No that's called pre ignition. But anyways it doesn't matter scientifically speaking, the fuel explodes. That's what if does. It doesn't matter if it's early or later. Go read any encyclopedia for the word "COMBUSTION" for an explanation as to what happens. Your not going to make any combustible engine run just by burning fuel inside it. The burn is the after effect not before. If that was possible, a blown rotary would still run like a top with no compression. You have to have pressure, a fuel, and an ignition source to create the explosion event. That's basic science. The improper timming of this event is what damages the engine. Burning is what happens when you have no pressure.

i know its wikipedia, but they have you at word 3!

http://en.wikipedia.org/wiki/Combustion

i know we're kinda talking semantics here....

Pre-ignition is when a hot spot ignites the air/fuel mix before the spark plug does.

Pre-ignition can CAUSE detonation, because you essentially are running with wildly advanced ignition timing, but they are two separate phenomena.

Combustion isn't exploding. What happens in the combustion chamber is essentially a fast candle. What happens in detonation is essentially a spark ignited grenade...

Check up on your history. The original IC engines did not compress the air and fuel before igniting it. They drew in a combustible mixture of air and fuel, and then ignited that while still along the same "stroke" (up, in this case). Power takeoff was when gravity pulled the piston assembly back down, probably because it was a lot more predictable than the ignition methods of the time allowed combustion to be.

One of the major innovations in internal combustion engine history is the concept that you get a more useful burn if you compress the mix before trying to ignite it. Gets the molecules closer to each other, concentrates them. The added heat is a nice bonus for helping combustion happen. (Technically, you can't have one without the other...) Too much heat and pressure causes the mixture to spontaneously ignite *everywhere* instead of propogating smoothly from the spark plug... this leads to a tow home in high horsepower applications :goodrebuild:

At any rate, I wonder if your torque increases were due to increased velocity at the port exit helping to prevent reversion. It's always an interesting problem with rotaries.

Nah that's just wikipedia and they leave some things out. ;) Hears from my "New Standard Encyclopedia" hard copy.

"Combustion, the chemical combination of two substances (fuel and oxygen) accompanied by the production of light and heat (since were talking rotary---spark from plug). As commonly used, the term applies to the combination of a substance with oxygen causing fairly rapid oxidation, or fire. EXTREME rapid combustion (which is what happens inside a combustion engine), in which the fuel and oxygen are united INSTANTANEOUSLY, is called an EXPLOSION. Flame is a product of combustion."


Not to confuse anyone but everything above in parentheses is my own inclusion for reference and not written in the book I just copied from. Your right though we are talking semantics.

Well I really don't see where much reversion could be occurring at partial throttle with the majority of the air coming from the primary ports at partial throttle opening. The primary port is closed before the compression stroke. Now the 5th and 6th ports are a different storey. They close late so this is where any reversion is happening. With the mod I did while cruising, I can feel myself pressing down the throttle less to keep the same velocity. Seriously I know how far I need to push my gas pedal to the point that the secondary throttle plates open. In most cases, it's not enough throttle to open the secondary throttle plate. I literally have to push my gas pedal down only about 1/4" to cruise at 70mph on the hwy. So I'm mostly running off the primaries at cruise but yet I have more torque than before. Since I now have no overlap, my exhaust port is already closed when my primary ports are opening so there is no way for the incoming air to reverse downward into the low pressure area of the exhaust as it closes. Now truthfully I can't prove that there really is low pressure at that point but, I don't think their is enough exhaust back pressure at this low of an rpm to create a hi pressure point when the exhaust closes. Since it can't reverse, it has to go through the combustion process and now more of it is being burned therefore, creating more push against the e-shaft. Hell the rotor is only spinning at 1000rpms at 3,000. So anyways that's just my speculation and how I see it working. I may be completely wrong but it makes since.


For those of you that didn't know, the secondary throttle plates have a mechanical delayed opening to help keep the air velocity through the primary ports hi. This helps with chamber filling and improved low end torque.