92 240sx octane use

[nissan24000]

What are the current members using for gas?

I use 91.

Is it okay to seafoam the 240sx?

92 240sxoriginal owner165000 miles original clutcheverything original except water pump and radiator, brake pads

[Rucca]

I use 87, seafoam is fine.

There is no point in running a higher octane if your car isn't tuned for it.

[nissan24000]

The operators manual specifically says to use 91 and 87 as alternate.

[danielsan]

The operators manual specifically says to use 91 and 87 as alternate.

yep, it even states use premium unleaded on the fuel door. 91 is recommended for maximum performance.

from my owners manual.

[modulation]

yep, it even states use premium unleaded on the fuel door. 91 is recommended for maximum performance.

Unless you live some where that it's really hot (like above 85 degrees F for most of the day) I really don't think 91 is needed.

I've got nistune.I advanced my timing 4 degrees.I run 87 octane (california crap 87)I don't get any knock.

If I don't get knock with advanced timing and it's not very hot where you live there is no way you are going to get knock with stock timing.

But that's like my opinion.

[youngun21a]

I use 93 octane,

[danielsan]

it as it states in the manual its not really needed. but i guess they recommend it to get the full advertised hp and torque out of the beast. i usually run 87 one day and then 91 the next trip, i can tell the car runs a little smoother and is bit more responsive with the 91.

[240M1ke]

if they are willing to tell you to use 87 as an alternate, imo it'd be safe to use it normally because if it did cause knock or hurt the car in any way, you'd think they wouldn't mention 87 at all

[rogue240sx]

The car has a knock sensor. In the event of knock it should retard the timing to prevent knocking. This will decrease power output of the motor.

[janda240sx]

You don't have to use any higher than 87 but I always use 93. I get better fuel mileage out if it and it turns out being cheaper that way. I have tested many times.

[Rucca]

Higher octane fuel resists detonation. Lower octane fuel will burn more. You should make more power with lower octane fuel.

[rogue240sx]

doesn't work that way Rucca. The inconsistency of the fuel's exploding at less than optimum times in different cylinders before TDC hinders performance.

[Rucca]

I can barely understand what you said, but, I think you are telling me that running 87 results in the fuel exploding at less than optimum times before TDC?

The fuel explodes when the spark plug goes off, before TDC. Unless you get predetonation, which you won't by running 87. The amount of time the fuel burns and the even nature of the burn depends on the mix, compression, and head design. Octane is just the ability of the fuel to resist knock.

[rogue240sx]

You're contradicting yourself. Seriously man, you ARE NOT going to get more power out of lower octane fuel.

edit: octane defines at what point it explodes not how much of it that is burnt. Besides, there's more to how an engine runs than the intensity of the explosions. It has to be timed right as well. Remember 240sx came from the factory setup to run on 91 not 87 like most other cars. if you want to run well on 87 you'd have to retard your timing slightly which will lower your horsepower.

btw i usually run 93 because 91 isn't always available. every time I've tried to use lower octane the car has run noticeably worse
Modified by rogue240sx at 8:24 PM 4/23/2008

[Rucca]

"Paying extra for gasoline with a higher octane number than the engine requires is literally a waste of money. If the motor doesn't detonate on regular, then burning premium gas will not increase power or improve fuel economy. In fact, the compounds that are added to gasoline to raise its octane rating typically have less energy content than regular gasoline."

http://www.competitionplus.com....html Crappy article I know but I'm sure you could find better to prove this.

Higher octane fuels have lower energy output when run on the same engine. Allowing you to increase compression is how they make power.

I doubt you'll see a difference in power or fuel economy between 87 and 93. Just in theory 87 has slightly more energy potential.

[rogue240sx]

In theory bumble bees can't fly. Well **** better tell them that because those ****ers are flying.

Theories are just that, theories. the 240sx is set for 91 octane. yes putting 91 in a toyota econobox isn't going to do anything but a 240sx was built for use with that octane rating.

edited my upper post

[twofortyridaS13]

I run 93 and get 25+mpg on a 260k+ engine and many have told me it runs WAY to good with that mileage including this guy boosting 12lbs on his suby. I ran 87 a few times and the good ol ka didn't like it. Spit and sputtered and I got like 260 miles on a tank when I was getting 300+. Action speaks louder than words so give it a shot and see what happens.

