prospective buyers before purchase. Not that I intend to (I do my own tuning), but if I shelled-out money for your tune and found out afterwards that I couldn't share logs I would be pretty pissed and vocal about it. This community is very mis-informed in many avenues to begin with and the only real way of disseminating real information is by sharing and evaluating real information.
The best-supported platforms tend to be the most well-informed, but that's mostly just my casual observation.
