Fuel - Octane Really Matter?

[i30daretodif]

I did a quick search but couldnt find good info for this - so I appologize if this has been covered before.

I have a '96 i30 with 130k on it - runs like a champ. Fuel is getting mighty pricey and makes me wonder if I should keep putting Super in the car (as I've always done). Some of my friends seem to think regular is just fine. Is there any common knowledge about octance levels and what should/shouldnt be put in the car?

Any info would be appreciated - sorry if this is an old topic.

[maxnix]

Did a search on "octane" in the Infiniti General forum and got 13 pages of replies. Why don't you start with the one titled "Informative Gasoline Article" at Q45tech's first post:

"Cheapskates burning regular in cars designed to run on premium fuel can expect to trim performance by about the same percent they save at the pump.".......20 cent saving up to 10-12% power decrease!"

You have read all of Q45tech's posts and followed his supplied links, right?

[I30T]

I did a quick search but couldnt find good info for this - so I appologize if this has been covered before.

I have a '96 i30 with 130k on it - runs like a champ. Fuel is getting mighty pricey and makes me wonder if I should keep putting Super in the car (as I've always done). Some of my friends seem to think regular is just fine. Is there any common knowledge about octance levels and what should/shouldnt be put in the car?

Any info would be appreciated - sorry if this is an old topic.

I ran reg. for a year in my car, and i've run premium for about 2 months now. There is a difference in response, but it's not very big, and my car is running smoothly after running on 87 for a year.

In my opinion, if you need the money, dont buy super/premium.

[HeavyDuty]

Power or Price?

Pick one.

Power? Pay the price.Price? Sacrifice power.

Or, may I suggest a hobby like soapbox derby's or kite's?

[spoolthis]

Run the lowest octane recommended by the factory. Assuming an unmodified setup.

Running premium in a engine designed for regular is a waste, plain end simple. Too many years of petrolium propoganda has had a prolific negative effect.

People really start questiong it when prices go up though. Info is critical here. There's ton's of it out there. You've just got to do your due diligence and make up your own mind.

[Mr1der]

in my case it's price or pinging.

but uh, yeah...

octane helps to prevent a preignition in higher compression of the fuel.

pre ignition is a bad thing, combustion with open valves isn't a good thing.

[AlabamaDan]

Does anyone here add some type of octane boost to their tank?

[spoolthis]

Unless you're talking about toluene, that crap at the auto parts store doesn't do much.

[redmanfx]

BG44K from Joe. $17.00.

red

[DAEDALUS]

BG44K is not intended to be used as an octane booster, but if it cleans your injectors, spray pattern will improve, along with combustion efficiency. Even if it was 150 octane, it would not be a cost-effective octane booster when you add it to 20 gallons of gas. Toluene is the better approach, and gets relatively cheaper the more gas taxes rise, since it is not taxed as a fuel. Not a price-consious additive choice right now, but maybe someday.

But Spoolthis is right: "Running premium in a engine designed for regular is a waste, plain end simple". That is NOT to say that you can or should run regular in a car designed for premium, which is what many people misconstrue the statement to mean.

[jtesensky]

Higher compression engine require a higher grade of octane. I beleive the G50 is a 9.8:1 compression (I may need some correction). I have seen a lot of high compression engines that knock & ping when 87 octane is used, & they generally run like crap. If your not going to use 91 octane all the time use it in a cycle, something like every other or every third tank. This of course after my wife just yelled at me for paying $37.86 to fill the tank in the QX4 with 91!

[Q45tech]

Q engine is a very high 10.2:1 CR when brand new and gets higher with deposits.

OBD2 [96 and later] with its faster ecu is better able to control sudden tip in fuel, so you might be able to get away with suboptimal fuel.

Haven't tried mid grade since 1997 [100,000 miles] it was a horrible experience.

JWT ecu warns not to even try it as the extra advance/leaner mixtures creates severe pinging on acceleration besides at the tip in.

Always cheaper to buy premium than to try to add octane with supplements. Unless you have a source for cheap MTBE.