Best Octane for Edelbrock?

warrenbh

Member

Feb 25, 2010

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6

Apr 3, 2010

#1

• Apr 3, 2010

• #1

Hello,

I just got an Edelbrock 600 for my 66 GT.

Should I stick to 93 octane gas??

Thanks for your response.

Warren

 

blown65

Founding Member

Jul 7, 1999

1,938

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39

Queen Creek Arizona

Apr 3, 2010

#2

• Apr 3, 2010

• #2

Octane is dependent on your motor build, not the type of carb you have.

Whats the compression/heads ur running?

93 wont hurt though, but you may be just fine running 89.

 

J

j69302

Active Member

Jan 31, 2006

325

1

29

Apr 3, 2010

#3

• Apr 3, 2010

• #3

That depends mostly on your compression ratio and cam specs. List your engines specs.

Running a higher octane does nothing for you unless your engine NEEDS the higher octane.

 

rbohm

Founding Member

Apr 12, 2002

6,698

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tucson,az

Apr 3, 2010

#4

• Apr 3, 2010

• #4

unless you need 93 octane, dont use it. run the lowest octane fuel you can to save money at the pump, and reduce engine deposits.

 

warrenbh

Member

Feb 25, 2010

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6

Apr 3, 2010

#5

• Apr 3, 2010

• #5

I never realized how little i knew about cars until i bought this mustang.

It's engine was rebuilt by my late friend. I ended up purchasing the car from his parents.

Needless to say, I don't know the specs. All i know is that the engine is blue and a 289 (windsor v8?). My friend put an edelbrock intake manifold on it and added headers.

Maybe I should take it to a performance shop to get more info . . .

 

warrenbh

Member

Feb 25, 2010

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Apr 3, 2010

#6

• Apr 3, 2010

• #6

He also added a cam.

 

blown65

Founding Member

Jul 7, 1999

1,938

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39

Queen Creek Arizona

Apr 4, 2010

#7

• Apr 4, 2010

• #7

You could run 89 and watch for signs of detonation by noise, or evidence of speckling of the spark plugs. If they get a peppered look on the porcelain then its got too low of octane or too much timing advance.

No reason to pay for premium if un-needed.

 

C

C0V3R

Member

Feb 14, 2003

524

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Australia

Apr 4, 2010

#8

• Apr 4, 2010

• #8

I find it interesting that you guys have such low octane fuels. 91 octane here is regarded as very low. We have 98 octane for all the sport/euro cars.

Anyway as the guys say, run what you have been running and retune if necessary. The carb shouldnt dictate the fuel used.

 

65ShelbyClone

Founding Member

Sep 9, 2000

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Antelope Valley, SoCal

Apr 5, 2010

#9

• Apr 5, 2010

• #9

C0V3R said:

I find it interesting that you guys have such low octane fuels. 91 octane here is regarded as very low. We have 98 octane for all the sport/euro cars.

Click to expand...

North America's fuel rating is an average of research and motor octane (R+M/2). Yours is rated only by the research octane so it appears higher than ours, but actually isn't.

 

D

D.Hearne

New Member

Sep 29, 2000

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south louisiana

Apr 5, 2010

#10

• Apr 5, 2010

• #10

C0V3R said:

I find it interesting that you guys have such low octane fuels. 91 octane here is regarded as very low. We have 98 octane for all the sport/euro cars.

Click to expand...

Ours used to be as high as yours, but that changed in the early 80's. 93 now is the equivalent of the old 98.

 

D

D.Hearne

New Member

Sep 29, 2000

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south louisiana

Apr 5, 2010

#11

• Apr 5, 2010

• #11

warrenbh said:

Hello,

I just got an Edelbrock 600 for my 66 GT.

Should I stick to 93 octane gas??

Thanks for your response.

Warren

Click to expand...

In additon to what everyone else advised you, I'll also add that octane requirement is also dependent on the ignition timing. More advance in the timing usually requires more octane, if your motor's built to use the higher octane. Set the timing at 10-14*BTDC and try a lower octane fuel, but listen for a pinging noise on accelleration. If it pings, then go higher on the octane till it stops pinging. If it pings on 93 at this timing setting, back off the timing til it stops. I run my 331 on 93 with a 10.4 to 1 comp ratio and the timing set at 12-14*BTDC. The 5.0 in my 89 Ranger uses 87 in the winter, 89 in the summer with the same timing setting but a lower comp ratio (9-9.5 to 1) but also with a wider LSA cam (stock F4TE roller)

 

C

C0V3R

Member

Feb 14, 2003

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Australia

Apr 6, 2010

#12

• Apr 6, 2010

• #12

65ShelbyClone said:

North America's fuel rating is an average of research and motor octane (R+M/2). Yours is rated only by the research octane so it appears higher than ours, but actually isn't.

Click to expand...

Ah you learn something every day. Interesting!

 

JonK

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Jun 6, 2007

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Nashville (Smyrna), TN

Apr 6, 2010

#13

• Apr 6, 2010

• #13

I would also look for stations near you that sell 100% gasoline if it's available and avoid the "may contain up to 10% ethanol". The ethanol will dry out the gaskets in your carb. eventually and you get better mileage from 100% gasoline. Don't know what state you're in though as I've heard some states don't allow octane free gas to be sold, welcome to the new america...
Jon

 

D

D.Hearne

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Sep 29, 2000

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south louisiana

Apr 6, 2010

#14

• Apr 6, 2010

• #14

JonK said:

Don't know what state you're in though as I've heard some states don't allow octane free gas to be sold, welcome to the new america...
Jon

Click to expand...

Octane free gas ?

 

JonK

Member

Jun 6, 2007

276

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Nashville (Smyrna), TN

Apr 6, 2010

#15

• Apr 6, 2010

• #15

DOH! amnit:

Typed too fast, meant Ethanol free...
Jon