12.4:1. this is your final or corrected compresssion ratio(FC). By that I mean adding in corrected altitude
your cam selection (see Keith black pistons calculators for dynamic and static compression)
and if you are running a supercharger
(boost / 14.7+1) x compression ratio= FC
Piston companies list there compression ratios for a factory combination. Factory deck height, rod lengths, and head gasket thickness because they don't know what you are running. This calculator takes into account the things you can change and the closing event of your intake valve to give a true compression rating or dynamic.
I learned this from Blower Drive service Tech info on there web site.
Also I have a supercharged 2003 harley Davidson editon F-150. Stock static compression is 8.5:1. I am running 12 pounds of boost and I have run as high as 16lbs, on 91 octane.
That would put my static compression ratio over 15:1 on 91 octane.
(12lbs / 14.7 +1)=1.81x8.5(static compression)=15.44
(16lbs / 14.7 + 1)= 2.08 x 8.5=17.75
YES I did tune the computer for my changes, and it does remap the fuel and ignition, and aluminum heads help too.
If you do all the math and build it to the edge for where you live, don't go cruz the California beach from Denver because the altitude will change the air density and your compression ratio.
It can ..but the compression ratio require 91 octane minimum...
Cadillac 1958 with the compression ratio of 10.25:1 should not run on gas below 98 octane.
So the engine can run on regular 87 octane gasoline.
It wouldn't necessarily run better at all - it all depends on your ignition and timing setup and compression ratio.
Stock can run 93 octane and if its modded you need 100 octane or higher if its a high compression build.
cars & vehicles
Congratulations you have just added to the Misinformation Superhighway. Stock specs for Hondas is about 10:1 COMPRESSION The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting. The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more
It runs. High octane is what is required by high compression engines in order to prevent pinging. Unless you put the hi octane fuel in the oil filler. Then it will only briefly run before it explodes.
Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking. (Note that it is the absolute pressure (compression) in the combustion chamber which is important - not the compression ratio. The compression ratio only governs the maximum compression that can be achieved). It might seem odd that fuels with higher octane ratings explode less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation as opposed to the ability of the fuel to burn (combustion). Using a fuel with a higher octane lets an engine run at a higher compression ratio without having problems with knock. Actual compression in the combustion chamber is determined by the compression ratio as well as the amount of air restriction in the intake manifold (manifold vacuum) as well as the barometric pressure, which is a function of elevation and weather conditions. Many high-performance engines are designed to operate with a high maximum compression and thus need a high quality (high energy) fuel usually associated with high octane numbers and thus demand high-octane premium gasoline. Using high octane fuel for an engine makes a difference when the engine is producing its maximum power or when under a high load such as climbing a large hill or carrying excessive weight. This will occur when the intake manifold has no air restriction and is running at minimum vacuum. Depending on the engine design, this particular circumstance can be anywhere along the RPM range, but is usually easy to pinpoint if you can examine a printout of the power output (torque values) of an engine. On a typical high-revving motorcycle engine, for example, the maximum power occurs at a point where the movements of the intake and exhaust valves are timed in such a way to maximize the compression loading of the cylinder; although the piston is already rising at the time the intake valve closes, the forward speed of the charge coming into the cylinder is high enough to continue to load the air-fuel mixture in. When this occurs, if a fuel with below recommended octane is used, the engine will knock. Modern engines have anti-knock provisions built into the control systems and this is usually achieved by dynamically de-tuning the engine while under load by increasing the fuel-air mixture and retarding the spark. Here is a link to a white paper that gives an example:  . In this example, the engine maximum power is reduced by about 4% with a fuel switch from 93 to 91 octane (Excerpts taken from Wikipedia)
Octane cannot be seen, but it is of utmost importance when it comes to gasoline. One thing for sure, higher octane fuel costs a lot more. Simply put, octane is a measure of gasoline's ability to resist detonation, which you hear as pinging and knocking in your engine. The higher the octane the more the fuel can be compressed without detonating before you want it to. Detonation, ping, knock, whatever you want to call it, occurs when the air/fuel mixture ignites before the spark plug fires. The mixture ignites from compression and not from the flame of the spark plug. In other words, the higher the octane the less likely it is to ignite prematurely. The only benefit to a high octane fuel is that it allows an engine to run at a higher temperature and with a higher compression ratio without pinging. Higher octane fuel does not provide more energy, more power, better mileage, more torque, burn cleaner, clean your engine, and is not better for the environment. If the engine is pinging when using the correct octane fuel, then it may be necessary to move to the next higher octane to prevent pinging, and damage to your engine, unless there is another problem. If you are using higher octane fuel for any of these reasons, STOP, you are throwing your money away. Also, never use a lower octane fuel than is recommended by the manufacturer. If the manufacture recommends 89 octane then use 89. If they recommend 87 then use 87. The key is knowing what was the engine designed to run at to achieve optimum performance and mileage. One exception is when you are towing a heavy load with a vehicle designed to run on 87 and you experience pinging. In that case it may become necessary to switch to 89 while towing. In conclusion, race car engines are designed to run on high octane fuels due to their high compression engines. You cannot make your engine a race engine just by upping the octane. Save your hard earned money, and use exactly the octane you need. <<>> Octane C8H18 can be mixed with heptane C7H16 to form petrol (gasoline). Heptane being a less-heavy molecule has a lower ignition temperature. An octane rating of 95 gives the same ignition temperature as a mixture of 95% octane and 5% heptane. Higher-octane fuel detonates at a higher temperature. High-octane fuel can be used in an engine with a higher compression-ratio to produce more power. The extra power comes from the compression ratio and the higher thermodynamic efficiency, rather than any change in the chemical energy in 1 kg of fuel. In earlier days high-octane petrol was reserved for aero-engines so motorists had to use the lower octane stuff and tolerate an engine with a lower compression ratio producing slightly less power for its cubic capacity.
I would run a mix of 32:1 with 89 octane fuel.
Yes and No. Hydrogen only has a octane rating of 50, but the properties of Hydrogen let one run higher compression on your engine which in turn will give more power.