gas

[justinc]

I have a 91 nissan 240sx should i be using premium or regular gas?

[West]

Only if you are modded.

[justinc]

So if i get exhaust ill need to use premium

[cheater240]

My '91 owner's manual calls for 91 octane (premium).  I put in 89.  I suppose Nissan bumped up the timing a little to get some more power and that required the 91.  

Anyone feel any difference with the 91 octane?

[West]

Hmmm, I thought the manual said 87. I always run the highest anyways, even when I was stock but it doesn't really matter for most of us. I had a JWT ecu in my old 91 so I had to run 91 no matter what. I run 91 in my Turbo now and it does fine.

You dont really need to start using higher octane gas until you have about 3-5 of the major bolt ons IMHO. Still you can get away with 85 octane.

Only thing I really noticed different when I would switch from low octane to higher octane was less engine knock and honestly the lower octane felt faster sometimes when I wasn't highly moded. Remember the higher the octane the harder the fuel is to ignite.

[cheater240]

Yes, the harder the fuel is to ignite also means a slower burn.  This means the computer can advance spark.  THIS means (up to a point) more power.  

Does the KA have a knock sensor?  If not, I sure wouldn't run anything under 91.

[justinc]

Im running regular gas and im stock is that okay or will something happen to my car?

[justinc]

If i switched to premium does this mean more power ?

[West]

Nope.

[anthony240]

just better gas mileage.

[drifterx]

i feel my car rides like shit when i put in 87 Octane
it only rides bad when i gas hard but if u drive slow it doesnt feel different

[justinc]

im at a half a tank if i add premium gas will anything happen if i mix the two?

[cheater240]

There can be power gains from higher octane fuel, IF your car was calibrated to take advantage of that higher octane (read slower burn).

Since the 240SX (at least my '91) calls for 91 octane, I would believe there to be a power loss by switching to a lower octane fuel.  I have felt this loss, and it sounds like others have as well.  Not much, but noticable.

Now, if you put 103 octane race fuel in your Ford Festiva are you going to see any power increase?  NO WAY!  But the 240SX was calibrated to run BEST on 91.  

Running on a lower octane probably doesn't hurt anything because the computer will retard spark timing to compensate for the quicker burning fuel.

[justinc]

Is it okay to switch between the two?

[cheater240]

If the car has a knock sensor, it will adjust spark advance to compensate for the lower fuel.  

I wouldn't say its OK to run less octane than what the manual says to run, but everyone (me too when I'm cheap!) does it and the computer strategy will compensate for it

[justinc]

Dude i always thought i should run regular gas thats what it says in the manual

[justinc]

If im at half a tank can i put some premium gas in to fill it up?

[bison]

NO JUSTIN!!! NEVER DO THAT OR YOU WILL SCREW UP YOUR ENGINE BEYOND REPAIR!!!

Just kidding.  Of you course you can fill up with premium even with a half tank of regular.

[drifterx]

it is ok for 240sx to run the best stuff cuz it is not a domestic car...
the manual said u have to run atleast 89 octane right?
if a chevy ran premium the car would be messed up...
i noticed gas milage increase with better octane and i feel more power but that is me,

[drifterx]

i forgot
VOTE ME FOR PRESIDENT 2016

[96SEChick]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from drifterx on 11:53 pm on July 13, 2001
it is ok for 240sx to run the best stuff cuz it is not a domestic car...</td></tr></table><span id='postcolor'>

Actually, it depends on which domestic car you own. &nbsp;Camaro's and Trans Am's pretty much have to run on premium, or else the engine won't run as smooth and you will get a slight ping. &nbsp;On a Cavalier or a pickup?--87 octane is good enough.

Depending on the gas prices (which look like a seismograph for the past few months), I use 93. &nbsp;91 is kinda hard to find in OK for some reason. &nbsp;

[Jeff240sx]

Higher octane= better gas milage. &nbsp;KA motors have a knock sensor in them. &nbsp;Less octane=more knocks and pings in your engine. &nbsp;There is a slight power difference using 87 octane since our engines have been advanced from the factory. &nbsp;I KNOW my manual and my gas door says PREMIUM (93 octane) ONLY. &nbsp;I wouldn't run brake fluid where the manual says ENGINE COOLANT ONLY, would you?
-Jeff

[justinc]

I live in canada and i seen mostly 91 octane

all cars sold in north america must be able to run on 87 in order to be sold here

[gt7152b]

Not in my part of North America. Several cars sold in the US require 91 octane or more. Higher octane just resists detonation better than lower octane. If you don't have knocking with 87 octane, it will work fine in your car. If you want to run higher octane, you should probably advance your timing to take advantage of it. Some cars have ECU's that will automatically advance timing for higher octane fuel and will back it off via the knock sensor for lower octane fuel. My Chevy Blazer is like this and I switch back and forth between 87 and 93 octane all the time. I can tell the increase in performance with 93. Many cars that run high compression like the LS1 Camaro's/Firebird's and Maxima's require higher octane to prevent detonation from the higher compression. Alot of turbo/blown engines are the same way because the effective compression is raised under boost.

