Tuning VE with supercharged engine

[mecanicman]

I am working on a 2003 truck with a 6.0L, a cam, headers, no cats, exhaust, and a vortec supercharger. I have tuned the wide open throttle and idle to an acceptable level. With only minor changes, the stock parameters are working relativly well for driveabiliy. I want to tune the VE table, but am unsure about how to procede safely. While in open loop, with all adders including PE disabled, the pcm will try to command 14.7:1. I need to tune this table to at least 4000 rpm and will see boost already. If I change my stoich value to a safer 12:1 to perform this, will I get the same results? Will this work? Will be using wideband.
Is this a logical plan? Any input from some one with expieriance would be appreciated!

[x454gtox]

Very interested in this post. I am in the exact same position as you with an almost identical setup. I am running meth also though which adds another variable. I assume you are sticking with a 1 bar maf tune?

[mecanicman]

Yes, MAF 1 bar tune. Once I have it tuned to 4000 rpm, the MAF table will be next.

[x454gtox]

Same as me. How much boost are you running? I am right around 11 lbs. I drive the truck almost exclusively on the street, debating whether a 2 bar sd tune would be worth the effort or not.

[98Camarod]

That's not the way I did mine. You should have your idle, cruise and part throttle as close to stoich as possible for the best performance. Just have you BE set to your desired AFR and when those requirements are met that will be your commanded AFR.

[mecanicman]

10 lbs boost is the most I have seen so far, but I am at a relativly high alltitude. We are probably running the same pulley.

[x454gtox]

Ya we probably are I am located at around 4500 ft elevation. Are you running meth? I was just looking over some of the information I have gathered about VE tuning and I didn't see that you should disable PE mode. The information I have states to set the pe table to your desired eq ratio. I could be missing something though. I had all intentions on trying this today but ran into some problems with my vista laptop.

[mecanicman]

No meth. Have not seen the need for it yet. I have read many different methods of doing VE. Some mention disabling VE, some dont. As I understand it, and why I am looking for clarification, as any fuel adder period will mess up your results. To correct the table, you can only log the AF ratio created by the table. PE would influance that(I think)

[x454gtox]

I may be way off here but in my thinking, the pe table is a divisor that scales the value of the stoich afr table. Therefore, it should have no more influence on the ve table than the values of the stoich table. So I don't see the difference in changing the stoich values while disabling the pe, or maintaining the stoich and altering the pe. I may be completely wrong though. I do know one thing for sure, I do not want to be going into boost at 14.7 afr. Hopefully someone with some experience will chime in and set us straight.

[mecanicman]

98camarod, to clarify, I would only set stoich to 12:1 to tune the ve table, not leave it there. My concern is being to lean with boost during datalogging to tune the ve table. I just want to know if this give me the same results to fix the ve table.

[cobaltssoverbooster]

im new to v-8 but v.e. tuning with a supercharger i have done on lsj I4. what we do is set the limits on pe mode to engage at 100 so its basically off and then we adjust the main ve until the graph reads very close to zero when set for stoich. last we adjust afr by changing the pe enrich table or fuel multiplyer x rpm as it shows in my tahoe. would this be the same for your setup?

[98Camarod]

98camarod, to clarify, I would only set stoich to 12:1 to tune the ve table, not leave it there. My concern is being to lean with boost during datalogging to tune the ve table. I just want to know if this give me the same results to fix the ve table.

You don't want to change the stoich value, leave it alone. Change your boost enrichment tables to compensate for the extra air in the boosted areas and set the threshold so that once you get into boost your AFR is what you want it at.

When you are just starting to get into boost, 1.14 N/A, 1.20 just when it starts making boost, and 1.25-1.28 from 3 pounds up, and set your PE table the same.

[cobaltssoverbooster]

close to the same i wish we had those boost enrich tables in the I4 that would be handy

[x454gtox]

The problem with that, is when using a stock os with maf there are no boost enrich tables. Really the only enrichment table short of IAT, is the pe table. He and I are in the same boat, still running the maf. This is one of the reasons I have been thinking about switching to a 2 bar SD tune.

[cobaltssoverbooster]

oh well even if you bumped the ve table to run afr 12.6 for a cquick say it will always be rich, and if you leave it alone it will always be 14.7 it will always adjust by removing or adding to achieve the set stoich. yea got a little hurdle there will take alot to set it out right unless you switched os as you say is poss.

[LosLS2]

I'm not really clear on what you are trying to do here. I do know that you dont want to change the stoich or it will throw everything off once you put it back. Why can't you just disable the MAF, set the PE for whatever it is that you want at WOT, and tune it with the wideband? If you meet the WOT criteria and get into PE, it will not mess up your data and you can still adjust the fueling based on the % error that it is showing.

[mecanicman]

Thanks LosLS2, that was what I was confused about, having read conflicting instructions. x454gtox, you were right about leaving PE enabled. Im off to try!

[x454gtox]

Great, Let me know how it goes. I am all but ready to try it myself.

[cobaltssoverbooster]

if you adjust ltft then it will always adjust to the stoich setting, thus changing the tables to get more fuel gets you nowhere. i think what you need is to turn the fuel trims off and run a maf only s.d. tune so now its per rpm and airflow the ltft always adjust to a set afr so turning the maf off and running boost on the adjusted ltft will always run a given afr until pe is enabled. which means if you get part throttle boost like going up a hill for example you will run lean and i see way more part throttle action than pe wide open so good chance internal parts will not be happy as it runs lean which everyone knows already.

[98Camarod]

if you adjust ltft then it will always adjust to the stoich setting, thus changing the tables to get more fuel gets you nowhere. i think what you need is to turn the fuel trims off and run a maf only s.d. tune so now its per rpm and airflow the ltft always adjust to a set afr so turning the maf off and running boost on the adjusted ltft will always run a given afr until pe is enabled. which means if you get part throttle boost like going up a hill for example you will run lean and i see way more part throttle action than pe wide open so good chance internal parts will not be happy as it runs lean which everyone knows already.

SD is without a MAF. When you tune SD, you turn the fuel trims off until you are satisfied and you can turn them back on if you like. Then thats a CLSD. With them off, its OLSD