91 vs 93 octane!

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warrioralumni08

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Guys, I have been putting V-Power 93 in my car, and it has performed very well. Need to take a long road trip to get my average mpg. With 93 in about 30 miles, I averaged 21.7 mpg with speeds of 65 and 55. Today my brother put some gas in my car and he said he put in 91. I am not sure where he got it from, don't remember seeing it around here. Maybe he put in 89! I don't know what happened, but I must say damn. :eek: Car loves it, and I took the same trip today and averaged 24.3 mpg with the same speeds as stated above. The car seems to respond better, and seems faster! Is this possible?
 
During normal driving the octane rating of the fuel should not have a statistically significant effect on mileage.
 
93 octane like you said is premium or v power at shell gas stations i always thought that was best. at the moment i drive a 2004 mazda rx8 and wen i put premium(93) octane i can feel a significant vs regular
 
My car is chipped, and I feel a considerable difference between 89 and 91or93. Before the chip though, I didn't notice any difference.
 
warrioralumni08 said:
Guys, I have been putting V-Power 93 in my car, and it has performed very well. Need to take a long road trip to get my average mpg. With 93 in about 30 miles, I averaged 21.7 mpg with speeds of 65 and 55. Today my brother put some gas in my car and he said he put in 91. I am not sure where he got it from, don't remember seeing it around here. Maybe he put in 89! I don't know what happened, but I must say damn. :eek: Car loves it, and I took the same trip today and averaged 24.3 mpg with the same speeds as stated above. The car seems to respond better, and seems faster! Is this possible?
Click to expand...


Perhaps while he had the car he added one of these

http://www.ebay.com/itm/AIR-INTAKE-...s=Model:Mark+VIII&vxp=mtr&hash=item1c2048705d

and one of these

http://www.ebay.com/itm/2-pcs-Magne...Parts_Accessories&vxp=mtr&hash=item2c603d2046

Always a possibility
 
Atleast you guys have 93 octane.. Around here the highest is 91 and within the last month most all stations have dropped down to 90 octane :mad:.
 
When I first switched from 87 to 93 I got 1 - 3 better MPG. Thats the only difference I noticed.
 
I pour 91 on my black 93. I pour 93 on my prairie tan 97. Ofcourse that's because the company pays for my fuel :)

Don't know what to tell you though. It's not just the octane but the fuel company too. Of course now there's the 10% ethanol as well.
 
Octane is based on engine compression, thats all. My car calls for 96, but that is pretty hard to find. So I only go as low as 93 and dont even use 91 unless I have to. But for most 91/93 is one in the same.

Now putting 93 in a car calling for regular, does nothing at all. But putting 87 in a car calling for 91 or 93, is a bad thing. Detonation or knocking occurs.

With that said, there is that nasty ethanol blend. Some 91/93 fuel do not contain 10%, but some do. If it is a blend then there should be a very, very slight milage drop. Since ethanol is harder to burn, you need more of it. This is why putting E85 in a Mark will drop its milage a lot. Then the flip-side is that ethanol produces more power. In a 10% this why little milage loss is noticed. But E85 can hamper performance if the car does not have big enough injectors or a program to handle the blend. And a lot of fuel is needed since it hard to burn. In the end there is little savings from cost of fuel to economy. Maybe a buck or two unless you are highway only. I got 22-24 on E85, 28-30 on VPower.

Any, FYI, all the gas you use comes form many, may sources. Shell buys from BP, BP buys from Amaco, etc. And refineries share pipes, etc. One could say its like being rich, on paper. My town is a depot. Only ONE ship comes in to fuel all the brand name depots around here. What make it different is the additive packets blended in at the time the tanker trucks come in. Otherwise your Shell gas is the same an Exxon station.

Now as for the milage change the OP is stating, any number of conditions can change the reading. Outside temps, wind, etc. When I had my Mark there were times I would get 32mpg highway. Other times 24mpg. I would think that any Mark out there should get on average 26mpg highway with reasonable driving and driving conditions.
 
Ah, thanks for the input people! It turns out, he did put 91 in it. Went to the place he told me he got it from. It was Conoco Phillips gas and it had the 10% ethanol blend. So pretty much, I should put 93 in, since that's what alot of people on here run, and it seems to perform the best with?
 
UltimateSVT said:
I pour 91 on my black 93. I pour 93 on my prairie tan 97. Ofcourse that's because the company pays for my fuel :)

Don't know what to tell you though. It's not just the octane but the fuel company too. Of course now there's the 10% ethanol as well.
Click to expand...

i havent seen 91 anywhere in fl always 93. usually its an altitude thing, when i drove to colorado, coming out of GA., it went to 91 octane never saw 93 again till i came back. that was in my 5.0 only noticed a lack of performance at higer altitude due to air density, had a guy adjust my carb it ran great, but when i came back to flatland, it was a little lean, but it felt faster.
 
i believe 91 is what the owners manual recommends for our cars.

increasing octane when the engine doesnt require it is a waste, octane deters combustion, effectively higher octane than required will produce less power (in theory), but know one can really feel the difference, now conversely if the engine is tuned for 93 and you use 91,you "should" notice the drop in performance.

in summary: Octane makes gas less explosive :D
 
Moes8 said:
i believe 91 is what the owners manual recommends for our cars.

increasing octane when the engine doesnt require it is a waste, octane deters combustion, effectively higher octane than required will produce less power (in theory), but know one can really feel the difference, now conversely if the engine is tuned for 93 and you use 91,you "should" notice the drop in performance.

in summary: Octane makes gas less explosive :D
Click to expand...

my point is some states dont have 91 its 93 at sea level,the recommendation should read highest octane available, without race fuel.:)
 
Moes8 said:
in summary: Octane makes gas less explosive :D
Click to expand...

I would not say that, I would say that the higher the octane the more pressure it can withstand without self-ignighting. So i would say its more stable, but its not less explosive.

By the way, E85 has a rating of about 103-ish! Some super cars are designed to run on 96 octane, for example, but when E85 is put in they gain an extra 200 HP!
 
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