87-octane vs. 91-octane

[Matej]

Hey guys, I recently read some article explaining common myths about octane rating, and I have a couple questions.

I always run 87-octane in my KA. It backfires quite often, usually when I let go off the gas while the engine's at higher rpm's, and sometimes I get lucky and it even shoots a flame. Is this caused by detonation?

Recently I found out that the KA is actually supposed to take 91-octane. I have used 91-octane on a few occasions before, such as before a long trip or an event. I wanted to be nice to my car, which I guess I was since it is actually supposed to take 91, and I also thought I'd get slightly better gas mileage. However, on top of that, I always assumed that a higher octane gasoline is supposed to make a car be at least a little faster, but apparently that is actually just a common misconception and lower octane burns better. Is that really true? I was surprised, because I always assumed it was the higher octane that burned easier.

That brings me to my question, if I want my car to backfire and shoot flames as often as possible, should I just keep using 87-octane?

[bbejj123]

http://zilvia.net/f/2519915-post34.html
read it youll learn a lot

[jewbaca]

http://zilvia.net/f/2519915-post34.html
read it youll learn a lot

woooow good thread!

[rockmafb06]

If your only objective is to have a car that shoots flames and back fires, you should not breed.

[Matej]

If your only objective is to have a car that shoots flames and back fires, you should not breed.
My good sir, I disapprove of what you say, but I will defend to the death your right to say it.

[kushlivin]

hahaa that was funny yo

[JRas]

87 will ignite quicker than 91...

I always use 91.

[Def]

Oh my... this again. I didn't realize we had so many ICE fuel experts on zilvia.

[sr20turbonetics]

i believe that the higher octane the more combustion you will have leading to more power. but if if your just looking for the flame and backfires just get a dodge srt4 lol. or a flame kit

[Hawaiian240]

i believe that the higher octane the more combustion you will have leading to more power.........

NO! Your belief is based on assumptions.

Octane rating is the FUELS "RESISTANCE TO DETONATION"!

It's actually an average between two different methods(as calculated in the US). It is called the Pump Octane Number or PON. The PON is an average between the Research Octane Number(RON) and the Motor Octane Number(MON). So the equation is:

PON= (RON + MON)/ 2

Look familiar?? It's on the pump when you put gas in your car!! The yellow sticker!!!

Newer cars have premium gas requirements because they have typically higher compression engines to get higher horsepower numbers. Some of those engines can get away with using lower octane gas and be fine, some can't.

We all know engines with high compression(NA) or boosted engines should use higher octane gas because detonation is bad for the life of your engine!!! A good tune is also recomended for longevity. Using a higher octane gas with a good tune will net you more power.

Some put in a higher octane gas and then advance their timing some, I used to do this with my '73 Mach 1 and '89 5.0 back in the day. It gave me some power, not a lot, but it was easy.

Read this:
http://zilvia.net/f/2519915-post34.html

or this:
Octane rating - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Octane_rating)

bbejj123 already posted those links for everyone to read and get educated.

Stop spreading wrong information!!

Hope this helps someone.............and HAVE A NICE DAY!!




To the OP, get a flame thrower kit if you want to shoot flames............but I think their illegal in most, if not all, states.

check this out!!

http://www.youtube.com/watch?v=JSmpus3JA9I

http://www.youtube.com/watch?v=YhA69ShcIA0

[handinpants]

My good sir, I disapprove of what you say, but I will defend to the death your right to say it.

haha, hey welcome to reality, where opinions are like assholes, everyone has them

[Bigsyke]

All in all, octane wont make a single difference in performance, if your bypassing your knock sensor.

[crzycav86]

I always run 87-octane in my KA. It backfires quite often, usually when I let go off the gas while the engine's at higher rpm's, and sometimes I get lucky and it even shoots a flame. Is this caused by detonation?



no



Recently I found out that the KA is actually supposed to take 91-octane. I have used 91-octane on a few occasions before, such as before a long trip or an event. I wanted to be nice to my car, which I guess I was since it is actually supposed to take 91, and I also thought I'd get slightly better gas mileage. However, on top of that, I always assumed that a higher octane gasoline is supposed to make a car be at least a little faster, but apparently that is actually just a common misconception and lower octane burns better. Is that really true? I was surprised, because I always assumed it was the higher octane that burned easier.
use the recommended octane rating. that will provide the most power and gas mileage. however, if your ka is all messed up with the wrong timing, running too rich, and other such balderdash, then it probably doesn't matter because your car will still run like a constipated adolescent. to answer your other question: define "better" and "easier'...


