VE Tuning

[OneSlowGTP]

:huh2:
I am a little confused as to how to inturpret and thus tune the VE table for Supercharged V6 engines.

First off MAP pressure is limited to 140kPa however a typical boost values are in the 180 - 190 range.

I've heard this doesn't mater because the PCM does not use the VE table for WOT fueling?

:huh2:
Second: What exactly are these numbers? The Help documentation claims these are displayed in percentages for convienence.

As far as I know "VE" or Volumetric Efficiency = The ACTUAL amout of air the engine ingests compared to the theoretical maximum.

If that is true, in a boosted application, why are these numbers so small? :huh2:

How would a larger cam affect this table if at all?

This table makes no sense to me given the stock table values.

:-/

[OneSlowGTP]

99 GT VE Table:


34 45 68 82 91 97 93 98 95 99 102 99 107
34 45 68 82 91 97 93 98 95 99 102 99 107
41 46 54 57 60 63 68 91 96 100 110 117 119
51 59 63 64 63 69 72 72 72 76 86 87 92
61 56 60 68 67 72 72 73 73 74 72 75 77
63 61 68 71 73 72 72 75 73 70 72 73 70
74 62 71 73 73 74 75 74 74 73 74 73 72
73 65 71 73 74 77 76 75 75 74 72 70 68
73 76 73 74 76 78 77 77 77 74 72 72 72
93 84 76 76 78 79 79 78 78 75 71 70 72
98 87 79 77 79 80 80 79 79 74 73 70 69
113 92 77 76 79 82 80 79 78 75 73 71 67
117 93 77 75 76 78 78 78 76 72 71 70 67
128 100 84 72 74 77 77 76 74 71 69 66 63
134 97 79 68 70 72 72 72 70 70 66 64 63
125 91 74 64 65 67 67 67 65 65 62 60 59
125 91 74 64 65 67 67 67 65 65 62 60 59




99 GTP Table:

37 43 48 55 56 58 60 63 66 67 70 71 73
43 48 53 60 62 63 65 67 69 71 72 74 75
47 53 58 63 65 66 68 71 72 73 74 75 76
51 56 61 66 67 68 70 72 73 74 75 75 76
52 57 63 67 69 70 71 73 74 74 75 76 76
53 58 63 68 70 71 72 73 74 75 75 75 76
54 59 64 69 70 71 72 73 74 74 75 75 76
54 59 65 69 70 71 72 73 74 74 75 75 76
54 60 65 69 70 71 72 72 73 74 75 75 75
55 60 65 69 70 71 72 72 73 74 74 75 75
55 60 64 68 70 71 72 72 73 73 74 74 74
55 60 64 68 69 70 71 71 72 73 73 74 74
55 60 63 67 69 70 71 70 71 72 73 73 73
54 59 63 67 68 69 70 70 71 72 72 72 73
53 59 62 66 67 68 69 69 70 71 71 72 72
52 59 62 65 66 67 69 68 69 70 71 71 71
51 58 61 64 66 67 68 67 68 69 70 70 71

[Bill@HPTuners]

hpt has stated that in v6 applications the ve table is only used when maf failure occurs & has little effect on fueling under normal driving conditions...as far as why the values differ from car to car in stock form, you should see the tables that have 80 in every cell...basically gm didnt waste much time on setting up a ve for the v6's

[OneSlowGTP]

Supposedly the table provides transient correction, and checks for MAF failure. If the tables were that far off, wouldn't the PCM think the MAF has failed?

Lets say hypothetically I disconnected my MAF. How would you tune this table?

[Bill@HPTuners]

Supposedly the table provides transient correction, and checks for MAF failure. If the tables were that far off, wouldn't the PCM think the MAF has failed?

Lets say hypothetically I disconnected my MAF. How would you tune this table?

Chris@HPTuners
HP Tuners Owner





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Posts: 1933
Re: VE table effect on WOT fueling?
« Reply #7 on: Sep 20th, 2005, 7:13pm » Quote | Modify

--------------------------------------------------------------------------------
on the V6's the VE table is only used if the MAF fails if it isn't failing cos you set the fail freq very high then it is never used. Personally i would leave it high "just incase".

Chris...

[jk99gtp]

I find this hard to believe, however I am not doubting anyone here, just need more info if possible.

When I tuned my VE table, my LTFT's moved to the rich side tremendously, and I had rescale my MAF table to get the LTFT's back into check. And yes, I did reset the fuel trims after tuning both the VE and MAF tables..

That told me that the VE table was looked at by the PCM when it couldn't trust the MAF, and not just used in case of a failure. Now granted, I tuned my VE table from 0-100kpa ONLY, as I did not want to go into boost with the MAF unplugged...

