Since I want to air some ideas to make them more public. Octane etc. and preignition...

Okay. Supposing you had infinite-octane fuel. Now your compression ratio could theoretically go from "10.5:1" on up to "Any further and you would be hydro-locking your cylinder due to the air liquefying from sheer compressed density."

The first order of business, to get the theory out there especially for the crowd that hasn't been in this since they were 7, would be to just find the point of diminishing returns. At what point is:
A) the effort expended on the crank and connecting rod just going to be too great to justify going past 100:1 or whatever compression? What use is a compression ratio that your crank just doesn't have the strength to actually perform without breaking?
B) How close can the piston and combustion chamber get before the thin little pancake (no, crepe) of air and fuel is just too stupidly thin to even allow proper flame-front propagation?
i) Properly-shaped (LIKE A MODERN HEMI) combustion chambers would help here.
C) When is spark timing going to be best-placed to make the most of the newfound 1Megaoctane?
D) unfettered by octane limits, we are then free to find just WHERE in the cycle the best spark timing is both for power and efficiency. Screw emissions. Catalytic converters can take care of that.
E) Now, having established this, how do we get our real-world cars as close as possible to whatever the theoretical ideal is? We may find that a spark advance of 50 degrees is truly wondrous, or we may only need 10 degrees due to the twin spark plugs and compact initial air/fuel mass shape.
F) Then, we do what is necessary to augment our ability to approach the no-hold-barred ideals.

Why take the "go for perfect first, then find a reality that fits" approach? Because with this approach, you can find stuff like "If we spend an extra 20 thousand dollars on this motor, we only get five percent more than we would on a far-less-perfect motor" and other relevant data.

This format of thinking is what led me toward favoring the Magnuson blower, the most underhyped supercharger in the world, but that is a side note.

We may find, as we do our research, combing the world, often via the 'net, anecdotal evidence that really opens our eyes, such as one experienced 5-second-class Mopar racer told me: "Toothed belts instead of ribbed belts on PD superchargers lead to them failing more often." This was on a street-driven machine or machines, his experience. Now, all my research had never indicated that to me, but this racer had found that Gilmer belts on the various Hellcat blowers led them to fail more often. Suddenly, the ribbed belts made sense to me, as did the gigantic lack of interest by people in going with Gilmer belts on them.

What my research has turned up is a piston that is closer to whatever the holy grail is for piston design for the Gen III: The piston on the 1600hp Drag Pak 5.7L 10,000 RPM supercharged beast. One look at it told me that some SERIOUS R&D had gone into this.

Witness the beauty:
https://www.dcperformance.com/p-drag-pak-pistons-dsr-performance-srt354scab125

Notice the cutouts around the spark areas that enable the initial combustion to have less of a pancake-flat obstacle course to squeeze through, but instead move the initial-combustion-via-spark area closer to being a pair of mini-hemispheres.

I had never seen this exact configuration, and I know the compression ratio on the Drag Pak with its deep-breathing Whipple Gen V are not the run-of-the-mill engine.
But, those spark plug reliefs MAY be a useful feature for pistons in general, not just this one. Even diesels have a special relief in the top, often, exactly centered on the injector's spray cloud.

What this may offer in the way of benefit is the ability to use higher compression for a given fuel quality, while still offering excellent ratio of burnt to unburnt fuel. I don't know from direct experience, but 1600hp from 5.7L shouts pretty loud that, empirically, they seem to be doing something right.

Could it be that, like the diesels, we need to design pistons more so a somewhat-hemispherical relief surrounds the spark plug(s) to aid in initial flame propagation?

I have seen F1 pistons where four tubs were in the top of the pistons: two each of exhaust and intake round valve-shaped tubs, and one big rectangular tub right under the spark plug. A flat-top piston does not seem to be the way to gain ideal mixture placement, shape, and burn, and I believe there is more to find in this area.

What if we had a piston that made it so at TDC, we have two spark plugs protruding into somewhat spherical spaces? Would this, too, aid and assist in a more complete burn?

As you can see, engineering is more than just staring at a slide rule, but keeping one's eyes open to the potential to make use of someone else's innovation and then expand upon it.

But, the central idea is "How much compression can we get away with if we shape the shape of the air/fuel mixture such that closer-to-ideal flame propagation occurs?

The "quench" areas along the top and bottom of the picture are not for "quench" at all, they are for turbulence near TDC, as on primary purpose. Violently tumbling air/fuel emulsion leads to a more complete burn.

The IDEAL combustion space is completely spherical, with ignition occurring at the very center. How can we approach this in piston and cylinder head design?

The Hemisphere, as Jon Bon Jovi said: "Ooooh, we're halfway there!" What can we do to improve on it further?

I believe the Drag Pak pistons are the best-designed American V8 pistons in history. What can be done to improve them even further? Have both spark plugs nosed further into the combustion chamber? Taller electrode and ground strap? Jumping one spark all the way from one plug to the other?