That brings me to my question, if I want my car to backfire and shoot flames as often as possible, should I just keep using 87-octane?
ya. you'd be wasting your money if you don't care about performance.

[sillyvia13]

I add acetone and xylene for better burn and a higher octance...
also I get way better gas mileage and engine runs smoother. look into gas ingerdents in this counrty then in say japan.

[Bigsyke]

Check your o2 after the acetone, plus its been mythbusted countless times.

[sillyvia13]

Check your o2 after the acetone, plus its been mythbusted countless times.


Yea... myth busted my ass.
lets say mythbusters is a corp. and so is gas comp, they are buddies.
o2 sensor, who runs those now a days...
I tossed o2 and knock sensor out the window.

I been running it for about 1 year.

I even add diesel... lmao.

3 oz. of each to 10 gal.
Good stuff.

HHO was also told to be failed.
I also see cars running 100 mpg on hho...

if you havent tried it... or have no exp... then try it, then come back and speak.
tests conclude...

[Bigsyke]

Ive tried it, 4 years ago on my civic. Nothing.

Then after all the hype, tests were done that show an actuall decrease in fuel economy.

[eastcoastS14]

91? we only have 87 89 and 93 I use 89 and my exhaust backfires loud and often

[BoostedCoupe]

I run 93 and my car back fires alot. If i shift at 3,100 its almost a guranted flame. All i have is a 3" catback. It also back fires alot while below 2,500 in gear while out of the gas.

[Shift n Drift]

whats the deal with that autozone octane booster and shit then?

[mrmephistopheles]

I only run 87. No backfires, etc. Runs just fine.

[aNskY]

whats the deal with that autozone octane booster and shit then?


Scam.

The "One Point" of octane boost they claim is actually a tenth of a point, effectively bringing 87 to 87.1 octane per treatment.

just use better gas.

[Bigsyke]

Nissan recommends 91

[lflkajfj12123]

91? we only have 87 89 and 93 I use 89 and my exhaust backfires loud and often


same here

so what should i use

93 or 87 lol

[boost_addict]

KA's use 91? lol maybe KA-T but not stock...

[crzycav86]

open up your gas cap cover and read what it says....

[Bigsyke]

KA's use 91? lol maybe KA-T but not stock...

Get your mind right, its 91, stated IN THE FUCKING FSM

BONE STOCK KA24DE

91 OCTANE!

[gun]

^ my FSM's always said," For best performance results" to use 91 octane. None of my previous s chassis' ever said 91 was required.

[steve shadows]

If your only objective is to have a car that shoots flames and back fires, you should not breed.

Back firing and shooting flames is actually a symptom of an engine running improperly and dangerously - I find it funny that this has become the measure of a cool or fast or threatening competition car -because in the real race car tuning world it is a sign of totally improper tuning or improper setup

Backfiring under the car due to lean pop off of the wastegate is completely different than the (backfire-flame) that has made such popularity- it's kind of like bragging about your new tatoo when in reality it's just a arrangement of herpes scars- this is like bragging or even mentioning this backfiring phenomenon.

Also -

Where did you "Find out" that the KA is "supposed to run on 91" ?

The GAS CAP? Maybe for a dual cam- if this were the case then the Car would be throwing a KNOCK COde = via engine warning light - if it really was essential - It may be recommended but it is in no way required on 100% stock KA24 motor

If it is REQUIRED then your check engine light would come on any time you ran anything else - this is what happens in every other nissan car that actually REQUIRES 91 or higher octane. - suggesting it for best performance is common with many manufacturers which sell their motors/cars in the USD market

[98s14inaz]

We've dyno tested both 87 and 91 and the difference on a nearly stock ka is negligible. Run 87 for na, 91+ for forced inducted. End of argument. Fucking Americans are so stupid, that is why there is 89 octane too (useless). The higher octane only prevents detonation. The ka is 9.5:1, which is hardly considered high compression and thus only needs 87 octane.

