Automotive Question

[Jeddak]

Honestly, of your engine is not designed for premium you will actually get less performance from premium fuel...premium fuel is designed to ignite at higher temps to prevent detonation.

You are wasting your money using premium in cars and mowers not designed for it. Fact.

You are also likely to get older fuel when buying premium since it costs more and sits in tank longer.

You do not seem to know what Octane number is. Premium gas burns at exactly the same temperatures as Regular. Higher octane gas allows engine to compress the fuel/air more (increase timing), thus producing more horsepower. Some fuel-injected vehicles (like my Isuzu) can advance timing enough to benefit from it. I get better gas mileage on Premium, since I do not step on the throttle as much to accelerate to speed.
Some fuel additives do help. PEA is the only additive that has proven to clear the injectors AND not to create deposits in the processes. Techrone, 3M, Redline SL-1, Regaine Full fuel system cleaner have high PEA amounts and they do work.
I also use MMO (slightly less than the recommended 4 oz to 10 gal) as an Upper Cylinder Lubricant and Fuel pump lubricant. Ethanol in modern fuel, while increasing the Octane number, robs fuel of its lubricating purposes and absorbs water. MMO helps with that.
Seafoam and 3M Tune up Kit are very good in cleaning up the throttle body and carbon deposits. I use 3M's kit to on my cars (easier to use than Seafoam, since it has a straw to go directly into air-intake past MAF)

 

[Tony2X]

I went to a Gm training course and this was half of the course. If memory serves me correctly the fuel pressure there running is in excess of 10,000psi in a gas engine lol.

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[speednut]

I have seen Cummins diesels in there B series with a common rail fuel system running 10000 psi also some John Deere big 6 cyls.

 

[Bgolden84]

I have seen Cummins diesels in there B series with a common rail fuel system running 10000 psi also some John Deere big 6 cyls.

Yes this is true. But this is not a diesel engine it is a gasoline engine. You won't find a gasoline engine that runs over 100psi.

 

[Constitution Hour]

Funny,octane is easy to research and has more to do with flash point (volitility/@ temprature)than anything else. It is used in higher compression engines to prevent detonation (pre -ignition) of the air fuel mixture due to heat or compression (resulting in heat). Egr is used to lower combustion temps by introducing inert gas and displacing oxygen in the combustion chamber. Ford has been working on a compression combustion gasoline engine for several years now,as mentioned by my son the Nox emission is very high due to increased combustion temps. The catylist materials required to scrub the nox is very expensive.Just my two cents.

 

[Bgolden84]

Effects of octane rating

Higher octane ratings correlate to higheractivation energies: This being the amount of applied energy required to initiate combustion. Since higher octane fuels have higher activation energy requirements, it is less likely that a given compression will cause uncontrolled ignition, otherwise known as autoignition or detonation.The*compression ratio*is directly related to power and to thermodynamic efficiency of an internal combustion engine (see*Otto-cycle). Engines with higher compression ratios develop more area under the Otto-Cycle curve, thus they extract more energy from a given quantity of fuel.During the compression stroke of an internal combustion engine, as the air / fuels mix is compressed its temperature rises (PV=nRT).A fuel with a higher octane rating is less prone to auto-ignition and can withstand a greater rise in temperature during the compression stroke of an internal combustion engine without auto-igniting, thus allowing more power to be extracted from the Otto-Cycle.If during the compression stroke the air / fuel mix reaches a temperature greater than the auto-ignition temperature of the fuel, the fuel self or auto-ignites. When auto-ignition occurs (before the piston reaches the top of its travel) the up-rising piston is then attempting to squeeze the rapidly expanding (exploding) fuel charge. This will usually destroy an engine quickly if allowed to continue.There are two types of induction systems on internal combustion engines:*Normally aspirated engine*(air is sucked in using the engine's pistons), or forced induction engines (seesupercharged*or*turbocharged*engines).In the case of the normally aspirated engine, at the start of the compression stroke the cylinder air / fuel volume is very low, this translates into a low starting pressure. As the piston travels upward, a compression ratio of 10:1 in a normally aspirated engine will most likely not start auto-ignition. But 11:1 may. In a forced induction engine where at the start of the compression stroke the cylinder pressure is already raised (having a greater volume of air / fuel) Exp. 2 Bar (14.7Psi), the starting pressure or air / fuel volume would be 2 times that of the normally aspirated engine. This would translate into an effective compression ratio of 20:1 vs. 10:1 for the normally aspirated. This is why many forced induction engines have compression ratios in the 8:1 range.Many high-performance engines are designed to operate with a high maximum compression, and thus demand fuels of higher octane. A common misconception is that power output or fuel efficiency can be improved by burning fuel of higher octane than that specified by the engine manufacturer. The power output of an engine depends in part on the energy density of the fuel being burnt. Fuels of different octane ratings may have similar densities, but because switching to a higher octane fuel does not add more hydrocarbon content or oxygen, the engine cannot develop more power.However, burning fuel with a lower octane rating than that for which the engine is designed often results in a reduction of power output and efficiency. Many modern engines are equipped with a*knock sensor*(a small*piezoelectricmicrophone), which sends a signal to the*engine control unit, which in turn retards the*ignition timing*when detonation is detected. Retarding the ignition timing reduces the tendency of the fuel-air mixture to detonate, but also reduces power output and fuel efficiency. Because of this, under conditions of high load and high temperature, a given engine may have a more consistent power output with a higher octane fuel, as such fuels are less prone to detonation. Some modern high performance engines are actually optimized for higher than pump premium (93 AKI in the US). The 2001 - 2007 BMW M3 with the S54 engine is one such car. Car and Driver magazine tested a car using a dynamometer, and found that the power output increased as the AKI was increased up to approximately 96 AKI.Most fuel filling stations have two storage tanks (even those offering 3 or 4 octane levels): those motorists who purchase intermediate grade fuels are given a mixture of higher and lower octane fuels. "Premium" grade is fuel of higher octane, and the minimum grade sold is fuel of lower octane. Purchasing 91 octane fuel (where offered) simply means that more fuel of higher octane is blended with commensurately less fuel of lower octane, than when purchasing a lower grade. The detergents and other additives in the fuel are often, but not always, identical.The octane rating was developed by chemistRussell Marker*at the*Ethyl Corporation*in 1926. The selection of*n-heptane*as the zero point of the scale was due to its availability in high purity. Other isomers of heptane produced from crude oil have greatly different ratings.

 

[herebyproxy]

OK....I have always run 87 in my civic......I will put mid grade in it next fillup..........If I notice any difference I will stick to it.....if I don't........pfffffft

 

[linebacker]

Two minor flaws here,
1) Sugar doesn't dissolve in gasoline, try it sometime.
2) Injectors can and do "clog" or become obstructed.

I wonder if piss will dissolve in gasoline.

 

[BackWoods]

I wonder if piss will dissolve in gasoline.

Amonia as a gas, should actually burn cleaner than gas : D

 

[Wrencher]

I have seen Cummins diesels in there B series with a common rail fuel system running 10000 psi also some John Deere big 6 cyls.

The Duramax diesels also run a pressure common rail setup, pressures at idle are from 4-5K and peak close to 23,000 PSI at WOT.