[ds968]

Any thoughts on the theory that higher octane results in cleaner emissions ?



Smog test coming up for my car and even though flash's 968 with roughly the same mods as mine passed without any problems, I don't want to take any chances; I'll drive it hard the day of the emissions test, make sure the engine is hot, etc.. but will it also help to add a couple of gallons of 100 octane in the tank ? Furthermore, does it make a difference if the tank is full, or less than half ?

( another theory I vaguely recall seeing somewhere in a post on 968.net I think..)

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[rustech]

I think my opinion on this question is known, but I will restate anyways...

There once was a caddy driven by a good friend. It failed emissions. It was recommended by a mechanic to add a can of octane booster to only a couple gallons (why only a couple gallons? So the concentration is higher). The second time I had it tested, most of the levels of emissions were cut by more than 50%. I've been doing something similiar in every car eversince.

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[ds968]

it's relatively cheap enough to give it a try then - I'll mix 3 gal. of 100 oct with the current 3/4 tank of 91 oct

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[ds968]

test done, passed. <img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[Greimann]

From what I understand about these cars, as well as any modern fuel injected car, if it is running properly, you will have no problem with a smog test.



If you had an old clunker, then the additive tricks sometimes will help because they contain ethanol, which is an oxygenate that is currently added to gasoline. It help dilute the hydrocarbon emissions as well as burn them.



High octane doesn't necessarily burn cleaner, it just help make sure that the computer has not retarded the timing too much and increase emissions.

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[Dave]

Well, I was running out of time so I ran the car through emissions testing while still burning off a tank of 100 octane fuel.



Passed just fine here in Illinois. Not sure what this means, but readings are shown below:



All are in GPM (grams per meter?)



[color="blue"]Hydrocarbons: 0.21 (std = 0.80)

Carbon Monoxide: 3.0 (std = 15.0)

Carbon Dioxide: 452.3

Oxides of Nitrogen: 0.90[/color]



It was fun to watch the tester climb past the roll cage and into the race bucket. Actually, he did a nice job, found all six gears, and never grabbed reverse <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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