what octane gas to run on drag strip?

65notch

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#1

• Mar 20, 2007

• #1

im going to a test and tune tommorow and i'm curious if it would be worth buying some race gas and mixing with 91 to give me a higher octane...would this be benifical or pointless?
my mods are in my sig...thanks guys!

 

classic boost

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#2

• Mar 20, 2007

• #2

you left out the most important spec- compression ratio.

 

brianj5600

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#3

• Mar 20, 2007

• #3

If it does not detonate with 36* of timing, you will not gain anything. Even 36* is a little high. It seems 34* is about all most motors need with modern heads.

 

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Soaring1

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#4

• Mar 20, 2007

• #4

gas

What headers do you have?

 

coolblue65

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#5

• Mar 20, 2007

• #5

From what I have read and heard, you should use the lowest Octane your motor will allow, as higher Octanes actually burn slower and can cause a loss of HP in cars that don't need it. There was a test in a car magazine some time ago iwth dyno tests proving that.

 

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Soaring1

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#6

• Mar 20, 2007

• #6

coolblue65 said:

From what I have read and heard, you should use the lowest Octane your motor will allow, as higher Octanes actually burn slower and can cause a loss of HP in cars that don't need it. There was a test in a car magazine some time ago iwth dyno tests proving that.

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Yep, that's true. I really don't see that you have enough engine to be worrying about the octane. Pump gas is just fine for your set-up.

 

washMO66

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#7

• Mar 20, 2007

• #7

Your fine with 91 or 93 pump gas. I learned the hard way after wasting my money on race fuel for a whole season until I learned that my car actually ran the best on good old 93 pump gas. I'll run some 100 low lead AV through it every once in awhile.

 

65notch

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#8

• Mar 20, 2007

• #8

paul302 said:

you left out the most important spec- compression ratio.

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i actually dont know my compression ratio, maybe sombody here can help me figure it out. i was running 9.5:1 with the stock 65 cast heads. now i have the edelbrocks with a 60cc chamber. is it possible to figure out compression ratio with this?

Soaring1
What headers do you have?

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i have patriot coated tri y's

brianj5600
If it does not detonate with 36* of timing, you will not gain anything. Even 36* is a little high. It seems 34* is about all most motors need with modern heads.

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im actually running like 30 at full advance, which is something else i have to mess with...

 

S

Soaring1

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#9

• Mar 20, 2007

• #9

engine

No, you were running 10.3:1 ratio with the stock 289.

 

65notch

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#10

• Mar 21, 2007

• #10

Soaring1 said:

No, you were running 10.3:1 ratio with the stock 289.

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the bottom end of the engine wasnt stock, just the heads were stock size. thats why i was at 9.5:1

 

D

D.Hearne

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#11

• Mar 21, 2007

• #11

About 9 to 1 with 60 cc heads. It ought to be fine with 87-89.