On a 200? gen 3 5.3 with a 411 pcm, when following the hptuners help section user submitted VE tuning.
The MAF is shut off, I have some high timing numbers. What is used to calculate it?
Running normally with everything running I can convert lb/h to lb/s to grams/cyl and that equals whats in the program.
You mean like the cylinder airmass?
The timing table uses cylinder airmass and rpm.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Yea thats the problem when following the guide to tune the VE table. You program it for OLSD, it uses no MAF. Seeing how it uses no MAF what timing table does it use is the question. Has no idea what the cylinder airmass is with the MAF tuned out.Originally Posted by 5FDP
Of course it knows the cylinder air mass when not using the maf. It's a calculated value.
Cylinder airmass still works without the MAF.
This is from the HP Tuners help page.
Primary VE vs. RPM vs. MAP: This table is used to determine airmass per cylinder in case of MAF failure (Speed Density Mode) and also to provide a base airflow value to check for MAF failure. It is also used to provide transient condition correction to the VCM main airmass calculations.
This thread may also help.
https://forum.hptuners.com/showthrea...-Speed-Density
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Thats what I was looking for. I appreciate it.
The write up that I read says to copy the high octane spark table to the low octane spark table, which is misleading I think, because it doesn't use either table in speed density. Is that correct?
It will use one or both.
A factory OS with it put into SD will use the low octane timing table but if you went to a 1 bar speed density OS or 2/3 BAR OS it will use both.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
I was just running in OLSD to tune the VE table. The user contributed write up in the hptuners help section says to copy high octane to low octane.
I got some pretty big timing numbers in some areas and it caused detonation.
Some say tuning the VE table is useless since it uses the MAF most of the time. I made the ve table a lot richer it seems. Seems to run better though.
There are tons of write up and opinions on what and how to tune. Look for more than one opinion if you question something, don't just think that it has to be done one specific way.
Like said, the timing tables depends on what OS you are using. If the factory OS with no upgrade will revert to the low octane table if the MAF is failed but will still use both tables if using a upgraded OS for like a turbo/supercharger.
VE tuning NEVER useless. The VE is always working with the MAF no matter what. MAF only tunes still reference the VE table for several things. If you were to look at a factory truck calibration you'd see that the dynamic airflow switch over is at 4,000rpm. Meaning that it's using both a blended tune of VE and MAF up to 4,000rpm and then switching over the filtered MAF calculations afterwards. So to say that the VE is useless is just silly.
Use a wideband when tuning open loop and you'd know for sure if you made it richer or not. Takes all the guess work out and you'll know it's accurate.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
^^^AGREED!!!
Jason,
Some operating systems use the VE tables more than others. For example the old Black Box PCMs and the LT1 PCMs are heavily biased toward the VE tables. Even on the 0411 tunes the L31s for example do not switch to MAF only until 4,400 rpm. Having learned to tune those before having ever messed with the LS stuff is actually the reason I have been able to fix other peoples tuning disasters. I copy the high octane table to the low octane table. With the MAF enabled the PCM should always use the high octane table unless detonation is present anyway. If detonation is present you need to pull timing anyway rather than relying on the knock sensors to retard the timing. I ALWAYS first fail the MAF and tune the VE tables until I get them into the -5 to 0 range. If the vehicle is setup for a wideband I tune for an OL air/fuel mixture of 13.5:1 with closed loop disabled and the OL tables set for 13.5:1. Once you have the VE tables dialed in, enable the MAF. With the MAF enabled tune the MAF tables to reach the same values. Getting BOTH the MAF and VE tables dialed in will give the best driveability and the most stable AFR possible. You can tune only the MAF table by setting the switchover to something like 400 rpm, however I have found it better to just start with a dialed in VE table then tune the MAF in blend mode. With a well tuned VE table and MAF table, I often disable the switch over completely and run blend all the way to fuel kill. My switch point is set to 6,400 rpm on my 5.7 Express van and the fuel kill is set at 6,000.
Last edited by Fast4.7; 04-16-2018 at 12:55 PM.
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Last edited by Jason B; 04-17-2018 at 08:48 PM.
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