VE tuning again

[maudyZ28]

Hi all, im new here and this is only my second post, 1st is in the trans stuff

Anyway, i have a 1999 camaro Z28 with CAI and k&N and cat back at present and want to learn this VE stuff before I get my headers and LS6 intake on that are in my bedroom.

I have done EGR, AIR and rear O2 delete and all is fine

I don't have a wide band

I have read the calcVE tutorial by Weatherman Shawn

From what i understand i want to adjust my VE table by the BEN factor that is measured, in this case using LTFT, but I have also heard i can use STFT?? Secondly is this the method failing the MAF or not?

From the stuff I have read and other auto VE etc, I think i need to fail the maf, thus VE is used, make sure commanded fuel is 14.63 and STOP PE (which currently commands 11.7 wtf??) Then i measure a BEN factor after a drive and multiply my existing VE with it then the VE is prob quite near, but I need to watch for knock and set it to zero retard so i can still get fueling? Also the 99 OS says there are like 64 CL modes? and each has a different O2 shift point for rich to lean?? not all 450 mv. I'm a little confused

[joecar]

Hi maudy,

Try Weatherman's first, see what result it produces, become familiar with looking at the logs and calibration [ use the link feature to highlight the operating cell in the calibration tables ], and use your wideband to monitor the process...

Then later, try doing AutoVE and AutoMAF... they are more involved and require you to sanity check your steps and your wideband.


You'll find that 11.7 is cat protection kicking in, GM wanted to be ultra safe.


For AutoVE you may want to leave PE enabled and set it to something like 12.6... you want to avoid a lean condition under load (any significant load at any rpm). Yes, fail the MAF and disable CL, LTFT, STFT.

Use the throttle progressively and steady to get good data so the transient filter doesn't throw out too much data.

Watch for knock, but don't disable knock retard (it protects your motor), just filter out those log samples.

CLMODE: look at tables B4107 and B4105... supposedly (from GM) the NBO2 switch point varies with airflow... a new replacement NBO2 probably has a switchpoint that stays closer to being constant at 450mV.

Cheers
joe

[WeathermanShawn]

Hi all, im new here and this is only my second post, 1st is in the trans stuff

Anyway, i have a 1999 camaro Z28 with CAI and k&N and cat back at present and want to learn this VE stuff before I get my headers and LS6 intake on that are in my bedroom.

I have done EGR, AIR and rear O2 delete and all is fine

I don't have a wide band

I have read the calcVE tutorial by Weatherman Shawn

From what i understand i want to adjust my VE table by the BEN factor that is measured, in this case using LTFT, but I have also heard i can use STFT?? Secondly is this the method failing the MAF or not?

From the stuff I have read and other auto VE etc, I think i need to fail the maf, thus VE is used, make sure commanded fuel is 14.63 and STOP PE (which currently commands 11.7 wtf??) Then i measure a BEN factor after a drive and multiply my existing VE with it then the VE is prob quite near, but I need to watch for knock and set it to zero retard so i can still get fueling? Also the 99 OS says there are like 64 CL modes? and each has a different O2 shift point for rich to lean?? not all 450 mv. I'm a little confused

Just to expand on Joecar's response.

You could plausibly use STFTS, but they are more 'temporal' and the peaks from High-Low can be greater. Sometimes a 1% chance in STFTS does not always equate to a 1% chance in MAF/VE airmass..I have only tested it rigorously using LTFTS. But, I think it could be done using STFTS..

The method does not require failing the MAF. In fact it uses the MAF to calculate the VE Table (its uniqueness). But, the formula is very accurate. So, if you were to fail the MAF at some point, the Calculated VE results would very accurate.

I think in reality there are not 64 CL Modes. I believe they are bunched up into ~ 9 (combined in successively higher Airflows). Some of the earlier year OS's have differing mv. I believe it has to due with the cooling of the narrowband sensors at various airflows. Basically it is very confusing. I and others have had more luck just making them a uni-value. Otherwise, it seems to add to a very peaky VE Table (opinion)..

Joecar had a great synopsis of the various types of tuning that I think was a great summary. You might want to check it out...http://forum.efilive.com/showpost.ph...0&postcount=21.

There are many good method to tuning. Let us know if we can help..

[maudyZ28]

thanks guys, i think im kinda getting it. Ill do some logs first.

Joecar, sorry i dont have a wide band yet hense I cant check whats happening and have to 'trust' the fuel trims. I disabled B0701 cat protection, and am removing them when i get the exhaust done, hence rear O2 code set to NOT REPORTED , is it just standard that it commands a 11.7 for 'cat protection' at WOT all the time??

EDIT just checked and B3618 PE based on rpm is 0.8 Lambda, so 14.63*0.8 ~ 11.7

weatherman, i have read you tutorial again and again and guys i'll spend this weekend logging to see what my engine does, and to check o this CL mode. I dont have the wide band so will have to see if its ok and i dont get knock. Before I start do you think I should just reduce the PE (as above at 0.8 to 0.86??? ) all over to reduce the commanded to about 12.6??

[WeathermanShawn]

I would go for 12.6 AFR. I.E., unless governed by local law I would 'Disable' Catalytic Converter Protection. Its the one that makes WOT overly rich. If you have cats, just stay away from 2-3 consecutive WOT runs that last over 8-10 seconds. P.S., I have cats and have run that set-up for years with no problems.

Thats fine on the O2 Code. You can set it to No Report (check Emissions Laws). But 'Disable' on Cat Protection will get the job done.

Just monitor any KR. At your convenience I would get a reliable Wideband with Serial Connection if possible. You can get 90% of the CALC VE Table done via your Narrow-Bands. Just make sure they work! But, again..as soon as you can advise a wideband. Don't want your engine to blow up! So, stay conservative on WOT Spark...

Post up any tune and log when appropriate. Within 1-3 runs you can usually get things ironed out.

Good luck..

[joecar]

Disclaimer: offroad usage in Mexico or the Northern Territory only.

[5.7ute]

Disclaimer: offroad usage in Mexico only.

Or the Northern Territory.

[joecar]

Updated disclaimer...

[maudyZ28]

thanks guys, well im in UK so 'off road use only' IE on my drive way only

yeah no cats weatherman so think 12.6 will be fine, I'm going to leave the spark standard, see how it runs at WOT and maybe only advance slightly. I think it is only at 24 deg or so now and heard most LS1s like 27 -28 but get some knock up high, so i wont go that far.

Also could someone tell me when the PE table is used, i assume its part throttle when PE conditions are met, Ie PE enable at rpm and MAP and use the table (sorry dont have code im at work) and uses B3618 only at WOT ?

Finally how should I expect VE to change vs stock? up or down or a change up and down in different areas? the LS6 intake is going on this weekend so and im not changing the tune till after. I have some other ideas or thoughts but ill test then first, due to my nature i try and find out as much before i mess it up, but i need to test these so i will (and ill be careful )

[WeathermanShawn]

MaudyZ28:

Read somewhere LS6 Intakes do not really need more than 25 degrees of spark at WOT. I would start with that until you get wideband.

As far as B3618 it is probably easiest to make it all one value to start with. You can get more sophisticated with a PE fuel curve as you advance. B3616 is RPM vs TPS.

I would imagine headers and LS6 Intake would increase VE 5-10%..lower down low, then after 4000 Rpms you should see an increase. Somewhat of a guess on my part..I did not get into tuning until I had H/C..

Have fun..