can octane ever be too high?? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

silvia S13 · 09-09-2002, 04:57 PM

Can the octane level ever be too high for a car?
For example, those NOS octane boosters, I am guessing they are really high octane, because they increase a couple octane points.  And if you fill your whole tank up with those, what would happen?  No, I would never do that, I am just curious.

the3SecondJerk · 09-09-2002, 05:03 PM

I was always under the impression that the higher the octane the harder it is to ignite. Therefore turbo vehicles are required to use it to prevent detonation. But don't quote me on that. As far as filling your tank with octane boost....only way to find out is to try it. Let us all know what happens...I'd guess you will never get the gas ignited and it'll just turn over.  But then again I am not an ignition fuel specialist.

gabossie · 09-09-2002, 05:05 PM

You certainly wouldn't have detonation, that's for sure. The only bad thing i could see coming out of it is that you wouldn't have enough money left over to make your next insurance payment  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'> . I don't really know, interesting question though. Anyone have a more relevant answer, I am interested too?

silvia S13 · 09-09-2002, 05:22 PM

Actually, I just thought of something, maybe I can ask my Chemistry professor, he should know.

*DSC* · 09-09-2002, 05:57 PM

I was on E and put 1/4 tank of 100 octane in my s14 and it ran just fine.  I was told it can foul your o2 sensor from running so rich, but the o2 sensor seems fine (no codes thrown) so I guess it was fine.  As for running too high, I'd imagine if you got up really high you could actually not have enough heat to ignite the fuel but I can't really see that happening, even at 110 you'd prolly just not have enough heat to ignite ALL the fuel but it'd still go boom and make the car move...just spit out unused fuel to ignite in the cat.

blatch · 09-09-2002, 05:57 PM

Yes, you are correct. The higher the octane, the harder it is to ignite. So for a turbocharged, inline-four, higher octane is good. But for a N/A V6 (like my accord) it turns out you get more horsepower from 87.

gh6o6 · 09-09-2002, 08:17 PM

its my understanding that the octane boost doesnt make it harder to ignite, but not ignite in several places.  Instead the burn starts by the spark plug and burns evenly through the combustion.  Running a full tank (or only octane booster) of it will cause the engine to run extreemy hot, causing it to most likley need a rebuild

if you need a reference, search jet fuel - i think it was discused in one of those topics

*transient* · 09-09-2002, 08:28 PM

Yeah, the SR71 blackbird uses a jet fuel with an octane rating so high, that it will actually put out a match if you dropped one in a puddle of it. That definately wouldn't burn in your car <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt='

'>

mbmbmb23 · 09-09-2002, 09:54 PM

I heard the SR71 Blackbird uses a flammable gel for fuel.

The higher octane will definately give you more throttle response, but in some cars it will burn out the catalytic convertor faster than lower octane gas.  I wouldnt use anything under 91 octane w/ a turbo....or anything over 94 octane period.

-m

uiuc240 · 09-09-2002, 10:22 PM

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (transient @ Sep. 09 2002,9:28)</td></tr><tr><td id="QUOTE">Yeah, the SR71 blackbird uses a jet fuel with an octane rating so high, that it will actually put out a match if you dropped one in a puddle of it. That definately wouldn't burn in your car <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt='

'></td></tr></table><span id='postcolor'>
Not correct.  The SR71 uses something other than jet fuel...and it is a gel.  But this is something the switch over to after they go out of the first level of the atmosphere...then there is essentially no oxygen.  

In fact, jet fuel is just kerosene, and it actually has a LOW OCTANE, being that it is more difficult to light a fire at higher altitude.  This is the same reason that high altitude cities, like Denver have 85/87/91 instead of 87/91/93 like we do out here in Illinois.  You don't need as much resistance to detonation, because the air is less dense and therefore less prone to ignition.

Bada bing.

Eric

misnomer · 09-10-2002, 12:15 AM

I've noticed no difference at all with high octane gas on my '92. Stopped buying high octane alltogether <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt='

'> You really only need it if you are high compression or forced induction.

240 2NR · 09-10-2002, 09:07 AM

The blackbird also has to be refueled just after takeoff because the expansion undergone at mutiple mach speeds is so great that it is impossible to seal the fuel tanks, so while on the ground and durning takeoff will weep almost half its supply.

