Basic VVT Tuning info

[cobaltssoverbooster]

for LNF is it best to set the dals at a stationary value say 255 wich lands me at 19.5 psi with factory stage kit wastegate settings, then i raise the wastegate till like 82% until i reached 24psi and fine tuned it a little for the high rpm range OR raise the dals until i get higher boost levels and then once its close to say 24 psi throughout then use the wastegate controlls to fine tune?

[silverbullet08]

for LNF is it best to set the dals at a stationary value say 255 wich lands me at 19.5 psi with factory stage kit wastegate settings, then i raise the wastegate till like 82% until i reached 24psi and fine tuned it a little for the high rpm range OR raise the dals until i get higher boost levels and then once its close to say 24 psi throughout then use the wastegate controlls to fine tune?

The best way that i have found that i like it to set a steady 255 or higher "255 is supposed to be the highest the computer can read" in the right hand column for your DALs. Then use waste gate control to dial in third gear, then use Max engine torque vs.rpm.vs. Gear to limit 4th and 5th gear. If you dont max the DAL table and try to limit your boost in that table then you will notice a major boost loss in first and second gear. I believe this is how many other people are doing this as well. There are a lot of different tables posted here in ither threads to help you out. I posted a pretty good wastegate table to start with in BYTs E85 gasmilage thread. Its a little steep for other cars youll need to adjust the high load column.

[cobaltssoverbooster]

right im at 255 now and using the the wgdc% to reel in the boost but i dont have the proper space for a 4th or 5th run so the max trq X rpm X gear is currently like 90% until i get the space. the best way seems to be the way i have in mind.

[hhrfreek]

I thought with the LE5 that 0 degrees of advance was some random number on the table like 17 or something and any lower number was retard and any higher was advance.

I couldn't find any info on this. Anyone else?

Last fall I was following this thread and tried making vvt changes and logging and did not notice any changes in lb/min, accel. Now that I have a solid tune to go from I'd like to get back to the vvt tables for possible gains, especially up top since I am going to rev out to 7800rpms with SC/cams. Right now I am on the stock VVT tables.

silverbullet08, I noticed you mentioned elsewhere you were in the midst of working out an LE5 SC. Any progress/info on the cam timing?

[viceroykarl]

On the LNF that seems to be similar to the case but I have not been able to determine with confidence where the values in the table correlate to in terms of absolute values for the LE5. However heading the numbers towards 0 does retard the cams and going towards 25 does advance them. Its a bit tricky too because if i remember correctly the cams have 10 degrees of overlap already. I find that i make best low end torque by having my exhaust cam about 6 degrees more in retard to the intake and they both will be set in the table around 20 and 15 degrees for intake and exhaust respectively. I reintroduce the overlap as the revs get up while generally heading towards an overall retard in timing of both cams. Below 2800 rpm and the difference between the 2 is about 10 to 12.

hhrfreek, you should be able to kill out the overlap that the stock tables put in on the stock cams going past 3200 rpm in airmass areas above 0.76 g/cyl
I would think that should improve things so your not pushing the air right through when your in boost areas. Just set up the tables similar to the way they are for 2800 rpm and lower in between 0.6 and 0.76 g/cyl regions. Though I'd bring both intake and exhaust values away from as advanced they are in the lower rpm regions. probably something like 15* and 5* for intake and exhaust


Edit: Attached files are where I'm currently at with my NA LE5.

[hhrfreek]

Gosh! I just reread this entire thread

Now I think I have a grasp on this. Im gonna try what you said as it looks like I can eliminate quite a bit of overlap in the mid-high especially since it only increased with the zzp cams. I'll get around to this within the next couple weeks. I am going to try a few combinations on the same day/place so I can gather consistent info.

[viceroykarl]

Also I should note that the 2 tables I uploaded are for my current N/A setup. I forgot to label what the were. But it kinda shows what I did to increase my low end torque and increase the throttle response a bit down there while still trying to keep the EGR zone mostly unmolested so I can still get decent cruising economy.

[hhrfreek]

Tried to tackle this today, but no matter what I command from the variable cam tables I cannot get them to work. They stick within 1-2 degrees from the stock tables even if I am trying to retard them 5 degrees. Tried various numbers for both int/exh cams and they don't do anything. Almost like they are hardcoded. What am I doing wrong? This makes more sense as to why I didn't notice anything when I tried this before.

