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M1tch

Question on VVTi on basemap

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Hi there,

I have currently got a VVTi inlet target using the 1UZ basemap which uses the TP vs RPM to work out the VVTi, I have also had a look at a few of the basemaps for the black, Xtreme as well as the Altezza VVTi values (3S-GE I believe), I think the Altezza one uses a MAP figure vs rpm for the inlet target.

Just wondering what values I should use on my 1zz engine, should I look to run the base values from the Xtreme basemap? I can't really tune VVTi on a road tune so would just be looking for the most aggressive but still safe set of values - the 1UZ map has a max value of 35 (35 degrees from fully retarded), the Xtreme basemap pushes this to 55 which is fully advanced (tailing off at higher RPMs) - just checking that this should be ok to run considering its a basemap so should't cause any issues.

Thanks in advance!

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8 hours ago, M1tch said:

looking for the most aggressive but still safe set of values

There is no such thing.  Every engine is different, you can use values from a completely different engine and expect it will be anywhere near optimised.  If you cant get it on a Dyno then you will have to come up with a tuning strategy based on logging to find the best cam angle to achieve best VE.   

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11 hours ago, Adamw said:

There is no such thing.  Every engine is different, you can use values from a completely different engine and expect it will be anywhere near optimised.  If you cant get it on a Dyno then you will have to come up with a tuning strategy based on logging to find the best cam angle to achieve best VE.   

Apologies, I didn't necessarily mean 'aggressive', and I know that road tuning the car won't get my the perfect tune as there is no way of measuring wheel torque etc. Was about checking if it was ok to use the basemap VVTi figures as the +55 setting for VVTi would be at its most advanced - just need to check that this won't cause issues with piston and valve clearance considering it is a generic starting basemap which I would be guessing would be a safe starting map.

I have some VVTi settings from some previous tuning on the Apexi PFC which I think were optimised closer to the 1UZ from memory (in terms of maximum advance) - unless of course the PFC and Link ECU are opposite in terms of what is the maximum advance number.

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not really sure why you're referencing the 1uz basemap for a 1zz...  Take a powerfc 1zz vvt map and translate that across to work.  In Datalogit or the hand controller, a value of 50 is equivalent to zero cam advance in the Link.  So you export the powerfc vvt table to excel, then do some simple math to subtract the table value from 50, and you will have the equivalent Link advance number.

The challenge will be the powerfc load values don't correlate easily, but once you see the shape of the vvt table with regard to RPM it's easy enough to get in the ballpark for a Link table.

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19 hours ago, M1tch said:

Apologies, I didn't necessarily mean 'aggressive', and I know that road tuning the car won't get my the perfect tune as there is no way of measuring wheel torque etc. Was about checking if it was ok to use the basemap VVTi figures as the +55 setting for VVTi would be at its most advanced - just need to check that this won't cause issues with piston and valve clearance considering it is a generic starting basemap which I would be guessing would be a safe starting map.

I have some VVTi settings from some previous tuning on the Apexi PFC which I think were optimised closer to the 1UZ from memory (in terms of maximum advance) - unless of course the PFC and Link ECU are opposite in terms of what is the maximum advance number.

If it has stock cams then you should be able to advance all the way to the mechanical limit without clashing.  Having said that, it is unlikely to result in optimum performance, often they advance that much more for EGR rather than performance.

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3 hours ago, Adamw said:

If it has stock cams then you should be able to advance all the way to the mechanical limit without clashing.  Having said that, it is unlikely to result in optimum performance, often they advance that much more for EGR rather than performance.

Thanks for confirmation, yeah these are stock cam at the moment, but as you mentioned, maximum advance isn't going to give optimal performance, when I was running the antiquated PFC I did try back to back with the VVTi tables optimised vs all 0s, made quite a difference in low end torque.

13 hours ago, JMP said:

not really sure why you're referencing the 1uz basemap for a 1zz...  Take a powerfc 1zz vvt map and translate that across to work.  In Datalogit or the hand controller, a value of 50 is equivalent to zero cam advance in the Link.  So you export the powerfc vvt table to excel, then do some simple math to subtract the table value from 50, and you will have the equivalent Link advance number.

The challenge will be the powerfc load values don't correlate easily, but once you see the shape of the vvt table with regard to RPM it's easy enough to get in the ballpark for a Link table.

I was using the 1UZ basemap as a starting point as I didn't have any other VVTi figures to go from, not ideal but going from a table with all 0s to the 1UZ map has yielded a fair improvement in drivability low down although not optimal.

I did fire up FCEdit again last light and loaded one of my old PFC maps, I had been using them to check the maximum ignition timing the engine was running on previously (was using Copilot to log and adjust ignition depending on knock), I have matched up the PFC map with the Link map, it would seem that full load on the PFC was at around 11,500 - as the engine is NA that would equate to full vacuum, I had previously logged which cells were being read from as well and can match this up using the mixture map view.

I believe the maximum value in the PFC for VVTI was at 28 or 30, 55 would be the highest value in the PFC so that would equate to between 25-27 in the Link so might nudge back the VVTi figures using the 1UZ or perhaps one of the basemaps to get the curve. I think I also saw a setting within the Link help file that stated that I can set it to degrees advanced rather than degrees from fully retarded which might mean I can use the figures from the PFC.

I will be going a few drag runs in the next month or so, will be logging data for each run and might do a few adjustments where needed, I did find however that the VVTi optimisation is only really useful at the lower RPMs meaning that for a 1/4 mile drag run it will only be of use in 1st as after that the RPM will probably only drop to 4k or so between shifts so it will probably only run through the VVTi cells once in each run.

@Adamw thanks for confirming that if the VVTi goes fully advance it shouldn't cause issues from a mechanical standpoint - that is mainly what I was concerned with.

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