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I am looking at an 08 FX35 and the owner said it doesnt need premium gas, and i know that it does. what are the effects on the engine from not putting premium gas in the engine?

thanks,
David
 

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Although the FX35 doesn't NEED premium, there COULD be problems depending on each individual car... good case scenario, there's nothing wrong... bad case scenario, the engine could have experienced knock and will severely shorten its life...
 

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"The knock sensors that detects detonation may automatically retard the spark to compensate for 87 vs. say 93. The delay means maximum gas expansion occurs when the piston is farther along in its downstroke and thus there's more room in the cylinder head. This reduces peak cylinder pressure, eliminating knock but also giving you less power and poorer mileage."

In short, I would use premium. I don't know the exact numbers, but they would be close to breaking even in terms of gas mileage per dollar by using 87 vs 93. And you'll end up with better hp/torque while you use 93.

Maybe someone can run the numbers as some like actual proof, but the difference to me appears non-material so sticking with premium sounds like the way to go.
 

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might it also void the warrranty?
 

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codeggs said:
might it also void the warrranty?
This cannot be true. The manual explicitly states that premium fuel (what grade exactly does that mean?) is recommended for the FX35. If it would void the warranty to use anything less than premium fuel, then Infiniti would pretty much need to explicitly say that nothing less than premium fuel should be used. The FX45 on the other hand, does say that you must use premium fuel, so any moron using 87 grade fuel could be damaging the engine and void the warranty.
 

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GgHrOeSyT said:
I am looking at an 08 FX35 and the owner said it doesnt need premium gas, and i know that it does. what are the effects on the engine from not putting premium gas in the engine?

thanks,
David
As Chedman explained, the ECU in the FX constantly checks for engine knock/predetonation. If you run a lower grade of fuel, such as 87 octane, the engine will start to have some amount of predet. The ECU will then retard the timing to prevent any damage, which means your engine won't be running at full power. Now, whether the engine can run on 87 octane regularly without causing any permanent damage is a debatable topic. Some say no, some say yes. I believe that this is a premium vehicle that should get premium fuel. Really, is it worth the loss of performance to save a $2.50 at the pump?

Here are some existing threads you can read through, and add to if you want:

viewtopic.php?f=1&t=18671&hilit=+octane+gas
viewtopic.php?f=1&t=21707&hilit=fuel+maps
viewtopic.php?f=1&t=18412&hilit=+octane+gas
viewtopic.php?t=12718&highlight=premium++unleaded
viewtopic.php?f=7&t=14694&hilit=+octane+gas
 

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I just use regular 87 oct in winter; I get roughly the same mileage. Not worth the extra $5.

But in summer, i try to use premium.
 

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Not sure why anybody would put 87 in their FX. Just to prove you can?

The people who designed the car... people much smarter than me - say i should use premium. It would be silly of me to think i know better than them.

Even a half and half blend of regular and premium would be better. At 87 and 93 respectively, that would average out to 90 octane.
 

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kieranlavin said:
Wow, for a difference of $5, I'd just do it. That's just one less caffe latte mochawhateverthefuck a day from Starsucks
Yes, Kieran, that would make sense to most people.....unless you are the type of FX owner who professes to have exorbitant amounts of money, and yet your platinum savings plan is to siphon mere dimes from your weekly fuel bill by using 87.
 

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kieranlavin said:
That's better than my platinum savings plan... picking up quarters on the sidewalk and picking them out of the seat cushions in my couch!
Sink all your money into Lotto tickets - that's my retirement plan!
 

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I tracked my mileage for multiple tankfulls and did not see any increase in milegae from running premium. The car definitely had more pep, but since it is my daily commuter, I went back to 87 octane. At 136,000 miles, that's roughly $1,400 dollars I've had to spend on other things. I bought the car primarily for its looks and for how I drive it and neither of those require premium fuel.
 

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There is always going to be a difference of opinion on this issue -- what type of motor oil to use, what grade of fuel to use, how often to change the spark plugs, etc. For the type of person who is less particular about things and views a vehicle as simply a mode of transportation, they will be fine with dino oil and regular fuel....."gas is gas", as they say. But for the type of person who is discerning and considers their vehicle as more than just a way to get from point A to point B...... perhaps one could say they hold their vehicle in high regard...... they are the ones to use premium fuel and synthetic oil without a second thought. They are true enthusiasts, the true afficianados.
 

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GixxerSteve said:
There is always going to be a difference of opinion on this issue -- what type of motor oil to use, what grade of fuel to use, how often to change the spark plugs, etc. For the type of person who is less particular about things and views a vehicle as simply a mode of transportation, they will be fine with dino oil and regular fuel....."gas is gas", as they say. But for the type of person who is discerning and considers their vehicle as more than just a way to get from point A to point B...... perhaps one could say they hold their vehicle in high regard...... they are the ones to use premium fuel and synthetic oil without a second thought. They are true enthusiasts, the true afficianados.
I completely agree with you :thumbright: Less particular people are probably also okay with small dings throughout the surface of the vehicle... or letting a sticky coffee spill dry in the bottom of the cup holder... or parking in the smallest parking spaces in order to make the walk to the grocery store shorter... I will never be one of these people.
 

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GixxerSteve said:
...... they are the ones to use premium fuel and synthetic oil without a second thought. They are true enthusiasts, the true afficianados.
When I lived in Jersey City and it was not self serve, I had a guy put regular in my car. This is the track car with an aftermarket ECU (well aftermarket everything) that CANNOT take regular gas. Within 5 miles I noticed detonation, pulled over to check the receipt, and went right back and bitched the guy out. I then went home and ciphoned the crap gas out and went back to a different gas station and put premium in. Maybe a bit overboard but the engine still runs strong after 250k ish miles (busted odometer) and approximately 30k HARD track miles
 

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FX4BR said:
GixxerSteve said:
There is always going to be a difference of opinion on this issue -- what type of motor oil to use, what grade of fuel to use, how often to change the spark plugs, etc. For the type of person who is less particular about things and views a vehicle as simply a mode of transportation, they will be fine with dino oil and regular fuel....."gas is gas", as they say. But for the type of person who is discerning and considers their vehicle as more than just a way to get from point A to point B...... perhaps one could say they hold their vehicle in high regard...... they are the ones to use premium fuel and synthetic oil without a second thought. They are true enthusiasts, the true afficianados.
I completely agree with you :thumbright: Less particular people are probably also okay with small dings throughout the surface of the vehicle... or letting a sticky coffee spill dry in the bottom of the cup holder... or parking in the smallest parking spaces in order to make the walk to the grocery store shorter... I will never be one of these people.
I think i'll fill up with some CAM 2 gas!

That's a smart way to look at it. I can't assume every FX owner cares about their car the way we/I do.
 

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codeggs said:
kieranlavin said:
That's better than my platinum savings plan... picking up quarters on the sidewalk and picking them out of the seat cushions in my couch!
Sink all your money into Lotto tickets - that's my retirement plan!
Like my Grandma always says, lotteries are taxes on people who can't do math.
 

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GixxerSteve said:
> snip< ...... perhaps one could say they hold their vehicle in high regard...... they are the ones to use premium fuel and synthetic oil without a second thought. They are true enthusiasts, the true afficianados.
Wow. I've never been called an "afficianado" before, even indirectly. Thanks, Steve!
 
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