six_string_wiz

I did some searching and got a little insight into my question.
From what I understand,I can run un-leaded 100 or so,if I want and not hurt a thing?
I ask cause I honestly dont know the adverse effects,if any it could have on my car.
As long as its un-leaded its useable?
I was curious as to how the computer would react?
Is it even worth splashing a little for some runs?


~Will~

six_string_wiz

Arizona will have 116 degrees of hot weather tomorrow.
I plan to attend the track,Friday evening.

waldershrek

iTrader: (1)

My buddy runs 105 in his when we go and he hasn't had any problems

JDM74

It's not worth it unless the computer is tuned to take advantage of the extra octane rating.

black01_WS6

iTrader: (13)

it is reall a waste of money, if your car is tunes it is optimized at 93 octane. Anything over that will just burn off.

Now if you would be spraying or using forced induction and thats a different story.

six_string_wiz

Gotcha
Mostly stock vehicles,just dont have the tuning needed to benefit.

RacerScott

iTrader: (6)

You would not gain a single thing.

You would gain more by running the LEAST octane possible without the knock sensors pulling timming back.

six_string_wiz

Thats interesting.
My car has:
lid/catback/msd wires/ram air, as far as little bolt-ons go.
Care to elaborate just a little on the lower octane?
Are you saying the car would advance timing(I think ...)to compensate for the low grade fuel?Thus gaining,however much.

Formula413

iTrader: (1)

If your engine is knocking the computer will retard timing to try to correct it, which robs power. However, depending on the car and the conditions under which it is run, you might be able to use lower than 91 octane without causing any knock. Lower octane fuel can produce slightly more power than higher octane. But to know whether you can use lower octane without causing knock you would need a way to monitor knock retard, this would probably something like data logging equipment. Considering you are going to be running in a hot climate, I wouldn't bother trying to get away with anything less than 91. Because if the computer pulls timing to prevent knock any small gains from the lower octane fuel would be lost. Does that make sense?

six_string_wiz

Absolutely.Thanks for the info.

RussStang

Exactly where did you come across this information? It is certainly contrary to what I have come to understand.

I have heard someone suggest this before, only to be immediately made aware that it was incorrect by someone who seems to know what they were talking about when it came to gasoline.

Starz T/A 17

iTrader: (6)

I always thought that you should use what your car is tuned for, anything more with just burn off and anything lower will not maximize your power.

six_string_wiz

From what im getting,an engine running a high octane fuel, that is not tuned to burn the fuel at the proper rate will detonate and knock.Resulting in a power loss,as it applies to a 91 octane tuned engine???
Am I getting the right idea on this???

Formula413

iTrader: (1)

As I understand it, the additives used in gasoline to raise the octane number are not as volatile as the gasoline itself and therefore do not produce as much power. So higher octane fuel, having more additives, produces slightly less power. Of course, when you are talking about fuel being used in a high compression engine like the LT1 or LS1 it's more complicated. The higher octane fuel allows for much higher compression and greater timing advance due to it's increased resistance to detonation. This more than makes up for the slightly lower power available from the higher octane fuel. If you do a search in the advanced tech forum there is a thread about octane boosters which has some good info. I don't claim to be an all knowing expert on this subject by any means, if anyone with more knowledge of this than me sees any innacuracies in what I just wrote by all means chime in.

six_string_wiz

Im a newb when it comes to some aspects of my car.Fuel and tuning being a couple.Thanks for the help,im just listening and learnin,so all the info is appreciated.

Zealot

The octane number gives the percentage of iso-octane by volume in a mixture of iso-octane and normal heptane that would have the same anti-knocking capacity as the fuel that we are comparing it to. Put more simply, since gas is not simply a mixture of iso-octane and n-heptane, but rather a conglomerate of various hydrocarbons, the octane number is an non-literal reference to the fuel's anti-knocking capacity in terms of the ratio of iso-octane to heptane. When we break down the composition of race fuels vs. your every day pump gas, we usually see more xylene, toluene, ethane, methane, benzene, and iso-octane, among others, due to their resistance to autoignition under the dynamic temperature/pressure conditions typically found in the combustion chamber thanks to the high activation energy required to initiate combustion of these compounds.

With regards to the power contained per unit volume of fuel, premium racing gasolines can both have a higher octane and a greater energy content. The power that an engine produces depends on the energy content of its fuel, which unfortunately bears no correlation to its octane rating. I'm just rambling on now, but what I'm trying to say is that gasoline is such a complex mixture that any combination of octane rating and energy content is possible, it just depends on the precise mixture of the fuel in question. In a nutshell, an engine will not benefit from a higher octane alone, but it is possible that a premium higher octane race fuel might have more energy content per unit volume. Conversely, the hydrocarbons added to increase octane rating might also have a lower energy of combustion resulting in a fuel with high octane rating and low energy content. Without a precise analysis of the exact fuel you are going to use, there is no way to know.

six_string_wiz

Believe it or not I understand what youre saying.
TUNING.Its all in the tuning,spark and compression.
Without adjusting for Higher grade fuels,a mostly stock engine will not have the tuning required,to make proper use of the energy content held within a specific grade?

Correct?

1meantransam

iTrader: (8)

i figure if you run some 110 at track maybe you can clean some of the engine out with that high occcccctttttane stuff... would that work?

six_string_wiz

Seafoam is cheaper

Formula413

iTrader: (1)

The simplest answer is no. Some oil companies like to market their premium gas as having the ability to clean out the engine or fuel system. They only do this because they know most people don't know any better and will buy premium thinking they are helping their engine somehow. All grades of gas have additives to help keep the fuel system clean, and you can use a product like Seafoam to do an even more thorough job. But higher octane gas will not in and of itself clean anything that regular gas wouldn't. If regular low compression engines could benefit from 91-93 octane the manufacturers would reccomend it; they don't, the owners manual in a car with a low compression engine will call for 87 octane fuel. Don't buy into any marketng BS; use Seafoam or an equivilant product to keep the engine internals clean.