Burn rate... not really, automotive gasolines actually burn at about the same rate no matter what the octane level is. A blend with a heavy dose of aromatics like toluene or xylene takes a little extra to light off (a side effect in high octane blends of their higher resistance to pre-ignition) but this is fairly minor & usually results in a slightly richer exhaust, mainly at idle & light throttle cruising.

So the meat & potatos of octane & fuel is; the higher the octane number the higher the fuel's resistance to pre-ignition or detonation. Hence the need for a re-tune ( more boost, more timing, etc..) to see noticeable power gains from running high octane fuel. It doen't make more power in & of itself, octane simply allows you to up the ante so to speak.

Doug C.

 

So what is good on cleaning the injectors captain? Is chevron techron fuel system cleaner worth the money at $12 a bottle? Or is the an alternative or they are all a waste?

 

I bought my truck used with 2,500 miles on it. It seemed to be more of a garage queen. I was told it belonged to a car collector from a city near me. A little backround info proved at least the truck originated from where they said it did. So it was apprx a year old when I got it.

Now, I got it with 2,500 miles on it. I had never added fuel additives to the fuel. When I started modding I decided to change the plugs......around 5k miles or so.......the white ceramic portion of the plug around the electrode was purple on all 8 plugs. Yes purple, like that stupid dinosaur!!!

So that goes to show how quick these additives can affect your plugs. I've had my plugs out 2 more times and i'm at 15k now and they look like they should.........white.

 

I agree about how the typical octane additives affects the plugs. On my supercharged 93 Cobra I use to use the 104 octane additive and would get the reddish coating on the plugs. It did help me run more timing and I would get less detonation problems, but I was changing the plugs every time I took it to the track (it ran noticeably better with new plugs).

 

Techron is actually an effective fuel system cleaner, but $12 a bottle is about twice as much as what it sells for in my area. One quart of xylene or toluene a month added to a full tank of gas is also a very effective deposit cleaner & should be plenty to prevent varnish & carbon buildup.

tallimeca, never heard of or seen purple deposits on spark plugs before.... any idea what kind of additive the previous owner was adding? Maybe a fuel stabilizer of some sort???

Doug C.

 

Lets just fill our tanks with liquid hydrogen and liquid oxygen(space shuttle fuel) and be done with it!!!

 

Heres probably a easy question for many of you. What makes the octane rating of race gas so much higher? Ive seen around 110+ octane ratings. Is there any wya to make race gas?

 

Well , I called it purple, it could have been more of a maroonish (red) color. It is quite possible there was stabilizer used. 2500 miles in a year.............

 

I would assume it's the lead content in the gas that will give it over the 104 octane rating.

 

Octane rating is a measurement of a gasoline's resistance to pre-ignition (detonation, ping, knock, etc..) & is measured on a calibrated, variable compression ratio, single cylinder engine commonly called a knock motor or octane engine. There are many different ways to raise the octane number of gasoline, such as adding an aromatic hydrocarbon like xylene (117 octane) or toluene (114 octane), MTBE (which replaced the last two a few years ago, is ~112 octane and is now being replaced by more expensive methanol / alkylate blends.)

Tetra-Ethyl Lead is gram for gram, the most potent octane booster out there. Unfortunatley it also poisons the environment, is dang hard to get, highly toxic to the human nervous system, very expensive & coats your spark plugs, O2 sensors & catalytic converters with a nice layer of uncombusted lead.

Your best bet for making a homebrew racegas is the "formula" I gave earlier in this thread, a 1:3 mix of xylene to 93 pump gas will net a 99 octane final mix & (I know this is apples to oranges) is enough for me to push my Turbo Buick to 11.4's@119.5mph running 22~23 lbs of boost & a moderately timed (20°) chip. Some guys swear by the TORCO additive, but from the evidence I've seen/heard it has a big slug of MMT in it.

Doug C.

 

Its great to see a newbie who actually brings some great, valuable information to the board!

Thanks for your expertise CaptainInsane-O.

Jason

 

any particular Toulene better than any other?

what Brand do you use?

 

You can get Xylene at H-depot for $5.00 a qt. and $13.00 for a
gallon. Of course thats a little price-y , but I picked up a
gallon to test with.

Mybe I'll put some in my lawn mower and see if the rod
comes fling out the side !!!!!

 

 

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