That is so true I bet a bunch of member smoke and drink and do all sorts of stuff they wopuldnt do to there car kinda funny

 

agreed... that's why i said it wasn't a big point, but since this is an already confusing issue that a lot of people are misinformed on, i mentioned it.

people, use premium gas in your high compression ratio motors. thank you

 

Actually, Ethonal has very hight octane levels.

 

It's not whether I can afford the gas or not. I can. Also I did not say I eat fat all the time, I was just trying to make a point. A lot of things are recommended. Do you follow every suggestion or recommendation?

No one made a coherent response about the rental car example I gave. People who rent these cars put regular gas in it and they work fine afterwards and most Infiniti dealers buy these fleet cars back and sell them to people on this forum I bet. They can't sell a car where people use regular gas and they know it causes long term damage and then sell it to consumers with warranties and extended warranties. It's all about liabilities and the fact that if there was some damage someone would sue, saying you said recommend or sue the rental car company because their renters put 87 in it. We live in a country where people sue because the coffee is too hot at McD's or someone lost their pants at the dry cleaners.

They can not design these cars and say the word recommend about premium gas and then if you use regular there is damage to the car. If the car is damaged using regular they would say require... actually there lawyers would say it because of liability reasons.

The reason they say recommend is because of the fact that the car runs fine on regular and there is no damage to running the car that way, but the performance is less. So they cannot say 305HP if they don't say use premium gas.

So you can quote whatever you want or say whatever... but that is the bottom line. At the end of the day Infiniti/Nissan is a money making company first and foremost and if changing that one word in the manual from require to recommend would save them one dollar in lawsuits they would do it, and they haven't. Think from a bigger picture.

 

and with that i'm outta this thread...

 

you'll be fine...when there are hurricanes down here in S.FLA and the gas stations run out sometimes only thing you can get is 85-89 octane. But does'nt ruin your motor if you do a couple of fill ups.

When i was living in Dubai all i use to put in my G was 98 octane and i always noticed better performance. Gas out there was a lot cheaper i was paying like 1.89 a gallon for 98 octane

 

damn...

 

This is from Nissan....

The ignition timing is controlled by the ECM to maintain the best air- fuel ratio for every running condition of the engine. The ignition timing data is stored in the ECM. This data forms the map shown.

The ECM receives information such as the injection pulse width and camshaft position sensor signal. Computing this information ignition signals are transmitted to the power transistor.

e.g. N: 1,800 rpm Tp: 1.50 msec
A "BTDC"

During the following conditions the ignition timing is revised by the ECM according to the other data stored in the ECM.


At starting
During warm-up
At idle
At low battery voltage
During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed within the anti-knocking zone if recommended fuel is used under dry conditions. The retard system does not operate under normal driving conditions. If engine knocking occurs the knock sensor monitors the condition. The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.


This is from a technical resource we use at the shop:


>I know that detonation is when fuel begins to burn before
>the spark jumps the electrodes on the plug,

You've described PREIGNITION not
detonation. (I know I'm gonna get called out on this, but
I'll proceed anyway)

Preignition occurs when the mix combusts before the plug
fires, either due to a hot spot, or enough latent heat from
compression to ignite the mix in the cylinder (which is why
higher octane fuel would be used ONLY in cases such as
this- it's LESS flammable)

>I can imagine how
>cooler air, a richer mixture and a higher octane fuel can
>prevent detonation, but i don't see why retarding the
>timming can. Please, can anyone explain me?

Detonation is when the charges does ignite when intended,
but the pressure wave occurs before the point where the
work can be extracted from it. In other words, the flame
happened too fast, or simply too early.

Retarding the timing helps here, since it clearly allows
the point of ignition to occur later in the stroke, and
thus, the point of combustion.

We often think of the point of ignition and the point of
combustion as being one and the same. Once we can see the
delayed action between the two distinct events, we can
maximize the effect of the two.


With that said I run 89 on the street and if I ever get to the track I will run 93. I have heard no pinging on 89 and my mileage is exactly the same as 93. Flame away now....

 

That's right. I run on ethanol diluted with barley, hops and water; she runs on 93 Octane (just not at the same time).

The G likes the good stuff to get me to work on time and treat the 10.6 CR entine to what it was intended for, but the manual allows 87 octane; the only limitation mentioned is the tradeoff in performance. There is no warning against its use even at every fillup will not void the warranty. With a manufacturer giving a 60k warranty for the engine, and considering the cost of engine rebuilding/replacement to Nissan, it would be a huge liability and not make good business sense to expressly allow use of 87 octane if there is even a very low risk of causing engine damage.

IMHO I would not worry about it.

 

We can get 95 octane here in Canada (Sunoco) and I also do notice better performance

 

I'm not trying to derail this thread too much here, but let me ask you this:

Why would it be in Infiniti/Nissan's best interest to tell people to use 91 octane gas? They have nothing to gain financially, the oil companies aren't subsidizing them... so are they just lying to us?

 

They tell us to use 91 because that is what gets us the 305HP they advertise. I agree 87 won't get you the performance they advertise. My point is that there is no damage caused to the car if you use a lower grade gas.

 

To get the 306HP, ignition timing is adjusted/set at the factory for the recommended fuel. Will 89 octane cause knocking? It can, but not always. If you drive conservatively I don't think 2 less octane will cause knocking. If you start pushing it hard, it can and probably will knock. Aside from engine load, altitude and temperature plays a role too. Lower temperatures and higher altitudes will decrease the tendency to knock.

My opinion, if it's designed for 91 why put in something else? Sure 89 will run fine in most cases, but why risk any knocking? 10 cents compared to the current fuel price that is well over $3.00 is nothing. Assuming the average 12k miles per year and 22mpg this equates to just under $55 per year.

BTW, an FYI for those outside of the US and Canada. Here octane is measured using the (RON+MON)/2 method. Most other countries use RON which is usually higher than the MON counterpart. E.g. 95 RON is about 91 using R+M/2.

 

what is knocking? so overall its recomended putting premium gas, what if you want to put in regular for everyday regular driving no harsh driving? what could go wrong?

 

do you change your oil at the 3k intervals? or you follow your own intervals?

I wonder why people would follows some recommendations and not others.