SbFormula

LAST UPDATE 10-06-2023

Just posting this custom BIN, APYS, for '89 Camaro IROC-Z, 5 speed (M39), LB9, 3.08 gear (Canadian car)

Car is completely stock, 22k miles and all maintenance/tune-up was up to date at time. A heated O2 sensor was installed. Fuel pressure was confirmed at 43.5psi. Battery voltage was normal and engine temperature was controlled at around 195°F while cruising. Initial timing was confirmed at 6*. There was no excessive carbon build-up in chambers (borescope camera). Did not do compression test yet.

SA Latency tables were corrected for accuracy after testing.

Speedometer was verified to be accurate with GPS (ECM and Dash cluster).

Tuning was accomplished at sea level with barometric pressure between 101.0 to 104.0 KPA (sea level), 40-85% humidity, air temperature ~32 to 86°F and 91 octane ethanol free gasoline. Keep in mind that 93 octane is not readily available in Canada and 91 octane quality is questionable (creates more knock).

TunerPro RT V5.0 was used along with an AEM AFR gauge with sensor in Y-Pipe monitoring both engine banks.

For tuning, ALDL Spark Adder was zeroed out, A.I.R.S. was put on full time divert and knock test was disabled. All were enable after, except ALDL Spark Adder.

Some of the issues that were recorded with the OEM tune (APYS):
Overly rich in PE with fuel injectors working at 95% DC (AFR high 9s to low 10s)
Discrepancies with Commended SA and SA recorded at balancer
Too lean on startup and open loop making a bit rough idle
BLM too rich
Knock retard (KR) at WOT, up to 8* with slow recovery
Audible engine knock when engine cold at mid-load going up hill (knock control disabled from factory)
Inaccurate Highway Mode AFR.
Engine temperature going up to 230°F while idling (fan#1 set at 226°F from factory)
Lack of power at WOT
Delay in entering closed loop operation due to O2 sensor not warming-up at idle
SES code 36 for no apparent reason (voltage was peeking for a fraction of a second at around 2.10volts (on MAF blue wire during burn off cycle). ECM will trigger code if voltage is over 1.90volts after 6 occurrences.

Best 0-60mph, 7.0s
Best 1/4 mile, 15.2s @ 90.0mph
AFR at WOT: high 9s to low 10s, (O2 voltage 924-963mv)
Ave effective SA at WOT: 28.9* (2nd), 28.4* (3rd)
Ave KR at WOT: -2.9* (2nd), -3.5*(3rd)

What was modified (extract from my personal notes and files):
FLAGS


SCALARS


TABLES


Fan#2 switch was replaced with a 209°-199F° one, Four Season part# 35946 (GM #3053190). Fan#1 comes on first, then Fan#2 comes on moments later avoiding both fan coming on at same time resulting in temporary major voltage drop, specially at idle.

All issues resolved

There is still KR at WOT but way less. Effective SA average is lower. Upon testing, SA was not a significant contributor to power. Pulling as much as 8* on effective SA average at WOT did not make much difference on power! However, knock events was reduced greatly and throttle response was sluggish. Also, KR was a combination of false knock and real knock events (testing showed). It was impossible to distinguish between false and real knock events. The overly rich AFR at WOT was killing power. By adjusting AFR at WOT around 12:5.1 and having PE come on earlier, it made the throttle response and acceleration feel better. Car was more enjoyable to drive and felt quicker. The fuel injectors are now under 80% DC at WOT.

Best 0-60mph, 6.7s
Best 1/4 mile, 15.0s @ 91.5mph
AFR at WOT 12.3-12.8, (O2 voltage 850-890mv)
Ave effective SA at WOT: 26.0* (2nd), 25.2* (3rd)
Ave KR at WOT: -0.6* (2nd), -1.4* (3rd)

If you decide to use, please study it carefully using Tuner Pro. USE AT YOUR OWN RISK. It was tuned for my specific set-up and issues. Any differences with your set-up, specifically but not limited to: fuel pressure, injector flow rate, fuel octane and MAF type; could cause engine damage. Don't hesitate to ask any questions.

Also attached, a tool to help with MAF scalar/table tuning.

SbFormula

Just an interesting chart showing WOT-SA comparison.

"Custom" blue line is the actual WOT-SA of APYS CUSTOM_4.0. It is calculated at 176Deg.F CT.
OEM 176" orange line is the WOT-SA of OEM APYS at 176Deg.F
OEM 176 REAL" yellow line is the WOT-SA of OEM APYS at 176Deg.F CT with SA Latency error added.

So OEM calculated WOT-SA at 4800rpm is 36* but actual SA is 40* due to SA Latency error. No wonder, knock was constant at WOT on stock tune!!!
APYS CUSTOM_4.0 brings it down to 32*.

SbFormula

For @F-body-fan