On that graph, is the -100 the same as 0 and -0 same as 100? Thats a little confusing to me, i want to make sure i am reading it right.

What is the VVT angle showing at idle for those with megasquiret? Mine seems to be higher than expected. VVT request is 3.0 while the actual angle is around 14 as shown in tunerstudio.

 

0kpa is full load/WOT anything below that is vacuum

 

What Tunerstudio parameter do I monitor to determine the min/max cam angles when I change the duty cycle from 0 to 100%? I have VVT_ang1 (to monitor actual cam advance) and VVT_target1 (to monitor the requested cam angle), but both of these are relative values, showing just the amount of advance.

 

Gunna read more of this thread

 

Set min/max values to zero, then use the test mode. The VVT angle gauge will show the actual angles for 0 and 100 duty cycle. Write those numbers down, and use as your min/max values.

4.19.2 (pg102): http://www.msextra.com/doc/pdf/Megas...ing_Up-1.3.pdf

 

Ok, guys... need a little advice on my VVT tuning.

Stock '01 motor in NA chassis, except for the intake tube and filter, and the exhaust from the stock downpipe back. MS3/MS3X, idle control on IDLE, fan control on FIDLE, and VVT on NITROUS 1. Also, I live at 5000ft, so atmospheric pressure is ~ 81kPa.

VVT settings:


VVT table:




The issue I'm having is instability in the VVT angle, sometimes on the upslope, but more often on the downslope. Sometimes it will spike after an advance event when no advance is called for. I've played with the PID settings quite a bit, and the behavior seems to be best where they are in the settings above.

Example of upslope instability:



And on the downslope:






The last one concerns me the most, since it's showing a big spike where no advance is commanded.

I'm a total newb to this tuning thing, but even after spending endless hours reading the manuals and threads I'm afraid I've missed something simple... I attached log and tune files.

Anyone have an idea what changes to try?

 

Ps, none of the pictures work. Yo need to link to the "Direct" link, it can be found on the right within photobucket.

 

OK, I've never had an issue before, but I edited the post... Are you seeing them now? I can't tell a difference because they were working for me before...

 

The're working now.

 

Roda stupid question but was the oil up to operating temperature? I believe I have noticed in my data logs that engine temp is playing a role in target/command discrepancies.

Otherwise it's closed-loop tuning as far as my limited knowledge of the subject.

 

I have the minimum temp for VVT set to 140*. This particular log should be normal operating temps. I'd look at the log, but I'm at work and don't have access to MLV here. I had not noticed any correlation to temperature while tuning, but I wasn't really looking as it was always in the 180* range.

 

Try to make it more linear. VVT has a certain window of operation and going from basically 0 to 40 can and will cause loss of power. Try to set your 2700 rpm column to 25 degrees.

 

Just got my vvt working properly (I think), but my min/max values are only 287/315 which seems like a smaller sweep than usual, can anyone chime in as to why that might be?

 

Hello from Germany,

I know, this thread is so old it could be the first of this forum, but my question is directly linked to it - call me grave digger if you want.
I was setting up VVT today and realized that I have maybe an issue with my intake cam.
Car is a '89 Miata with 1.9l VVT engine, EFR6758TS, Laminova water to air intercooler, RX7 drivetrain and MS3x on 100octane.

In most cases, the Min and Max for VVT angle posted in the forum is around 270 and 315-320.
However when I was testing the VVT it starts at min 291 and maxed out at 336. DC is Min 36 and Max 45.


Now I made some WOT pulls in third gear without boostcontrol (just wastegate spring), adding 10° each time and the difference is tremendous.
Not just spoolup and low end torque was effected but also torque over whole rpm range is improved a lot.


Power calculation is based on rpm/speedchange over time. Black lines are with 30° advance (from datalog, in TS I entered 40° ... strange enough) and green & red lines are 0° advance (no VVT)


Due to the fact, that the Min and Max values in this Forum differs from mine and the torque improved over the whole rpm band I consider, that maybe my Cam-timing
isn't correct. However I checked that when building the engine but **** happens sometimes.

Would like to hear your comments to that ... if you have one

 

Hi Tim,

we had this with a friends build (also a VVT swap in an earlier Miata)- and other instances - the timing is very likely one tooth of.