is there any real differnce between 1 octane point.. for the cars that require 93 octane ->

 

I doubt it, we have 92 at the pump and 120 for race, that's a 28 point jump which is noticable but I'm sure that you'll be fine with 93... I've just never dealt with a 1 point increase so I don't really know... Latez

 

the reason why this popped up is.. here in the nyc/jersery area.. the highest octane you can get at gas station is 93... but then sunoco has their ultra 94 octane gas..... i was thinking .. is there a need for cars that detonate early.. to use 94 octane.. when they can use 93.. i mean there is only a 1 octane point jump? does it make that much of a differnce..

 

the way they rate the octane of the gas is they basically guess.. say its 93 octain its really 93 +- .xxx so the real difference might not even be as much as 1 octane its not worth it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1hotintegra &raquo;</TD></TR><TR><TD CLASS="quote">the way they rate the octane of the gas is they basically guess.. say its 93 octain its really 93 +- .xxx so the real difference might not even be as much as 1 octane its not worth it</TD></TR></TABLE>

No. Gasoline octane ratings are very accurate to the mixture they sell, and are derived from actual testing on variable compression motors. You know, RON + MON /2 = octane rating, you see it on the pumps every time you fill up.

And even by your logic, the real octane difference may be nearly 3 points instead of less than one, so again how do you arrive at it not being worth it?

 

Depends what car. In my b16 crx, it was worth it, and so I now put it in my gsr (except they don't have Sunoco 94 where I live ).

Either way, it made a huge differenc in my crx. I'm talking from 15.0 to 14.7 on the 1/4 mile, with a couple mph on top. I don't know if it was the octane or whatever else they put in that gas, but that's the difference it made. I'm sure it was the gas, because I raced that car over 100 times during one summer and can account for each tenth of a second I shaved off...from 15.4 down to 14.2.

 

Higher octane does NOT create more power, it is simply the gasolines resistance to ignite which allows you to add more timing, boost, compression, etc... Now if you can advance up your igntion timing a bit more because of 1 octane point then maybe it's worth it... I've never tried this but there is a difference between 87-92 and 89-92 here in Oregon... Peace

 

tried 94 ultra didn't notice any gains but here sunoco offers race gas 100 octane for 4.59/gal so maybe that should make a difference....

 

Damn that's some expensive stuff... Here in Oregon we can get unleaded 110 for ~$4.00/gal and ~$5.00/gal for leaded 120... Yea it kills oxygen sensors but oh well, haha... We're gonna destroy our fuel sytems too Oh well, just more intesting stuff... Laterz

 

Exactly what you said....if the knock sensor retards the timing due to too little octane, then higher octane WILL result in more power.

 

In a boost situation, is there a general rule on how much more you can boost (of course depending on your turbo), per an increase in octane by 1.0?

 

In case your wondering I'll get technical.

Octane is simply a measure of flurocarbon ocurrence in gasoline (i.e. 93 octane is 93 has a lower occurence of flurocarbons than 94 octane - I don't think it's a percentage 'cause you can get 120 octane race gas and there no way you can have negative amounts of flurocarbons).

Flurocarbon occurence is bad because they are like metalic particles. Because they are like metal, high compression (high heat) tends to heat up the flurocarbons to the point that they can actually ignite the fuel-air mixture before the piston passes Top Dead Center (TDC), this pre-ignite (called detonation) can cause the piston to be forced back down the cylinder in the oposite direction that it was turning in before, which could destroy the engine if it was putting out enough power to actually break its internals.

For this reason high-compression engines retard the timning to ensure that the explassion happens after TDC. It should also be noted that higher octane fuel burns slower than lower octane, but with a slightly more powerfull explosion rate. You can therefore advance your timing so the spark ocurrs even sooner, keeping the compression as high as possible when the explosion occurs, and higher compression = more power.

Therefore, even though higher octane (without further tuning) will not net any really noticeable gains (especially for such a small increase in octane level), with proper tunning (i.e. ignition advance, more fuel, more air), low octane increases will give you slight gains, high increases moderate gains, high increases + turbo or super charged intake charges (HUGE gains).

