Higher Octane Question

DJester187 · Post by **DJester187** » November 4th, 2005, 6:34 pm

I was just wondering, to settle a conversation, if a engine that has been designed to use 87 octane was running on 93 what would be the drawbacks (besides the cost)? I had heard that a small amount of power would be lost due to the full ignition of the fuel would be in the 'exhaust cycle' of the engine. Any truth to that?

PATDIESEL · Post by **PATDIESEL** » November 5th, 2005, 12:55 am

No not really any cumbustion in the exhaust cycle. But not any real gain unless you have some timing or fuel and air controller.
Higher octane burns slower letting you advance the timing safely. That is the benefit, but only in conjunction with the afore mentioned parts.

Code_Kid · Post by **Code_Kid** » November 5th, 2005, 3:18 am

high octane allows u to get better mpg well least ive noticed with my storm. also little more get up and go. cost sucks, but if u turbo or nos your mx3 u should run high octane to prevent detantion.

vozaday2000 · Post by **vozaday2000** » November 5th, 2005, 10:02 am

but in cars such as the newer 2.0 "neon's" it is rated for the 85 octane and will actually perform worse with the higher octane. but with most cars it doesn't matter, it is just that the computer doesn't agree with the octane level on some cars

Code_Kid · Post by **Code_Kid** » November 5th, 2005, 12:27 pm

yep but basicly if higher octane didnt do something or wasnt required no need to have it for sell, but good idea to run 91-93 octane with turbo or nos setups

johnnyb · Post by **johnnyb** » November 5th, 2005, 12:46 pm

higher octane is useless in our cars. Unless you've tuned it for the higher octane it does nothing for you except empty your wallet faster. Keep buying it if you want but you dont get any improvements whatsoever from it.

Rick Johnson · Post by **Rick Johnson** » November 5th, 2005, 1:02 pm

Everyone in the world seems to say "I get better MPG with higher octance and my car is faster", is think thats a load of crap. I have never noticed an increase in MPG using a higher octance then specified, Although I have noticed that using a lower octane then the manufacturer recommends will worsen MPG and power <retards timing> for the average econobox the only benefit from higher octane will be a lightened wallet - unless you have the mods to use the higher octane. Although in some rare cases higher octance can be a benefit - The SCC 350z dyno results show that a higher octane did gain a few HP IIRC.

jschrauwen · Post by **jschrauwen** » November 5th, 2005, 1:09 pm

After owning the same MX for nearly 11 years I can be very intuitive as to how it's running. That said, from nearly day one of owning the MX I've strived to use higher octane gas. Why, because I actually noticed the difference. There was a difference in ease of starting, normal highway driving, acceleration/passing and bumper to bumper driving. Always kept the KL08 and ZE tuned to normal specs. On those occasions when I wasn't able to use a higher octane for a couple of successive tank fulls I noticed a difference in almost all of the above mentioned situations, to the negative. After the fact confirmation to me is the colour and condition of my spark plugs and the numbers from my compression checks. It tells me that I must be doing something right because when I see plugs from others that subscribe to the lower octane (cheaper) gas, there is a noticeable difference. I don't profess to know the science behind it all, but only what has worked for me in the past and it gives me that piece of mind that I must be doing something right. I'll gladly pay the extra 12 cents per litre difference between the 87 octane and the 94 octane for the results that I achieve. A cleaner, better (perhaps a little hotter) running engine that should last a long time. Then again, to each his own.

Vanished · Post by **Vanished** » November 7th, 2005, 6:26 pm

Octane # just mean how easily the gas burns. Do the math.

ocshaman · Post by **ocshaman** » November 9th, 2005, 9:06 am

Test your mileage. My dad's civic got enough more mileage to make up for the increased price.

The higher the octane, the more resistant it is io predetonation, and the slower burning it is. Your car will run the best with the least amount of octane required.

slowmx3 · Post by **slowmx3** » November 10th, 2005, 7:56 pm

People think their cars run better with high octane because they paid more for it. A car is designed to work for a certain octane. When you put higher in, it hurts you more than helps you. There is more additives in the higher octane fuels at the pump to clean your engine out etc.. Performance wise, you are hurting yourself. Unless you are in a situation where you are detonating you don't need a higher octane.

jschrauwen · Post by **jschrauwen** » November 10th, 2005, 10:27 pm

slowmx3 wrote:People think their cars run better with high octane because they paid more for it. A car is designed to work for a certain octane. When you put higher in, it hurts you more than helps you. There is more additives in the higher octane fuels at the pump to clean your engine out etc.. Performance wise, you are hurting yourself. Unless you are in a situation where you are detonating you don't need a higher octane.

What do you attribute the increase in power and performance in vehicles that have the opportunity and use a really high octane (106 octane) race gas on their street vehicles when on the track? Your partially right ... cars are designed to work for a certain minimum octane. The key word here is minimum. When you put higher in, it does not hurt more than it helps you. What more additives are you refering to? If you're refering to the possibility of a possible ethanol content of 10%, I'm more than happy to see that in there. You're absolutely right that if you encounter pinging (detonation), switching to a higher octane is a good alternative.

deathman · Post by **deathman** » November 12th, 2005, 4:10 am

PATDIESEL wrote:No not really any cumbustion in the exhaust cycle. But not any real gain unless you have some timing or fuel and air controller.
Higher octane burns slower letting you advance the timing safely. That is the benefit, but only in conjunction with the afore mentioned parts.

i am with him on this one

lakersfan1 · Post by **lakersfan1** » November 12th, 2005, 9:18 am

jschrauwen wrote:
slowmx3 wrote:People think their cars run better with high octane because they paid more for it. A car is designed to work for a certain octane. When you put higher in, it hurts you more than helps you. There is more additives in the higher octane fuels at the pump to clean your engine out etc.. Performance wise, you are hurting yourself. Unless you are in a situation where you are detonating you don't need a higher octane.
What do you attribute the increase in power and performance in vehicles that have the opportunity and use a really high octane (106 octane) race gas on their street vehicles when on the track? Your partially right ... cars are designed to work for a certain minimum octane. The key word here is minimum. When you put higher in, it does not hurt more than it helps you. What more additives are you refering to? If you're refering to the possibility of a possible ethanol content of 10%, I'm more than happy to see that in there. You're absolutely right that if you encounter pinging (detonation), switching to a higher octane is a good alternative.

Actually, it depends on the car's computer. I've seen tests where cars lost power going from 87 to 93. But I've also seen where it gains a few. But the gains are minimal either way on a normally aspirated engine. More gains can be had running higher octane than the owner's manual says if you're running turbo or supercharger.

Nd4SpdSe · Post by **Nd4SpdSe** » November 12th, 2005, 11:39 am

With my compression being low on my car, last week i decided to try a tank 87 to see what would happen...man, it drank that like water