K Series Mapping: Why so many revisions for a proper map?

A question I get very frequently here at VitTuned. The short answer is very simple: do you want it done right, or do you want it done fast (and lazy)?

For the long and descriptive answer, let’s take a look at an example of a Hondata FlashPro (same idea with Hondata KPro and KTuner maps) map. The heart of the tune is the ignitcammapion, fuel & cam angle mapping, with the proper VTEC point being the final slice of pie.

The following graphic depicts these basics — but the thing to note is there are actually *10* ignition and *10* fuel maps, at various break points. So now at the very heart of the tune are 10 of each of the “big ones” (ignition/fuel) that need to be properly mapped for the vehicle & its modifications.

Now we can begin to understand why so much work — not only do you have to do all the individual mapping, you then have to combine it for a “final” fully tuned map, adding in any further tweaks necessary to smooth out the motor’s operation as well as doing any necessary part throttle tuning whimapsle the power tuning has been going on.

To the right is a screenshot of how many “revisions” a proper all motor map involves — this was a tune done in person on the shop Dynapack dyno. Every log is either a WOT pull or load based part throttle mapping while the vehicle was on the pack. Took about 34 “revisions” (IE, changes to the tune before more logging & testing was done).

This is how I do every tune, every single one. Whether it’s your basic stock K series vehicle or highly modified turbo built motor beast. Do it right, or don’t bother doing it at all.

I’ve seen some claim they tune like I do — short story is they may try to duplicate, but they can never replicate.

Let’s dig a little bit deeper.

The most important thing to note is the fuel mapping — on a setup that breaths very well there can be as much as a 30-40% difference in fueling between the 0 degree cam break point and the 50 degree cam break point. Even if you set up the cam angle map to have a mostly “fixed” cam angle map — guess what? The cam still moves, it’s a simple mechanism that’s powered by oil pressure — not to mention the phasing between the high cam and low cam (VTEC on and VTEC off) maps. Then what happens if the ECU ever limp modes for any reason? It will default to the 0 degree maps in the ECU during fail safe scenarios.

So let’s take for example a map where every single cam break point is the *exact* same, they are identical or very nearly so. Or fuel maps that were put together with no thought — I have yet to see a single K series motor that will demand the exact same fuel at every break point. In three words — it is impossible. As the cam angle moves, the VE (volumetric efficiency) of the motor changes, and as a result the fueling demand drastically changes which is then depicted in a map with properly tuned fueling.

Now what happens in this scenario? The cam will phase, the motor’s fueling demand will change, and you’ll start to experience some drivability concerns — some hesitation there, some weird lag here. What if the ECU limp modes? You’re left with a potentially undriveable (if not unsafe to drive) vehicle.

I’ve heard several excuses for lazy K series mapping — “AEM doesn’t ┬ádo it like this” (or insert “Blah blah stand alone doesn’t do it like this”) or “you’re obviously getting your information from someone who’s never seen anything but Hondata”. That is by far some of the worst excuses I’ve seen for laziness on this specific platform. And to break some hearts — I tune over a dozen different engine management systems. Simple fact is — you tune Hondata like Hondata, AEM like AEM, SCT like SCT, HPTuners like HPTuners, etc. Every EMS has it’s intricacies — you learn them all, or in my opinion, don’t bother touching it if you don’t have the motivation to do it right to begin with.

So I’ll leave you with that — you can have fast & lazy, or done right (but takes a bit more work). Ultimately it’s the customer’s money paying for the work & experience they’d like to receive.