Quick octane question
05-11-2013, 09:48 PM
#1
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Location: Gainesville,FL,USA
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Quick octane question
1995 Firebird Formula, stock except K/N filter and cat back exhaust. Daily driver, never raced or really driven hard anymore, 113000 miles.
There is a gas station here in Gainesville that now sells ethanol free 90 octane. I usually run 93 with the up to 10% ethanol and was wondering is it better to run pure gas and can an LT1 run 90 octane, I think the manual says it has to be 91 octane. Anyone have any thoughts?
There is a gas station here in Gainesville that now sells ethanol free 90 octane. I usually run 93 with the up to 10% ethanol and was wondering is it better to run pure gas and can an LT1 run 90 octane, I think the manual says it has to be 91 octane. Anyone have any thoughts?
05-12-2013, 02:34 PM
#2
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Re: Quick octane question
The manual says to run 91 octane for maximum performance. It also indicates that you can run as low as 87 without engine damage, but you will lose performance. The knock sensor will cause the PCM to pull timing.
The octane rating determines if you will encounter spark knock. Doesn't matter if it's pure gasoline or an ethanol blend. 91 is 91. You may get better mileage without the alcohol.
The octane rating determines if you will encounter spark knock. Doesn't matter if it's pure gasoline or an ethanol blend. 91 is 91. You may get better mileage without the alcohol.
05-12-2013, 04:58 PM
#3
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Re: Quick octane question
Thanks for the answer. I dont really mind my mileage, at 70-ish in 6th gear I still get 25 or mpg. I just am afraid the ethanol is doing bad things to the rubber fuel lines and other parts. Maybe I worry too much.
05-19-2013, 05:42 PM
#4
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Re: Quick octane question
I just recently read the manual and it states that I should run 91 or higher. The car has 48,000 miles and the guy who owned it for about 14 years before me said he ran 87 in it, so that's what I've been doing. Will I notice a difference with 93 like we have here? I didn't know if the car was maybe used to running 87 now or something...
05-19-2013, 11:18 PM
#5
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Re: Quick octane question
Read the manual again. It says for the V8 engine:
If you switch from 87 to 91, you should notice improved power. Depends where you live. The higher the altitude where you live, the lower octane your engine needs. But you didn't show your location in your profile, so I can't tell. And you provide no info about your vehicle - year, engine, etc., but I assumed you have a V8 engine.
You need to add a "signature" with basic info about your car - year, model, engine, trans and any major mods. The more info you provide, the more accurate help we can give you.
Use premium unleaded gasoline rated at 91 octane or higher. You may use middle grade or regular unleaded gasolines, but your vehicle may not accelerate as well.....
Be sure the posted octane for premium is at least 91 (at least 89 for middle grade and 87 for regular). If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough it can damage your engine.
Be sure the posted octane for premium is at least 91 (at least 89 for middle grade and 87 for regular). If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough it can damage your engine.
You need to add a "signature" with basic info about your car - year, model, engine, trans and any major mods. The more info you provide, the more accurate help we can give you.
05-20-2013, 06:33 PM
#6
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Re: Quick octane question
Read the manual again. It says for the V8 engine:
If you switch from 87 to 91, you should notice improved power. Depends where you live. The higher the altitude where you live, the lower octane your engine needs. But you didn't show your location in your profile, so I can't tell. And you provide no info about your vehicle - year, engine, etc., but I assumed you have a V8 engine.
You need to add a "signature" with basic info about your car - year, model, engine, trans and any major mods. The more info you provide, the more accurate help we can give you.
If you switch from 87 to 91, you should notice improved power. Depends where you live. The higher the altitude where you live, the lower octane your engine needs. But you didn't show your location in your profile, so I can't tell. And you provide no info about your vehicle - year, engine, etc., but I assumed you have a V8 engine.
You need to add a "signature" with basic info about your car - year, model, engine, trans and any major mods. The more info you provide, the more accurate help we can give you.
05-21-2013, 02:15 PM
#8
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