P.S. Higher octane also allows you to use higher amounts of boost for the same reasons as ignition timing advance.

 

Very well said jztyper !!!

 

can you tell us if there is a way to dermine how much an increase in octane will allow you to increase the boost? I know it will differ between turbos, but is there a set of equations I can play with for this?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Lsos &raquo;</TD></TR><TR><TD CLASS="quote">Either way, it made a huge differenc in my crx. I'm talking from 15.0 to 14.7 on the 1/4 mile, with a couple mph on top. I don't know if it was the octane or whatever else they put in that gas, but that's the difference it made. I'm sure it was the gas, because I raced that car over 100 times during one summer and can account for each tenth of a second I shaved off...from 15.4 down to 14.2.</TD></TR></TABLE>

I think you just had a good run!!! I EXTREMELY doubt that you gain 3 tenths from higher octane gas... why don't you run 93 or 94 then put in octane booster and gain another 2 tenths!!!

 

Maybe I did have a good run, but it's highly unlikey that I had 10 consecutive good runs on 10 consecutive occasions, and then 10 consecutive bad runs on 10 consecutive occasions (while coincidentally using 93 instead of 94), and then repeated this whole process a couple more times throughout the season with the same exact results.

Like I said, it wasn't just the ETs that went down, but the mph went up as well...significantly.

If you raced as much as I did you could pretty much pinpoint exactly what caused any differences in your runs.

I was just as skeptical as everyone else is. I tried a couple runs with a gallon of 108 octane, and didn't see any further gains. Octane booster doesn't actually boost octane, from what I understand....it just kind of says it does. Like I said, it probably wasn't even the octane that resulted in the increases...but something in the gas did.

 

There's lots of things it could have been... traction, air temp, relative humidity (normally doesn't change too much), driver (launch/shifting), etc. They all play a role in how fast you make it down the track... I'm just curious but what is you ignition timing at and did you advance it any on race gas? On a stock motor you probably won't see too much of a difference but if you didn't do it before try it sometime... Just my $0.02 again... Latez

 

my initial question was.... would there be a difference if someone used 94 octane pumped gas.. rather than the usual 93... as regular driving gas... im talking about using it to get to work school.. basically your everday daily driver.

 

94 will probably, if noticeable last you longer......

 

There could have been a million things. There was only so much variance due to those factors though. The Main factors I controlled were amount of gas, octane, car weight, and exhaust. I could tell you before each race what I was going to run +- a little based on what I did to each of these variables, and I would be right. A hundred times.

You can't run 50 times doing 15.0@92, then pump up 94 octane and run 14.7@94.....and then next week pump 93 and run 15.0@92....and next week 94 and run 14.7@94 and repeat five more times with the same results, and then only pump 94 and always run 14.7@94, and still have reasonable doubt that the gas did not make you faster.

I noticed at first that my car was significantly faster one day than another. I couldn't figure it out why until I came up with the 94 theory, and started doing the 94 experiment...sure enough, it became the only sane explanation.

Sure, the temperature, humidity, traction, and pressure could have all swayed towards making my car slower on the days I would pump 93, and then sway to make it faster by .3 on the days I pumped 94, and they could have done it apparently 10 times over the course of three months. I'm just going to go ahead and go with the simplest explanation, though.

Anyways, I did not change my ignition timing, but I imagine my knock sensor did.

As for daily driving, it will probably give you better gas mileage if your engine can actually benefit from it.

 

here's some fuel for thought. har har. I'll go sit in the corner now...

"Sometimes the MMT 'coating' can foul the spark plugs causing misfires, high emissions, and possible damage to the catalytic converter due to un-burnt gasoline entering the catalytic converter. Also the MMT covers the oxygen sensors, making it difficult for it to sense the actual oxygen in the exhaust, any maybe reducing the life of the oxygen sensor."

"Then I found out that the Sunoco Ultra 94 does not have any MMT, it is low in sulfur (&lt;100 ppm), and it smells much better than any other gasoline. "

http://www.motorvate.ca/mvp.php/506