With the ill quality of today's gas and type of engine mods used in Corvettes gains from them are lost due to engine knock as the PCM via 2 knock sensors yank timing out to react to the knock but also kills off performance.

Engine Knock (Detonation) and Preignition
It is important to understand the mechanisms that cause knocking and preignition to set up an ignition map that is suitable for the engine. Auto ignition, also known as knocking, pinging, or detonation, is generally caused by improper combustion in an engine. An internal combustion engine runs properly when the spark-initiated combustion wave expands rapidly but smoothly throughout the combustion chamber. Combustion knock is caused by spontaneous ignition in the hot unburned portion of the fuel mixture (typically referred to as end gas) in the combustion chamber. The remaining charge portion is compressed first by the upward piston movement and then by the moving flame front. Knocking is the almost instantaneous ignition of part of the remaining mixture. This mixture auto ignites because the rapidly rising pressure and temperature caused by the piston movement and the expanding gas from the flame front are sufficient to ignite the remaining gasses. To illustrate the loads imposed on the engine components by knocking, note that normal combustion speeds are about 12-25 m.s-1 while knocking combustion speeds may be as high as 250-300 m.s-1.

If the gasoline-air mixture auto-ignites somewhere in the cylinder (other than at the spark plug) just after spark ignition, the auto-ignition combustion wave can collide with the spark-initiated combustion wave, causing the vibration we hear as a knock or ping. Depending on its intensity, knocking combustion may range from barley audible “pinging” to a rather violent thumping. The point at which the knocking becomes damaging to the engine is dependent on the components used in the engine. If sustained knocking occurs, then the pistons may be damaged. When knocking reaches a violent thump, engine operation should be ceased or at minimum the load and temperature reduced to prevent engine damage. Light knocking that happens during acceleration is less harmful and may not damage the engine. Knocking tendency is increased by the following design or operational characteristics:
• High Engine loads encountered while towing a vehicle.
• Using low octane gasoline in a high-compression engine.
• Too much timing advance for the type of fuel being used.
• Higher air density, (this can be caused by starting a calibration at high altitude and then traveling to a lower one, or the addition of forced induction).
• Increased temperatures and pressure in the combustion chamber due to inadequate engine cooling.
• Excessive inlet air temperature.
• Spark plugs with an improperly high heat range.
• A non-central spark plug location in the combustion chamber.
• An elongated combustion chamber design.
• Too lean of an air/fuel mixture.
The following tuning adjustments can be performed on an engine to reduce or eliminate knocking:
• Reduce ignition timing.
• Verify that the air/fuel mixture is adequate for your engine set up.
• Verify that the spark plugs are of proper heat range.
Preignition
Preignition is the ignition of the charge in the combustion chamber before the spark occurs. This type of ignition is caused by a very hot, or even incandescent surface in the combustion chamber. These “hot spots” can be an overheated spark plug, a glowing remnant of carbon in the chamber or even a hot exhaust valve edge.
The preignition condition flame front rapidly expands while the piston is still on its way up the bore. Due to the very high pressure generated by the expanding flame front and the piston approaching TDC, the combustion chamber pressure rises rapidly causing audible knocking. Detonation and preignition typically have a cause and effect relationship; when detonation is prolonged and overheats the spark plug to the point where the tip glows, preignition occurs.
Preventative measures can be taken to avoid preignition by using spark plugs with the correct heat range, avoiding detonation by using fuel with the correct octane rating for your application, and when building an engine, ensuring that there are no machined components with sharp corners in the combustion chamber.

Also, the cooling system must be in good working condition to effectively cool the combustion chamber. Sustained operation of an engine in either of these conditions can result in severe engine damage.

The LSx engines not being steel as in the old days is more prone to carry sound and being a knock sensor simply triggers off a certain frequency it is possible with mods or even noisy fuel injectors can trip false knock which the PCM only assumes is real knock and responds. Noise can even be picked up from drivetrain or headers and transmitted to engine.

The engine in our 1999 is stroked, CAM, larger injectors and headers. The engine compression is 11.3:1 which only makes the fact 91 octane smaog gas can be gotten so knock has been a constant issue.

