ygmir wrote:oh, ok......I get the ignition adjustment thing......a fancy one of what I made so long ago, when I drove cars with distributors and spark plugs.......
wow, that must be interesting to vary a supercharger for compression........and, or altering the combustion chamber, how would they do that?
yeah, tet/lead is quite toxic, but, IMHO, the best octane increaser....
are you sure it's false octane? I thought that was a measure of burn rate/volatility, and, therefore, knock/ping resistance........higher allowing for less pre-ignition due to either increased compression or advanced timing .
dang, that hurt my brain.......
Lead controls burn but adds no energy.
There are much better approaches.
Lead was used primarily due to cheapness and valve lubrication.
It does affect octane but without adding any potential power.
There are some much better mixes out there.
There are a few additives left with lead in them.
Reviews are mixed.
The Saab Variable Compression (SVC) engine is comprised of a cylinder head with integrated cylinders, which is known as the monohead, and a lower portion consisting of the engine block, crankshaft and pistons. The compression ratio is varied by adjusting the slope of the upper part of the engine in relation to the lower part by up to four degrees. This alters the volume of the combustion chamber and changes the compression ratio.
The energy in the fuel is better utilized when the compression ratio is as high as possible. However, if the compression ratio is too high, the fuel will pre-ignite and cause "knocking," which could damage the engine. Due to its variable compression ratio, the SVC engine can be run at the optimum compression ratio of 14:1 at low load in order to maximize the use of the energy in the fuel. The compression ratio can then be lowered to 8:1 at high load to enable the engine performance to be increased by supercharging without causing engine "knock."
The SVC engine concept reduces fuel consumption by up to 30 percent when compared to a larger conventional naturally aspirated engine of similar power output. It also provides the tremendous power output of 140 Ib.-ft. of torque and 150 horsepower per liter of engine displacement.
Engine displacement 1.598 liter
Number of cylinders 5
Cylinder bore 68 mm
Piston stroke 88 mm
Compression ratio 8:1 to 14:1, depending on engine load
Max. compressor boost pressure 2.8 bar (40 psi)
Max. monohead tilt angle 4 degrees
Maximum torque 224 Ib.-ft.
Maximum horsepower 225 hp
http://www.autoworld.com/news/saab/saab ... ession.asp
http://paultan.org/archives/2008/02/07/ ... -concepts/
http://www.memagazine.org/backissues/me ... /otto.html