ARC-TUNING — VE Main Table

✦

Scarecrow Briefing — VE Main Table for your build

Same '99 C5 build context, different table family. VE on this 0411 PCM is what predicts airmass when speed-density math takes over — and on a swap car like yours, that math is wrong from the moment you flash. Four build-driven decisions shape Section 2:

(1) The PCM is hardcoded for 5.7L; your engine is 6.0L. Every VE cell under-reports airmass by ~5.3% at any operating point. That bakes into lean cruise, drifting LTFT, and eventual CEL. Section 2.1's SUGGESTS column scales the entire grid up to compensate. (2) The 0411 runs MAF-primary + SD-backup — not a blended transfer curve. For your stock-cam 6.0L the MAF stays in. The VE table still has to be right because LTFT corrupts long-term when SD math (used at cold start, deceleration, MAF dropouts) is wrong. (3) Catless long-tubes reshape upper-RPM cells. Empirically +3–5% in 4500–6500 RPM for catless mid-pipe and another +2–4% peak from LT primaries — flagged MEDIUM confidence, verify on your data. (4) Texas race-car operation soaks the intake. The IAT density correction curve in 2.4 reshapes for engine protection at extreme intake temps — same posture as PE 1.4's ECT bias.

Verification is cruise-first, not WOT. 15–20 minute mixed cruise log, ±2% AFR target across populated cells. 3×3 block adjust first, single-cell once within 3%. (See 2.7.)

2.1 VE Main Table (MAP × RPM) 📍 LOCATE

HPTEngine → Fuel → VE Main

EFILivetool path TBD

TunerPro XDFtool path TBD

LS1 Edittool path TBD

⚠ Attention needed

The primary VE table. Maps MAP (kPa) × RPM to volumetric efficiency %. PCM uses VE × cylinder_volume × MAP × density_correction to predict airmass when speed-density is authoritative. Stock '99 LS1 cal sized for 5.7L bottom; with your LS2 6.0L the entire grid under-reports by ~5.3% at any operating point. Stock cells biased for cat'd / stock-manifold backpressure profile — catless + LT reshapes the upper-RPM region.

The VE table is your engine's . The PCM reads it to know how much air is going into the cylinders, which tells it how much fuel to add. Your PCM is set up for a smaller engine than what's actually in the car, so every cell of the VE table is a few percent too low. That's why your drift over time.

⚠

Log axis check — Scarecrow's grid uses the stock 0411 breakpoints

If your tuning software has modified the OS, the actual VE table in your tune may have different RPM/MAP breakpoints than what's rendered below. Drop a log into 2.7 first — Scarecrow will reconcile axes against your actual data before applying any cell-level changes.

CURRENT Stock LS1 cal

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	88	90	91	92	91	90	88	86	83	81
90	83	85	86	87	86	85	83	81	78	76
80	76	79	81	82	81	80	78	76	73	71
70	70	72	74	75	74	73	71	69	66	64
60	64	66	68	69	68	67	65	63	60	58
40	52	55	57	58	57	56	54	52	49	47
20	38	42	44	45	44	43	41	39	37	35

Stock LS1 cal — sized for 5.7L bottom + cat'd/stock-manifold backpressure. Wrong for your hardware in two ways.

✦ SCARECROW SUGGESTS LS2-corrected + header reshape

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	92	94	95	96	96	96	94	93	90	88
90	87	89	90	91	91	91	89	88	85	83
80	80	83	85	86	86	86	84	83	80	78
70	74	76	78	79	79	78	76	75	72	70
60	67	70	72	73	72	71	69	68	65	63
40	55	58	60	61	60	59	57	56	53	51
20	40	44	46	47	46	45	43	42	40	38

~5.3% baseline scale (LS2 displacement) plus +3–5% upper-RPM bias for catless/LT header backpressure profile.

Δ DIFF Current → Scarecrow

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
90	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
80	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
70	+4	+4	+4	+4	+5	+5	+5	+6	+6	+6
60	+3	+4	+4	+4	+4	+4	+4	+5	+5	+5
40	+3	+3	+3	+3	+3	+3	+3	+4	+4	+4
20	+2	+2	+2	+2	+2	+2	+2	+3	+3	+3

Largest deltas in upper-RPM upper-MAP — that's where displacement scale stacks with header reshape.

