Odd problem when scaling back L67 MAF and injector tables

[skalor]

For reference, this is a '99 L67 with a ported TB and an AFC set to 90%. I hit about 10,750 Hz on 16 psi but I'm maxing out the airflow value in the last eight cells of the MAF table(ie. they all read 67.725). I thought 'no problem', I'll just scale back the airflow tables and injectors together and I'll be fine. So, I scaled them both back to 70% as that would net roughly 67 lb/min in the last MAF cell. Loaded in the tune and the AFR is exactly where it was before and the trims are inline with what they were before. There is a problem however and the RPM decay is much slower than it was before. It takes a while for the RPM to come back down to idle(900). Even after the slightest blip it's at 1500 rpms and it takes like 30 secs for it to drop. The IAC values don't seem to decay as fast as they did when it wasn't scaled back. Anyone run into this before??

I'll get a scan of it sometime today, but here are the original and scaled files for comparison.

[5_Liter_Eater]

you will need to look at all other airflow/airmass tables and scale them accordingly too. Most notably the spark table. For that one you'll need to take the values in the airmass columns and shift them. So the values in the .80 g/cyl table will need to go in the .56 g/cyl column. Start at the top and work down. Watch out for overlaps.

This won't help your RPM decay though and unfortunately you do not get to see the tables you'd need to modify with your PCM. All you have in the idle tab is the target idl speed. You don't see the minimum idle airflow that is seen in other PCM's. Unless you can get HPT to add them, if thats even possible, you are stuck.

[5_Liter_Eater]

If 70% put you well under the airflow limit perhaps you can bump it back up until you're right at the 67#/min at redline and that would make the hanging RPM less noticable.

The other thing you can do, which is sort of a hack, is see what RPM you're hitting the limit at with the IFR and airflow tables not scaled and increase the PE artificially from that RPM up to redline. It is a "hack" as you're not metering airflow at taht point but without a way to cure the hanging RPM that is your only other option.

[skalor]

I did try it at 80% and 90% and it was still there but was significantly less. The problem is that I really need to scale it back 70% because I want to run a couple more psi and I'm already maxing it at 16 psi with 6 cells left in the MAF table. I have another tuner that lets me edit raw binary files. I wish HP Tuners still saved as binary because now I have to start from scratch and edit the values with that and then open it with HP Tuners and copy over the rest of my tune.

I looked at an LS1 file and it looks like we get the short end of the stick again. I can't believe how many extra parameters and tables there are that we don't have. I wish Keith was still a V6 guy.

[skalor]

I went out a logged it with the scaled tune and it was at ~.64 lb/min at idle, which is 4.91 g/sec at ~900 RPM. After looking over a couple tables, it looks like I'm almost underflowing the table in the screen cap like you mentioned. Am I on the right track??