But, the main point is this: Octane versus compression and advance.

Engine Masters competitors have ROUTINELY used 13:1 (or higher?) static compression on their engines, across a broad RPM range required to win in the competition, not just the jagged-pointy-horsepower-peak at only between 6200-6205 RPM that is functionally useless.

This forced me to look into WHY are lunking carbureted engines able to use what we have been TOLD is FAR TOO MUCH COMPRESSION for 93 octane?

This leads to an entire rabbit warren of thought, not just a trail.

It is a FACT, it has been done, and done very successfully.

Then why aren't we doing it?
And what is the upper limit? 14:1? 15:1?

The more gracefully and excellently the airspace of initial combustion is designed, the higher you MAY be able to get higher static compression.

Is the cam a dual-pattern with shovels full of overlap to bleed the heck out of static compression at lower RPM, and only allow higher compression due to snappier valve action at higher RPM?

Is the spark stupidly retarded in the lower RPM ranges?

Food for thought.

 

PS My goal is to own a car one day that has at a least 13:1 compression engine that runs 93 octane gas regardless of how much supercharging or turbocharging it has.

I am not against having aggressive compression-bleeding valve timing that bleeds compression (BTW, this means that it shoves intake air back out the intake valve) at lower RPM, where lower compression is needed, but due to the dynamics of the air column velocity, this actually works to provide greater cylinder fill at higher RPM. Similarly, more overlap will bleed compression out the exhaust valve at lower RPM, but function well to invite in more air with better cylinder fill at higher RPM, as the valve timing is absolute in degrees, but the amount of time the air has to slam into that cylinder is shorter and shorter the higher the RPM goes.

Surprisingly, the exhaust valve often opens at around 90 degrees BBDC on the power stroke. Another reason low-RPM diesel engines get better fuel mileage. They don't open the exhaust valve so early because the engine is not turning fast enough for that combustion pressure to be counterproductive with the piston so far down the cylinder.

What these factoids tell us is "the sooner we can get complete combustion of the intake charge, the more power is used to drive the piston down and the less is discarded in the exhaust stroke." That actually makes the six-stroke engine look appealing.

A six-stroke engine has two power strokes
1. Intake
2. Compression
3. Power
4. Compression again
5. Power: using up the last bit of power from the pressure generated by the initial power stroke combustion
6. Exhaust.

The advantage of this is that the initial power stroke is a full 180 degrees from TDC to BDC, not just 90 degrees or so after TDC. The final power stroke may only by 90 degrees, depending on RPM, but, hey, at least the initial power stroke was 180 degrees instead of 90. That's 270 degrees of power stroke, with the already-hot exhaust being compressed prior to the second power stroke to very high temperatures which would make it more likely to burn up any unburnt hydrocarbons.

Now, averaging this over 1080 degrees of crank rotation necessary (3 full revolutions) means 270 degrees of power stroke, 360 degrees of compression stroke, and the usual amounts of other strokes.

So, The power-making strokes add up to 270/1080 degrees, or 25 percent of all crankshaft degrees in the whole cycle.
Normal engine: 90/720 degrees, or 12.5 percent of all crankshaft degrees. in the whole cycle.
Six-stroke exhaust: 270/1080 degrees, or 25 percent of all crankshaft degrees in the whole cycle
Normal exhaust: 270/720 degrees, or 37.5 percent of all degrees of rotation
Six-stroke compression, the REAL power-robbing stroke: 360/1080 degrees 33.3 percent of all degrees
Normal compression: around 180 degrees or 25 percent of all degrees.
Power versus compression on the six-stroke: 270/360=0.75:1
Power versus compression on a normal motor: 90/180=0.5:1


The hope is that the six-stroke will overwhelm the added resistance and drag of an additional compression stroke with its 50 percent of additional crank degrees (as a ratio of overall crank degrees) spent on power versus the power-costly compression.

The six-stroke would enable more generous valve lift events due to the longer time frames. I'm somewhat curious why no one has done much with it. I don't subscribe to the lemming-like "Well, if it was good, they'd have done it." No, that's a lie. Disk brakes were not on all four wheels of most cars until just a few years ago. That cost lives, unnecessarily.

So, to get the same total power output (ignoring efficiency) then how much more fuel and air would we need to burn per combustion event to balance things out? (BTW, with the extraction of power from the crank being stretched out over two separate strokes, There would be less whipping of the crank in torsional harmonic vibration.)

This bears some study. Exhaust temperatures would be reduced (and overall exhaust heat BTU per second) as that energy is being used more to push the piston around, and thus that energy is being extracted to a greater extent. This may mean more heat retained in the piston and combustion chamber due simply to hot gas sitting around in the engine longer.

Ramps on the cam would be steeper, as the cam is turning more slowly for the same opening and closing rates. (Cam speed is 1/3 of engine RPM instead of the usual 1/2.)

In low-load situations, efficiency would drop, because cylinder pressure is lower at times than is even required to overcome friction.