VE % heat scale 40 low → 60 cruise → 75 mid-load → 88 peak-torque → 95 peak Sequential ramp — no good/bad implication, VE is a measurement

✦ SCARECROW REASONING CONFIDENCE: MEDIUM

Two corrections stacked into the SUGGESTS column:

Baseline displacement scale (~5.3% across the board): pure ratio inference from 6.0L / 5.7L = 1.0526. This OS doesn't expose an editable Cylinder Volume scalar (per 2.5 — verify in your editor), so the only place to absorb the ratio is the VE table itself. Confidence MEDIUM because no source directly empirically confirms "+5.3% across the board for LS1→LS2 swap"; it's mathematically the right answer but verify on cruise data.
Upper-RPM header reshape (+3–5% in 4500–6500 RPM, +2–4% peak from LT primaries): industry-consensus magnitude for catless mid-pipe and long-tube headers on stock-port LS heads. Confidence MEDIUM — empirical magnitudes aren't grounded for your specific header pairing. Will refine when 2.7 verification loop sees real data.

What I'm NOT certain about: the lower-MAP region below 40 kPa. These cells are visited at idle and decel, and reversion from your stock cam is minimal so MAF should still be authoritative there. The +2–3% bias I've applied is conservative — verify on a cruise log before considering them final.

Two reasons every cell is going up. One: your engine is bigger than what the PCM was set up for, so every cell is too low. We add about 5%. Two: your let the engine breathe better at high RPM, so the upper part of the table needs another bump. The bigger the bump in a cell, the more both of these stack up there.

Drive the in 2.7 with the wideband — that's how we know if these cells are right
If stop drifting after this, we nailed it
If they don't, look at sensor sanity in 2.6 first — bad makes every cell look wrong

70 cells changed · avg +4.4 VE% (peak +7 @ upper-RPM/MAP)

2.2 SD Strategy & Tuning-Mode Enables 📍 LOCATE

HPTEngine → Air Intake → MAF → General · Engine → Fuel → O2 → Closed Loop · Engine → Fuel → DFCO

EFILivetool path TBD

TunerPro XDFtool path TBD

LS1 Edittool path TBD

⚠ Attention needed

Two distinct decisions live here. Strategic: MAF Primary vs. Pure SD vs. MAF Backup. The 0411 doesn't blend smoothly — it's an either/or config. For stock-cam reversion-clean engines, MAF Primary is correct; the VE table still has to be right for cold-start / decel / MAF-dropout cases where SD takes over. Tactical: the cruise-log capture in 2.7 requires temporarily disabling closed-loop and DFCO so they don't contaminate the AFR error histogram. Documented trick: set their min-coolant-temp triggers to 284°F so they never fire during a hot drive log.

Two things in one box. First: should the PCM trust the or the VE table for figuring out airflow? On your stock-cam build, keep MAF in. Second: when you go drive the cruise log in 2.7, the PCM has two systems that will mess with the data — turn them off temporarily by lying to the PCM about coolant temperature. Flip them back when you're done.

MAF Hardware Enable

TRUE → TRUE

no change

Stock-cam reversion-clean → MAF stays in.

MAF Software Enable

TRUE → TRUE

no change

Same as above — keep enabled.

Use MAP for VE (when SD active)

TRUE → TRUE

no change

Standard SD lookup behavior.

Closed-Loop Min Coolant Temp (logging trick)

75 °F → 284 °F

+209°F (temporary)

Temporary value during cruise-log capture only. Closed-loop O2 corrections contaminate AFR error data; engine never reaches 284°F so it stays disabled. Revert after logging.

DFCO Min Coolant Temp (logging trick)

75 °F → 284 °F

+209°F (temporary)

Same trick. DFCO reversion ruins decel cells. Revert after logging.

✦ SCARECROW REASONING CONFIDENCE: HIGH

The MAF/SD framing matters because most online VE tutorials assume "go pure SD, disable MAF entirely." That's the right move on cammed engines where reversion confuses the MAF — yours isn't one of those. Keep MAF as the authoritative airmass source and fix VE so the PCM's backup math is correct for the cases where SD takes over (cold start, MAF dropouts, deceleration). The 284°F closed-loop and DFCO disable trick is a documented logging-pass technique — it lets you capture clean AFR error data without contamination. Both of those scalars revert after the log; they're not permanent cal changes.

Pure speed-density tuning is the standard advice in YouTube videos but it's not the right call for your engine — your cam isn't aggressive enough to confuse the MAF, so MAF stays in as the main airflow reader. The VE table still needs fixing because there are moments (cold start, off-throttle, etc.) when the PCM uses VE math instead. The two coolant-temp tricks are just clean-data tricks for the logging session — flip them back when you're done logging.

