VE table tuning philosophy - need help

[JimMueller]

Rumor has it new NBO2's are more accurate at stoich than new WBO2's, and also that the NBO2's should be trusted for everything except PE. For PE, you need to worry about making sure your HPT AFR readings match up across the entire range with what your WB scanner is reading. I consider the latter a real PITA. Even if you use WBO2's to tune in OL (which I've done also), you still need to insure the readings are accurate before you start... and supposedly you need to re-check regularly.

[69lt1bird]

If you tune correctly in OL and get the VE table right and then the MAF table right, when you go back to closed loop the narrow bands just do the minor tweaking to keep you at stoich for everything except WOT.

You can set up STFT vs MAF tables to do some fine tuning at lower RPM/MAP readings also. You can't just tune with the NB's and expect to have a quality tune. The are slow and are design to help the PCM try to maintain stoich.

If you are running in hybrid mode (VE and MAF like factory) you should not have o retune or recheck once you are done.

[ysb02]

imo Greg's dvd is great place to begin if you're new. There's a lot of wrong, slightly wrong, and horribly wrong info out there. After spending $650 on HP Tuners it was worth spending $250 to know how to use it correctly.

I believe he was showing MAF tuning done before VE btw.

[Frost]

....

I believe he was showing MAF tuning done before VE btw.

I think that's a Ford thing You can do either one first. Since VE helps idle/driveability, I do it first my self and then put the car 'on the MAF'.

[69lt1bird]

Yep, either way works.

Greg's DVD is good but it does not get in depth enough for a true beginner.

[gsegse]

Greg's DVD ..still back order ?

[oscareltemblo]

My stock PE does not enable until 5000rpm and my max shift points are at 4700rpm, so I'm never getting to the 5000rpm enable point. Should I lower my enable rpm for tuning VE table, if so to what?

Why not set your PE enable 3000 and raise your shift points.

[superwagon]

The 8.1 is not really a high rpm engine so I dont think increasing my shift points that far would help much. I can lower my pe enable to say 3000 rpm and get it to go into enrichment at any point I would like. I think my main question back when I had my question was trying to understand why so many say it is so bad to delay pe while tuning ve table. If gm was okay with the factory calibration never going into pe then why would it be bad to calibrate my ve table the same way? Now I do understand that commanding say 12.5:1 under higher load and rpm would be much better for performance and longevity in my final tune. I was just having a hard time seeing why it would be so bad to leave it that way while tuning.

[majorpayne317641]

The 8.1 is not really a high rpm engine so I dont think increasing my shift points that far would help much. I can lower my pe enable to say 3000 rpm and get it to go into enrichment at any point I would like. I think my main question back when I had my question was trying to understand why so many say it is so bad to delay pe while tuning ve table. If gm was okay with the factory calibration never going into pe then why would it be bad to calibrate my ve table the same way? Now I do understand that commanding say 12.5:1 under higher load and rpm would be much better for performance and longevity in my final tune. I was just having a hard time seeing why it would be so bad to leave it that way while tuning.

I don't think that it is a problem at all. GM probably did not intend this engine to have PE if this is a stock file that you first scanned with the PE set above your shift rpm's at WOT. If the PE settings are useful when you lower the RPM's they are enabled at then keep them that way, just watch your WB to see the AFR % error. It may or may not have a negative effect on your % errors and your performance. I know my Corvette's PE enables at a MAP and throttle position so the RPM thing is a little different.

[LSROVER]

On my editor I have " STFT OPEN LOOP". While I'm tuning VE with Wideband do I want this on or off?

Thanks

[Matt Vardaman]

On my editor I have " STFT OPEN LOOP". While I'm tuning VE with Wideband do I want this on or off?

Thanks

You commented on an ancient post, but you want that STFT open loop off while tuning with the wideband. Otherwise the pcm will be trimming fuel similar to closed loop. Turn it back on when you are finished tuning.

[LSROVER]

I know. I figure I reply to this one instead of starting a new thread.

Thanks for the clarification on the stft open loop.