Alright, I see a lot of people on here talking about premium versus cheap fuel for the Maxima. No doubt, the manual recommends premium. But why? It seems the issue always relates to the knock sensor. If that's it, here's some math to disprove conventional wisdom. First, I will be making four assumptions. I know what assumptions do, but I have to work with something here. These seem to be realistic averages.

Assumptions:
1. Maximas get 25 mpg
2. Premium fuel costs $0.10/gallon more than cheap fuel
3. Knock sensors will fail after 100,000 miles of cheap fuel
4. Knock sensors cost $100 to replace

Using the above figures, 100,000 miles will burn 4,000 gallons of fuel. The difference in price between 4,000 gallons of cheap fuel versus 4,000 gallons of premium fuel will work out to $400.

That means that burning premium fuel for 100,000 miles will cost $300 more than burning cheap fuel and replacing the knock sensor when it fails. Besides, the premium fuel car will be riding on an old sensor and the cheap fuel car will have a brand new sensor. If the difference in price were, say $0.20 instead of $0.10, the difference would be $700!

If only there actually was such thing as cheap fuel.

 

...and I still don't care because I'd rather treat my car well and get the most out of it.

 

Would be nice but i like getting the good fuel makes me feel better plus I have to or else bang my car will blow up.

 

Only the people who DO NOT know how their car works are the ones who believe cheap fuel causes knock sensor failure.

 

MPG wont be the same with 87 and 93

 

yea I've actually done some research on this and the MTBE levels and additive levels are the same in all gases which is what clogs your o2 sensors, among other things but none have to do with the knock sensor.. refining the fuel to the premium 93 octane level helps slighty if at all the only thing it does more for your car is provides a slightly smoother overall run and a slighty more proficient burn and that is it.

 

so what... id rather have maximum power and pay more than save money and have a slow car.. by the way the ks doesnt go out cuz of crappy fuel...it goes out cuz it's poorly constructed.....

 

Precisely...the amount I save by getting better mileage sort of balances out the extra cost. So if it evens out, why bother with 87?

 

maybe you should do more research and find out that ks done get clogged.... the main reason they fail is because the plastic case cracks....

 

My ECU has a cheap decal on it too.

 

knock sensor failure has nothing to do with actual knocking of the engine. It's just a cheap sensor that commonly goes bad. When knocking does occur, the ECU retards the timing, which means worse gas mileage, and less power.

I'll stick to my 93, thank you.

 

so you are saying that you'd rather drive around on cheap gas all the time, even though your performance is going to suffer greatly? Cheap gas causes predetonation,(aka "knock"), from a lower octane rating. The knock in turn trips the knock sensor and sends a signal to the ECU, which then retards timing to reduce the knock. So basically, you put cheap gas in your car, it hurts the engine, so it compensates to protect itself and therefore drives like ****.

P.S. Tavarish, I just wanted to extend on your comment. I know all you other guys know this, just trying to explain a little for the kids who don't.

 

NmexMax seriously haha

 

Thread failure...

 

The things you say about the timing, etc. is true but the argument was does lower octane fuel destroy the knock sensor.. answer is no it doesnt, ppl run 93 in the cars for the things I've previously mentioned which has to do with the timing and ECU I just didnt run into the technicalities of the whole ordeal.

 

I'd like to know where this "clogged" rumor got started. It's a sensor held on top of the engine block with a bolt. What would "clog" it?

 

It honestly states 92 or higher.

 

... you can run cheap gas... why don't you redo your calulcations taking into account the reduced gas milage when running the cheaper gas... You should find that the cost per mile is the same on either one, and you get more power with the premium, it's a win win, running premium You don't have to fill up as often, you get more power, and because you get more milage, the cost winds up being the about same.

 

YUP

 

I wish I had some chapstick

 

Buy a Civic.

 

uhhhhhhhhh. alright then.

 

ROFL. I wouldn't mind trading my 29mpg car for a 4th gen maxima.

 

why, you have a busy night ahead of you?

 

ok, so you may have saved $300 dollars...

but lets say that 87 costs $2.50/gal or so. so if i go through 4000 (or even more since i'm not always driving in order to get the most efficient mileage), that would already cost me $10,000. i'm not gonna notice the extra $300 or so when gas already costs that much. plus the more gas prices increase, the less difference that savings is going to make.

i'd rather put that money into peace of mind in my car rather than be a penny-pincher.

so let's see. you have been disproved on the mechanics of a car, and now on the financial end. anything else? just drive on the gas that you want and we'll drive on what we want. have fun with your new-found fortune!

 

My 4th gen gets 29 mpg

 

I only have access to 91 octane....

 

ur talking about 100,000 mile increments, u know how long that'll take....8years from now i wont know i lost $300, nor will i care too much...

 

yeah on the freeway....

I get 29mpg mixed.

 

Lucky. I get ~20 all city

 

Stop trolling it gets old:

 

I would much rather just put 93 in my tank. It isn't easy on the wallet, but it is better for the car, and that is the ultimate way to do it.

 

Lock or delete this thread. Hell isnt this issue in one of the Stickies? If not, I will have to add it one day.

 

Bad assumption. Lower octane gas will result in decreased fuel economy.

 

true dat. this is retarded. USE WHAT THE MANUFACTURER SAYS TO USE

 

Stop playing with greddys toys and then you'll have time..

 

I don't know what you are talking about

 

Neither does anyone else in this thread....

 

Stop post whoring...

 

To the author of this thread....

Your reason for using cheap gas is lame. Here's why the VQ30DE requires high octane fuel (w/o getting into lengthy details):

If you are familiar with an engine's compression ratio, you'll know that a typical engine might have a compression ratio of 8-to-1. The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting. The compression ratio of the VQ30DE determines the octane rating of the gas that must be used in the car. So you might ask, what is the compression ratio of the VQ30DE? A quick google search reveals that this engine has a compression ratio of 10:1! This means that a higher octane fuel is required in order for this engine to perform optimally. High-performance engine has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

For more details, go here: http://auto.howstuffworks.com/question90.htm .

If you are willing to sacrifice engine performance just to save yourself $300 during 100,000 miles of engine operation (according to your calculations), then you might as well sell your Maxima to someone that will treat it right and get yourself a Honda or a Hyundai.

Time to this thread!