91 octane?

the98stang

Active Member

Aug 12, 2005

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Clovis, CA

Mar 16, 2006

#1

• Mar 16, 2006

• #1

Hey guys I was just wondering if 91 octane gives our 4.6L engines more power? (assuming the car is naturally aspirated, with no tuner). I always thought our engines would LOSE power if we didn't run 87? Someone please explain the science behind this. Sorry if this is a stupid question, I just never really understood octane.

 

sgarlic

Founding Member

Apr 21, 2001

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#2

• Mar 16, 2006

• #2

Simply put, the higher the octane rating, the more resistance to detonation.. the more compression it takes before the contents of the combustion chamber will spontaneously combust. So running higher octane on a stock engine does you nothing besides empty your wallet more quickly, unless you have problems with detonation.

Running higher octane allows you to do things like advance timing, run higher compression, etc.. won't help you with the stuff you've got.

 

the98stang

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Aug 12, 2005

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Clovis, CA

Mar 16, 2006

#3

• Mar 16, 2006

• #3

sgarlic said:

Simply put, the higher the octane rating, the more resistance to detonation.. the more compression it takes before the contents of the combustion chamber will spontaneously combust. So running higher octane on a stock engine does you nothing besides empty your wallet more quickly, unless you have problems with detonation.

Running higher octane allows you to do things like advance timing, run higher compression, etc.. won't help you with the stuff you've got.

Click to expand...

Thanks for clearing that up

 

sgarlic

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Apr 21, 2001

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#4

• Mar 16, 2006

• #4

Eh.. you know. Late nights, a 6 pack, wife sleeping, nothing better to do than explain octane ratings.

 

DocG

5th graders > me. They're not bant

Sep 25, 2005

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Cincinnati area

Mar 16, 2006

#5

• Mar 16, 2006

• #5

My wallet is draining from high octane as we speak. Just as I was going to trial some 93 octane to see if it gets rid of my rattling noise, the prices jumped 30cents! One tank in, still rattles. So anyways, like he said...stick with the 87, gas itself won't give you a power increase. Unless there's a hot gal at the pump next to you, then you could impress her by pumping the good stuff...and spray a little 93 all over the parking lot just to show her you've got money to blow.

 

shallowreef

New Member

Nov 3, 2005

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illinois

Mar 16, 2006

#6

• Mar 16, 2006

• #6

Isn't 93 octane better for your engine though? Or is that a bunch of B.S.?

 

LB0193

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Dec 6, 2005

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IL

Mar 16, 2006

#7

• Mar 16, 2006

• #7

I run amaco ultimate 93 they claim it "cleans your motor"...but I have to run it because of my blower....if I could run 87 I would...with gas prices in this country those oil tycons dont need any extra money from me

 

shallowreef

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Nov 3, 2005

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illinois

Mar 16, 2006

#8

• Mar 16, 2006

• #8

I pay for premium all the time i was always told its better for the car. Its only an extra two dollars to fill up with premium verses unleaded.

 

CanadaStang

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Sep 7, 2003

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Mb

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#9

• Mar 16, 2006

• #9

sgarlic said:

Eh.. you know. Late nights, a 6 pack, wife sleeping, nothing better to do than explain octane ratings.

Click to expand...

And you do it so well too!!!

 

jstreet0204

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Jun 26, 2003

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Winston Salem, NC

Mar 16, 2006

#10

• Mar 16, 2006

• #10

shallowreef said:

Isn't 93 octane better for your engine though? Or is that a bunch of B.S.?

Click to expand...

If your car isn't set up to run higher octane, you may be doing more harm than good. Higher octane fuel burns slower. If your engine isn't burning it all off it can leave more carbon build up.

 

shallowreef

New Member

Nov 3, 2005

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illinois

Mar 16, 2006

#11

• Mar 16, 2006

• #11

So what octane should i be burning?

 

jstreet0204

Active Member

Jun 26, 2003

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Winston Salem, NC

Mar 16, 2006

#12

• Mar 16, 2006

• #12

shallowreef said:

So what octane should i be burning?

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The lowest you can run without pinging.

 

F

FalconGuy016

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Oct 26, 2004

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Northern VA

Mar 16, 2006

#13

• Mar 16, 2006

• #13

jstreet0204 said:

If your car isn't set up to run higher octane, you may be doing more harm than good. Higher octane fuel burns slower. If your engine isn't burning it all off it can leave more carbon build up.

Click to expand...

Yes!! And you will actually lose the slightest bit amount of HP and gas mileage on the stock tuning.

However my SCT mail order tune can barely run on 93.

 

K

kstang69

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Aug 14, 2003

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atlanta, georgia

Mar 16, 2006

#14

• Mar 16, 2006

• #14

The manual (i know its crap) says only use 87 if you wanna go by the book

Different without stock tune