DannyDeuce

Hey guys,

I just want to know what octane gas is better for lowering your emissions. I have a turbo'd d16y8 right now and use 91+ octane. I swear i read on here that lower octane gas reduces emissions? Is this correct?

I'm gonna try to do the emissions test with my turbo kit hooked up...if that don't work i'll swap my stock ecu back in, put my stock injectors back in, and slap a filter on the throttle body.

Just wanna see if i pass first without having to uninstall anything.

Please advise, thanks guys.

DAN

Muckman

iTrader: (2)

87 octane is best for emissions and gas mileage.

DannyDeuce

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">87 octane is best for emissions and gas mileage.</TD></TR></TABLE>

Perfect......thanks Muckman for the quick response.
DAN

RE- v8killa121

what the ph..
are you serious?? i alway's thought the higher the rating the higher the gas miliage...

phildo1219

i think its higher octane the cleaner it burns so ive heard anyways...

p0gi

That is what ive read also. They recommend using the highest octane available for smog.

Everyones Hero

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DannyDeuce &raquo;</TD></TR><TR><TD CLASS="quote">I'm gonna try to do the emissions test with my turbo kit hooked up...if that don't work i'll swap my stock ecu back in, put my stock injectors back in, and slap a filter on the throttle body.</TD></TR></TABLE>

You know, I never thought of doing that. Just pop off the charge pipe right by my BOV, throw on a filter and wire the WG open. Go through, get cleared, pop my charge pipe back on and be on my way.

Thanks dude. (BTW, I know there are going to be people saying "That's bad for the turbo! It'll over-spool!" Do it right before you get there in the parking lot of some other store and take it through.)

But I would use my turbo map, but maybe lean out the VAC map just a bit.

DannyDeuce

So HIGHER octane gas is better when going for emissions testing?

Please advise.

DAN

p0gi

Trying to pass emissions with the turbo is sometimes more difficult because the CAT doesnt get as hot. So make sure you do some driving before you go so that the cat will be up to operating temp. I dont think removing the charge piping would make much of a difference since during the test youll never be in boost.

Everyones Hero

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by p0gi &raquo;</TD></TR><TR><TD CLASS="quote">Trying to pass emissions with the turbo is sometimes more difficult because the CAT doesnt get as hot. So make sure you do some driving before you go so that the cat will be up to operating temp. I dont think removing the charge piping would make much of a difference since during the test youll never be in boost. </TD></TR></TABLE>

They don't rev the motor up while in boost?

I was thinking about putting a 3k rev limiter on my car next time I have to go in. Can they fail you for having a low rev limiter? I'd just say something like "My mom doesn't want me to drive fast and ****, so she had my dad put a rev limiter on the car." Of course I'd be wearing my "I'm with stupid" T-Shirt and my bike helmet.

DannyDeuce

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by p0gi &raquo;</TD></TR><TR><TD CLASS="quote">Trying to pass emissions with the turbo is sometimes more difficult because the CAT doesnt get as hot. So make sure you do some driving before you go so that the cat will be up to operating temp. I dont think removing the charge piping would make much of a difference since during the test youll never be in boost. </TD></TR></TABLE>

Yeah thats what i'm gonna do...drive it around till its nice and hot.

I was taking the charge pipe off, putting in the stock injectors and putting in the stock ecu so it runs like stock again.

So what OCTANE gas would be good for lowering emissions? Lower or higher?

DAN

phildo1219

put racing gas in ur car it burns really clean....its higher octane burns cleaner

p0gi

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

They don't rev the motor up while in boost?

</TD></TR></TABLE>

Ive tried to pass my car with the apexi bb turbo and they never went into boost. They dont accelerate fast enough and even if they did, that part of the test doesnt seem to be measured. Plus most turbos dont make boost at the low rpm they test at, 1500 and 2500. I ended up taking the turbo off since it just wouldnt pass. It was close like 1 point over . I ended up just going back to stock manifold.

all go teg

here is a complete how to on passing emissions, it says to use lowest octane gas possible, and gives some other ideas. he also goes thew his results
https://honda-tech.com/zerothread?id=1305346

DannyDeuce

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by all go teg &raquo;</TD></TR><TR><TD CLASS="quote">here is a complete how to on passing emissions, it says to use lowest octane gas possible, and gives some other ideas. he also goes thew his results
https://honda-tech.com/zerothread?id=1305346
</TD></TR></TABLE>

I knew i read it somewhere on this site..... that lower octane gas reduces emissions. Thanks for the link.