There is too much of a good thing and while a stock 240 may run on 100+ octane (I think over 108 conatins lead so it's a no no for cat equipped cars), it's probably not making any more power and is probably making less.  Remember that even when nissan specifies 91 octane be used, it is still idiot proofed for people who run 87 (though again, power may not be ideal).  

As for a tank of octane booster.  I wouldn't try it as I don't think it conatins any gasoline, just like a full tank of any other fuel addative would probably not result in favorable engine output.

Rownan · 09-12-2002, 09:47 AM

What if my KA was running at 11:1 compression and the computer was tuned for higher octane pump gas like 93..  Would octane boost give a horsepower increase?

AKADriver · 09-12-2002, 10:32 AM

If it's tuned for 93, run it on 93.

Stock, they're tuned for 87 (SOHC) or 91 (DOHC).

Generally speaking, an engine will make the most power on the lowest octane that doesn't cause detonation, or in the case of a knock sensor equipped car, cause the ECU to cut in and retard timing.

Now, if you took that 93 octane, 11:1 engine, and used an aftermarket ignition box and/or messed with the distributor to advance timing, then higher octane fuel could be beneficial.

Ni5mo180SX · 09-16-2002, 09:51 PM

I think if you used to high an octane, you're car would have trouble igniting most of the fuel.

the3SecondJerk · 09-17-2002, 12:42 PM

right, also the higher the compression the pistons are the higher the octane must be. Nobody wants to hear their engine knocking do they? Thats why race cars and turbos use higher octane. Detonation!   <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/cry.gif" border="0" valign="absmiddle" alt='

'>

/etc/shadow · 09-18-2002, 12:30 AM

NEVER EVER EVER FILL YOUR TANK WITH NOS OCTANE BOOST. Some tard did that to his civic. The car never ran again.

adey · 09-18-2002, 04:10 AM

NOS octane booster adds a few points of octane, yes... but it doesn't make 91 octane gas into 95 octane, it actually changes 91 int more like 91.5 (or was it 91.05??). Their use of "points" is HIGHLY HIGHLY HIGHLY misleading.
That said, I'd follow ^his^ suggestion and NOT try it. it's a bleeding waste of money.

As for octane too high... I've run straight 100 (which isn't as high as one could go) in my VW GTi (1.8Turbo) and it felt absolutely GREAT, despite peoples' telling me it wouldn't make a difference (since the car was 'tuned' for 91 here in ca/93 elsewhere). I swear it pulled harder with 100 in there.
I think with higher octane gas you will also see a decrease in gas mileage. (or at least that's what I noticed.)

Were our KA24DEs made for 91??! i was told (was under the impression) that it was made for 87/89 octane... anyone still have their instruction manual? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

240 2NR · 09-18-2002, 07:53 AM

The KA24DE (at least my 93) does in fact call for 91 for optimal performance.

adey · 09-18-2002, 09:43 AM

oh damn.  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>  I've been feeding the baby the wrong fuel the whole time. I guess it doesn't help that the last owner has been, too... <sigh> Thanks for going and checking up for me though! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

240 2NR · 09-18-2002, 10:49 AM

I'm sure the stock timing is conservative enough that unless you're under full load on a really hot day going up a hill, 87 isn't going to kill the engine.  At the same time, it should perform better on 91.  Anyone know if the ECU "learns" the fuel you run and should be reset before switching to 91?

tnord · 09-18-2002, 10:59 AM

OBDII learns, OBDI does not, iirc

actually, i doubt it's that simple. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'>

drifting240sx · 09-18-2002, 02:17 PM

what year did they change to OBDII? i forgot, was it 94?

tnord · 09-18-2002, 04:29 PM

96 i think

*DSC* · 09-18-2002, 09:00 PM

I think some of that later year 95's had obdII as well.

flipboi13 · 09-18-2002, 09:05 PM

No, I think its like 94 too.

