Anyone got logs from different ecu's for how accurate they can control the variable cam on a honda k series?

Hiya

When setting up the cam control options - i see in the webinar that Andre suggests using a polling hz of between 200-300hz for the cam solanoids

What sorts of effects would having a lower hz apply to the cam response to target vs having higher hz rate

would you get to a point where you have too much of a polling rate and the oil isnt able to meter through the solenoid to move it in a timely manner for large requested changes?

would you get to a point where you have too little of a polling rate and the changes become "blocky" and lose resolution?

It does seem to be a case of choosing what you want at what load and rev range and tune the haltech ecu for that.

Ive looked at datalogs from a hondata and they have VERY nice cam control (and all the extra tables in the ecu needed to allow that to happen seeing its OEM stuffs) very accurate tracking under any load or revs rising or dropping

Haltech works great to the limits of the tables it can use but gets flakey ouside the conditions you tuned it for - tune for 100%tps low to high rpm ramp over 5 seconds - no worries - its accurate - but after that if you have high to low rpm drops itll get inaccurate - light load itll get inaccurate - faster ramp rates (lower gears) it gets inaccurate

How accurate is say a link ecu for the cam control - anyone got logs of cam angle vs target for one of those ecu's running a k series?

what other ecu's can do variable cam control and get it as accurate as factory - yeah - motec would - i cant afford a motec :)

I didnt want to mod my factory jdm type r ecu for hondata - as their base roms are not based of a jdm k20a ecu and settings and it seems at least the knock limit tables would be slightly different.

@adam from link - got any input on how link handles things or can you show screenshots from logs on a tuned k series showing empirical results ?

@andre - got any input on what ecu's you have seen on a k series and how accurate their cam control is?

@anyone else who's got practical experience with a honda k series and tuning the cam control on an aftermarket ecu - how good has it been from your point of view?

You have already ruled it out, but the Cam control on my 280,000km old K24 with teh stock 25 degree VTC gear is more than fine on an M1 ecu.

In my configuration, the solenoid is high side driven on the factory wiring arrangement, at 200hz. I haven't had time to get around to scoping the factory control frequency, and have no changed from my initial setting of 200hz, as the control has been more than acceptable.

I just finished a swapping an M130 onto a K20 that was connected to a DTAfast ECU (I hesitate to say "controlled by"). I was going to post something showing how good it was, but Nathan's screenshot tells the story.

Yup - "Motec F.T.W." literally :) If it was affordable to me i'd get one of their units - but its priced for teams (or people with more income than me lol) and you get what you pay for :)

Also - What oil do you guys run on those engines?

for reference : hondata accuracy

Compared to either the motec or hondata results - I am nowhere near close enough to their results be happy with my results. The results I currently have are not worth comparing to these so I wont embarrass myself by posting em :)

I will say tho, if all i did was drag racing, then I'd be suuuuuuper happy with the haltech and in a drag racing situation I can beat the hondata for accuracy and be closer to the motec results than the hondata results. Its just a pity mines a street car tho where the revs rise and fall a lot lol

Anyways if any other people have screenshots of cam control on a k series - please can you post em and from what ecu is doing it?

@Nathan - just noticed something thats given me a new idea to experiment with at some stage - It looked like the Motec was indexing its pid values against cam error/temp and not rpm/temp would that be correct?

Hi Lawrence,

That's correct, oil temp (and the viscosity and pressure changes caused by it) has a large influence on the stability of the control of the camshafts. I have seen some engines that a 1~2 degree increase in the temperature of the oil over a certain temperature will cause a complete loss of cam position control as the actuators cannot maintain enough force to hold the commanded position.

Thank you everyone for their input :)

And thanks to Stephen for the input about oil cooling solutions on a street car in the other topic I had- it was directly related to this topic for me as well :)

That Motec screenshot is a great goal to aim for in accuracy - as it proves out that the cam control can be damn accurate and gave me some good things to experiment with when i have some more free time :) Gotta love the information you can get on these forums :)