First on my plate is infinitely variable valve timing. No, I'm not talking about Honda's V-TECH or some other fancy computer-controlled, expensive, unreliable, and generally ineffective valve actuation. I'm talking very simple, reliable, and effective variable valve timing. You don't lose top-end, and low-end is increased 250% on average (even more with a "hotter" camshaft). Take a normal race engine that has to "idle" at 2000rpm and idle it down to 300 rpm. How is this achieved?
First, let's discuss why
low-end torque is lost with a huge camshaft.
The "high-RPM" camshafts open the intake valve BTDC on the intake stroke, and close them quite a ways ABDC. This is done to maximize inertial fill. It's opened early because the inertia of the air in the exhaust stroke (right before the intake stroke) helps to "pull" air into the chamber. The valve is closed late due to the same inertia. The fast-moving air will "over-fill" the chamber. Generally, the more air/fuel in, the more power you get.
The problem, however, is this "inertial charge" only works at relatively high RPM's because the air has to have decent velocity. At lower RPM, the inertia of the air charge is much lower, and the air stops and reverses shortly after BDC on the intake stroke. Likewise, on the exhaust stroke there is some pressure left in the chamber and some of the air is forced back into the intake manifold during overlap. This blows some of the spent air back into the intake (reversion). This is what causes the "lumpy" idle on these engines, and a general lack of low-end torque.
How do you eliminate this reversion effect? You can always install a low-RPM camshaft, but you'll sacrifice high-end horsepower. Camshafts, by design, can only optimally work in a relatively narrow RPM band (especially narrow considering the RPM range of these high-revving engines).
The only other viable solution is variable valve timing. Historically "conventional" VVT has been expensive, unreliable, and generally "on-off" (gives you a limited choice of timing events). It's usually been reserved for more expensive "tin cans" and econo-boxes.
There is hope, however, and they're called PowreValvz
or Omni Valves
. They were designed to eliminate the reversion problem that is inevitable with high-RPM oriented camshaft profiles. They basically act like a check valve in the intake.
There is no extermal mechanical or electronic controlls, and they are "auto tuning" and infinitely variable. They're simple, very reliable, and cheap (especially when compared to other methods of VVT).
Here's a couple of pics:
The first one is of the valve "closed," which operates like a "normal" valve when the camshaft is in its' optimal torque band.
An "open" valve: The "flap" closes off the intake port while the pressure is greater in the chamber, then "snaps" shut when pressure is equalized (opening the intake port).
With the help of these valves, the "area under the curve" is greatly increased without sacrificing all-out horsepower. The valves can be customised for flap-travel, so you can basically tune your camshaft for a much wider RPM range depending on your application.
There is a "downfall," however (if you can even call it that). Since the net low-RPM volumetric efficiency is so much higher, your dynamic compression ratio at these engine speeds is also much higher. If your engine is a high-compression beast, this could
cause pinging. This would be fixed with two other very simple mods:
Originally Posted by www.fueleconomytips.com
The first mod is called "edging." What it involves is rounding all the sharp edges in the combustion chambers. “That’s been around for decades,” you say. Well, this is taking things to the utter extreme. What has been around is the practice of just taking the sharp edges to reduce the potential for hot spots. This has been effective in warding off detonation under extreme cylinder pressure conditions. But Edging is more.
To get an illustration of how it works, take a cardboard quart milk carton and place a birthday candle about 1” behind it. Use a mirror so you can see the candle and blow on the other side. See the candle flicker? Blow harder and see what it takes to blow the candle out completely. Now take a spray can or something round of about the same diameter as the width of the milk carton. Place the candle behind it and blow. Wow! It hardly took any effort and the candle was out!
So what good does it do in an engine, you ask? On the intake stroke the air/fuel charge is able to maintain the swirl better. As it enters the chamber and moves around, there are fewer sharp turbulent pockets that knock the liquids out of suspension. When the spark plug fires, the flame front is able to walk right up and over the squish pads to better ignite the entire mixture. This same phenomenon puts a more even pressure across the face of the piston, making more power from the same cylinder pressure. On the exhaust stroke, the exhaust gasses are able to find their way to and through the valve, better evacuating the cylinder.
Dana 44 claimed to have a 13:1 compression small block Chevy that would not detonate on cheap regular fuel. He claimed superb power and drivability characteristics, and only ever got it to ping while in Mexico. The best fuel he was able to find down there in one place was 75 octane!
The next mod is a usually considered a little more unconventional and is a bit harder to swallow. It's been proven to work, however, and helps to further increase the detonation threshold, allowing for higher dynamic compression ratios at low RPM.