Nerfdude · 09-18-2002, 09:12 PM

wait... so you're telling me that if i stop feeding my car 93 and start feeding it 91, it'll perform better? i'd actually save money AND get better performance?! ugh... what about engine knock, would it increase or decrease...
*will fill his tank with 91 on friday*

silvia240 · 09-19-2002, 01:35 AM

Ok so i have been using 91 octane for about the past 3 years and a couple months but the guy before me always used 87 octane.  I have noticed that i get better gas mileage with 91 than i do with 87 and i feel a difference, only on the highway, but for all i know that could just be in my head.  So what i want to know is that what does everybody use because if i can save money and the car would feel the same, i would definately go to 87.  But the manual does say 91 is recomemded for optimal performance.  So what should i do?

adey · 09-19-2002, 02:32 AM

Duh! Maybe that's why my gas mileage is so unbelievably poor... on second thought, it probably isn't just the octane of the fuel I'm using. I'll try a tank of straight 91 next time.
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/whatsthat.gif" border="0" valign="absmiddle" alt=':whatthe:'>
I tend to get crappy freeway gas mileage (trip to/from Irvine from/to Down Town LA used up over 1/3 tank) but it seems that spirited, high-rpm driving (a lot of gear shifting) doesn't drink nearly as much... <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'>

nrcooled · 09-19-2002, 05:47 AM

I use 93 oct in the SR and have used 91 oct before.  I don't really notice a difference.  The only difference that I feel is that of the "hot outside->cold outside"  When its cold the car is almost scarry fast but when its hot I might as well be rocking a n/a KA ::no offence KA dudes:: <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt='

'>  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt='

'>  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'>

09-09-2002, 05:03 PM	#2
the3SecondJerk Zilvia Junkie Join Date: Jul 2002 Location: Fort Collins, CO Posts: 305 Trader Rating: (3) Feedback Score: 3 reviews	I was always under the impression that the higher the octane the harder it is to ignite. Therefore turbo vehicles are required to use it to prevent detonation. But don't quote me on that. As far as filling your tank with octane boost....only way to find out is to try it. Let us all know what happens...I'd guess you will never get the gas ignited and it'll just turn over.  But then again I am not an ignition fuel specialist. __________________ Drive it like you stole it.

09-09-2002, 05:57 PM	#5
DSC New Title Join Date: Aug 2001 Location: VA Posts: 3,454 Trader Rating: (0) Feedback Score: 0 reviews	I was on E and put 1/4 tank of 100 octane in my s14 and it ran just fine.  I was told it can foul your o2 sensor from running so rich, but the o2 sensor seems fine (no codes thrown) so I guess it was fine.  As for running too high, I'd imagine if you got up really high you could actually not have enough heat to ignite the fuel but I can't really see that happening, even at 110 you'd prolly just not have enough heat to ignite ALL the fuel but it'd still go boom and make the car move...just spit out unused fuel to ignite in the cat. __________________

09-09-2002, 05:57 PM	#6
blatch Leaky Injector Join Date: Sep 2002 Location: Bloomington, IN Age: 39 Posts: 127 Trader Rating: (0) Feedback Score: 0 reviews	Yes, you are correct. The higher the octane, the harder it is to ignite. So for a turbocharged, inline-four, higher octane is good. But for a N/A V6 (like my accord) it turns out you get more horsepower from 87. __________________ 98 White S14

09-09-2002, 08:28 PM	#8
transient Premium Member Join Date: Jun 2001 Location: Los Angeles, California Age: 41 Posts: 2,947 Trader Rating: (0) Feedback Score: 0 reviews	Yeah, the SR71 blackbird uses a jet fuel with an octane rating so high, that it will actually put out a match if you dropped one in a puddle of it. That definately wouldn't burn in your car <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=''> __________________ Learn everything you can, while you still have the chance.

09-09-2002, 09:54 PM	#9
mbmbmb23 Zilvia Contributor Join Date: Oct 2001 Location: Charlotte, NC. Posts: 1,776 Trader Rating: (1) Rides Gallery: mbmbmb23 Feedback Score: 1 reviews	I heard the SR71 Blackbird uses a flammable gel for fuel. The higher octane will definately give you more throttle response, but in some cars it will burn out the catalytic convertor faster than lower octane gas.  I wouldnt use anything under 91 octane w/ a turbo....or anything over 94 octane period. -m __________________ 400x200

09-09-2002, 04:57 PM	#1
silvia S13 Join Date: Aug 2002 Posts: 41 Trader Rating: (0) Feedback Score: 0 reviews	Can the octane level ever be too high for a car? For example, those NOS octane boosters, I am guessing they are really high octane, because they increase a couple octane points.  And if you fill your whole tank up with those, what would happen?  No, I would never do that, I am just curious.