DAN

adseguy

Hey Muckman I think the FI forum is becoming like the Integra forum .

The guys saying this and that have NO proof or experience. If I say something I always refer to others, provide science, or prove it in testing myself. It's not cool to blurt things out that you "think" are true when you can't prove it or can't totally explain why. Why would higher octane burn cleaner? Can you explain this please ? I was going to point to my write-up but thanks all go teg. Here's a pop quiz guys &gt;&gt;

Does the denatured alcohol...
a.) lower octane
b.) increase octane
c.) do nothing
d.) Whatever d00d 116 oct@ne all day on my stock GSR cause it's ALWYAS bett0r

all go teg

yea, sorry i have your post bookmarked, i thought i would spread the light

p0gi

"If you are fighting a high Nox problem, or even if you have to pass it, the state test books say running premium gas can help. I’d always thought premium was just for octane, but apparently it can do a little more in some circumstances."

This was taken from http://www.firstfives.org/faq/smog/smog_faq.html

I guess it depends on what your problem is that they recommend higher octane.

Muckman

iTrader: (2)

adseguy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by p0gi &raquo;</TD></TR><TR><TD CLASS="quote">"If you are fighting a high Nox problem, or even if you have to pass it, the state test books say running premium gas can help. I’d always thought premium was just for octane, but apparently it can do a little more in some circumstances."

This was taken from http://www.firstfives.org/faq/smog/smog_faq.html

I guess it depends on what your problem is that they recommend higher octane.

</TD></TR></TABLE>

If you think about this it makes total sense. I might get a little complicated here, but try to follow. Higher octane is less "volatile" because it resits better against detonation (heat, pressure). So by the end of the combustion cycle you have a better chance of getting more unburnt fuel because it is less likely to burn if it is tetering on burning or not......get it? . Although this situation provides more hydrocarbons (unburnt fuel) you DO get less NOx emissions. In the same effect if you are having problems with too much hydrocarbons it will probably suggest to run the lowest octane for your vehicle. I treated this problem with adjusting timing in my writeup. By adjusting timing you can control how much fuel gets burned. Reduce timing (less complete burn) you get less NOx, but MORE HC's. Add timing (more complete burn) and you reverse the outcome.

You bring up a great additional idea to my write up though . If you still have NOx problems you can adjust your fueling needs. It's just that most cars with no CATs arre going to have HC problems because unburn fuel just isn't "reburned" in the CAT.

If I need to clarify anything please quote and point it out. I did the best I could and I'm no english major

Scott_Tucker

The AKI of the fuel (octane rating) has nothing to do with emissions. If you see any difference between the two in will be marginal. The biggest factor will be whether of not the tune is correct. If the car is lean, hydrocarbons go up and CO will go down and if it is rich CO will go up and hydrocarbons can go up (assuming it is richer than stoich). NOx emissions are highest slightly lean of stoich. Ignition timing will have the biggest effect on NOx. Oxides of Nitrogen are formed under high pressure and temperature so it makes sense that retarding the ignition timing will reduce NOx because peak pressures will be lower and the lower pressure will also reduce the temperature. Beware of retarding the ignition too much or the engine may misfire which would of course raise HC.

adseguy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AutoEng2002Si &raquo;</TD></TR><TR><TD CLASS="quote">The AKI of the fuel (octane rating) has nothing to do with emissions. If you see any difference between the two in will be marginal. The biggest factor will be whether of not the tune is correct. If the car is lean, hydrocarbons go up and CO will go down and if it is rich CO will go up and hydrocarbons can go up (assuming it is richer than stoich). NOx emissions are highest slightly lean of stoich. Ignition timing will have the biggest effect on NOx. Oxides of Nitrogen are formed under high pressure and temperature so it makes sense that retarding the ignition timing will reduce NOx because peak pressures will be lower and the lower pressure will also reduce the temperature. Beware of retarding the ignition too much or the engine may misfire which would of course raise HC.</TD></TR></TABLE>

Nicely put . I wish I could type that well