[andwys]

I use 91, and have noticed a little gain in gas milege but not to much. &nbsp;The car rides smoother and has quicker &quot;go&quot;.
Oh Lauren go to &quot;get-n-go&quot; they have 91 octane and they are friendy from the word go oh oo

[geerhedz]

cheater is right would you want to put 87 in a vette?.....no. higher octane dosent give everone more power. but a dual overhead cam 4 valve engine with somewhere around 9:1 compression likes 91 or higher. but to tell you the truth i dont like premium these days they dont crack the fuel right on the tower anymore (this is the process for turning crude oil into gas). in fact most outboard engine manufacturers tell you to run 89 cause the premuim is basicly doctored up cheap gas. thet they put a lot of antiknock chemicals in it so what ive been doing lately is running 89 with octane boost and i actually had better results with that. i recommend outlaw products but some premium ive had good luck with exxon, texaco, citgo.

[JeffNJ]

I know I mention it a lot, but I'm on my second 240 now, so I frequently compare them. &nbsp;I bought both cars used, so I assume each engine was already used to a certain octane? &nbsp;Is that possible?

Anyway, doesn't matter. &nbsp;When it comes to octane, the answer is simple for any car at all. &nbsp;Fill your tank with one like four times or so (to make sure you've flushed all of the other kind out of the lines and the bottom of the tank) and see what it feels like. &nbsp;Then, try it again with a different octane level. &nbsp;I do this every time I buy a car. &nbsp;Every time.

My '88 Jeep Cherokee (I wasn't always a sports car guy) seemed to absolutely demand 93. &nbsp;Anything less seriously reduced it's &quot;pep&quot;. &nbsp;My '91 240 SE honestly seemed to prefer 87. &nbsp;Of course, it never minded the good stuff, but it ran really strong on even the 87, so I just kept buying that. &nbsp;My lastest 240 doesn't seem to care one way or the other. &nbsp;I've run it for a full month each on 87 and 93 and for the life of me, I don't see a #### difference.

That said, just try 'em and use your favorite. &nbsp;I'm convinced octane is just not as important as gas companies want you to believe. &nbsp;Give your car what it seems to want, period. &nbsp;=)

[vancouvers14]

for some cars, higher octane is strongly recommended, but....
all cars the usa and canada MUST be able to run on 87. &nbsp;it is required

[transient]

What about the quality of gas itself? As someone pointed out, it's not all the same from station to station... Is there one gas station in particular that most of you go to?

don't know about in the USA, but here in canada I stay away from Arco. &nbsp;I've heard that they're the only company that doesn't test for water in their tanks. &nbsp;I usually go for chevron

[transient]

likewise i've heard bad things about mobil here in the states. Apparently the stations around here use baby powder on the dipstick to make the level easier to read, then put the stick back in with the powder on it.

I've heard good things about Mobil and bad things about Clark. I used Shell on my previous car and never had a problem with it. I once used Clark's gas on my previous car and found water in my fuel system. So now, I use Mobil's 93. Runs great on my car.

[carnal c30]

I've never had a problem with using 87-89-92 With my Maxima which recommends 92, I've used 87 and havent noticed anything different. I agree that when you mod your car alot, be prepared to always fill up on premium.

[96SEChick]

My car seems to be getting a little worse gas mileage since starting to use 91 or 93 for the past month. &nbsp;Is this normal or is it just a coincidence and something else is wrong with my car?

I get an average of about 15-17 mpg. It really depends if I'm using my air conditioning a lot, I noticed that lowers my gas mileage.
If you're concerned, check your fuel injectors and maybe your plugs. Or just check the whole fuel system. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

(Edited by s13grl at 7:35 am on Sep. 19, 2001)

[LanceS13]

Dang, that's pretty low. &nbsp;I average about 22-24 mpg on 89 octane.

[transient]

supposedly some 240's out there get like... 30 Mpg. Can't remember where I saw that, but I think it's bunk. I'm guessin I get around 20 to the gallon, but then again, I never check...

[LanceS13]

I think hwy mpg on a brand new 240 is like 28mpg. &nbsp;So I guess 22-24 mpg city/hwy combined is pretty good considering my car's 10 years old and probably could use some new plug wires.

[Grant]

naw, 87 is fine. esp with the fact that my car is almost completely stock with the exception of a exhaust.

Well, I also got those dope-ass cams which have a bit of a different timing and allow for more of my gas to get wasted. My fuel gallon capacity is like 14 or so. And the car is 10 years old. So... I'm just trying to make my car sound healthy. Have mercy on me!

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">

Depending on the gas prices (which look like a seismograph for the past few months), I use 93. 91 is kinda hard to find in OK for some reason.
</td></tr></table><span id='postcolor'>

I think all Quicktrips and Git n' Gos in Tulsa carry 93.

i put in premium today (91) i think and for the first time it really made a difference SMOOOOOTH accelaration car felt HEALTHY! WOOWOOWOOWOOOWOW GULF premium it is from now on!

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

[groundzero]

Yo justin, I just bought a 1989 240sx, and when I was test driving it, I notice that the acceleration wasn't what I needed. &nbsp;Since then I've been using premium or cheveron Supreme techron. &nbsp;My car runs better than it used to...I guess I think better gas cleans your engine...Just settle for something better than less...

[ca18guy]

Sound's like you need a tune up. Change the spark plug's, wire's, change the oil, oil filter, air filter (just get it over with and buy a aftermarket filter), maybe some injector cleaner and some other stuff I'm sure I forgot <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[MingMing]

it also depends on what u mod ur car with
like that previous guy said, the higher the compression, the better the fuel u should use
if u gotta turbo adding like 14 psi boost, then yea use better fuel, cuz it mite explode before the spark ignites it, which would be bad, whereas if you add headers and exhaust and whoopy a cold air intake, it wouldnt really matter

[AJ]

mingming.. i love ur quote.. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> i had a good chuckle over that. hehee

Lol, it's hillarious <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>