09-09-2002, 05:22 PM	#4
silvia S13 Join Date: Aug 2002 Posts: 41 Trader Rating: (0) Feedback Score: 0 reviews	Actually, I just thought of something, maybe I can ask my Chemistry professor, he should know.

09-09-2002, 08:17 PM	#7
gh6o6 Zilvia Junkie Join Date: Oct 2001 Location: Dirty Jersey Posts: 550 Trader Rating: (0) Feedback Score: 0 reviews	its my understanding that the octane boost doesnt make it harder to ignite, but not ignite in several places.  Instead the burn starts by the spark plug and burns evenly through the combustion.  Running a full tank (or only octane booster) of it will cause the engine to run extreemy hot, causing it to most likley need a rebuild if you need a reference, search jet fuel - i think it was discused in one of those topics

09-09-2002, 10:22 PM	#10
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 46 Posts: 2,093 Trader Rating: (0) Feedback Score: 0 reviews	</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (transient @ Sep. 09 2002,9:28)</td></tr><tr><td id="QUOTE">Yeah, the SR71 blackbird uses a jet fuel with an octane rating so high, that it will actually put out a match if you dropped one in a puddle of it. That definately wouldn't burn in your car <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=''></td></tr></table><span id='postcolor'> Not correct.  The SR71 uses something other than jet fuel...and it is a gel.  But this is something the switch over to after they go out of the first level of the atmosphere...then there is essentially no oxygen.   In fact, jet fuel is just kerosene, and it actually has a LOW OCTANE, being that it is more difficult to light a fire at higher altitude.  This is the same reason that high altitude cities, like Denver have 85/87/91 instead of 87/91/93 like we do out here in Illinois.  You don't need as much resistance to detonation, because the air is less dense and therefore less prone to ignition. Bada bing. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

09-10-2002, 12:15 AM	#11
misnomer Nissanaholic! Join Date: Jul 2001 Location: Nevada Posts: 2,293 Trader Rating: (0) Feedback Score: 0 reviews	I've noticed no difference at all with high octane gas on my '92. Stopped buying high octane alltogether <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=''> You really only need it if you are high compression or forced induction. __________________ Rowsdower saves us and saves all the world!

09-10-2002, 09:07 AM	#12
240 2NR Zilvia FREAK! Join Date: Dec 2001 Location: Denver Posts: 1,131 Trader Rating: (0) Feedback Score: 0 reviews	The blackbird also has to be refueled just after takeoff because the expansion undergone at mutiple mach speeds is so great that it is impossible to seal the fuel tanks, so while on the ground and durning takeoff will weep almost half its supply. There is too much of a good thing and while a stock 240 may run on 100+ octane (I think over 108 conatins lead so it's a no no for cat equipped cars), it's probably not making any more power and is probably making less.  Remember that even when nissan specifies 91 octane be used, it is still idiot proofed for people who run 87 (though again, power may not be ideal).   As for a tank of octane booster.  I wouldn't try it as I don't think it conatins any gasoline, just like a full tank of any other fuel addative would probably not result in favorable engine output. __________________ Steve 93 240sx FB currently very clean and for sale

09-12-2002, 09:47 AM	#13
Rownan Leaky Injector Join Date: Apr 2002 Location: Waterford, MI Age: 43 Posts: 133 Trader Rating: (0) Feedback Score: 0 reviews	What if my KA was running at 11:1 compression and the computer was tuned for higher octane pump gas like 93..  Would octane boost give a horsepower increase?

09-12-2002, 10:32 AM	#14
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 43 Posts: 3,517 Trader Rating: (1) Feedback Score: 1 reviews	If it's tuned for 93, run it on 93. Stock, they're tuned for 87 (SOHC) or 91 (DOHC). Generally speaking, an engine will make the most power on the lowest octane that doesn't cause detonation, or in the case of a knock sensor equipped car, cause the ECU to cut in and retard timing. Now, if you took that 93 octane, 11:1 engine, and used an aftermarket ignition box and/or messed with the distributor to advance timing, then higher octane fuel could be beneficial.