Does anyone here know how the PCM calculates the IPW on our cars? As in, what tables and sensors make up the final IPW? I would guess this would pretty much give us the answer right there...

Thanks!

[OneSlowGTP]

I agree, there is defiantly more too it then Injector size and MAF freq. Anyone who doubts this can easily run an experiment to prove it.

simply scale your injector size by 200%

then scale your MAF by 200%

All said and done, the car should run just like it did before, but your going to find that no. it doesn't, it won't even idle.

I'm not sure what table is the missing link. I'd like to think it's the VE table, but I don't understand the VE table well enough to make changes to verify.

Also: in regards to the "fail frequency" where is that even set? I've never seen such a field. (my maf reaches over 11,500Hz)

[Bill@HPTuners]

Also: in regards to the "fail frequency" where is that even set? I've never seen such a field. (my maf reaches over 11,500Hz)

what year is your gtp I can see where its set at. Im pretty sure most if not all gtps have it set for exactly 11,500 though.

[OneSlowGTP]

MAF range is 1500 - 11500Hz, I reach flow figures over 11500Hz, I'm still not sure what you mean by MAF Fail frequency?



Info about the car below:

1999 Pontiac Grand Prix GTP

Diamond Forged and Ceramic Coated w/Moly skirt Pistons with raised
compression (9.5:1)
Stage II Air to Water Intercooler
Quaife Torque biasing (posi) differential
3.69 Gears w/single chain conversion
Vacmelt 300M Hard Input-Shaft
Blue Plate Clutches
Street/Strip Shift-Kit
04 Diode Sprag Conversion
Hydraulic trans mount upgrade
Hydraulic engine mount upgrade
Several Valvebody upgrades including improved Boost Sleve and TCC apply
bores
Chromolly pump shaft with hardened splines
Hardened 4th gear clutch shaft
Edge Racing High-Stall Torque Converter with Carbonfiber Lockup clutch
Koni's
Eibach Gen² springs
Race-Bred Rear Swaybar
Next Level Strut Tower Brace
CompCams 218/224 High lift Camshaft
Titanium retainers
105lb Valve-Springs
180-Degree Thermostat
Jacobs wires
Autolite 103 plugs (3 Heat ranges colder then stock)
Ported Heads
3 angle Valves
Ported SC
Notched Block
Machined M90 Snout
Ported lower Intake Manifold
Gen2 Modular Pulley system
3.3, 3.1, 2.8, and 2.4" pulleys
Oversized Water-pump pulley
Cold Air Induction
Modified TB – Ported, de-screened, and MAF sensor removed and replaced with epoxy LS6 85mm MAF
ECM Programmer
Lucus 42.5lb Injectors
Modified Fuel Rail
Poleyurethane Motor Mounts, Swaybar links, and Endlinks.
ADR Sterling 20x8.5@+38mm Chrome Wheels with 255/35/20 NITTO 555 tires
S&S Exhaust Headers
Off-Road Pipe
Custom 2.5" Exhaust
Magnaflow XL series Muffler replacing Resonator
Magnaflow Wide Open Mufflers
ZEX Nitrous Kit
Clevite Rod Bearings
ARP Head Studs
ARP Rod Bolts
KVR Cross-drilled breaks w/Hawk Pads
Optima Yellowtop
I'm sure I'm missing some stuff in that list, but ya...

[Bill@HPTuners]

[OneSlowGTP]

Ahhhh, that makes sense

but...

My "General Tab" is blank :-\

I imagine I have no "Fail Frequency" based on that and the fact that I've never gotten a code for high maf freq as I'm typically seeing above 11,500

Thanks for the info though!

-A

[Bill@HPTuners]

you very well might...if you really need to up it I'd email [email protected] they might be able to give you what you need...i can only see the parameter on some applications ie 97-98 gtp's, some v6 fbodies...but i didnt see it on the 99 file i have sorry.

[FastFieros]

Ok, here is something interesting....

DTC 1514 in a V6 3800NA Fbody is

PCM uses the following info in order to calculate an expected MAF rate..

Throttle Position
BARO
IAT
RPM

OK, here is the conditions of setting this DTC.. From the Camaro service manual..

PCM detects that the actual MAF and speed density is much more than expected. or the calculated airflow rate...

>>>>>>>

Now, the weird thing is I opened my GTP V6 2004 file and I get a table to set this DTC1514, like I can control something in this table I have no understanding to..



Well, I go to the 2004 GTP service manual and there is no DTC1514 listed for it. However in the 2001 V6 L36 camaro service manual there is.


Loyde

[FastFieros]

Wow, I just opened a 2002 Fbody V8 file... Check all the stuff under DTC for it.



I would say the V8 stuff is getting well hacked.

Loyde