[ChuckNC]

Uh Huh! I may just have to take that challenge and see for myself. I owned a Mitsubishi Diamante that required premium gasoline and there was knocking and decreased performance the one time I mistakenly put in 87 octane. I haven't noticed any difference in mine, even when I use injector cleaner with a tankfull of premium gasoline every six months. I will run 87 octane for three tanks and then 93 octane for three tanks and keep records of fuel mileage and post back in the future.

[sr20deTsomeday118]

have you ever even done the math rucca...the cost to fill your tank with premium(93 octane around here) will only add up to about 3-4 extra dollars at the most...if your cant afford an extra 3 dollars at the pump for a better running engine and better gas mileage then

[twofortyridaS13]

It saves me money to run 93. I get an extra 30-40 miles a tank running premium.

[janda240sx]

^^^^ On regular i get like 23-25 mpg and oon 93 I get 29-31

[twofortyridaS13]

^^^^ On regular i get like 23-25 mpg and oon 93 I get 29-31

Whats your mileage? Cuz I want 30mpg Premium is 3.80 a gallon now.

[AE240SX]

I use midgrade and the occasional premium tank. i get better gas mileage than if i use regular. A bit off topic... I had an '87 MB 300E with Bosch CIS-E fuel injection and that engine was built for premium and extremely sensitive to gas quality. I couldlnt afford high test at the time so i tried every type of gas in my area and shell regular was THE only regular it wouldln't knock and sputter on. I once got racetrack swill, that was a mistake.... didn't make it 5 miles before thinking i had lost a cylinder or something.

[sr20deTsomeday118]

i get like 28mpg on 93 octane, and its like 3.99 around here

[ken240sx]

I use whatever's available, if they have 91 I'll put 91, if they have 87,89, and 93 I'll put 93. But if I filled my tankwith 93 I'll usually refill it with 89 or 87 when I get half way down again...But for the most part both 91 and 93 are readily available where I drive. For a while I had my timing advanced, and I used 93 only...but I don't think it would have made much of a difference between 91 and 93, it was more just a piece of mind.

Many newer cars have ecu's that will run your car off different fuel maps with different octane ratings. When a manufacturer tells you to run premium that means that the car is tuned for that fuel. If you tuned a built engine for 109 octane, but decided to always run 103, you're definitely down syndrome positive. I know that's with tighter tolerances and higher performance, but the same concept goes for stock engines....would you run 87 in a z06? well I'll bet you could, and the engine would compensate, but bye bye 505hp, you might be running low 400's. It won't effect an engine like the KA as much, but I prefer to get everything I can out of my motor.

[sr20deTsomeday118]

I prefer to get everything I can out of my motor.

hit the nail on the head..who wants lower hp than stock...

[ken240sx]

It's not like our cars are fast or anything, but that's exactly why you wouldn't want to takes steps to make them any slower than they are.....

[low91240sx]

to rogue 240sx higher octane gas DOES burn slower man try it out i'm sure your car would love you for it fill up on 87 and track your gas mileage then use 91 and track it you'll get more out of the 91 if u come back and say that you didn't well then A. you raced it a couple of times or B. your flat out lying. I use 91 most of the time but if i go somewhere like bp or sunoco i'll put 93 in her if it's available and get Awesome mileage 25-40 more miles to the tank easy compared to 87 octance. i have put 87 in my tank once and will NEVER do it again it seemed sluggish in low end and I noticed little things performance wise that weren't there anymore that I knew my car had. but when i put 91 back in it I got my mileage and performance back. sounds nuts but it's true man read all the articles you want it's kind of hard for someone to tell you different when you notice it yourself and other people that own the car and drive it all the time say the same 91 octane or higher if you want the best gas mileage and performance sure it costs more at the pump but i would rather pay a couple of more bucks at the pump and know that my engine is running right than keep that couple of dollars and have my car running crappy and end up paying more anyway because i'm not getting top gas mileage. sorry i just noticed how long this was my bad

[direktdrive]

i get like 28mpg on 93 octane, and its like 3.99 around here

3.99 for 93 octane? wow nice, 3.99 will get you only 91 octane here where I live.

[rogue240sx]

I never said you didn't get better mileage out of higher octane fuel If you read my posts I definitely said running lower octane fuel in our 240SXes is less efficient.

I think you misunderstood me.

edit: Also, I always use 93 octane (or 91 if i can't find 93), which is 3.75 over here. I remember back when it was .89 a gallon........