Premium Gas in a 240

[hookedup240]

Today i was sitting in my car in between classes and i was reading my owners manual of my s-13 and I noticed that it said the recomended gas was premium.
I was wondering what you guys put in your cars. I have always put regular in. I don't see why it says premium. My friend has a 94 mustang GT and even he puts regular in.

Just wondering if anyone has read this too.

[Jeff240sx]

Wow.  After I drove my car home from the lot, the first thing I did was read the owner's manual.  
Yea, you need to run premium gasoline in the KA.  It has a very advanced timing, and premium gas allows the car to keep the timing advanced without detonation.  You can run lesser gas, but the ecu will retard the timing, and you will lose a lot of power.
-Jeff

[hookedup240]

i never new that i was suppose to use premium could using regular gas for the last 30,000 miles since i have had the car, is there any way that it can hurt the car?

[logo20]

what my 89 owner's manual says is:
All models are designed to operate on unleaded gasoline with an octane rating of at least 87 AKI (Anti-Knock Index) number (reasearch octane number 91).
where does it say anything about premium?

[SimpleS14]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (logo20 @ Dec. 08 2002,3:38)</td></tr><tr><td id="QUOTE">what my 89 owner's manual says is:
All models are designed to operate on unleaded gasoline with an octane rating of at least 87 AKI (Anti-Knock Index) number (reasearch octane number 91).
where does it say anything about premium?</td></tr></table><span id='postcolor'>
Some places have octane 91 as premium. &nbsp;So I'm asking thats premium in his area. &nbsp;Man I've been using 89 for awhile....a long while. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/huh.gif" border="0" valign="absmiddle" alt=':huh:'>

[SilviaDriver]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Jeff240sx @ Dec. 09 2002,12:25)</td></tr><tr><td id="QUOTE">Wow. After I drove my car home from the lot, the first thing I did was read the owner's manual.
Yea, you need to run premium gasoline in the KA. It has a very advanced timing, and premium gas allows the car to keep the timing advanced without detonation. You can run lesser gas, but the ecu will retard the timing, and you will lose a lot of power.
-Jeff</td></tr></table><span id='postcolor'>
well my 95 asys for best performance use Premium 91 octane, and regular use unleaded. but i have always been using 91. you can actually feel the difference between 91 and 89 IMO. my car would bog a bit in the beginning for 89. but in 91 it wouldnt.

Jeff - would u happen to know what the range for our timing is? i know for a 95 GSR stock is 14-18 BTDC [sorry, i was a honda man before i got my 240, still am id like a GSR, my bro has one]. if the range is 14-18 might as well advance it to 18, no? since its still in the range, advancing it past stock is wat damages the engine. so i was wondering if you[or anybody on this forum] knows our range for timing.

[Dousan_PG]

i always use 91 (highest easily available-in california and all my KA neesd). no ping, no detonation.runs great on track when pushing it hard and runs smooth on streets. 89 was ok but i wouldnt use it on the track. using 91 all the time is just easier, no 89 mixing in the the 91 or anything. i always get chevron too..either way. 91 is the most for the KA. wheni get my SR i'll be mixing a higher octane w/ the 91

[Toso]

Running higher octane does not make more power!

It allows you to tune for more power safely. &nbsp;Just filling up with 91 is not going to make your car faster. If it does, then your car was detonating like mad and the ECU retarded your timing.

[hookedup240]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (logo20 @ Dec. 09 2002,3:38)</td></tr><tr><td id="QUOTE">what my 89 owner's manual says is:
All models are designed to operate on unleaded gasoline with an octane rating of at least 87 AKI (Anti-Knock Index) number (reasearch octane number 91).
where does it say anything about premium?</td></tr></table><span id='postcolor'>
I have a 91 and This is what my owners manual says on the last page of the book.

Recommended fuel:
Unleaded premium gasoline, at least 91 AKI number (ron 96)

If unleaded premium gasonline is not available, unleaded regular gasonine with an octane rating of at least 87 AKI (research octane number 91) can be used.

However, for maximum vehicle performance, the use of unleaded premium gasonline is recommended.