I spent some serious time doing different experiments with PCM tuning calibration and finally came up with a tuning method that got rid of all the real and mostly false knock.

End results below show how much knock this engine had when hard launching and shifting near rev limiter and then after our knock style tune was done with results of zero ping, increased torque and horsepower due to no reduced timing due to knock.

Here is how GM plotted and set noise levels for LS6 as base noise for knock per cylinder, IE noise not equal to each

Great post.

I hope to be able to make another test run soon so you can do the final tweak. Will this testing be something that will carry over to the newer knock sensors and calibrations?

I looked at your flash and other C6 model and years with LS2edit V2.0H and that base noise table is not there. You might contact carputing and find out why
I then looked at C6 with like hptuners and it shows a different table for each cylinder. Not sure if its even valid but that is what they show.

Day 3 of testing
Weather only 20 degrees and the traction issues seen in results below. Be sure to look at the Throttle and RPMs to see what it took to get through the gears from a launch.

This test we leaned up the fuel trims even more and still got no knock

Day 4 of testing, this time we leaned up PE and WOT fuel and still have good results with 27 deg WOT timing and zero knock.

Weather 34 deg, still allowing water/meth to be functional though it would have no bearing on cooling air temp at this cold of weather but would have had ill effect to knock with stock GM calibration.

Further testing we on purpose set the fuel trims via tuning so that they were 8 percent lean on average.

As seen even being this lean there was no knock at all, the WOT timing at 27 degrees with engine compression at 11.3:1 with 91 octane smog gas.

This also points to the fact of the cyberspace myth that the fuel trims must be rich on average when all that really does is reduces gas mileage and less torque as the leaner AFR is the more torque is seen as we shown in these results.

Weather for this test was about 45 degrees.

Last day of testing where fuel trims were set to an average 8% too lean.

Proven over these tests proved.

1. the Long term fuel trims do not need to be bias rich for part throttle as the cyberspace bullshit states to have good WOT conditions

2. Knock can be tuned out even when engine compression is 11.3:1 and using 91 octane gas.

3. WOT timing has to be 22 degrees or less proven also to be bullshit as seen here with this stroked LS1 with high compression runs best at 27 degree WOT timing.

4. The design of our water/meth smart controller even used in 35 degree weather not only handles lean issues but also preserves performance while increasing gas mileage as with our vette with a 3.73 rearend gear still got 17 MPG city and 29 MPH on highway using 40 lb/hr fuel injectors.

This testing was 30 days after last tests were done to see if over that period of time if anything changed in forcing the fuel leaner, esp during power enrichment and WOT.

Weather was between 45-50 degrees.

Due to that and all the cinders on the road city uses for ice on road I could not do hard standing start WOT launches so the maximum performance could be seen but enough hard engine load to see if any knock would occur or loss of timing due to it.

Maximum speed was 121 MPH
Maximum RPM was rev limiter at 6,700 RPMs
Maximum airflow was 45 lbs which shows engine was pulling very nicely
Average WOT timing was 27 degrees which shows no loss due to being too lean.

Combined driving had a 27 MPG average.

Zero knock or misfire. Not even 1 degree of timing lost.

Even though flywheel HP was 468 the maximum injector cycle of these 40 lb injectors was only 64 percent while the maximum injector needed for this testrun was only 32 lb.
Consider a stock LS1 uses a 26lb and that is for only 350 HP.

This shows :

1. again that the engine does NOT have to be tuned to be rich as in this case LTFTs were set as seen in the results that WOT engine loads fuel trim cells 15 and 22 were about 5% too lean yet no ill effect to engine or performance.

2. Using water/methanol correctly reduces the load on how long injectors are on, less fuel needed and engine can use a smaller injector that has better response times.

O2s reported for NON WOT at 489 mVolts which is about a AFR of 14.2:1 which is correct for smog gas and during WOT reported 875 mVolts which is about 12.5:1 AFR even though fuel trims going into WOT was 5% too lean.

This extended test period proves you can save gas, run leaner, have no knock by tuning leaner and that w/meth with our smart 2D controller can save fuel yet give good performance