Had very little luck finding quality information on theory for tuning intake VVT on turbo TT & race cars.

My theory is the best/only reason for VVT on a turbo car is to help with spool, which given my EFR 6258 is almost instant anyway, but bigger turbos or heavier compressors could use a push.

After warmup lap I'm never below max boost window except for shifts and cornering. Tuned for high flat HP curve, so high torque falling off to maintain even HP.

Question about dropping down to zero on shifts creating overly aggressive VVT sweeps and integral windup trying to match.

Would it be better just to keep VVT angle the same as on boost angle to prevent bashing the VVT up and down? Realize it may drive like crap in the pits but really don't care.

Mine is an extreme case as i run nearly to 8K, although I run zero VVT angle above 6K. Have to retune anyway as I'm going return system so may as well address everything.

Normally only run 9 degrees at 2&3k dropping to nothing by 7k but thinking some changes are in order?

2nd photo shows start of my new but thinking of filling in 20-40KPA with equivalent to 70?

NOTE; I would not recommend anyone copy and paste as my graphs are for a specific need and purpose.

 

full advance vs full retard at ~8psi:

 

I don't think he was asking if it was effective throughout the rev range, rather what scaling is best for his use.

Blkbrd69, I have seen the VVT gear unable to return to full retard when not commanded soon enough, so I would suspect you're right, you want it commanded 0 advance in higher boost, however I might even 0 out the 5000rpm column. Best bet is to datalog it and see if angle tracks target during a ~2-6 gear pull.

 

Braineack;
I'm familiar with torque vs RPM gains w VVT as I played a bit while doing my TT3 dyno to flatten my HP curve for NASA TT3. Mine never crossed at 5252 as pictured does when doing a HP calculation. Find it a bit odd in that representation it does, of course I was using 20* not 40*?

Curly;
Correct I have seen high RPM lack of control of VVT, my motor changes RPM so quick it seems VVT cant keep up on rapid changes. (lightened rotating assy. & dual clutch) In my car 20 degrees seems a safe zone. I am thinking a little VVT loss is acceptable to achieve a soft landing.
More than looking for gains in HP or TQ I'm looking at completely using it for spool and stability during shifts where at lets say turn 7 at Sebring I'm going from 5th to 3rd then letting torque pull me out without lighting up my tires and saving a shift. (Closed loop EFR so I can compensate).

Very difficult to get true consistency on dynos I have available to me. Also to get true overlapping runs I would have to run on spring pressure only, and that doesn't account for changes in optimum spark for VVT angle. (possible reason you see large swings in some VVT dyno profiles?) No load bearing hub dynos I know of in Orlando, and pulls add up $$$ & heat up quickly. NASA is very specific on what dyno I can use.

Really wondering if I should use an oddball road course only tune, to not have VVT try and change so extremely during shifts??????

Emilio / Savington / Trackspeed & other race tuning gurus are you still out there?

 

I can confirm experiencing VVT angle error when transitioning from advance. It is especially noticeable in lower gears. I spent too much time on this and am convinced it is a limitation of the VVT, not a tuning thing. This is more of an issue with heavy doubles.

Honestly, if I was to start from scratch today I would ditch VVT and stick with BP4W. I do not track though.

 

In MS3, I'd often have to fine tune PID settings for each engine to reduce or eliminate lag/overshoot on VVT commanded vs actual. Would also have to adjust baseline. Every BP6D engine was different. Gotta wait until oil is hot before messing with PID settings of course.