5 scalars · 2 temporary (logging-pass), 3 confirmed-as-stock

2.3 Displacement Correction Math 📍 LOCATE

HPTCylinder Volume parameter — exposure tool-dependent (see 2.5)

EFILivetool path TBD

TunerPro XDFtool path TBD

LS1 Edittool path TBD

✓ No separate change required

Math expansion only — no separate parameter to apply. The 6.0/5.7 displacement ratio (1.0526) is mathematically equivalent to multiplying every VE cell by ~5.3%, which is what 2.1's SUGGESTS column already does. If your editor exposes an editable Cylinder Volume scalar on this OS (see 2.5), edit there instead and revert 2.1's baseline scale. Default path is bake-in.

No separate fix here — the math we're doing in section 2.1 already handles the engine-size mismatch. This subsection just shows the work.

✦ SCARECROW REASONING CONFIDENCE: HIGH

Two paths to apply the displacement correction:

Path A (default — what 2.1 does): bake the 1.0526× ratio into every VE cell. Editor-agnostic. Works on every tool. Downside: every future cal flash carries the ratio in the table values; if you swap engines back to a 5.7 short, you have to scale the table back down.
Path B (cleaner — if your tool exposes it): edit the Cylinder Volume scalar in OS metadata (5.7L/8 = 0.7125L → 6.0L/8 = 0.7500L). VE table values stay generic. This OS may not expose this scalar — verify in your editor. Section 2.5 (PRO) handles this.

Mathematically, A and B produce identical airmass calculations. Bookkeeping is cleaner with B. Pick one, not both.

Two ways to fix the size mismatch: change every cell by the same percentage (what we're doing) OR change one number that tells the PCM how big each cylinder is (only possible if your tuning software lets you — check 2.5). Either way works the same. Don't do both.

No parameter change — math is baked into 2.1. This subsection is informational.

2.4 IAT Density Correction 📍 LOCATE

HPTEngine → Air Intake → IAT → IAT Density Correction

EFILivetool path TBD

TunerPro XDFtool path TBD

LS1 Edittool path TBD

⚠ Race-car bias

IAT density correction is the air-density multiplier the PCM applies downstream of the VE table. Stock GM curve is calibrated for a street car that backs off when the intake gets hot. On a Texas race car at sustained WOT, intake-side temperatures climb fast (heat-soaked plenum, hot underhood air) and the stock curve will lean the mixture exactly when you need it richest for thermal protection.

Hot air = thinner air = less oxygen per cubic foot. The PCM uses this table to adjust fueling. Stock GM logic assumes "if it's hot, the driver will back off — so save fuel." That logic is wrong for your race car at WOT during a 90°F+ Texas track day. We tilt the table to richen at high IAT instead of lean, which protects the engine.

CURRENT Stock GM curve

IAT °F	40	70	100	130	160	180	200
Density mult	1.030	1.000	0.970	0.935	0.895	0.870	0.845

Standard volumetric density correction. Leans progressively as IAT climbs — assumes driver backs off at high IAT.

✦ SCARECROW SUGGESTS Race-car protection bias

IAT °F	40	70	100	130	160	180	200
Density mult	1.030	1.000	0.978	0.955	0.930	0.915	0.900

Less aggressive lean-out at high IAT. The PCM still corrects for density loss, but more gently — preserves fuel margin for thermal protection during Texas heat-soak track sessions.

Δ DIFF Current → Scarecrow

IAT °F	40	70	100	130	160	180	200
Δ mult	0	0	+.008	+.020	+.035	+.045	+.055
≈ ΔAFR	0	0	−.10	−.27	−.48	−.62	−.76

No change at normal/cool IAT. Progressively richer than stock as IAT climbs into heat-soak territory.

✦ SCARECROW REASONING CONFIDENCE: HIGH

Posture-twin of PE 1.4 (Base AFR vs ECT). Both stock GM curves assume a driver who throttles back when something gets hot. Race car under sustained WOT can't and shouldn't throttle back — needs more fuel as charge temps climb, not less. The shape preserves the cool-side curve exactly (no change at 40–70°F) and only relaxes the lean-out at IAT 100°F+. Grounded in documented air-density correction principle (volumetric vs. mass airflow) plus the consensus race-car-thermal-protection bias.

Same logic as the ECT table in the PE section — the factory thinks you'll lift off when it gets hot. You won't. So we keep the cool-air behavior the same, but tell the PCM to be less aggressive about leaning when the intake gets hot.

