LSA tuning, A/F ratio adjustments

[Eightsecv6]

I bought the shop version of HP Tuners and VCM suite. I have yet to even install it on my PC. I have a Dynojet 224x and plan to tune my personal vehicle a 2011 CTS-V to familiarize myself with the software. This brings up my question, I have read a little and this seems to be a nightmare to adjust something as marginal WOT A/F ratio. I am proficient in tuning Accel DFI, BS3 and F.A.S.T. efi systems. Is this software that difficult? For example, if I have a flat A/F ratio of 13:1 from 3000-6000 RPM an I want to increase it to 12:1, what steps need to be taken? I can accomplish this in less than 30 seconds on an aftermarket EFI.... Am I missing something? Thanks in advance!

[ScarabEpic22]

Welcome, and no you're not missing anything. With the Gen IV ECMs, GM went to a coefficient-based VE table. As in, there isnt a VE table available to edit. You will want to look at Bluecat's EQ_VE to dial your fueling in. Once you have the fueling done, then it is as easy as changing the WOT PE table from 13:1 to 12:1. BUT, you HAVE to have the coefficients dialed in correctly otherwise 13:1 could really be 14:1 (get your wideband out!).

Hope that helps a little.

[SultanHassanMasTuning]

if your tuning via MAF to adjust your fueling follow these steps

under the fuel tab

go to power enrichment

EQ ratio which is a division of the stoich AFR so (14.68/1.33)=11 commanded AFR

if your vehicle is stock with little mods adjust your Maf curve to reach your commanded fueling (by adjusting the curve) WOT MAF hz above 5,850 and above is where you wanna be adjusting.

the software is not complicated, its just requires more time to get familiarized with then from the standalone EMS's

[MikeOD]

I bought the shop version of HP Tuners and VCM suite. I have yet to even install it on my PC. I have a Dynojet 224x and plan to tune my personal vehicle a 2011 CTS-V to familiarize myself with the software. This brings up my question, I have read a little and this seems to be a nightmare to adjust something as marginal WOT A/F ratio. I am proficient in tuning Accel DFI, BS3 and F.A.S.T. efi systems. Is this software that difficult? For example, if I have a flat A/F ratio of 13:1 from 3000-6000 RPM an I want to increase it to 12:1, what steps need to be taken? I can accomplish this in less than 30 seconds on an aftermarket EFI.... Am I missing something? Thanks in advance!

I think what everyone is saying is first you need to dial in the actual AFR to be equal to the commanded AFR...this can take a little bit of time to actually get enough data points to dial it in and have it be smooth, but you'd have the same situation with a standalone like you mentioned...especially starting from scratch on a new combo...once you understand where the data lives and how the PCM uses it, you'll see that you can actually setup the scanning software so that all you have to do is click copy and paste to make commanded equal actual.

Once you've got that dialed in, if you make a pull on the dyno and you decided you want to go richer or leaner, from one specific AFR to another, yes, you make 1 very quick change to the commanded AFR in the Power Enrichment table, and reflash (takes seconds on these new cars), and you'll hit the new desired AFR right away...once you've got commanded equaling actual, the wideband is a nice reference, but you really won't need it, you'll just need the HP/TQ charts to decide what fuel and spark you want, just like you're used to.

[RACELS1]

IF your vehicle is completely STOCK, all you should have to do is change your pe tables to your desired afr. IF your vehicle is MODIFIED in any way you must recalibrate for your mods.

[MikeOD]

I've never seen a stock vehicle hit the commanded PE AFR as accurately as I'd like. I've seen them come close, but never as accurately as they can be with better calibration.

[Eightsecv6]

Thanks all for the tips, im still stumbling through the software to get a better understanding of what is going on. There is a whole bunch of stuff that evidently will never be used by most! I cant seem to locate the "commanded AFR" anywhere in my PE table screen.

[Eightsecv6]

ok got the EQ RATIO part figured out on the PE table as the commanderd AFR. If my actual AFR is not in line with the commanded, what table is used to add or subtract to trim the fuel to fine tune? And why do I have a high octane and low octane table on the spark setting and how do I know which one im using???

[ScarabEpic22]

ok got the EQ RATIO part figured out on the PE table as the commanderd AFR. If my actual AFR is not in line with the commanded, what table is used to add or subtract to trim the fuel to fine tune? And why do I have a high octane and low octane table on the spark setting and how do I know which one im using???

If actual doesnt equal commanded, time to redo the airflow coefficients and MAF table(s).

High vs low can be logged with the spark scaler PID in the scanner.

[10_SS]

ok got the EQ RATIO part figured out on the PE table as the commanderd AFR. If my actual AFR is not in line with the commanded, what table is used to add or subtract to trim the fuel to fine tune? And why do I have a high octane and low octane table on the spark setting and how do I know which one im using???

