race gas

[Guest FBody Addict]

So what is the deal with race gas

 

1)I thought that the higher the octane, the more resistance to pinging there was

 

So is race gas really

2)only for people running forced air induction running alot of boost

 

Or 3)does race gas actually burn faster and cleaner

 

4)with more force than regular gas

 

If somone could clear this up for me please i thank you

[Guest mudbutt]

The higher flash point is an advantage when running higher compression, more timing, boost; situations where combustion pressures are higher. I ain't got no smarts to tell you more though.

[Dave1647545494]

the higher the octane rating the slower the fuel burns. so what you want to do is run the LOWEST octane possible without detonation running to high of an octane for your combination can actually hinder performance. generally a street motor will never need more than 94 octane. now if your running on the ragged edge with high compression and boost , lots of bost , lots of spray, or very high compression(over 12:1) you need more octane to control the burn rate so you don't torch a piston. lots of other things play into this though like combustion chamber design, cylinder head cooling, piston shape, timing, fuel air mixture, and rod to stroke ratio. thats why a turbo buick at 30 psi needs c16 but an 13:1 big block with a new style head design and a conservative solid roller that makes the same power can survive on 94

 

HTH

[Black ITR Guy]

Originally posted by GAS,GRASS,OR ASS:

the higher the octane rating the slower the fuel burns. so what you want to do is run the LOWEST octane possible without detonation running to high of an octane for your combination can actually hinder performance. generally a street motor will never need more than 94 octane. now if your running on the ragged edge with high compression and boost , lots of bost , lots of spray, or very high compression(over 12:1) you need more octane to control the burn rate so you don't torch a piston. lots of other things play into this though like combustion chamber design, cylinder head cooling, piston shape, timing, fuel air mixture, and rod to stroke ratio. thats why a turbo buick at 30 psi needs c16 but an 13:1 big block with a new style head design and a conservative solid roller that makes the same power can survive on 94

 

HTH

alot of times i run an unleaded 100 octane gas mainly when im heading to the track or want to clean it out. so what your saying here is that im actually hindering my performance by running this stuff?

[desperado]

Originally posted by BLACK ITR GUY:

alot of times i run an unleaded 100 octane gas mainly when im heading to the track or want to clean it out. so what your saying here is that im actually hindering my performance by running this stuff?

Not really, BUT, you only need a fuel with an octane rating required by the combination, anything more is a waste. But I understood that Higher octane fuels burn faster, not slower due to the aeromatic solvents that are what sets the octane rating to begin with. At least with UNLEADED fuel. Leaded fuel uses TetraEthelLead (TEL) to increase octane, and not aeromatic solvents like Xylene, Toluene and Acetone all of which are much more flammable than gasoline.

 

Now as far as cleaning it out. Injector cleaner, is typically make out of several solvents, those mentioned above, and kerosene. The solvents breakup the deposit's and wash them through the fuel system. So high octane unleaded has most of these except Kerosene.

 

Now, a slower burning fuel, will create MORE power than a faster burning fuel. Reason is that combustion occurs longer, thus creating more heat and expansion of gases to push the piston down.

To better understand this, you must TRUELY understand how power is created in an engine.

 

The fuel and air are burnt, creating heat. Heat causes the gases in the cylinder to expand, pushing the piston down. The ONLY time that the force of the actual burn is against the piston is when the motor is in a state of detonation. And the force is not a pushing, but rather forceful impact from an explosion. That is also why it is refered to as detonation.

I am not going to go into the specific causes of detonation here, as it would take a great deal of time and typing because there are many.

 

Back to fuel octane and burn speed, and the other rating that no one seems to talk about, but it is the true measure of the capability of any fuel to be converted to heat and then power is it's BTU rating. BTU or British Thermal Unit is a measurement of the heating value of a combustable, the amount of energy that it truely contains. And burn rate has ALOT to do with most liquid fuels, and it's not always how hot but how hot for how long.

 

The reason this is important with performance cars is this. The longer that there is heat expanding the gases and pushing the piston down, the more time through the stroke there is power. If a fuel only burns for 50 of the 180 degrees of the power stroke of a motor, the rest of the stroke, 130 degrees, everything is just sort of coasting. The power that is stored in the flywheel is carrying the motor for the rest of the stroke. Now the fast that 6 8 and higher cylinder motors have overlapping power strokes, the peak torque number will be higher than the horsepower number. But that to is a different topic. But in understanding this, the length of time that the fuel burns in the cylinder, and what effect it has. Then relating it to lower octane fuels having slower burn rates explains why this is important for street motors that never see the high side of 8000 RPM. Now, for higher reving motors, like bike motors, and Formula 1 engines, this doen't apply. Reason is piston speed and stroke length. This all equates to the time that it takes for the power stroke. The shorter the length of time, the faster you need combustion to occur.

 

This is why, with a slower turning long stroke motor, it is important to run the right fuel. And to attempt to combat detonation in other ways, instead of just increasing the octane rating of the fuel so that you can run more timing. Which has a big impact on two things, the first being power output of the motor, the second being detonation. More timing advance, will increase power to a point, but it will also increase detonation.

 

 

Here are some links to other related things that I have contributed to the tech section that may answer some questions on this. Sort of that, if you have other questions feel free to ask, but do so in here so that the comments can be read by all that are interested.

 

http://www.columbusracing.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=23;t=001328

 

http://www.columbusracing.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=8;t=001446

 

[ 25. July 2004, 01:10 AM: Message edited by: desperado ]

[Guest Bottlefed70]

The higher the octane the slower it burns.

[desperado]

Originally posted by Bottlefed70:

The higher the octane the slower it burns.

I take it that you read NOTHING of what I said.

 

Don't take my word for it. Even though it's not my words. Go to the library, checkout High-Performance Automotive Fuels & Fluids by Jeff Hartman. Research the topic on the internet, and not what some fool says on another fourm, it the information is not on the Unical, Chevron, or VP Fuels site, it's probably speculation.

[desperado]

Originally posted by wickedpyroclown:

So what is the deal with race gas

 

1)I thought that the higher the octane, the more resistance to pinging there was

 

Being specific, yes, this is true to a point. But you need only enough octane rating to stop the pinging.

 

So is race gas really

2)only for people running forced air induction running alot of boost

 

No, high compression N/A motors will also benifit from higher octane fuels if there are detonation problems (pinging) But you have to remember that forced induction does something similar to increasing compression ratio, and in fact there are specific numbers that X pounds of boost will equate to an increase of Y compression ratio.

 

Or 3)does race gas actually burn faster and cleaner

 

It does burn faster, cleaner however has less to do with octane and more to do with the way that it's refined, and the additives in the fuel.

 

4)with more force than regular gas

 

That is too broad a statement. If you take a motor that is running 350 HP on pump gas, without ANY detonation due to timing, and you switch to racing gas (increased octane) WITHOUT changing the timing of the motor, the power level will NOT increase, and can actually fall depending on the burn rate of the fuel.

 

If somone could clear this up for me please i thank you