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Originally Posted by Leitner
did you even read the whole thing? it had all the support systems like cams and such. he actully stated that they could retard the timing and get lower egt's and the same power. its about burn quality. my car starts fine in -20 celcius weather. he runs 13.5:1 on 92 so whats your point? read everything before making silly statements or didnt you understand what he was saying?
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No where in that entire article did it sa;y he ran 13:5:1 on 92 octane. also these are all of the main things that I thought were important enough to list. Also he said static compression ratio's. Point is clearly that you don't need the highest compression in the world to make power in a STREET CAR.
I suspect that about now some readers are wondering how to eliminate the intake valve relief in the piston of a performance-oriented engine. It requires some rather special camshaft design with little or no valve opening during the "normal" overlap cycle. We’ll discuss this aspect when we get to the "support systems" which relate to cam design.
So we want to mechanically force the mixture to the exhaust side, ignite, and briefly confine it for complete combustion.
To make this particular concept even more efficient, we can shape the piston dome and quench pads to force the mixture to swirl into the preferred portion of the chamber, creating swirl combustion. As the inlet port will induce a swirling mixture to the cylinder which is rotating due to inertia, the proper piston to chamber shapes can effectively reaccelerate the swirling charge, while ever confining it to our exhaust side "sweet spot" for ignition and initial burn propagation.
If the combustion process is quick and complete, there will be very little burning when the exhaust valve opens, and the exhaust gas temperature will be very low. A quick burn also permits us to use less ignition timing advance to complete the combustion cycle and, therefore, the engine is doing less "negative" work since we’re not trying to compress as much ignited and rapidly expanding mixture. Unfortunately we can’t light the mixture at TDC and still complete the burn by BDC (with gasoline), but we can run only 5 - 15 degrees advance and create a thorough burn cycle.
Now we’ll look at some of the support systems, starting with the camshaft. In order to configure the piston dome so that at TDC, there’s minimal volume on the intake side, the camshaft must open the valve very little prior to TDC on the overlap cycle. Once past TDC, the valve may open at the same rate the piston is traveling down the bore until approximately 12 degrees past TDC, when the piston’s out of harms way.
The actual length of the cams' events is entirely a function of maintaining the correct combustion space, while allowing enough fresh mixture in and spent gasses out, as required by the engines displacement, desired output, and permissible operating RPM range. This now brings us to the subject of ports.
All our original data that was made public indicated that we were achieving a very homogenous mixture in the cylinder with swirl inducing ports. The increased power and fuel efficiency were simply due to better mixture quality control prior to ignition and during the "confined" burn on the exhaust side of the chamber. Our assumptions were only partially correct.
Normally when designing the chamber and piston configuration we never check the static compression ratio as long as the "combustion space" is acceptable, regardless of application (normally aspirated or force fed.) We have found that many of our engine's compression ratios were well over 23-1, and we also learned that allowing new customers to know those numbers was not always good for business. Monday mornings are still always fun when we get the call regarding how well the combinations ran, then we’ll let them to know part of the reason why. Regardless of the weekend performance, it still scares them to death.
is the same as H 1, but the piston is at TDC. Note the dome design is displacing almost the entire mixture to the exhaust side for the burn. This piston / chamber interface is why we can run this configuration on both N/A and blown engines. The static compression ratio is high, but in order to achieve the combustion kinetics we desire, it must be. This chamber bias is the basis of the "Soft Head" and. As you can see, it's easily adapted to many engine styles.
i just personally wouldnt do it for long-term reliability reasons. if i had more money, id do it daily and not even worry about it. its a task, but as long as its tuned correctly itll be AOK 
