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Discussion Starter · #1 ·
I have read a lot of threads that touch on octane ratings. It looks like a lot of owners are running 91 and the 300C calls for 89. I didn't pay any attention when I first got the car. I have run a couple of tanks of 87 and it runs fine. What am I missing (or doing to the car) by not running 89? I always thought if it doesn't knock or ping, you are fine!!!
 

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i've run 89 with no problem, but right now running 91(4month) only because I'm using the superchip flashpak 91 octane program.
 

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91 does nothing unless you have the Superchips Flashpack and tune it for 91.. it changes something in the PCM that alters the knock sensors.... So with the 91 tune you will see 1 - 1.5 MPG better.

the Manufacturer Recommends 89,

87 isn't an issue but over time you will get more deposits on the valves and your MPG will suffer.

to quote NotYet "ask me how I know"

at 87 I was getting 9 - 11 MPG with city driving (I work 6 miles from home)

at 89 I was getting 9 - 11 MPG with city driving

at 91 with S/C tune I was getting 12 -14 MPG with city driving.

at 50k miles (now at 53K) I had a fuel injection flush and clean done.

now with the S/C Tune at 91 but using 89 I get 14 - 16 MPG with city driving..

with 91 I get the same, but closer to the 16 mark.

is the $.25 cents a gallon difference worth it?

not to me..

any way I cut it 17 gallons never yields me more that 240 miles out of a tank unless I take a long highway trip.
 

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I don't understand why people wanna F**k around and not put the recommended gas into their cars. The difference between 87 and 89 is 10 cents people. Let's assume you drive a lot and go through 40 gallons a week.

40*.1*52/12 = 17 friggin dollars a month.

If you can't afford 17 dollars a month extra for gas, ride a bike to work. I can't believe people are willing to f**k around with a $40K vehicle to save $17 a month. Maybe Ms. Teen South Carolina can explain it to me.

/endrant

any way I cut it 17 gallons never yields me more that 240 miles out of a tank unless I take a long highway trip.
Good thing you don't have an SRT8....
 

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I'd say the only disadvantage to running 87 (other than what Marc already mentioned) is you might get some knocking or pinging, if you hear that I'd go back to 89.
 

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Well...I'll just state the same things over again. You will get worse gas mileage...you will get less power....and you will get engine buildup...and eventually at some point you will hear pinging or knocking. Though you might not now because the computer is forcing itself to run without knocking and therefore eliminating power. It will probably take a few tanks of 89 to get things back up in octane rating as you will be mixing gases for a little while.
 

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I don't understand why people wanna F**k around and not put the recommended gas into their cars. The difference between 87 and 89 is 10 cents people. Let's assume you drive a lot and go through 40 gallons a week.

40*.1*52/12 = 17 friggin dollars a month.

If you can't afford 17 dollars a month extra for gas, ride a bike to work. I can't believe people are willing to f**k around with a $40K vehicle to save $17 a month. Maybe Ms. Teen South Carolina can explain it to me.

/endrant



Good thing you don't have an SRT8....

part of the reason I opted not to buy an SRT8.. I only drive 12 -14 miles a day. I would be getting like 5 MPG plus be buying tires every other month. :D


as for the Manufacturer recommended octane.. well.....

all the Octane rating is, is a rating that determines how efficiently the fuel burns in the car and how much knock/ping you get as a result.

Manufacturer recommended is well, the Manufacturers being "in bed" with the oil companies and stiffing the general public into spending more $$.

there actually isn't a car made since 1996 when the 89 octane "standard" was introduced, that "recommends" anything below 89.

you will not find any car made in the past 10 years that recommends 87. so why even have it? Well for the same reason they have E85. Federal regulations, and consumer demand.

is there a big difference between 87 and 89? no not really.. most people won't notice. as most cars are do not have high compression motors. The SRT8 does, you can still use 89 or 91 in them, but performance with be effected because the cars computer is designed for 91 or higher.

the biggest issue with the different octane ratings is valve deposits and fuel injection clogging. Which proper maintenance can reduce as well as proper fuel.

it is also the biggest difference between cheap gas and good quality gas.

for me, I would NEVER use none name brand or ARCO/BP brand fuels. They are cheaper for a reason, I worked for Chevron and Texaco years ago, the "bleed off" fuel companies (Thrifty, Valeo, Fast Fuel) use the fuel that doesn't meet the quality standards of the higher companies.

there are at least 2 members on this board that do work in the oil industry and they know the difference in the types of fuel available. and they both know motors pretty well. so hopefully they will chime in.
 

