Even for an avid reader of this forum it is near impossible to discern a good tuner from a bad one. However probably there will be only a few ways to tune an engine in the right way. What should the tuner do when the bike is on the dyno, where should he start for example? When the VE of the engine has changed because of AC's mufflers or cams, should he first try to establish a new VE table and after that the AFR and ignition and what about the MAP?. or is it a more iterative process? Should he push the limits of the system and use the ion-sensing capability of the ECM to increase performance. Should more attention be paid to partial load conditions and the AFR in those ranges or will they be correct when the WOT dyno sheets look okay. As for the latter, the only sheets I see posted around these fora are the WOT acceleration sheets to show max power/torque and apparently you should see a 13,5 or 14 AFR. But what about cruising for an hour or so at part-throttle with too rich or too lean a mixture, that would really harm the engine. Please some hints as to which question to ask to see whether the tuner knows his business and does the right thing.

 

Start here.... https://www.hdforums.com/m_3162234/tm.htm
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This subject has been beat well past the point of death, and is now entering it's 3d afterlife...

 

Only the 3rd? Hahaha!

I did not follow the link and do not feel like devoting the time to it.

In my non-expert opinion, once the VE tables are properly populated, the dyno time is done. After that it comes down to juggling (other) parameters. Tuners are like jugglers. Some cannot hardly juggle one ball, others can keep half a dozen in the air. The better ones are worth more money. With a good combination of intuition and experience (usually in that order) the better ones rise to the top.

 

That's my point exactly. The impression I get is that the tuning of Harley's is not an exact science, while it is hard to imagine that engineers at Delphi, Porsche and others are the same kind of jugglers. So to repeat one of my questions which is not answered in the other thread: what should the tuner be doing to get the VE tables populated correctedly - if that's the part he has to start with. When I know that I can see at least that he is (trying to) tuning the engine instead of performing a 750 US$ circus act.

 

Once the map is installed into the bike, a BASELINE VE run is done in ALL of the throttle positions, to VALIDATE where the VE's and the Desired AF are set at, and what corrections need made...
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This MUST be done for both cylinders, to ensure that the final VE corrections are spot on...

 

What about setting up the AFR table to find out at what AFR max power is made? And the timing table? It seems to me setting up the VE tables is just the first step in dyno time.

 

Thanks Bob,
Since I am no technician, how do you validate the VE table? I understand that VE means volumetric efficiency, the amount of air that is pumped by the airpump/engine, and that the yield of the pump changes by changing the input (SEAC/throttle openings/cams/valves),the pump action sort of (bore, stroke, volume) and output (valves cams,headers, mufflers). I also get that the amount of air pumped should determine the amount of fuel injected (AFR, which differs depending on acceleration, cruising etc indicated by the throttle opening). So lacking a air mass flow meter how do I validate the VE table and why can't I put an air mass flow meter in front of the AC intake, when the bike is on the dyno? The last issue which brings me back to a earlier question is why it is not possible to have a dual throttle body with longer intake pipes, kind of like the S&S setup, in which you could fit a permanent air mass flow meter, or would that put too many "tuners" out of business?

 

When the value in the AFR table for a cell matches the value from the dyno sniffer when running in that cell, the VE table value for that cell is correct.

 

 

Well, those factors rather come back to my statements regarding juggling other parameters, and that based upon intuition/experience. Sure, you could use the dyno to tweak them to the utmost. But are we trying for the best trap times or just generally great driveability? Do the best numbers often produce the best driveability anyway?