[g6civcx]

I thought the issue was already settled.

If your engine is stock, then read the owner's manual/FSM. Pay very close attention to the recommended rating.

Pay particular attention to the octane rating of the recommended octane. As said above, there are several ways to rate octane, e.g. RON, MON, PON, (R+M)/2, etc.

Also pay attention to the language of the manual, e.g. "at least", "recommended", "x or more", "only", "acceptable, but prolonged use not recommended", etc.

Sometimes the manual will give different recommendations based on your application, e.g. high elevation, climate, etc.

Determine the safe octane rating, including the rating method (RON/MON/etc.), for use on your engine. If in doubt, contact a representative from the auto manufacturer for clarification.

For example, Subaru recommends 93 RON for the STI; however, CA folks can use 91 RON for acceptable performance. For this car, I would use 93 RON whenever possible. If not, only then would I use 91 RON.


Go to the gas pump and read the label. Match the rating number and method with what you're looking for.

If you can't find what you're looking for or its equivalence, ask the station manager. If they don't know, go to a different gas station.


If you are modified, consult your engine builder. If you don't have one, then I tentatively recommend 93 depending on your compression, timing, forced induction, and other things that affect detonation.


It's simple. Use your head and do your research, even if just by reading the manual. This is not something that only gearheads should know. Everyone should know this. It's scary that most people don't know this.

Now you know why I steer clear of used cars.

[Bigsyke]

Where did you "Find out" that the KA is "supposed to run on 91" ?

The GAS CAP? Maybe for a dual cam- if this were the case then the Car would be throwing a KNOCK COde = via engine warning light - if it really was essential - It may be recommended but it is in no way required on 100% stock KA24 motor

If it is REQUIRED then your check engine light would come on any time you ran anything else - this is what happens in every other nissan car that actually REQUIRES 91 or higher octane. - suggesting it for best performance is common with many manufacturers which sell their motors/cars in the USD market

The CEL will NOT come on with improper octane. The only time you will get a CEL with the KS, is if its unplugged or completely shot. In fact I doubt you would ever know your pinging most of the time due to KA's Knock sensor being complete garbage, and probably throwing the KS code from freyed wiring.

If 91 octane was NOT the correct octane then nissan wouldve put in a different, why?

If the required octane is not used, and you start pinging, from the factory usually the KS will detect a ping and pull the timing 2-3*, and increase injector load. This doesnt do ANYTHING for fuel economy and efficiency. They tuned the KA on 91 octane so thats the correct octane to use, STOCK.

You can use a lower octane, but if your KS picks it up you then throw the money saved right out the window with the increased injector load, and reduced timing.

We've dyno tested both 87 and 91 and the difference on a nearly stock ka is negligible. Run 87 for na, 91+ for forced inducted. End of argument. Fucking Americans are so stupid, that is why there is 89 octane too (useless). The higher octane only prevents detonation. The ka is 9.5:1, which is hardly considered high compression and thus only needs 87 octane.

Americans are so stupid? Your fucking stupid, since when did you start being credible to rewrite nissans octane requirements? Get the fuck out of here with that sloppy shit, keep your guessing to yourself.

[crzycav86]

put in race gas ur car will b faster thats wut my boy did at the strip

[LA_phantom_240]

Let me google that for you (http://www.letmegooglethatforyou.com/?q=Does+91+octane+make+a+difference%3F)

[BoostedCoupe]

Let me google that for you (http://www.letmegooglethatforyou.com/?q=Does+91+octane+make+a+difference%3F)
Hold on wait, what? wtf just happended. where did you find that. thats the best thing since porn.

[Matej]

Apparently people have two very opposing viewpoints on what to run.