5 cells modified (IAT 100–200°F band) · cool-side untouched

2.5 Cylinder Volume Constant PRO 📍 LOCATE

HPTEngine → Specs → Cylinder Volume (exposure tool/version-dependent)

EFILivetool path TBD

TunerPro XDFtool path TBD

LS1 Edittool path TBD

✦ Tool-dependent — verify in editor

Some HPT VCM Editor versions expose Cylinder Volume as an editable scalar on the 12200411 OS; some don't. If yours does, edit it directly (cleaner — keeps VE table values generic) and revert 2.1's baseline scale leaving only the header reshape. If not, default to bake-in (2.1). Exposure on this OS is not confirmed in source materials — production crawler target.

Pro path: if your tuning software has a setting for "cylinder size," changing that one number is cleaner than changing every cell of the VE table. Not every editor shows this setting on this PCM — check yours first.

Cylinder Volume (per cylinder)

0.7125 L → 0.7500 L

+0.0375 L (+5.26%)

Apply only if your editor exposes this scalar on the 12200411 OS. If applied, revert 2.1's baseline +5.3% scale (keep header reshape). Mathematically equivalent to bake-in.

✦ SCARECROW REASONING CONFIDENCE: MEDIUM

Cleaner than baking the ratio into every VE cell, because:

VE values stay engine-independent — if you ever swap back to a 5.7L short, the cal still works without re-scaling
Other downstream calcs (boost setpoint logic, idle airflow targets) that reference cylinder volume also get correct numbers
Easier to read in the cal — "engine is 6.0" stated once vs. "every VE cell baked +5.3%"

The catch: exposure of this parameter on the 12200411 OS is not confirmed in source materials, and it may be locked in OS code such that the only correction path is the VE table. Verify in your editor before applying. If exposed, apply this and revert 2.1's baseline scale.

If your software lets you change cylinder size, do it here instead of changing every cell of the VE table. Cleaner. But not every software/PCM combo shows that setting — yours might not.

1 scalar (PRO) · displacement correction alternate path

2.6 MAP / IAT / ECT Pre-flight Sanity PRO 📍 LOCATE

HPTEngine → Air Intake → MAP / IAT · Engine → Engine Diagnostics → Coolant

EFILivetool path TBD

TunerPro XDFtool path TBD

LS1 Edittool path TBD

✦ Halt-gate before VE work

Wrong MAP sensor model number = every VE cell is wrong. Wrong IAT scaling = density correction is wrong. Wrong ECT scaling = closed-loop trigger and DFCO triggers fire at wrong temps. All three sensors define the input space the VE table is looked up in — if any is mis-scaled, no amount of VE tuning will land. Scarecrow refuses to apply VE corrections (2.1) until these are confirmed.

Before changing the VE table, make sure the PCM is reading air pressure, air temperature, and coolant temperature correctly. If any of these is mis-set, fixing the VE table won't help — you'd be tuning to bad inputs.

MAP sensor model

GM 1-bar (NA)

expected for stock NA build

✓ MATCHES — proceed to VE work

IAT sensor scaling

Standard GM

expected

✓ MATCHES — proceed to VE work

ECT sensor scaling

Standard GM

expected

✓ MATCHES — proceed to VE work

⛔ SCARECROW HALTS HERE IF…

MAP MISMATCH If the cal references a 2-bar or 3-bar MAP and the SUGGESTS column above expects 1-bar (or vice versa), Scarecrow refuses to apply 2.1's VE corrections. Symptom of an aborted boost build, swap-time cal carryover, or wrong-tune-loaded scenario. Resolve sensor scaling first.

IAT MISMATCH If IAT scaling has been altered (cold-air-tuned for relocated sensor, racing IAT sensor, etc.) the IAT density correction in 2.4 will be wrong by the same scale factor. Confirm sensor type before applying 2.4.

ECT MISMATCH If ECT is mis-scaled, the 284°F closed-loop disable trick from 2.2 may fire too early or never. Verify the 284°F target maps to "engine never reaches this temperature" before logging.

All three sensors define the input space VE is looked up in. A wrong-scaled input means tuning to fiction. This subsection is the gate.

