Basic VVT Tuning info

[viceroykarl]

I've stopped using GMVE all together and have been using MAF(SAE) in conjunction with VE Airflow. So far I've been able to get in some great settings on vvt. It definitely feels like its pulling harder. The intake cam heads towards 4 as the rpms increase to 7k and the exhaust heads to 16.

I tried setting the tables to have 25 all the way though, then logging as i ran out 2nd gear (automatic) and then set all the tables to 0 and did the same. Airflow was much higher at 0,0 than at 25,25 on the cams so i was able to figure that the tables for the LE5 are degrees of advance added. at full advance it was struggling to hit 16 on the maf and it felt slow, while 0,0 got to 18 and felt stronger higher up. Used that to settle into the settings iv got now.
Only thing i notice is that it really falls on its face after about 6700 rpm. The power just dies. Im seriously deciding on if i should upgrade to bigger lift/longer duration cams zzp makes or just wait ti'll next summer and just install a turbocharger and build up the trans since i've heard some good stories of some other 2.4 owners melting their trans after installing the zzp turbo kit. not to mention the stock 4t45e isnt rated for anything near that power
I can't really find any people saying anything about zzp's cams for the le5 though such as how the powerband is shifted since i'd rather not have to rev out to 8k to get peak power.

I'll post up what i've worked out after i test some new tweaks. Its based off the stock tables and then modified in the areas that are touched by heavy throttle areas that way it mostly keeps the stock mpg when cruising but (hopefully) gives better power when your putting the hammer down.

[cobaltssoverbooster]

no because the charge pipe sensor is not acurate under boost its accurate over 20psi
and my boost gauge is way over 25 psi so i know for sure its 40

[cobaltssoverbooster]

edit got the boost roped back in and shes accepting 22* at 3k and total timing is 24-25* an max hahah this ported head loves the timing holly F!

and she apparently wants more....

[cobaltssoverbooster]

good news on the ported head situation......running 24* of timing at 3k and maxing 27* up top 55-6 . she now has a useless second gear and is damn near about to spin third from a 3k pull. i am running the cams from gmtech that he posted was just curious how they worked on the head and they seem to be lovin it. and im running 23 psi on 93 10% ethanol pump blend from florida

[silverbullet08]

good news on the ported head situation......running 24* of timing at 3k and maxing 27* up top 55-6 . she now has a useless second gear and is damn near about to spin third from a 3k pull. i am running the cams from gmtech that he posted was just curious how they worked on the head and they seem to be lovin it. and im running 23 psi on 93 10% ethanol pump blend from florida

I would back the timing down. IAB pointed it out to me. I was running 25* from 3k up. I backed it down and tapered it up to red line. I noticed no power decrease... possibly more if anything.

[gmtech16450yz]

I would back the timing down. IAB pointed it out to me. I was running 25* from 3k up. I backed it down and tapered it up to red line. I noticed no power decrease... possibly more if anything.

Yeah, that much timing on pump gas might be too much, the motor will tell him though if it's too much. If he's running 93 with 10% E it should still knock before or at least right around MBT. You have to remember, not all motors are created equal, some of them won't take any timing and others just keep running stronger the more you give them. If he's in Florida (how come your sig says San Clemente?) maybe it's that hot humid air that's letting him get away with a bunch of timing.

I'm running quite a bit of timing on my setup, the more I give it the more power it makes. I've got logs with pretty much zero KR, pretty amazing for one of these motors. You should be able to run more with the E mix you've got too. Yes, you can go past MBT on Ethanol and not know it because it's not gonna knock, but you also need a little more timing since it takes a little longer for the E to burn compared to gas.

[silverbullet08]

good news on the ported head situation......running 24* of timing at 3k and maxing 27* up top 55-6 . she now has a useless second gear and is damn near about to spin third from a 3k pull. i am running the cams from gmtech that he posted was just curious how they worked on the head and they seem to be lovin it. and im running 23 psi on 93 10% ethanol pump blend from florida

Just reread your post.. Are you spraying meth? I dont see how you are getting 0 kr on 93 with 27* up top??

[cobaltssoverbooster]

im in flordia Military status hahah like forced vacation man its awesome.
aneways the ported head flows so much air its actually running very cool in the cylinder. i do have 2 step colder plugs. i have made every cell knock and now they are backed off 2 degrees from the point of knock for some leway. every adjustment made more power so pretty happy with where its at. my external egt is lower than before the head by like 20*

[wrickm]

Good Stuff, really want to thank GMTech and Viceroykarl for the general and LE5 infor respectively.
Let me just review what i have learned Thati might apply to my beloved Solstice
1.Best NA power is acchieved by limiting overlap at low rpms and inreasing overlap at higher rpms to create some scavenging
2. the LE5 charts are only in *advance with no negative values.
3. the raised value for advance in the middle of the charts are the "EGR hump" and are there to increase gas mileage.

This seems to be supported by the stock charts as the intake shows more advance at the low end (20) decreasing at the high end (5). whereas the exhaust remains the same throughtout wit the exception of the MPG adjustments in the middle.