[aNskY]

when i had a stock ka i ran 87 for years with no problems, 30mpg

[BoostedCoupe]

when i had a stock ka i ran 87 for years with no problems, 30mpg
why the hell cant i do that. I cant get 27mpg highway. thats shifting under 2,500

[Felipe]

Let me google that for you (http://www.letmegooglethatforyou.com/?q=Does+91+octane+make+a+difference%3F)


lmao :s101: its magic!

[unlegendary]

Apparently people have two very opposing viewpoints on what to run.

you could listen to "them" or read your factory service manual, or read the text on your gas cap.

lock

[LA_phantom_240]

Hold on wait, what? wtf just happended. where did you find that. thats the best thing since porn.

Let me google that for you (http://www.letmegooglethatforyou.com/?q=letmegooglethatforyou)

[Bigsyke]

Let me google that for you (http://www.letmegooglethatforyou.com/?q=letmegooglethatforyou)

Were you refering to this? (http://www.letmegooglethatforyou.com/?q=Big+booty+hoes)

[LA_phantom_240]

Were you refering to this? (http://www.letmegooglethatforyou.com/?q=Big+booty+hoes)

No, I was referring to "where did you find that"

[Markdawg20]

When the car backfires and shoots flames it is under rich conditions. Unburnt fuel enter the exhaust and ignites in the cars exhaust system. How is this bad for the car in any way?

[DeathMetal]

Question:

To you with real knowledge on the subject, what would be a good way to guide how to time my 240 (KADE) for 93 octane if I wished to use it. Is there any sort of parameters or things I should look into for timing it for 93?

[LA_phantom_240]

When the car backfires and shoots flames it is under rich conditions. Unburnt fuel enter the exhaust and ignites in the cars exhaust system. How is this bad for the car in any way?

I've been told that excessive backfiring can cause burned exhaust valves. I don't have any first hand experience with this particular situation, so I can't say for sure.

[sillyvia13]

I just woke up.
and this thread has gone way of course.
So I will enter with a story.

GOOGLE, its in my tool bar, I love it.
I often try to act very smart, but I am not sadly, I am just as dumb as the rest of the stupid fucking country. Yup, as dumb as you! reading this fucking waste of time and gain of life. huh!/. Yea... anyways... I add my interest in to it... like if I was wondering about ahhh say octane rating.. I would google it and get like I dun know 1.2 million topics on it.

then I would look at the link and find one i thought had a decent website, like oh i dun no, mobil, or some gas related site...

then I would gain knowledge.
I really try to stay away from learning shit from fucking forum people named Sillyvia13 anyways.. wtf is that anyways, some cute way to say Silvia via s13 together GTFO!

So yea.. I have no clue what was just said. I use water to run my cars. octane is so 2007

[mikethebiker]

Back firing and shooting flames is actually a symptom of an engine running improperly and dangerously


not. backfiring is when you have unburned fuel in the exhaust that continues burning out of the exhaust pipe, or from being ignitied by the catalytic converter. ie after you close the throttle, which is why it happens why you shift.

i bet all the race cars ever are improperly tuned and running dangerously huh

[aziankingz]

goodbye cat... i run 87 all day..

[LA_phantom_240]

not. backfiring is when you have unburned fuel in the exhaust that continues burning out of the exhaust pipe, or from being ignitied by the catalytic converter. ie after you close the throttle, which is why it happens why you shift.

i bet all the race cars ever are improperly tuned and running dangerously huh

Improperly tuned for DD purposes maybe lol.

[renegade_ewok]

If the car is tuned right and there are no other problems which could cause it to run rich, one shouldn't be backfiring. The easiest way to make a car pop flames if your turbo is to vent your BOV. Instant richness, flame every now and then. Is it the best thing for the motor? Nope. Is it gonna kill it? Nope. If your popping flames/backfiring on an NA engine or any other way, I'd be concerned.

The BOV scenario above is mine. It will randomly pop a flame, but trust me, it sucks. I just don't have piping for a BOV... Do it in front of a cop and thats instant pull-over...

[wikun]

hmm i fill up 91 all the timee on my dual cam.. when you pop open the gas or whatever on the gas door it says premium fuel (91) recommended for maximum performance thats just my take on it.. but then again 240s are old cars now.