To bring actual AFR inline with commanded, adjust the MAF table in ENGINE/AIRFLOW/MAF CALIBRATION. I would personally just adjust the PE Fueling table until your happy with your ARF unless you want to spend lots of time fine tuning the MAF calibration.

And you have HIGH and LOW OCTANE spark tables because OEM PCM's are good like that. If the PCM detects too much, or almost continuous knock, it will start shifting to the LOW OCTANE spark table and There is a parameter you can log to show you what spark table is in use called KNOCK LEARN FACTOR. If it reads 0.00, then it's reading 100% from the HIGH OCTANE TABLE. You never want the Knock Learn Factor to start incrementing. If it does, you have too much timing for whatever conditions your running (heat, bad gas, something wrong, lean, etc).

[Mike@G-Force]

To bring actual AFR inline with commanded, adjust the MAF table in ENGINE/AIRFLOW/MAF CALIBRATION. I would personally just adjust the PE Fueling table until your happy with your ARF unless you want to spend lots of time fine tuning the MAF calibration.

And you have HIGH and LOW OCTANE spark tables because OEM PCM's are good like that. If the PCM detects too much, or almost continuous knock, it will start shifting to the LOW OCTANE spark table and There is a parameter you can log to show you what spark table is in use called KNOCK LEARN FACTOR. If it reads 0.00, then it's reading 100% from the HIGH OCTANE TABLE. You never want the Knock Learn Factor to start incrementing. If it does, you have too much timing for whatever conditions your running (heat, bad gas, something wrong, lean, etc).

Please dont tune like this!

[Ben Charles]

Mike I agree, set PE to what you want (commanded) and adjust the MAF to match. With AFR error setup right, only takes a couple of pulls on most setups.

[Iam Broke]

Just say no to PE raping.

[Eightsecv6]

thanks for the help guys, I have not had any time to mess with it this week. Im going to put a bung in the exhaust and use the wideband on my dyno to verify things. From what I have looked through and read, I basically only need to tweak the MAF calibration to get the A/F in line with whatever I have in my "commanded" table

[10_SS]

Please dont tune like this!

Why not? It's extremely quick. Fueling is adjusted the same either way. And this way is allot less work since he says his AFR is flat which is the most important thing.

[Iam Broke]

Because it is not the correct way. It is referred to raping the PE table. You are fudging commanded numbers for a different result, not the commanded PE. The goal is to reach your commanded numbers with little error.

[Area47]

To bring actual AFR inline with commanded, adjust the MAF table in ENGINE/AIRFLOW/MAF CALIBRATION. I would personally just adjust the PE Fueling table until your happy with your ARF unless you want to spend lots of time fine tuning the MAF calibration.

And you have HIGH and LOW OCTANE spark tables because OEM PCM's are good like that. If the PCM detects too much, or almost continuous knock, it will start shifting to the LOW OCTANE spark table and There is a parameter you can log to show you what spark table is in use called KNOCK LEARN FACTOR. If it reads 0.00, then it's reading 100% from the HIGH OCTANE TABLE. You never want the Knock Learn Factor to start incrementing. If it does, you have too much timing for whatever conditions your running (heat, bad gas, something wrong, lean, etc).

::face palm::

[10_SS]

Because it is not the correct way. It is referred to raping the PE table. You are fudging commanded numbers for a different result, not the commanded PE. The goal is to reach your commanded numbers with little error.

Original poster asked this: "For example, if I have a flat A/F ratio of 13:1 from 3000-6000 RPM an I want to increase it to 12:1, what steps need to be taken? I can accomplish this in less than 30 seconds on an aftermarket EFI."

The correct answer to fix this in 30 seconds is: Adjust the PE enrich table.

Modify the MAF if you want to make the PE table match the calculated value 100%... but that's not what he asked, and there is no advantage to this time spent since his AF is flat (no real need to smooth or correct the MAF if it's flat, now is there?).

Adjusting the MAF, then dialing in the PE will only satisfy the anal, which I have done, but only in my free time to tidy things up when I have the urge to tidy things up. It wont do anything else. The best part is, your explaining how to rape the MAF table to make the PE table match. Whatever makes you happy.

[2xLS1]

Everyone puts so much faith in their wide bands too. How far off the stock calibrations are. I had one of my personal cars on two different dynos 1 week apart with the dyno's wide band in a bung, not a tailpipe sniffer. Exactly the same tune on both dynos. The A/F was a full point different between the two wide bands.

[Eightsecv6]

Everyone puts so much faith in their wide bands too. How far off the stock calibrations are. I had one of my personal cars on two different dynos 1 week apart with the dyno's wide band in a bung, not a tailpipe sniffer. Exactly the same tune on both dynos. The A/F was a full point different between the two wide bands.

You make a good point there! I have had my dyno for about 12 years and have made well over 20,000 pulls with it, I know when the A/F readings start to look a little lazy, its as simple as installing a new sensor and it brings it right back up to snuff. Mine reads within a .10 of what I see on XFI or BS3 widebands, I always use it to verify, I consider it fairly accurate