[Evil S14]

ive used 89 on my 240 and it didnt do anything bad. most of the time the knock sensor will take over and automaticaly adjust for the lower octane, but make it run like poo.
as for timing i belive ours is 20 degrees.

so technically you dont have to use premium, but it is recommended.

i guess it kinda sux in those places where 91 is premium, hell we can get 94 octane gas here at the pump for 6 cents more than premium

ive even used cam 2 (115 leaded octane) in my 240 (bye bye O2 sensor) just to see what would happen <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'>

[FastBack 240]

I figured this out that hard way.................I would use 89 octane in my s13 and would reeeeeem the hell out of it and put a hole threw the top of the 2nd Piston because I used the shitty gas. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/withstupid.gif" border="0" valign="absmiddle" alt=':withstupid:'>

[Jeff240sx]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Toso @ Dec. 09 2002,4:25)</td></tr><tr><td id="QUOTE">Running higher octane does not make more power!

It allows you to tune for more power safely. Just filling up with 91 is not going to make your car faster. If it does, then your car was detonating like mad and the ECU retarded your timing.</td></tr></table><span id='postcolor'>
I think that you have just contradicted yourself. &nbsp;You cannot make more power just by dumping in better gas, unless you tune for it. &nbsp;And... since the ECU advances / retards timing by itself, it tunes the engine for more power while running premium (93 octane at every pump, 100 octane at Speedways in my area.) &nbsp;
-Jeff

[misnomer]

meh.

The ECU doesn't "know" you put lower octane gas in. It needs a reason to retard the timing, and that reason is detonation. If the car doesn't detonate on low octane gas, then you will really see no difference. You will likely notice the difference between shitty gas and good gas, but the octane rating has little to do with that.

I have run 87 octane gas in my car for a long time, and have never noticed a difference when I put in 91 (like I used to at the beginning). But, I always buy good gas. Keep in mind I'm at a pretty high altitude (~5000 ft), so the air isn't so dense up here. . . But, never have I even heard the ping of premature detonation.

[Toso]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Jeff240sx @ Dec. 09 2002,4:03)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Toso @ Dec. 09 2002,4:25)</td></tr><tr><td id="QUOTE">Running higher octane does not make more power!

It allows you to tune for more power safely. Just filling up with 91 is not going to make your car faster. If it does, then your car was detonating like mad and the ECU retarded your timing.</td></tr></table><span id='postcolor'>
I think that you have just contradicted yourself. You cannot make more power just by dumping in better gas, unless you tune for it. And... since the ECU advances / retards timing by itself, it tunes the engine for more power while running premium (93 octane at every pump, 100 octane at Speedways in my area.)
-Jeff</td></tr></table><span id='postcolor'>
I dont think you understand how the detonation sensor and timing adjustment works. Its not 'tuning' anything. If the detonation sensor detects pinging, it retards the timing from what it should be stock. Its on or off. Its very noticable. Its a saftey precaution. Not tuning. If you run 103 octane, your ECU wont advance the timing. It will just sit there. Its possible to run 87 octane and not ping. Octane is not the only thing that causes detonation. If you ran 87 octane and ran your car conservatively, you wouldnt ping. So I will restate my position for you. Running higher octane will not give you any more power. It will allow you to tune for more power. You do that by, advancing timing, leaning out the mixture, increasing boost...

Someone also mentioned that its safe to run 87 because the car will detect it... Thats not intirely true. The car does not detect octane levels. It detects detonation. Which sounds fine, but you have to realize that the detonation sensor is not active at higher RPM's when you would be most likely to detonate.

Hope this clears up any misinterpretations.

[hookedup240]

Would running regular gas account for poor emissions at inspection?

thanks guys for the help
gonna fill up next time with premium

[ridebmx]

i just use 87 octane in my 97 240, i have used higher octance and didnt notice anything...and iirc octane levels in gas drop after it sits for awhile (dont quote me on that but ive seen that) ive also been told/read that it really doesnt matter what octane u use unless ur motor is specificly tuned for high octance gas and u use low octane, so pretty much have a built up motor or what not, hell i could be wrong, but i have never had a motor go on me, and have put some hard miles on vehichles...so basicly ill save the 10 cents a gallon and stick with 87

[four]

for s14s, it says it on the gas tank DOOR that Premium Fuel is Recommended

[Alias]

I use 91 or 93 depending on where I am. I never use Speedway gas. My dad has always said it was bad. The manual says premium so thats what I use. It only cost me $36 more a year assuming Its .10 cents more a gallon......