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I don't understand why people wanna F**k around and not put the recommended gas into their cars. The difference between 87 and 89 is 10 cents people. Let's assume you drive a lot and go through 40 gallons a week.

40*.1*52/12 = 17 friggin dollars a month.

If you can't afford 17 dollars a month extra for gas, ride a bike to work. I can't believe people are willing to f**k around with a $40K vehicle to save $17 a month. Maybe Ms. Teen South Carolina can explain it to me.

/endrant



Good thing you don't have an SRT8....
when, how, where did this become about money and trying to save a few bucks? Yea, that's exactly why I do it...:i_rolleyes:
 

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Discussion Starter · #13 ·
I don't understand why people wanna F**k around and not put the recommended gas into their cars. The difference between 87 and 89 is 10 cents people. Let's assume you drive a lot and go through 40 gallons a week.

40*.1*52/12 = 17 friggin dollars a month.

If you can't afford 17 dollars a month extra for gas, ride a bike to work. I can't believe people are willing to f**k around with a $40K vehicle to save $17 a month. Maybe Ms. Teen South Carolina can explain it to me.

/endrant

Good thing you don't have an SRT8....

Wow! You forgot to turn rant on at the beginning of your message! I thought you had a lot of pent up anger until I saw your /endrant !!!!

Anyway, my main reason for pumping 87 (all 1 1/2 tanks so far) was because I never had a vehicle that needed higher. It was just habit.

Your math makes an excellent point for using 89. As you said, it assumes you drive a lot. My personal driving is even more telling.

I will probably be more towards 12k miles per year with mixed driving and guess that I can average 16mpg overall. That put's my personal cost at:

62.5 gallons per month ((12000/16)/12)

$6.25 per month! (62.5 * .10)

I think I can swing that!!!
 

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part of the reason I opted not to buy an SRT8.. I only drive 12 -14 miles a day. I would be getting like 5 MPG plus be buying tires every other month. :D
Even one more reason why you should have gotten an SRT. You don't even use the MDS.... ;)

there actually isn't a car made since 1996 when the 89 octane "standard" was introduced, that "recommends" anything below 89.

you will not find any car made in the past 10 years that recommends 87. so why even have it? Well for the same reason they have E85. Federal regulations, and consumer demand.
That's odd... I'm 100% sure my 03 4runner recommended 87...:4-dontknow:
 

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Even one more reason why you should have gotten an SRT. You don't even use the MDS.... ;)
nope cause I have the S/C and keep it autostick most of the time :D



That's odd... I'm 100% sure my 03 4runner recommended 87...:4-dontknow:
hmmm..

GF had a 1999 Camry that had no recommendation and the new Camry Hybrid we have has no recommendation, but it does say that higher octane ratings "can" yield better MPG.

different cars, i know, but same manufacturer...
 

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any way I cut it 17 gallons never yields me more that 240 miles out of a tank unless I take a long highway trip.
Wait you get 17mpg w/ 91tune SC? you gotta tell me your secret pleaseeeee lol Are you driving it like an old slow grandma style :D or do I just have heavy foot lol I get roughly 15.5mpg with the 91 SC . Either way I don't do much driving anyways and plus gas has gone down considerably here than before :D
 

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my C didn't like 87..it pinged so i went to 89 ran fine.

my SRT8 likes nothing less than 91. it's weird but i get better hwy mileage with the SRT8 than i did with the C.
 

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Wait you get 17mpg w/ 91tune SC? you gotta tell me your secret pleaseeeee lol Are you driving it like an old slow grandma style :D or do I just have heavy foot lol I get roughly 15.5mpg with the 91 SC . Either way I don't do much driving anyways and plus gas has gone down considerably here than before :D


re-read it...

17 GALLONS nets me 240 miles = 14.4 Miles Per Gallon
 
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