same as title. What gas is better to pass inspection sniffer test with. Which lets out less emissions. Thanks

 

whatever your engine is tuned to use, just use what your engine is supposed to use

 

what engine?!

 

d15?? its the stock 95 cx motor. What would burn cleaner?

 

oh that's smart, I like that question, I have teh same question, 'cept for a '95 civic ex D16Z6, I'm PRETTY SURE in NY they don't do emissions tests for cars under 96, but I could be wrong, but if everything is stock (just i/e), which octane would I use to get the emissions the least?

 

cheapest gas and retard hte timing always works for me...

 

yep, lowest octane available with correct ignition timing (retarded ignition timing will cause the motor to run richer) will give the best results on most engines. as long as everthing is stock and in working order dont worry, be happy, drive.

 

Im pretty sure they dont use a sniffer in NY, the 96+ cars are checked thtough the OBDII ecu, so you are fine if you pass the visual inspectoin

 

octane is fuels ability to prevent detonation. higher octane better antidetonation. this is not correct terminology but i am tired. dont know much about smog tests, but dont see how octane rating being lower would help anything.

 

i'd say the higher the better. but i have nothing to back it up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nello a. &raquo;</TD></TR><TR><TD CLASS="quote">

octane is fuels ability to prevent detonation. higher octane better antidetonation. this is not correct terminology but i am tired. dont know much about smog tests, but dont see how octane rating being lower would help anything.

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I don't know about that man, octane is how much it's concentrated....higher octane detonates better....there's no "antidetonation" things in gas, their whole concept is TO detonate as best as possible...higher octane would run the richest in your engine, meaning if your engine burnt 15 (15 of nothing, just using numbers for visual concept), and X = 15, and 87 octane made it able to detonate some of the gas, say X-17=-2 |-2| = 2 in emissions, oppose to say using 5 and X-20=-5 |-5| = 5... Your engine can only combust a certain ammount..

If an engine can only combust so much the lowest octane will produce the least emissions and the car should be, for all tenths and purposes, as lean as you can get it off of pump gas.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schardbody &raquo;</TD></TR><TR><TD CLASS="quote">

Im pretty sure they dont use a sniffer in NY, the 96+ cars are checked thtough the OBDII ecu, so you are fine if you pass the visual inspectoin

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Is it definately only 96+ cars? I'll pass the visual inspection no problem, I'm just worried of a chipped ECU failing it, my friend has a civic he's building, but he's building it slowly, it's same year, model as mine, I'ma borrow his virgin P28 and put that in for the original salvage inspection.....then I can put the other one back into it....after that it can pass all the other ones w/o emissions tests...hopefully...

 

Unless you have high compression or have forced induction use the lowest octane and save yourself some money.

Inspection wise, I would do an oil change and make sure the car is at full operating temperature during the test. Clean the air filter, change plugs, plug wires, dizzy, cap, rotor etc and you WILL have noticable gains. If you still fail try replacing your cat (if you have high miles) or replacing your o2 sensor(s). Also, ensure all your vacuum tubing is connected and you're not throwing a cel.

 

not sure about the ecu, but if all your exhaust compononets are present and you arent throwin any CELs you will be ok.

 

higher octane gas will put out more emmisions in a stock motor because it doesnt burn completely. just remember a lean motor will fail a sniffer from higher hydro carbons also.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Syndacate &raquo;</TD></TR><TR><TD CLASS="quote">

I don't know about that man, octane is how much it's concentrated....higher octane detonates better....there's no "antidetonation" things in gas, their whole concept is TO detonate as best as possible...
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by detonation he meant the cylinder firing before the piston hits tdc. 87 octane burns faster than 93, so 93 is less likely to cause detonation.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schardbody &raquo;</TD></TR><TR><TD CLASS="quote">

higher octane gas will put out more emmisions in a stock motor because it doesnt burn completely. just remember a lean motor will fail a sniffer from higher hydro carbons also.

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But u can't forget carbon dioxide, when O2 burns it releases gases, among them is carbon dioxide, the sniffer shouldn't detect CO2 content becuase it's only looking for gases that damage the atmosphere (CO2 does, but not to a point of anybody's caring). It's the other gases that it's bad about, yeah, if it's too lean, it'll fail, but say if u put it on a scale, 0 being the middle, + being rich, - being lean, it might have a range like -7 to +3 (it has to be more lean from normal to fail than more rich from normal to (if that makes any sense))

 

very true, just didnt want him thinking being lean is better than rich.

 

Well neither is good, but like I said, it'd have to go further lein on emissions to fail than it would have to go rich

 

[QUOTE=Syndacate]

I don't know about that man, octane is how much it's concentrated....higher octane detonates better....there's no "antidetonation" things in gas, their whole concept is TO detonate as best as possible...higher octane would run the richest in your engine, meaning if your engine burnt 15 (15 of nothing, just using numbers for visual concept), and X = 15, and 87 octane made it able to detonate some of the gas, say X-17=-2 |-2| = 2 in emissions, oppose to say using 5 and X-20=-5 |-5| = 5... Your engine can only combust a certain ammo

octane number:a numerical representation of the anti-knock properties of motor fuel, compared with a standard reference fuel, such as isoctane, which has an octane number of 100. Also called octane rating.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nello a. &raquo;</TD></TR><TR><TD CLASS="quote">

octane number:a numerical representation of the anti-knock properties of motor fuel, compared with a standard reference fuel, such as isoctane, which has an octane number of 100. Also called octane rating.

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Yes, and higher octanes are more combustable. Also, they produce more emissions. Also, they help your engine run better / last longer. I really don't know what to tell you if you don't believe a higher octane fuel would produce more emissions except to take what seems to be knowledge you have and do some research into it. Higher octanes DO produce more "unhealthy" as the US likes to call it emissions, or gases that poison the ozone, aka. gases that make the sniffer test fail...things that don't go up in the catalytic converter...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Syndacate &raquo;</TD></TR><TR><TD CLASS="quote">

...higher octanes are more combustable.... Also, they help your engine run better / last longer...</TD></TR></TABLE>

Wrong, wrong and wrong. higher octanes are less combustable and thats why you use them in "race" engines that generate more heat. They dont help your engine run better or last longer if your engine does not require the use of higher octane.

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. 87 can take the least pressure, then 89, 91, ect..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KoketsuCivicSi &raquo;</TD></TR><TR><TD CLASS="quote">i'd say the higher the better. but i have nothing to back it up </TD></TR></TABLE>

And you would be wrong.

 

Put it this way. Run the octane that your car was designed to run on.

Lets say you got a d series that takes a 87 you put 91 or 93 in there like a retard hoping that it will fix your emmisions.

Now that higher octane fuel is harder to burn because of the lower compression, you will end up with uncomplete combustion. This equal more HCs and COs. Unburned gases, bam you didn't pass.

And lets say you got a b16 that's supposed to take 91 and higher. You are a cheapass, or you are trying to pass emissions and you put 87 in there. This will prolly cause some preignition, and some high combustion temperatures. Not only this kicks your motors ***, but in some states they test for NOx that will be produced by this type of combustion.

Either way run the octane that your motor is supposed to run on. Some people especially the RX7 junks put alcochol in their gas tanks and manage to pass with flying colors. We just lower the cars to the point where they can't go on the rollers so they have to do idle test, and any car with a fresh cat will pass that.

 

This is a good question. I would imagine a lower octane would burn cleaner then a higher octane.

 

Higher octane is not more combustable its more resistant to combustion and burns slower.

You SHOULD get the the least emissions with 87 octane with a more complete burn on a stock d series motor.