fly_high_gsr

Lean Fuel Mixture or Too Much Nitrous.

A lean mix may burn slower than a fat mixture, but the heat of combustion is higher. When you raise temperature you also raise the pressure and you're just asking to generate a second flame front and detonate your main bearings away.

Too Much Ignition Timing.

Firing the cylinder too much before TDC means the piston is going to be dwelling at pressure , it builds to a point where the fuel self-ignites. BOOM! You have detonation. Retard the timing to a point where peak cylinder pressure occurs just after the piston starts down the bore and you not only stay out of detonation, you make lots of reliable horsepower.

Coolant/Engine Temperature.

You can get hot spots in the cylinder or combustion chamber from an inefficient or insufficient cooling system Hot spots raise the temperature in the combustion chamber and , well, you know.

Cam Choice.

Timing of closing the intake and exhaust valves controls then dynamics compression ratio of the cylinder and thus the cylinder pressure and potentially the tendency of a fuel to detonate. A cam with valve timing that fills the cylinder with more air and fuel promotes higher cylinder pressure and higher horsepower. It also increase the chance for detonation.

Compression Ratio, affect detonation.

Spark Plug Choice.

The proper heat range and spark plug type is a critical factor in keeping your engine from detonating, particularly on nitrous.

Air Inlet Temperature.

High air inlet temperature can push and engine on the edge of detonation rite over the cliff. The higher the inlet air temperature, the more chance you have detonating. Just once more reason not put your air cleaner rite by the exhaust pipes.

Oil in the combustion chamber.

If u get oil in the mix, from worn or broken rings, a bad guide, or ring flutter, your engine will detonate.

Carbon Buildup.

On the piston, valve, and combustion chamber surface can cause a hot spot. If you really get a lot of carbon built up, it can raise then compression ratio.


Any comments welcome, thanks.

sander

Lean Fuel Mixture or Too Much Nitrous.

A lean mix may burn slower than a fat mixture, but the heat of combustion is higher. When you raise temperature you also raise the pressure and you're just asking to generate a second flame front and detonate your main bearings away.

Careful here, detonate your main bearings away is not the only thing that will go wrong, more serious to look for is piston / head / damage. And your rod bearings get the brunt of the impact.

Coolant/Engine Temperature.

You can get hot spots in the cylinder or combustion chamber from an inefficient or insufficient cooling system Hot spots raise the temperature in the combustion chamber and , well, you know.

Remember that "insufficient" can also be looked at as low water level, if your water level is low, and you begin reading AIR instead of coolant temp, you may not always see a really high water temp while the cylinder head and piston are getting VERY hot. I have seen piston expansion on a few engines due to low water level, scored walls and everything.

Cam Choice.

Timing of closing the intake and exhaust valves controls then dynamics compression ratio of the cylinder and thus the cylinder pressure and potentially the tendency of a fuel to detonate. A cam with valve timing that fills the cylinder with more air and fuel promotes higher cylinder pressure and higher horsepower. It also increase the chance for detonation.

This is true in that dynamic compression will obviously change but air comes in and out at a greater rate if the cams are designed properly. Cylinder filling does increase but a number of other engine dynamics will change at the same time to help things escape at a proper rate, along with changing ignition timing to suit the cam and cylinder filling.

Air Inlet Temperature.

High air inlet temperature can push and engine on the edge of detonation rite over the cliff. The higher the inlet air temperature, the more chance you have detonating. Just once more reason not put your air cleaner rite by the exhaust pipes.

Yeah, this does not help.

Oil in the combustion chamber.

If u get oil in the mix, from worn or broken rings, a bad guide, or ring flutter, your engine will detonate.

Careful on wording here, your engine wont detonate just because of oil in the cylinder. It has a higher likely hood of the possibility of detonation because oil will degrade the octane of any typical gasoline fuel.

Carbon Buildup.

On the piston, valve, and combustion chamber surface can cause a hot spot. If you really get a lot of carbon built up, it can raise then compression ratio.

That is not what makes carbon buildup dangerous. Carbon buildup is dangerous because of the possibility of thin carbon flakes becoming red hot and almost acting like a diesel glow plug and assisting the possibility of detonation. Same theory goes with exhaust valves that are adjusted too tight, the valve does not have enough time to disperse the heat it has gathered from the combustion process by contacting the head when shut, the valve will become hot, red, possibly detonate, then fall apart and "burn"

sander