Originally Posted by www.mpgresearch.info
Let's say your engine has racked up way too many miles and you're debating whether to buy another vehicle or rebuild the old engine. I found a trick so simple and inexpensive (once you have the heads off) that after reading what it does, you'll want to rip into your perfectly good engine just to try it! With this simple trick, the engine feels 20% to 50% bigger yet runs 20% to 50% more efficiently! It works on gas and diesel, 2 and 4 stroke engines. The best part is many of you will be able to add this extra mod during your engine rebuild for FREE! Still, those of you less confident in your mechanical abilities should be able to have it done for $50 or less. We try to cater to all types of entheusiasts from the 'gasoline additive' type, to the engineer. This article is geared toward the machinist, engine rebuilder, racer, tuner, back yard mechanic, and even people willing to have somebody else do the work.
Vapor carburetors have proven their worth in improving power and economy. The principle is to vaporize the fuel and intimately homogenize it with the intake charge air. This fully prepares the intake charge to be combustible immediately after the spark plug fires. Today, they have proven rather impractical due to EPA regulations governing the tampering of factory emissions components, the poor quality and inconsistency of gasoline, and the complexity of the engine management systems prevalent on today's vehicles.
Somender Singh (pronounced 'Sing') has come up with a way to better vaporize the fuel and better homogenize it right in the combustion chamber of the engine. That means there is no failed visual on the IM test. There is no fabricating containers, brackets, fuel lines, linkages, or anything else. There is no explosion danger of having vaporized fuel under the hood if ever in an accident. All of the 'down sides' of the old 100 mpg carburetors have been eliminated. In it's place is a simple modification done to the cylinder head that moves the internal combustion engine into the 21st century.
Swirl port technology has been prevalent in automobile engines since the mid-80s. The principle creates high velocity swirls and vortecies to assist the fuel in vaporizing and homogenizing with the air. The cylinder heads of most modern engines are divided into 2 segments: the 'squish' area, and the 'quench' area. The squish area squeezes the air fuel charge and forces it into the larger quench area on the compression stroke. Squish creates high velocity streams inside the cylinder to vaporize and homogenize the fuel in the air.
Looking at the picture above, there are 5 lines carved into the squish area of the cylinder head. There are 3 lines opposite the spark plug, and 2 lines adjacent to the spark plug. Notice that all 5 lines are aimed straight for the spark plug tip. As the spark plug fires and the flame front traverses outwardly, this pressure wave will travel down the grooves to form high-pressure jet streams. At this point, the cylinder head and piston are still cool enough that this jet stream isn't dangerously hot.
Consider that the heavier elements in gasoline vaporize at 435 degrees F. at atmospheric pressure. Also consider that when the piston comes up on the compression stroke, this 435 turns into upwards of 1000 degrees F. under the extreme pressure. The liquid gasoline will go where there is the least activity in the cylinder, between the cylinder walls and the piston. The center groove shoots a jet stream down along the edge of the piston to blow this liquid fuel back out into the high velocity activity area of the combustion chamber where it can combust and produce power.
The other 4 grooves act to direct the swirl activity within the combustion chamber, as well as clean out the ring lands. They create a more intense, higher speed swirl which brings more of the fuel in contact with the flame front in a shorter period of time. This gives a more complete burn (read that lower exhaust emissions), less heat energy transfer to the cooling system, less carbon build-up on the piston rings and in the engine oil, more power, and better fuel economy.
In this picture there is only one groove. The cylinder head already incorporates high swirl design and the one groove is added primarily to clean out the ring lands of the liquid fuel. By visiting Somender's web site you'll find that the majority of the people incorporating his grooves are using just the single groove with impressive results.
The shape of the piston and cylinder head have their greatest affects on combustion efficiency when the piston is within about 10 mm of Top Dead Center (TDC). When the piston is more than 10 mm away from TDC, the cylinder head and pistons are just distant and innefectual walls bordering a large open expanse. So the grooves do their work within this 10 mm range. On the compression stroke, they force the compressing air/fuel charge into the quench area via higher velocity jet streams to better vaporize and homogenize the fuel. On the power stroke, they guide the explosion through these same jet streams but in reverse to create vorticies, to clean out the ring lands, and to some greater or lesser degree further excite the flame front.
Due to the rapid burn rate, higher compression ratios can be used without detonation problems. On turbo and supercharged engines, higher boosts can be run on the same octane fuel. In either case, lower octane fuel can be used than by conventional means.
Somender has a patent for his methodology, but encourages individuals to experiment with it. He does want feedback on your results so that he can learn more about his technology and improve upon it. Please visit his site to see what else he is doing at: SOMENDER-SINGH.com - Home
Utilizing these three simple and cheap mods will both increase your power producing abilities, it will also increase your RPM range, and since the low-RPM's are burning more efficiently, your fuel efficiency will go through the roof. The valves themselves will give you FE and VE similar to a low rpm, torquey camshaft while still allowing your high RPM power. Edging and Grooving will further increase your low RPM burn efficiency and therefore increase your RPM band further. Combing all three would make a helluva power house!!