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Discussion Starter · #1 ·
I have noticed that my gas milage has really decreased over the last month. My question is if you put the highest grade gas in your car would you get the same milage as putting the lowest grade gas in the car (filling the car completely, both times)? YES, I know these may be the stupidest question ever asked in these forums but I'm really interested to know if there is any difference.

Looks like I'm going to have to hunt down those champion gold spark plugs sooner then I wanted (money wise).
 

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Hey man good question im curious about it too, it seems to me since if put in my intake my gas milage went down, but ive also noticed that my gas mileage is really good above a half a tank and after a half tank it drops like a bomb on Afgahnistan!!
 

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i was always told that if your car is DESIGNED for higher octane then yes it wil perform better, MPG< etc, but if not, then it won't do anything to the car. liek the 3.3 are made for 87 and the 3.5's are made for 89, i have used 87 and it does go down a lil along with performance, but not a hole lot.
 

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daily driving the 3.5 won't get that much worse performance out of 87 vs 89 octane, however peak hp will drop. unless you are at the track i doubt you see a lot of difference. i run 89 all the time because it is the same price as 87 here, plus it has 10% ethanol.
 

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i get 87 when money is tight, but usualyl get 89
 

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woah... you like the fact that you are filling up with 10% ethanol? the big reason they put ethanol in the gas is to make the gas burn more lean. Essentially, the mixture is burning leaner. (more oxygen in the cylender).... the Oxygen sensors see this, and generally the computer dumps more gas in to compensate.
I definately noticed WORSE gas mileage with the 10% ethanol in in the milwaukeee area compared to filling up out in watertown were the gas was straight up gas........
 

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i like how i don't have to worry about it freezing in the cold. my mileage is so bad in winter that i don't even notice a difference.
 

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1st, I'm pretty sure ethanol will reduce gas mileage

2nd, I always use 91, simply because it's cleaner, the higher the octane, the cleaner it is.

3rd, I believe our computer advance timing when it realizes higher octane is used, how much exactly I don't know. That's why somewhere in the manual it says the car will run on 87, but recommends 89. It also says in the manual a higher octane will increase performance.
 

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Discussion Starter · #9 ·
Finally after a few days of searching at local shops I was able to find the Champion Gold spark plugs but when the shop got them in (had to order) I had them check the 2412 Champion Gold plug with an OEM spark plug replacement for the 94 3.3 and they were different. The Champion was longer in size and I guess this could have put a hole in my piston, good thing I checked. Anyway, he called Champion and they said that there was two different 3.3 litre engines for that year, something that I did not know!

All in all I got the LAST 6 plugs available in North America for Champion Gold (according to the company). They have discontinued these plugs:cry: :cry: I hope there worth it, should have them on Monday.

By the way, I filled my tank with 87 grade and got my a$$ smoked in a race (would have killed me anyway 3.5l). The preformance really makes a difference with the highest grade to the lowest grade. Just waiting to see if the milage will be any better.

Nic
 

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platinum plugs are NOT very good in the 3.5, OR most chrysler engines in general. as a rule chryslers eat platinum plugs very fast. champion golds are the best plugs you can buy for the 3.5.
 

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I have noticed a sufficient difference in mileage and performance to justify the difference in price. Reg. Unleaded around here is only 86 octane, and when I run it, my car sounds and feels like it is restricted. but when I run 90 or higher, it runs beautifully. Plus, I noticed this weekend, on the highway (600 mile round trip) that I got about 22mpg with 86 octane and got 31 with 92 octane. Granted, I will concede that there was a bit of a head wind during the leg of the trip that I filled up with the 86 octane, and no wind at all with the 92, but that shouldnt make THAT big of a difference on these cars, should it? surely not a difference of 9mpg?
 
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