*Update:

So I had someone tune my car and within their tune there is an issue with the Torque Management.Supercharger. Supercharger fitment. If it is selected as "fitted" it will disable the baro reading for some reason and the VVT must need that reading to run properly. It appears as though somehow the variable cam defaults to stock setting when there is no baro reading disallowing modification. Now that I have the tune changed to not fitted I get a baro reading and I can adjust the variable cams.

I will try to log some data soon, but I am in the middle of getting e85 going right now.

[Spawne32]

On the LNF that seems to be similar to the case but I have not been able to determine with confidence where the values in the table correlate to in terms of absolute values for the LE5. However heading the numbers towards 0 does retard the cams and going towards 25 does advance them. Its a bit tricky too because if i remember correctly the cams have 10 degrees of overlap already. I find that i make best low end torque by having my exhaust cam about 6 degrees more in retard to the intake and they both will be set in the table around 20 and 15 degrees for intake and exhaust respectively. I reintroduce the overlap as the revs get up while generally heading towards an overall retard in timing of both cams. Below 2800 rpm and the difference between the 2 is about 10 to 12.

hhrfreek, you should be able to kill out the overlap that the stock tables put in on the stock cams going past 3200 rpm in airmass areas above 0.76 g/cyl
I would think that should improve things so your not pushing the air right through when your in boost areas. Just set up the tables similar to the way they are for 2800 rpm and lower in between 0.6 and 0.76 g/cyl regions. Though I'd bring both intake and exhaust values away from as advanced they are in the lower rpm regions. probably something like 15* and 5* for intake and exhaust


Edit: Attached files are where I'm currently at with my NA LE5.

Hate to dig up an old thread but did you actually get good results with this?

[Ecotec2.4]

I'll be trying to mess with the VVT real soon on LE5 turbo.
So advancing my exhaust a little should remove some overlap correct ?
and advancing the exhaust should be making the table numbers higher ?

Long read this thread was, guess I need to reread it, so much info.


Any more updates from anyone ?

Thanks

[cobaltssoverbooster]

The le5 cams were very picky with me I found best results moving them on the dyno. At wot if you make a change and your airflow goes up ie: G/cylinder or lb/min ve and fuel starts to get leaner then you have effectively increased your pumping efficiency. A motor is just an air pump so without a dyno use the included factory parameters to verify it's pumping efficiency. Increase efficiency = more power. That's all you can do without a dyno. Move the cams by 2. If a change is good move 2 again. Nothing happens try halving it to finetune. The cams will eventually hit the physical stops in the adjusters so once the duty cycle increases but cam position doesn't change then you know hit the max usable value in the tables.

Good luck.

[Ecotec2.4]

Thank you

[cobaltssoverbooster]

i know it wasnt an exact answer but its how we figure it out from scratch when it gets explored for the first time.

[viceroykarl]

Higher numbers are more timing retard, lower numbers are advace. Setting it to 0 degrees on the intake and anything over 0 on the exhaust gives you some positive overlap at the furthest advanced position you can get from the intake cam phaser. That methodology has worked for me so far. I've tried with both tables set to 0 and both tables set to 25 to see with my ass where the car starts picking up the power. Framed it up from there and then just used the VE data with a wideband to get the best VE by playing with different cam angle combinations. For me, i seem to net more airflow up top past 6500 rpm with my exhaust cams at 9 and intake falling from 7,3, and finally 0 from 6800 rpm to 7400 rpm with the aftermarket cams I have installed.

The next milestone will be carrying all of this over when I have the turbo that is sitting around in my room installed on the car. I'll have to rezone my map zones for the speed density tables to include the new kPa regions from the new map sensor and fuel it from there.

I'll have updates when I get the ball rolling on this sometime next summer. But the idea is, I've been working with the speed density data, using the bluefish tool to turn it into something I can look at in terms of VE and then just fiddle with the vvt tables from there to see if I can start getting it to run lean in places where it wasn't lean before, update the VE, convert it to speed density, feed it to the car and log afr error again. If it worked out and the VE value is higher then it was a good move for the cams. If you wind up with lower VE values then you're going the wrong way with your cam adjustments. In other words, if you see positive %afr error you moved more air, if you see negative then you moved less air... assuming you had a good VE or SD table to start with (if not, then just look at the changes between each log you changed the cam tables on).

[cobaltssoverbooster]

i suggest you do your own le5 cam thread since these two platforms are different.
great work and thanks for sharing

[fst100]

bump on a dead horse, im currently tuning an LNF in my HHR SS and need some guidance please. currently i have my intake cam angle phaser from 4200-6500RPMs at -8* and tapering closer to zero stopping at -4* and the opposite with the exhaust cam angle phaser. am i on the correct track?