 

The science behind compression and valve timing is not what you would call textbook-documented.

There is "gold in them thar hills" though.

If you are an easily-offended retard, just stop reading now. Your mind can't process new ideas anyway.

I know the imbecilic merchants of the whole car scene shriek in fear at the idea of any new technology they aren't profiting from already, but science can advance without the input of such people, and, in fact, often advances in spite of all their efforts.

The less intelligent, inventive, capable, or in any way useful people are, the more new idea seem to terrify them. It is sad to see, for their sake. Closed minds do not advance anything.

Part of the equation is to time the injector pulses so accurately and to place the spray of the fuel so narrowly that it is aimed directly at the back of the intake valves, and arrives at the most optimal time to ride the air into the cylinder but NOT get pushed out the exhaust or pushed back up the intake tract by flow reversion when the exhaust valve is shut.

I have found that the Speed Hucksters get downright HOSTILE when you discuss new ideas on their narrow-minded forums, and attack you en masse. I never subscribed to the "keep them all stupid and buying only my stuff" mentality.

Injectors can be far better in their behavior than is currently the norm. Also, aftermarket fuel injection is just plain cheap and dumb, even the top-end stuff like Motec, Holley, and Haltech.

Having looked into it in detail, they are very, very, very sorely lacking in flexibility and granularity in how specifically you can drill down to time periods to inject fuel. I was apalled.

From zero to redline RPM, I should be able to place injection pulses anywhere from just-before-valve-opening (to take advantage of momentum to get the fuel close to the intake valve just prior to opening) to during valve opening at the beginning or near the end of the event, AND be able to run multiple events, of different durations.

The slop that is available is resoundingly pathetic. It is some of the most "easiest, cheapest, lowest, crappiest, lowest-expenditure" stuff I have ever seen. I THOUGHT going for Haltech and Motec would yield Le Mans-winning levels of capability.

Fat chance. They are all in the same bed. Injectors are low-technology, with extremely long minimal opening windows, so you can't rapidly fire a 70 pound injector to more accurately place the fuel than a 30 pound injector, because the minimum opening window of a 70 pound injector (or whichever) is just too large and would drown your engine.

Mentioning stuff like this can get you kicked off of some forums, evidently, as they hate to see anyone not braying about how great their latest super-overpriced "tuning package Stage VII" or whatever is.

All the tuners are just a small clique of relatively stupid profiteers. You NEVER see anyone doing anything new or different. They just regurgitate the latest stuff they licked up earlier, as long as they can mark it up for maximum profit.

You will never hear ANY of them speak of multiple injection events per cycle, multiple sparks, injector volume/time windows, or anything else. It's just the same vomit puked out of a different mouth.

There is NO innovation. Just profiteering hucksterism.

Even constant-flow injection would work marvelously, If it was controlled very accurately with electronic means (primarily pressure and flow modulation on a per-load basis.) It would also atomize better than most dribbly injectors.

Want to see a good injector atomization level? Look at a diesel injector being tested. High pressure and small orifices leads to far finer particle size.

What happened to innovation, intelligence, or even DISCUSSION? What happened to the whole car scene?

Try it on ANY forum, but most especially those owned by Vertical Scope. See how long you last. Forgive me, but this is frustrating to see played out over and over as Vertical Scope snaps up forums and eliminates free speech in the name of "tolerance for morons."

And we see, thus who is in bed with whom on the internet.

Mechanical control of fuel mixing is not something that has been completely maximized. It is not difficult. The Germans won Le Mans with it for many years before electronics. They mopped the floor with the competition in Can Am so long that the series used fuel consumption limits to limit the power production of the "Panzer" 917/30 Can Am cars.

This stuff is easier than ever to design using CAD and easier than ever to test and verify using electronics. You can build a system that monitors air pressure, manifold temperature, fuel pressure, and air temperature to meter fuel completely appropriately.

Carburetors did it for decades, more than a century. It is not beyond our ability. It has just been beyond people's inclination to actually explore and innovate.

The old constant-flow injection was somewhat limited in how much fuel it could introduce, as it did not change anything but fuel amount with RPM and throttle position. That is not a great deal of flexibility.

But it is SO sexy. And EMP-proof.

It is a small matter to vary the input of fuel based on a simple atmospheric-monitoring limiter on the injector pump. More air pressure, slightly more fuel volume. Higher altitude, such as in Colorado, and you get less fuel volume.

It ain't rocket science. But, even with fancy-shmancy new electronics, they still manage to screw this up. The Germans in WWII had a plane that could go from sea level to 30,000 feet with an automatically-adjusting supercharger drive, fuel injection, etc. What happened to us, the world?

Why did everyone get so fricking STUPID?

Or maybe I was just not noticing that things have been that way a long time. Lots of advertising, hucksters, etc. Basically carnival barkers.

I wonder how hard it is to just write a program and run it from your laptop for starters. I guess there is a way to find out.