09-16-2002, 09:51 PM	#15
Ni5mo180SX Zilvia Junkie Join Date: Dec 2001 Location: Orange County Posts: 423 Trader Rating: (0) Feedback Score: 0 reviews	I think if you used to high an octane, you're car would have trouble igniting most of the fuel. __________________ Mazda RX-7 FC3S: Jspec motor, ported turbo & wastegate, JIC FLT-A2 coilovers, Mazdatrix adj. rear camber link, TB mod, Koyo 53mm Radiator, Corksport Cat back/midpipe/downipe, 3" Al TID, Apex'i air cleaner, Mazda Comp. mission/motor/differential mounts, Mazdaspeed Strut Bar(R), FD torsen differential, HKS SSQV, HKS elec. boost gauge & elec water temp, Cusco Oil catch, 680cc secondary's, Walbro 255, Banzai Racing FCD, RB DTSS Eliminator bushings, Exedy Clutch & PP, Exedy chrome moly flywheel, RB oil baffle, RB dual alt. pulley, 5 lug conversion, FC3S.org thermal bypass pellet, KVR Cross drilled rotors, complete Energy PU bushings, stainless steel brake lines/clutch line, Aerodyne shroud panel, Azenis RS, and some other stuff. A hybrid of sorts I guess

09-17-2002, 12:42 PM	#16
the3SecondJerk Zilvia Junkie Join Date: Jul 2002 Location: Fort Collins, CO Posts: 305 Trader Rating: (3) Feedback Score: 3 reviews	right, also the higher the compression the pistons are the higher the octane must be. Nobody wants to hear their engine knocking do they? Thats why race cars and turbos use higher octane. Detonation!   <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/cry.gif" border="0" valign="absmiddle" alt=''> __________________ Drive it like you stole it.

09-18-2002, 12:30 AM	#17
/etc/shadow Zilvia Member Join Date: Jun 2002 Posts: 167 Trader Rating: (0) Feedback Score: 0 reviews	NEVER EVER EVER FILL YOUR TANK WITH NOS OCTANE BOOST. Some tard did that to his civic. The car never ran again.

09-18-2002, 04:10 AM	#18
adey Post Whore! Join Date: Mar 2002 Location: Hong Kong Posts: 3,072 Trader Rating: (0) Feedback Score: 0 reviews	NOS octane booster adds a few points of octane, yes... but it doesn't make 91 octane gas into 95 octane, it actually changes 91 int more like 91.5 (or was it 91.05??). Their use of "points" is HIGHLY HIGHLY HIGHLY misleading. That said, I'd follow ^his^ suggestion and NOT try it. it's a bleeding waste of money. As for octane too high... I've run straight 100 (which isn't as high as one could go) in my VW GTi (1.8Turbo) and it felt absolutely GREAT, despite peoples' telling me it wouldn't make a difference (since the car was 'tuned' for 91 here in ca/93 elsewhere). I swear it pulled harder with 100 in there. I think with higher octane gas you will also see a decrease in gas mileage. (or at least that's what I noticed.) Were our KA24DEs made for 91??! i was told (was under the impression) that it was made for 87/89 octane... anyone still have their instruction manual? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> __________________ Instagram: @SX180HKG

09-18-2002, 07:53 AM	#19
240 2NR Zilvia FREAK! Join Date: Dec 2001 Location: Denver Posts: 1,131 Trader Rating: (0) Feedback Score: 0 reviews	The KA24DE (at least my 93) does in fact call for 91 for optimal performance. __________________ Steve 93 240sx FB currently very clean and for sale

09-18-2002, 09:43 AM	#20
adey Post Whore! Join Date: Mar 2002 Location: Hong Kong Posts: 3,072 Trader Rating: (0) Feedback Score: 0 reviews	oh damn.  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>  I've been feeding the baby the wrong fuel the whole time. I guess it doesn't help that the last owner has been, too... <sigh> Thanks for going and checking up for me though! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'> __________________ Instagram: @SX180HKG