In theory to increase powerin the top end i would want to lower the number on the top end of the intake cam thereby retarding the cam further and increasing overlap?

stock value attached

[cobaltssoverbooster]

yes but its a game between both cams

[wrickm]

here are a couple scans one before i minor cam adjustment and one after. I only adjusted the top end and just retarded timing on both the intake and exhaust a few degrees. seems like i might have gained just a little bit of airflow. there isn't a ton of room to retard timing more. Seems the solstice cam timing charts are pretty agressive at the top already.

[cobaltssoverbooster]

are you recordig the ve airflow with your recordings. because as you move them you watch that and by the seat dyno and watching the numbers increase in the ve airflow you will know if you are doing a good job. im asking because i didnt have time to look at the vcm files yet

[wrickm]

are you recordig the ve airflow with your recordings. because as you move them you watch that and by the seat dyno and watching the numbers increase in the ve airflow you will know if you are doing a good job. im asking because i didnt have time to look at the vcm files yet

i have been using an MAF (sae) histogram to show differences in airflow. Showed a modest gain of .2lbs/min at 6800rpm. though i haven't done enough testing to be sure. guess i can add VE too.

[silverbullet08]

Did a test today. made a set of cam tables that didnt have the EGR hump in them. Got the idea from Gmtech and always wanted to test it out. They didnt do as much as i thought though. I basically copied and pasted the flat areas in over the hump then manually smoothed it out. Made it look alot like a DAL table in a way. I thought about getting rid of the big hump on the intake cam maximum load column but didnt get time to see what it would do. Throttle response was noticably increased but not enough to compensate for the maximum of 27 mpg that i could achieve at 55mph 5thgear feathering the throttle back as far as possible and maintaining speed. It did make take offs from lights and going through the gears much much smoother. After swithching back you could feel where you hit the high advance or retard areas like the power comes in then out then back it up top.

[cobaltssoverbooster]

eww i wish i could engine dyno these id sit there for days to figure these out sounds like fun in my mind

[Leafy]

Did a test today. made a set of cam tables that didnt have the EGR hump in them. Got the idea from Gmtech and always wanted to test it out. They didnt do as much as i thought though. I basically copied and pasted the flat areas in over the hump then manually smoothed it out. Made it look alot like a DAL table in a way. I thought about getting rid of the big hump on the intake cam maximum load column but didnt get time to see what it would do. Throttle response was noticably increased but not enough to compensate for the maximum of 27 mpg that i could achieve at 55mph 5thgear feathering the throttle back as far as possible and maintaining speed. It did make take offs from lights and going through the gears much much smoother. After swithching back you could feel where you hit the high advance or retard areas like the power comes in then out then back it up top.

You should be able to tune those weird spots when accelerating out, I would just leave the hump in the cells you actually use for cruise.

[wrickm]

Just did another test and with increasing the intake cam retard and leaving my exhaust the same i got a substantial gain from 17.54lbs/min to 18.814. But dyno felt ok, but i don't trust my butt. I submitted the solstice info to D Barhill to get them added to the Virtual Dyno. It might not be accurate but if it is consistant it be nice to see the delta.

i am pretty pleased with 18.814 for a NA. 20.045 VE

Agree i have been trying to find time on a chasis dyno but they all seem to be closed or removed.

[cobaltssoverbooster]

good job man like i said the cams are a game, some motors like them both moved and then solo adjusted and others are already in a decent spot and just want to be solo moved. just keep tinkering, im in my tune everyday moving stuff around.

[viceroykarl]

For all the N/A'd LE5 owners
Alright, my summer course ended and I've had a week to fool around with all the various hypotheses I've had and worked out some pretty sweet timings for the exhaust and intake timings.

I've attached a log of my recent testing efforts as well as the most recent tune.
Mainly what i've been trying to do is maximize between MAF airflow and VE airflow. The results from the scanning logs is pretty good. It definitely pulls harder all the way out to 7k rpm.
Im still washing out the KR though but im trying to sort out real knock from phantom knock since my car can get kinda moody with that (it'll still show some kr even with tdc spark timing). Results may vary on that front
PE is leveled out for consistency with a small increase in richness at the topend as a tiny safeguard to reduce kr, though that'll get set to lean out later on once im happy with the cam timings

wrickm, i think you've gone the same direction I've gone. Your log looks pretty similar to what i've got going on though yours has got this weird jump/hump just before the top of the revs that bumps up the maf and ve. My maf values are a bit lower since Im still using stock parts but the ve airflow seems to be about the same
Pulling the timing on the intake back to 0* is where im at now for revs past 6800. What im still testing is how far I can go with exhaust advance to increase some overlap before it starts decreasing performance

[silverbullet08]

You should be able to tune those weird spots when accelerating out, I would just leave the hump in the cells you actually use for cruise.

Yea you can to a extent, but you dont realize how much of a difference it makes when you accelerate through one of those areas until you have tried this test. If you tune for it then the car feels like it has decent torque coming off a light then you have to keep pressing the pedal to maintain the pull when you hit the hump. With no EGR hump you put it at say 1/8th throttle and it just keeps pulling all the way up to your shift point. Il post up a copy of what i used. It litterally feels like the car falls on its face during the EGR hump after going back to the gas milage cam tables. I wish the cam tables were set up like the spark tables giving you like a min and max. You could avoid this then. And yes i will be leaving the EGR hump in there, ive just got to find the sweet spot to give me power at a low load take off and a low load cruize since they share the same cells...