If anything run a fuel system cleaner. I use a Lucas octane booster, but I set my chip to run 95 octane. If no chip, 89 with a cleaner (not booster) every month or so. And I only use Shell, Chevron and if none of those are around, 76. I wouldnt drink the stuff under the sink, and neither would my truck.

 

89 with 10% eth here. It's $2.40 a gallon here, I haven't even seen a 87 pump lately.. I'm guessing it's from being next to Texas.

 

Strictly from a MPG point of view, I recently did a study of the effects. 89 octane did yield a higher MPG average over 15 tanks than 87 did. Though, the increase was not enough to justify the increase in price. If you want I can show you the numbers...

My $0.02

 

Hey guys just recently filled up with 91 after running a tank of 87 octane and the engine seemed to be a little louder, I'm wondering if its all in my head or if anyone else has had this happen too?

 

I'm currently on my first tank of 89 after years of only 87. I'm curious of the MPG gains compared to cost of fuel. However... it's not just the slight difference in price that matters to me. If 89 gives more efficient (better running) power, then even if it costs a little more, wouldn't it be better for the engine in the long run? Just a thought.

I have noticed (or at least felt like I noticed) that my engine runs quieter and "better" with the 89... but that could all be in my head too.

 

I used to run 89, mow I'm 100% running 92 octane on stock tune. as for cost, I have a 35 gallon tank and can get up to three weeks on a tank city driving, 250 to 300 miles of conbined city + highway.

highway I can pull as high as 750 to 800 miles on a tank. 60 mph, 6th gear.

In reality you pay the same running 87 octane and having engine issues later in life or paying top $ to run the better flue and have no issues down the road.

I'm convinced ( in my own mind ) running cheaper grade gas will lead to burning more flue than higher octane under identical driving conditions.

 

I run my HEMI on 95, which is the lowest grade available in Europe. Higher octane means less chance of uncontrolled combustion.

 

I switched from 87 (with 10% eth) to 89 (with 5% eth) couple of weeks ago and MPG improved but the price of 89 higher of 87 so I'm loosing money each fill up
BTW, in my part of Canada only 91 does not contain ethanol (usually )

 

Yes it does matter. Certain motors require a minimum octane to perform, and last, as designed. My 1968 Ford Mustang specifies 100 octane. Unfortunately, unless I want to pay $9.00 a gallon for VP 100 octane gas, the highest I can get is 91 octane. I have to use a bottle of octane booster at each fill-up to take care of the pinging. My 1998 Jeep Grand Cherokee specifies 91 octane. Even on 91 octane the motor will have a light ping, under hard acceleration, during the warm summer months.

 

Ok, so what about us folks that only have 87 or 91 and not 89 ANYWHERE in town? I just use 87...