09-18-2002, 10:49 AM	#21
240 2NR Zilvia FREAK! Join Date: Dec 2001 Location: Denver Posts: 1,131 Trader Rating: (0) Feedback Score: 0 reviews	I'm sure the stock timing is conservative enough that unless you're under full load on a really hot day going up a hill, 87 isn't going to kill the engine.  At the same time, it should perform better on 91.  Anyone know if the ECU "learns" the fuel you run and should be reset before switching to 91? __________________ Steve 93 240sx FB currently very clean and for sale

09-18-2002, 10:59 AM	#22
tnord Nissanaholic! Join Date: Dec 2001 Posts: 1,975 Trader Rating: (0) Feedback Score: 0 reviews	OBDII learns, OBDI does not, iirc actually, i doubt it's that simple. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'>

09-18-2002, 02:17 PM	#23
drifting240sx Zilvia Junkie Join Date: Oct 2001 Location: salinas ca Age: 41 Posts: 362 Trader Rating: (0) Feedback Score: 0 reviews	what year did they change to OBDII? i forgot, was it 94? __________________ PROJECT SIL-80

09-18-2002, 04:29 PM	#24
tnord Nissanaholic! Join Date: Dec 2001 Posts: 1,975 Trader Rating: (0) Feedback Score: 0 reviews	96 i think

09-18-2002, 09:00 PM	#25
DSC New Title Join Date: Aug 2001 Location: VA Posts: 3,454 Trader Rating: (0) Feedback Score: 0 reviews	I think some of that later year 95's had obdII as well. __________________

09-18-2002, 09:05 PM	#26
flipboi13 Zilvia Member Join Date: May 2002 Posts: 221 Trader Rating: (0) Feedback Score: 0 reviews	No, I think its like 94 too.

09-18-2002, 09:12 PM	#27
Nerfdude BANNED Join Date: Jul 2002 Posts: 495 Trader Rating: (0) Feedback Score: 0 reviews	wait... so you're telling me that if i stop feeding my car 93 and start feeding it 91, it'll perform better? i'd actually save money AND get better performance?! ugh... what about engine knock, would it increase or decrease... will fill his tank with 91 on friday

09-19-2002, 01:35 AM	#28
silvia240 Zilvia Junkie Join Date: Jul 2001 Location: SoCal Posts: 438 Trader Rating: (0) Feedback Score: 0 reviews	Ok so i have been using 91 octane for about the past 3 years and a couple months but the guy before me always used 87 octane.  I have noticed that i get better gas mileage with 91 than i do with 87 and i feel a difference, only on the highway, but for all i know that could just be in my head.  So what i want to know is that what does everybody use because if i can save money and the car would feel the same, i would definately go to 87.  But the manual does say 91 is recomemded for optimal performance.  So what should i do?

09-19-2002, 02:32 AM	#29
adey Post Whore! Join Date: Mar 2002 Location: Hong Kong Posts: 3,072 Trader Rating: (0) Feedback Score: 0 reviews	Duh! Maybe that's why my gas mileage is so unbelievably poor... on second thought, it probably isn't just the octane of the fuel I'm using. I'll try a tank of straight 91 next time. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/whatsthat.gif" border="0" valign="absmiddle" alt=':whatthe:'> I tend to get crappy freeway gas mileage (trip to/from Irvine from/to Down Town LA used up over 1/3 tank) but it seems that spirited, high-rpm driving (a lot of gear shifting) doesn't drink nearly as much... <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'> __________________ Instagram: @SX180HKG

09-19-2002, 05:47 AM	#30
nrcooled Nissanaholic! Join Date: Mar 2002 Location: Turn 8 'bout to get rolled by a SC'd ITR Age: 46 Posts: 1,849 Trader Rating: (0) Feedback Score: 0 reviews	I use 93 oct in the SR and have used 91 oct before.  I don't really notice a difference.  The only difference that I feel is that of the "hot outside->cold outside"  When its cold the car is almost scarry fast but when its hot I might as well be rocking a n/a KA ::no offence KA dudes:: <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=''>  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=''>  <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'> __________________ '91 hatch w/ SR Sold; '03 Evo Sold 401 HP; '03 MS Protege sold; '00 Evo 6.5 TME Sold 300HP

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