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I am wondering how to adjust the variable cam setting and What the limits are and how to go about making changes safely . I have a 2011 silverado 1500 5.3 flex fuel .
also want to know later if I change cams what would be the process to figure out how to adjust then, also will be eliminating all DOD in this engine any help is great Thanks in advance for any help.
Best just to mess with the wot cam setting only and that's if your still using a variable cam with the new one... Most cams are 3 bolt and fixed - just set these to none in the main switch parameter... No need to really mess with a stock cam setting - they're pretty spot on from the factory...
So on the WOT setting on the stock cam what would be the max safe limits to advance or retard the cam , would like to try a little but want to be on the safe side trying new things. from old school where cams wernt variable and used a degree wheel to set up initally and then run it and not worry. So with that like keeping things on the safe side.
If I remember right yours starts to retard at 4000RPM, is maxed out at 8 degrees (of retard) and does not even reach 8 until 6400RPM. GEN4 6.0 all seem to start to retard at 3800RPM and reach a max of 9 at 6800RPM. 1500 series pickup/suv 6.2 start retarding off idle and max out at 12 degrees by 5800RPM. Maybe somebody with a dyno knows if going over 12 is beneficial. Either way 12 is safe. As I mentioned in another spot I have picked up a good bit of light/medium load torque on GEN4 6.0 by using the GEN4 6.2 cam strategy. There is a noticeable power increase at the top too.
so if it is advanced 2deg to start and retards 8deg total it would end up 6 total retarded . and I could go as far a 12 retarded . and this is good for 5.3 . now the question is how to make the adjustments in te program the right way without messing up , I am being very careful want complete description before making changes so that I can study and think before i try anything thanks
Quote:
Originally Posted by IARLLC
would these be the intake base angle maps ; take the 6.2 maps and copy and paste them to my 5.3 map
Maybe this is a better place for this answer:
Yes. You can just open your tune file then do the compare file thing with a similar year 6.2. Engine>Airflow>Variable camshaft>Intake camshaft>Base angle> I blended all three tables (Low, Medium, and High) keeping the smooth blend from bottom to top but I reduced the major advance bump in the low/mid range to about 25% of what GM had.
In addition to this after LOTs of time looking at ignition profiles I decided to keep the tuned timing curve from the 6.0 and use the Engine>Spark>Advance>Variable Cam. Since I already had a functioning Variable Cam map to adjust timing during cam variation there was no reason to start over. Comparing map after map after map I saw that GM advanced the ignition timing about 1.5 additional degrees for about 4 additional degrees of cam retard. In a separate window I kept a map of my cam advance "show differences". And based on these differences I increased or decreased timing at a rate of 1.5 additional degrees of ignition advance for each 4 additional degrees of cam retard. Since the maps use the same axis it was pretty easy to just look at whether I increased or decreased cam retard and increased or decreased the ignition timing.
For example the whole right side of the cam advance map will be retarded 3-4 more degrees (12) than it used to be (8.5-9). So the same exact points on the variable cam ignition advance map I increased timing 1.5 degrees. In the lower/middle area that used to be 0, if it now has 1 degree of cam retard I add .3 degrees of ignition timing, etc, etc. I hope that was clear enough. It took a while to get my head around how I would do it.
It might take a bit of rework on the ignition curve after this depending on the gas quality and this and that...but this is what I did and I really liked the results. Enjoy!
so with that i will take my time and build the map slow and methodicly . one final question in the intake base map are all the numbers represented retard numbers . if so is there a way to advance the cam in the lower areas say another degree or two to help the bottom end as well
The cam's park position (0 on the intake base map) is 7 degrees (Some say 8.5, some up to 17(maybe crankshaft degrees). Since GM starts the motor in the park position and keeps it there up to 3800RPM, I think 7 or 8.5 must be correct.). So on the LY6 6.0 most of the table up to 3800RPM the map has the cam advanced 7 degrees and at 3800 the cam's position begins to gradually be reduced to 2 degrees retarded (9 on the table). Then there is the low/mid load range over-retard which reaches as much as 18 degrees of retard (25 on the table). mid load range .28-32 g. Cylairmass.
As I stated before, I seriously reduced the low/mid-range over-retard especially in the mid range. Some 0 it out which I am sure makes it even more responsive. If you have looked at the 6.2 tables you will see their "low" table has none of it, the mid table has a normal amount, and the high table has it even extending up to .56 Cylairmass (way too high for me, loss of response and mid-range power).
I am sure that reducing the low/mid-range cam over-retard on a 5.3 will make it more responsive...but I would still expect that 7 degrees of cam advance it too much up to 4000RPM. I am pretty sure that you will gain some more in the middle by starting the retard earlier (like the 6.2) and gain even more on top by reaching up to 12 or more (at least as much as the stock 6.2).
Made the changes in the VVT map , I went with a Linear layout. I started to pull timing at 2800 with 1* and worked to 12* at 5600. All I can say is that it is an unbelievable difference got a 5.3 truck stepping out and running , like I just added 50 to 75 hp way it feels probably isnt that much but is that dramatic of a change. I want to thank everyone for the guidance on where to start and how the vvt system works
That is awesome! So happy to hear it. Did you change ignition timing as well? Have you had a chance to log some driving and check for KR?