[kid_nissan]

wait so ur sayin if i put premium in my car i might get some power increase? cause i have been putting regular in, u suggest premium

[kid_nissan]

wait so ur sayin if i put premium in my car i might get some power increase? cause i have been putting regular in, u suggest premium

[AceInHole]

to both above posts... yes, but it's only a minor possible yes. &nbsp;take the extra couple bucks and try it for a tank and see.

as for me, i use 94 octane when i can get it. &nbsp;otherwise it's 93.

[Toso]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kid_nissan @ Dec. 10 2002,09:13)</td></tr><tr><td id="QUOTE">wait so ur sayin if i put premium in my car i might get some power increase? cause i have been putting regular in, u suggest premium</td></tr></table><span id='postcolor'>
Higher octane (premium) gas will not give you any horsepower! If you do nothing to take advantage of the higher octane, it will do nothing for you! If you feel a power increase with higher octane it is because you were detonating and your ECU caught it and retarded your timing.

[drift freaq]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">I figured this out that hard way.................I would use 89 octane in my s13 and would reeeeeem the hell out of it and put a hole threw the top of the 2nd Piston because I used the shitty gas.</td></tr></table><span id='postcolor'>

You blew your engine most possibly because your timing was to advanced for the octane and you were getting detonation. Its also possible you dropped a valve . A hole in the piston is usually caused by timing change failure which causes a valve to strike your piston.
As far as octane goes . you can run 89 and get away with it. I used to do it all the time in my Hardbody truck KA24e.
In my 91 I run 91 when I am getting on it and 89 when I am feeling cheap.
Engine runs fine.
Here in Cali the highest octane thats readily availible is 91 and you can tune your engine to work on 89 or 91.
You want more get some kind of octance booster.

[drift freaq]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">I figured this out that hard way.................I would use 89 octane in my s13 and would reeeeeem the hell out of it and put a hole threw the top of the 2nd Piston because I used the shitty gas.</td></tr></table><span id='postcolor'>

You blew your engine most possibly because your timing was to advanced for the octane and you were getting detonation. Its also possible you dropped a valve . A hole in the piston is usually caused by timing change failure which causes a valve to strike your piston.
As far as octane goes . you can run 89 and get away with it. I used to do it all the time in my Hardbody truck KA24e.
In my 91 I run 91 when I am getting on it and 89 when I am feeling cheap.
Engine runs fine.
Here in Cali the highest octane thats readily availible is 91 and you can tune your engine to work on 89 or 91.
You want more get some kind of octance booster.

[negular]

Whats with all the double posts? &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'>

[misnomer]

It's sometimes easier just to explain how something works than why bits and pieces work differently. Know the main causes of detonation, which is as far as I know the only reason behind high octane gas. . .

Here's somethign the newer folks need to keep in mind: A higher octane gas generally detonates less readilly. It's not to an extent that it will have a negative effect on your car's power output.

The reason behind this is to prevent detonation, or the gas exploding in the combustion chamber before the piston is back on it's downward thrust. Detonation is caused by many factors, compression is a common one. As the air/fuel mixture is compressed by the piston, it heats up. If it heats up to the point of combustion, you will have problems with detonation. This is why high compression cars and turbocharged cars often require higher octane gas. The KA from what I've read into is fairly high compression, though I've never had a problem with detonation (could be due to my high altitude),

Another cause of detonation, and what's being discussed here, is intentional and in the design of the engine - timing. Gas takes time to explode, higher octane takes more time. Basically, advanced timing means the splark plug fires while the piston is still compressing the air/fuel mixture in the chamber. In this case, the gas is beginning to explode at the top of the chamber while the air/fuel that hasn't yet combusted is being further compressed. This yields a more powerful explosion in the chamber, hence more power from the car. Here, you get ping (detonation) if the gas burns too quickly while it's being compressed. If this happens, the ECU has a sensor that detects it (dunno how offhand), and retards the timing as Toso said. This is the about the only time you will see a difference in performance between gasses.

Granted, both of these causes of detonation will be more likely if you ride your car hard, or if you are at lower elevation where the air is denser.

[Toso]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (misnomer @ Dec. 10 2002,2:39)</td></tr><tr><td id="QUOTE">It's sometimes easier just to explain how something works than why bits and pieces work differently. Know the main causes of detonation, which is as far as I know the only reason behind high octane gas. . .

