05-06 AVCS Logic & Testing

[covertrussian]

I've been messing with AVCS a lot lately and wanted to share my findings. I'll update this thread as I find more things that are relevant.

 

AVCS stays at 0* until water temperature is above 140F, even then you have to come to a dead stop for a second before ECU starts advancing the cams. What's interesting is if you reset the ECU, AVCS angle will be at 4-5* instead of 0*. This also explains why these cars suck on gas in the city, especially with short trips.

 

ECU forces 0* if your AVCS map calls for less then 7* advance below 2,000rpm. This one was very odd, I tried running 5* and 6*below 2k rpm, but ECU would force 0* advance until 2k rpm, after 2k it ran 5* no problem. Running 7*-10* would instantly advance even at idle. Perhaps this is a failsafe?

http://legacygt.com/forums/attachment.php?attachmentid=221836&stc=1&d=1451016987

 

Right AVCS tends to be higher then left. I've done a few logs recently, after summing up each AVCS angle column, right was usually around 500 points higher then left. I wonder if the right side, I'm assuming this is passenger side which is teed with turbo, simply sees more pressure (because of a different connection on the head). One caveat is highway, my highway log showed left side having about 20 point more.

[need bb]

Thanks for the info. I spent a lot of time researching AVCS and never found a consensus on what was best to run.

[covertrussian]

Thanks for the info. I spent a lot of time researching AVCS and never found a consensus on what was best to run.

 

That's because there is no answer that will 100% apply everyone. I personally found that running 10* cruising seems to yield me the best mpg's with my current mods.

[xt2005bonbon]

I am glad you're having a look into this. I've been paying very close attention to mine as well while driving on the highway, and did notice the left one (driver side) is hovering around 1-2 deg while passenger side around 0-1(but mostly zero). This occurs while cruising without real load (e.g. flat road).

On some days, I even see the left hovering around 3-4 with the right being 0. This makes me think that the left one may be slightly sticky?

[Phate]

I am glad you're having a look into this. I've been paying very close attention to mine as well while driving on the highway, and did notice the left one (driver side) is hovering around 1-2 deg while passenger side around 0-1(but mostly zero). This occurs while cruising without real load (e.g. flat road).

On some days, I even see the left hovering around 3-4 with the right being 0. This makes me think that the left one may be slightly sticky?

 

That might be intentional due to the unequal length exhaust.

 

AVCS stays at 0* until water temperature is above 140F, even then you have to come to a dead stop for a second before ECU starts advancing the cams. What's interesting is if you reset the ECU, AVCS angle will be at 4-5* instead of 0*. This also explains why these cars suck on gas in the city, especially with short trips.

 

Will vouch, have a short drive to work, during most of which the car isn't up to temp yet. It's not chevy tahoe-bad, but it's not too far off.

[xt2005bonbon]

That might be intentional due to the unequal length exhaust

 

Huh. I actually never thought about it. Why would this only affect low load cruise, and not all situations though?

[joeleodee]

I've always wondered what the AVCS should be set to for optimum performance as well. Is there also possibly a way to squeeze a few more ponies or torque in the lower rpm range by applying some AVCS adjustments. Subscribed.

[covertrussian]

I am glad you're having a look into this. I've been paying very close attention to mine as well while driving on the highway, and did notice the left one (driver side) is hovering around 1-2 deg while passenger side around 0-1(but mostly zero). This occurs while cruising without real load (e.g. flat road).

On some days, I even see the left hovering around 3-4 with the right being 0. This makes me think that the left one may be slightly sticky?

 

Did you pull out all of your banjo filters, even the driver side one? I believe I saw similar behavior on my left side until I pulled the banjo filter behind the timing belt cover. I think what might happen is, if the filter is clogged enough, the oil doesn't drain back as easily thus causing it to over advance.

 

My driver side filter:

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/Engine/General/Banjo%20Filters/CIMG0768.jpg~original

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/Engine/General/Banjo%20Filters/CIMG0771.jpg~original

 

 

That might be intentional due to the unequal length exhaust.

 

Since there are no bank specific compensation tables, it should follow the map to the dot.

 

I've always wondered what the AVCS should be set to for optimum performance as well. Is there also possibly a way to squeeze a few more ponies or torque in the lower rpm range by applying some AVCS adjustments. Subscribed.

 

It will vary greatly by your exhaust and turbo. I found that I was knocking a lot more with a stage 2 downpipe, thus had to reduce AVCS a good bit to get rid of that knock.

 

Here's an example. I was running this map on the stock downpipe, which is just the stock map with the 0's and 5's replaced with 10's in 2400-3200 rpm range

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/ECU/AVCS/AVCS10.png~original

 

With a stage 2 downpipe (still catted), I had to move the 15's and 20's back to higher loads.

http://i160.photobucket.com/albums/t188/covertrussian/Cars/05%20LGT/ECU/AVCS/DPSTG2AVCS10.png

 

I might test with getting rid of the 15's and 20's altogether, but I'm gonna be installing a bigger turbo soon, so probably wont get a chance to really play with this.

[DK76]

That very strange on banjo filters: my 05 had filter in pre-turbo bolt only, none of the others, although I couldn't reach the one behind timing belt cover, now Im concerned. On a side note, i have been running your stage 0 tune for the last 7 months and extremely happy with it. I'm itching to upgrade downpipe and maybe turbo, but want to keep all the safety and reliability of your tune. Advice?

 

Sent from my SM-G386T1 using Tapatalk

[xt2005bonbon]

I did get rid of the filter on the driver side as well. So that's not the reason for my 1-2 deg average on the driver side in low load+cruise situation. Your filter did look pretty dirty btw. Good timing.

