1.8 LUW VVT Tuning

[MikeRWK]

Does anyone have any info? Can the cams only advance or retard? How do the numbers correlate to cam position?

[KillboyPowerhead]

See last post here: https://forum.hptuners.com/showthrea...456#post658456

I found a non-stock LUW tune file and based on the cam tables it looks to be as tunerpro described: 0 is fully advanced and higher numbers retard the cams, for both intake and exhaust. The intake cam should be more advanced at lower RPMs and retard as the RPMs increase, and the file I found has lower numbers at lower RPMs and higher numbers at higher RPMs.

[MikeRWK]

On the LUJ/LUV (1.4T MPFI and probably other engines from that family as well like the 1.8L NA, etc), that is NOT the case, however. Both cams are fully advanced at 0*, and they both retard as the angle increases.

I'm not sure it works like that on the LUW/LWE, I'm seeing negative numbers in a few exhaust cam tables along with positive numbers.
Med baro.png
Screenshot 2023-05-13 142839.png

[KillboyPowerhead]

I was only looking at the High Baro and WOT Base tables. The Med Baro table is significantly different than the high table; I wonder if the Med Baro table acts as an adder/modifier and is being added to the High table (so positive numbers will retard the cams further, negative will advance), maybe as the barometric pressure drops? Or when the VIM "is in the long position"? Just going by the descriptions for the Baro and WOT tables and for the General > Method: Base/Global (the tune file I saw has method set to Global). Could try logging intake and exhaust cam actual and desired positions, then add 1 to the whole Med table and see what happens.

[MikeRWK]

It looks like the High/Med barrow tables are actually High=(Base table for everything besides wot) Med=(VIM adder table for everything besides wot). As the low tables are both empty in my tune.

[MikeRWK]

It turns out the tables highlighted in Yellow do absolutely nothing! Its the ones highlighted in green that control everything. Now to log and tune them!
vvt tables.png

[MikeRWK]

A little more info it seems those tables only control vvt above 25% throttle or so. With the tables zeroed I'm still seeing cam movement during cruise conditions but all I want is wot control of vvt anyways so its not an issue.

[legithackerman47]

There seems to be additional tables at idle as well that would likely have to be added. Even with High Baro (main) tables zero'd, intake cams are at ~20 degrees at idle. If you disable VVT by setting Camshafts to None, it seems to measure at 0 degrees advance. I would really like to use VVT, but it seems to be integrated with the torque reduction algorithm or something like that... All conjecture on my part but seems to hold up.