3 sensor checks · all pass for stock NA configuration

2.7 Verification Loop (cruise-first) ✓ Drop log when ready

Cruise log verification, not WOT. Drop a wideband datalog from a 15–20 minute mixed-cruise drive (highway, city, light tip-in, occasional mid-throttle, brief WOT pulls last) and Scarecrow renders per-cell ΔAFR. Method 2 (wideband) preferred; Method 1 (STFT+LTFT trim-based) is the fallback when no wideband is logged. Honest split: cells whose error tracks RPM/MAP load = fueling-math fix Scarecrow can apply; cells whose error tracks fuel pressure or trim swings = NOT a VE problem and Scarecrow refuses to chase them.

Drop your here. Scarecrow compares what the PCM commanded vs what your wideband actually saw, cell by cell. Some errors mean "VE cell needs to move" — Scarecrow can fix those. Other errors mean "your sensor is dirty" or "you have a vacuum leak" — Scarecrow refuses to fake-fix those by changing VE.

📊

Drop a cruise datalog here (.hpl or .csv)

Or click to load a sample log — Scarecrow will compare commanded vs measured AFR per cell and split corrections honestly:
fueling-math fixes Scarecrow can apply, vs. sensor / leak / hardware issues the user has to investigate.

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	88	90	91	92	91	90	88	86	83	81
90	83	85	86	87	86	85	83	81	78	76
80	76	79	81	82	81	80	78	76	73	71
70	70	72	74	75	74	73	71	69	66	64
60	64	66	68	69	68	67	65	63	60	58
40	52	55	57	58	57	56	54	52	49	47
20	38	42	44	45	44	43	41	39	37	35

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	92	94	95	96	96	96	94	93	90	88
90	87	89	90	91	91	91	89	88	85	83
80	80	83	85	86	86	86	84	83	80	78
70	74	76	78	79	79	78	76	75	72	70
60	67	70	72	73	72	71	69	68	65	63
40	55	58	60	61	60	59	57	56	53	51
20	40	44	46	47	46	45	43	42	40	38

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
90	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
80	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
70	+4	+4	+4	+4	+5	+5	+5	+6	+6	+6
60	+3	+4	+4	+4	+4	+4	+4	+5	+5	+5
40	+3	+3	+3	+3	+3	+3	+3	+4	+4	+4
20	+2	+2	+2	+2	+2	+2	+2	+3	+3	+3

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	88	90	91	92	91	90	88	86	83	81
90	83	85	86	87	86	85	83	81	78	76
80	76	79	81	82	81	80	78	76	73	71
70	70	72	74	75	74	73	71	69	66	64
60	64	66	68	69	68	67	65	63	60	58
40	52	55	57	58	57	56	54	52	49	47
20	38	42	44	45	44	43	41	39	37	35

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	92	94	95	96	96	96	94	93	90	88
90	87	89	90	91	91	91	89	88	85	83
80	80	83	85	86	86	86	84	83	80	78
70	74	76	78	79	79	78	76	75	72	70
60	67	70	72	73	72	71	69	68	65	63
40	55	58	60	61	60	59	57	56	53	51
20	40	44	46	47	46	45	43	42	40	38

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
90	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
80	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
70	+4	+4	+4	+4	+5	+5	+5	+6	+6	+6
60	+3	+4	+4	+4	+4	+4	+4	+5	+5	+5
40	+3	+3	+3	+3	+3	+3	+3	+4	+4	+4
20	+2	+2	+2	+2	+2	+2	+2	+3	+3	+3

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	88	90	91	92	91	90	88	86	83	81
90	83	85	86	87	86	85	83	81	78	76
80	76	79	81	82	81	80	78	76	73	71
70	70	72	74	75	74	73	71	69	66	64
60	64	66	68	69	68	67	65	63	60	58
40	52	55	57	58	57	56	54	52	49	47
20	38	42	44	45	44	43	41	39	37	35

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	92	94	95	96	96	96	94	93	90	88
90	87	89	90	91	91	91	89	88	85	83
80	80	83	85	86	86	86	84	83	80	78
70	74	76	78	79	79	78	76	75	72	70
60	67	70	72	73	72	71	69	68	65	63
40	55	58	60	61	60	59	57	56	53	51
20	40	44	46	47	46	45	43	42	40	38

kPa\RPM	1000	1500	2000	2500	3000	3500	4000	5000	6000	6500
100	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
90	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
80	+4	+4	+4	+4	+5	+6	+6	+7	+7	+7
70	+4	+4	+4	+4	+5	+5	+5	+6	+6	+6
60	+3	+4	+4	+4	+4	+4	+4	+5	+5	+5
40	+3	+3	+3	+3	+3	+3	+3	+4	+4	+4
20	+2	+2	+2	+2	+2	+2	+2	+3	+3	+3