[covertrussian]

That very strange on banjo filters: my 05 had filter in pre-turbo bolt only, none of the others, although I couldn't reach the one behind timing belt cover, now Im concerned. On a side note, i have been running your stage 0 tune for the last 7 months and extremely happy with it. I'm itching to upgrade downpipe and maybe turbo, but want to keep all the safety and reliability of your tune. Advice?

 

Sent from my SM-G386T1 using Tapatalk

 

It's there and depending on how your preturbo filter looked it might be a good idea to get it out. If you shave the bolt enough you can remove it with the covers still in place. See Hammer Down's post on how he did it.

 

Second part of your post is a bit off topic, but I'll quickly answer. Most stage 2 tunes have all of those safety features already in them, heck even stage 1 tunes. Reason I did the stage 0 tune is because I didn't want to crank up the boost just to disable factory issues. I should publish my stage 2 tune, but it's not something you can just blindly run like the stage 0 one.

 

I did get rid of the filter on the driver side as well. So that's not the reason for my 1-2 deg average on the driver side in low load+cruise situation. Your filter did look pretty dirty btw. Good timing.

 

I think your solenoid is on its way out then. That's the only thing I can think of.

[xt2005bonbon]

So, when you're cruising in low load conditions, can you confirm that both of your OCVs show 0 deg?

[DK76]

Thank you, my pre-turbo filter was absolutely clean so I'll wait another 10k to do timing belt and then remove filter from driver side bolt.

 

I know my question was off the topic, and I thank you for taking your time and answering it.

[covertrussian]

So, when you're cruising in low load conditions, can you confirm that both of your OCVs show 0 deg?

 

I don't run 0* anywhere, so don't have any logs to show it as such. I will say that while the car is warming up and I'm driving, my AVCS stays at 0* on both sides, it might go up to 1* tops.

[xt2005bonbon]

But, say you're on a flat road going @50mph with cruise on (note flat road), what do your OCVs report then?

[covertrussian]

I'll have to look at logs to verify but it's target is 10*, and actual will be +/- 1* usually. But keep in mind I'm not on stock AVCS map (you can see it above). I might reflash a 0* map, but I doubt I'll have the chance soon.

 

EDIT: I just remembered I did some 0* testing last year, I'll take a look at the log later on and will let you know what it looks like.

[xt2005bonbon]

OK thanks.

[covertrussian]

Well I looked and realized that I only logged one side. If I reflash a new tune on I'll try running AVCS at 0 and will report back.

[covertrussian]

Made a quick and dirty 0 AVCS tune, basically it's 0* until about 1.40g/s then goes to 10*, which means ECU will interpolate and start advancing at about 1.20g/s column.

 

Tried to upload the whole file, but got denied since it's 600kb. Split it off into a dedicated hwy log and dedicated city log.

1229_64f_AVCS0_Hwy.csv

1229_64f_AVCS0_City.csv

[xt2005bonbon]

ok I just plotted your Hwy log. But first, to make sure I understand, did you modify how your AVCS are supposed to perform in low load conditions prior to doing this log? You said you made a 'quick and dirty (..) tune'.

 

In any case, your log appears to be 70 sec long, and only once your vvt left jumped to 1 while vvt right stayed at 0. My left one keeps going back and forth between 0 and 1 (and maybe 2) in such conditions.

 

Interestingly, my 06 does the same thing as my 05.

 

Which oil are you using?

[covertrussian]

I just set the AVCS to be 0* under 3400 rpm and 1.40g/rev. My normal tune runs 10* from 800rpm to redline under 1.40g/rev and 15-20 above that load range.

 

That's about a mile long log, got on the highway quickly and dropped off on the next exit.

 

I use Valvoline Synpower 5w30, around 1k miles on it right now.

 

Check out this log, this from the bigger log but with filtered columns showing AVCS greater then 2 basically. You can see a little more inconsistency in the two cam angles in this one (probably due to quick throttle changes and cams weren't able to keep up).

1229_64f_AVCS0_Higher Load.csv

[xt2005bonbon]

Just looked at it. Interesting that you already have some flkc at such low load just after installing that tune.

 

Do you constantly view or log your ecu when you drive? What do you use to do this btw? I use the btssm app every time I drive.

 

I use Rotella 5w40 btw.

[xt2005bonbon]

Also, how many miles on these OCVs?

 

My 05 has 79k and I've never changed them

My 06 has 139k. Only owned the car for 1.5 years now. So I don't know if they've ever been changed. But they are performing OK. So I am not touching them.

[covertrussian]

I'm messing around with timing and lowered the FLKC and FBKC limits so that's why it's overly sensitive. I did find that with AVCS being at 10* it would knock less then with it being at 7*, guess at those low speeds UEL headers and small turbo doesn't provide that much backpressure.

 

When I'm recording logs yeah, I just have my laptop and Rom Raider in the passenger seat and I glance over it every now and then.

 

Rotella is some thick stuff, I got piston slap with it in winter months so I switched back to 5w30. Maybe it's staying around in the solenoids longer hence over advancing?

 

125k miles on the OCV's and whole Engine actually.

[xt2005bonbon]

I'm messing around with timing and lowered the FLKC and FBKC limits so that's why it's overly sensitive. I did find that with AVCS being at 10* it would knock less then with it being at 7*, guess at those low speeds UEL headers and small turbo doesn't provide that much backpressure.

 

When I'm recording logs yeah, I just have my laptop and Rom Raider in the passenger seat and I glance over it every now and then.

 

Rotella is some thick stuff, I got piston slap with it in winter months so I switched back to 5w30. Maybe it's staying around in the solenoids longer hence over advancing?

 

125k miles on the OCV's and whole Engine actually.

 

Gotcha. Yeah I also thought about the fact that Rotella is thicker and may have some impact on the OCV performance. I guess, what I should do is probably swap the OCV L/R and see what happens.