Here's somethign the newer folks need to keep in mind: A higher octane gas generally detonates less readilly. It's not to an extent that it will have a negative effect on your car's power output.

The reason behind this is to prevent detonation, or the gas exploding in the combustion chamber before the piston is back on it's downward thrust. Detonation is caused by many factors, compression is a common one. As the air/fuel mixture is compressed by the piston, it heats up. If it heats up to the point of combustion, you will have problems with detonation. This is why high compression cars and turbocharged cars often require higher octane gas. The KA from what I've read into is fairly high compression, though I've never had a problem with detonation (could be due to my high altitude),

Another cause of detonation, and what's being discussed here, is intentional and in the design of the engine - timing. Gas takes time to explode, higher octane takes more time. Basically, advanced timing means the splark plug fires while the piston is still compressing the air/fuel mixture in the chamber. In this case, the gas is beginning to explode at the top of the chamber while the air/fuel that hasn't yet combusted is being further compressed. This yields a more powerful explosion in the chamber, hence more power from the car. Here, you get ping (detonation) if the gas burns too quickly while it's being compressed. If this happens, the ECU has a sensor that detects it (dunno how offhand), and retards the timing as Toso said. This is the about the only time you will see a difference in performance between gasses.

Granted, both of these causes of detonation will be more likely if you ride your car hard, or if you are at lower elevation where the air is denser.</td></tr></table><span id='postcolor'>
Thank you so much! I wasnt sure if I was explaining it right. I think you're explination is a bit better than mine.

[240racer]

I was pretty sure that the KA24DE had a knock sensor, because I think it was retarding timing when I first put the DE in, since I didn't have the timing figured out yet. &nbsp;However, I was reading through Chiltons last night and it said that they were only on the the turbo models. &nbsp;Anyway, can anyone verify that there is one for sure, and can you tell me where it is. &nbsp;Thanks

[kandyflip445]

From what I have learned you CAN gain power from using a higher octane gasoline. When you talk about ignition timing the main goal for cars is to get the combustion to happen so that maximum pressure is present when the piston is at 10 to 23 degrees ATDC to produce the maximum amount of power. The fact that higher octane gas burns slower helps this cause the timing is advanced(yes you were right on this) and the combustion lasts LONGER through 10-23 degrees ATDC. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>
I'm kinda tired so if you don't understand this post and I'll try to clarify.

[kandyflip445]

Oh, and on detonation...the "knock" is caused by the colliding of two flame-fronts. Like you said compression makes the air/fuel mix easier to ignite. But the actual detonation(in a compression case) is when it is compressed enough to ignite itself and then the spark plug ignites another portion of the air/fuel mix then the two flame-fronts collide(sp?...still tired). This can also be caused by hot spots on the piston, cylinder walls, head, etc... the same thing happens...one part of the mix lights and then the spark plug lights then they collide. Also it's not limited to 2 flame-fronts. It can be any number of them.

[datkwikracer]

if u run lower octane gas the ecu retards timing right?

so if the previous owner of my car ran 87 constantly, then my timing should be retarted. since i got it i only use 91(best available)so will the ecu then advance timing, or does it remain the same.

[mrdirty]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Toso @ Dec. 10 2002,11:34)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kid_nissan @ Dec. 10 2002,09:13)</td></tr><tr><td id="QUOTE">wait so ur sayin if i put premium in my car i might get some power increase? cause i have been putting regular in, u suggest premium</td></tr></table><span id='postcolor'>
Higher octane (premium) gas will not give you any horsepower! If you do nothing to take advantage of the higher octane, it will do nothing for you! If you feel a power increase with higher octane it is because you were detonating and your ECU caught it and retarded your timing.</td></tr></table><span id='postcolor'>

-gasoline is a mixture of octane and hexane; the enthalpy of combustion for octane is higher than hexane something in the range of 5.5 Giga Joules : 4.3 Giga Joules per mole.

-the higher the octane rating the higher the octane content and thus more energy per unit mass of gasoline.

-if you preform an ideal otto cycle there is a difference in power for different octane levels although it is not earth shattering.

In the end you're wrong, you will gain power from a higher octane gas but that's not the main goal for increasing octane.