I have only seen a VE table delta comparison once between "auto tune" and dyno results. There was some differences. Unfortunately, that post didn't have the tables set up to show deltas as a percentage. Hard to tell really how far off they were.

I'm surprised in all this time that nobody has done such comparisons. Without such comparison, the proof in the puddin would seem to be a bit lacking. If I can ever get around to it, and find a competent pro in my area, I might take my bike in just to shed some light on this question. Last "auto tune" I did was with Target Tune/wide bands. If I had to bet before hand, I'd bet there would be a fair amount of error - perhaps more than one would care for. I'd also bet that one might be able to get closer with the narrow bands.

 

The best place for these questions (and often where the answers already exist) is over in The Dyno Room, where the Pros are instead of the marketing guys There have been a couple of very misleading threads/bun-fights of late.

Why do some M8 users seem to think normal EFI tuning doesn't apply to them (LOL)

Anyway, to the OP, and on the back of what Bob and T^2 very helpfully said...
"Autotune" "Smart Tune" etc (except for the TTS) ONLY map out your VE tables.

So, mapping out your VE tables is about getting GOOD/ACCURATE data to get to the right answer. The BIG difference (if that's what you are asking about) is going to be about the quality of data you are able to collect running around on the street, vs that which you could get in a controlled environment like on a dyno.

How much difference might you see is likely to depend upon your ability to collect smooth "autotune" data (I was dreadful when I started)

The algorithms used within the devices also seem to have an effect - I got slightly different numbers in places between PV Autotune and PV logging and using a log analyser to calculate the new VE for example.

But hey, like that great marketing video that was quoted in a recent thread, it will still run and slide the back tire out and the guy said, so must be bloody brilliant eh

 

I always run Full Exhaust An Air Cleaner,I have Had My last 3 Bikes Dynoed,And all have run very Well All the Time,I live in Upstate NY So we have All kinds of Weather,My Bike Runs The same all the Time Good.It helps When you have an Expierienced Tuner.I go to Hulten Speed Sports,A certified Power Vision Tuner.Ray knows what hes doing An has a lot of satisfied Customers An hes only 20 miles from my house so that's nice.Everone has there opinions But if your Bike is Dynoed Right you will notice the Difference All the Time.

 

Not an M8 ,but my twinkie. For comparison it should work. The initial run here was the product of many autotune sessions with PV Target Tune. The guy doing the tune suggested we unhook TT and just do the tune on the NB's. I asked why and he said there is a known issue with the algorithms in TT. He and several other tuners had talked with Dynojet about it and they told them, "Yes, we know. And we don't have the engineering manpower to get back into it right now." That's been a year ago so maybe they have addressed it since. I don't know. In any case the dyno tune was a nice improvement over the TT autotune. I don't use TT these days.

 

Appreciate the info... Particularly about the potential issue with TT.

Couple of points...

So - don't find it surprising that there may be differences after the guy did a dyno tune. But the difference may not be because of what one might think.

Remember "auto tune" (for purposes of this discussion) only attempts to calibrate the VE tables. It does not attempt to "tune" your bike. When the pro did the dyno tune, he presumably did "tune" your bike. So he may have altered other tables (like AFR, Spark, etc.) in addition to potential changes he made to the VE tables. IOW He may have made improvements to the tune you came in with (and which you had "auto tuned"). Those changes are likely what produced the gains (presuming that nothing else was changed on the bike).

The question here is... How well does "auto tune" perform at the job it actually does? IOW how well does "auto tune" actually calibrate the VE tables? To ascertain that, one needs to do a comparison of the VE tables produced by both "auto tune" (before dyno tuning) and the VE tables produced by the dyno tune. This can easily be done in WinPV. You simply open the tune file and do a compare with the other tune file. Look (see the compare menus) at the VE tables and set WinPV to show the deltas as a percentage.

 

Not many mention this (both human and technical factors) aspect... After all, based on the marketing material/documentation, you would think that all you need to do is push that magic button and ride around. The "thing" does whatever magic it does - and voila - your bike is "tuned".

Yup.

 

I believe the original question was how a street tuned bike by an owner cmpares to professional dyno tune, which, as mentioned includes much more than the street tuned (“autotune”) bike.
When you take your bike to a tuner he will not just readjust the VEs like autotune systems.
For this reason it is easy to understand why there are differences between the results from street tuning and dyno tuning.
Bob

 

The thing was...
The question might become, is this guy a tuner or just a dyno operator? so I wasn't sure what was being compared.

but "autotune" vs "professional dyno tune" you nailed in post number 2