93 octane requirement in 91 octane state

[mephim]

This is the first car I've ever owned that specifically calls for 93 octane in the owner's manual. Does anyone have good experience/data with octane boosters that helps to keep cars like this happy? Anyone from california/Midwest had success with keeping ecus from pulling timing with an additive?

I just was given a "necessary management promotion" (lucky me) that is moving me to the Oklahoma City area for two years. All corporate bs aside, can anyone give some advice?

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[Nataphen]

93 is not required, that's just what it needs to make 526hp. It makes a little less on 91, but it's still fine.

 

[mattlqx]

No additives required. Just fill up and drive the wheels off.

 

[Nataphen]

Watch the Motor Trend videos if you're worried at all. They filmed the GT350 episode and GT350R vs. Z/28 head 2 head in CA with 91 octane.

 

[cloud9]

This is what I'll use for track days in states that don't have 93 available. It will run $1/gallon to boost 91 to 93.

http://www.jegs.com/i/Race+Gas/814/100032/10002/-1

 

[dcasandman]

If you are moving to OKC there are 2 gas stations on the North Side of town that sale 93 and 100. I think there is one on the south side too, but I'm never over there.=. I only use about a tank of gas every 2-3weeks, so I will fill up with the 100 once a month then fill again at more local station at half at tank. Always try to keep 93ish in the tank at least. I can't feel any difference, and probably really isnt that important until FI. If I had an Eccoboost I'd probably more religious about it.

 

[mephim]

Thanks for all the tips guys. I might go with a 2 ounce additive on every tank of gas,
when 93 isn't available.

 

[Hughespj47]

I Googled Denver 93 octane and came up with several hits. Suggest you try similar search based on your location. Good tip above on the octane booster.

For daily driving, 91 will be perfect. Ford says it's Ok, so it will work, just down a few ponies. For track days I will definitely tank up with 93 or add booster. Increasing octane above 93 will not likely add any power boost, just drain your wallet faster.

If you drive across the country, you'll note that the higher altitude States don't generally sell 93 octane fuel. And they sell 87 as regular. For a NA engine this makes sense, because as altitude increases, air pressure decreases. In Denver, the air pressure is about 85% of sea level. As a result, the effective compression ratio decreases and so does hp. Higher compression engines require higher octane to prevent knock. Turbo and supercharged engines are a different story as they increase ambient air pressure and use knock sensors.

 

[Nataphen]

I don't know if you're interested, but if you want to get a custom tune for E85, it looks like there are several options for you. That's an easy way to add 40hp and make sure your engine isn't going to knock. They would give you a 91 octane tune to switch to in a pinch.

 

[mephim]

I Googled Denver 93 octane and came up with several hits. Suggest you try similar search based on your location. Good tip above on the octane booster.

Thanks for the tips guys. I am actually in lawton, about an hour south of OKC. After being moved on Friday I went into the office and talked to some people who have high compression toys. The general consensus, especially from the guy with a supercharged e90 m3, was to add octane booster to each tank. I might have to go that route. I know that it is viable to run the lower octane tables but as this is a toy, I'd rather pamper it.

 

[Hack]

Most octane boosters are snake oil IMO. I wouldn't trust them. I'd rather run 91 than put an octane booster in my tank.

 

[South40]

Thanks for the tips guys. I am actually in lawton, about an hour south of OKC. After being moved on Friday I went into the office and talked to some people who have high compression toys. The general consensus, especially from the guy with a supercharged e90 m3, was to add octane booster to each tank. I might have to go that route. I know that it is viable to run the lower octane tables but as this is a toy, I'd rather pamper it.

I am in Chickasha. No 93 around here either. We run Torco in our vehicles that need an octane boost. We buy a case at a time online.

http://www.torcousa.com/torco_product/un_acce.html

 

[mephim]

Was cruising around the main strip today and found a Valero with 93 octane. All is right.

 

[Hughespj47]

I don't know if you're interested, but if you want to get a custom tune for E85, it looks like there are several options for you. That's an easy way to add 40hp and make sure your engine isn't going to knock. They would give you a 91 octane tune to switch to in a pinch.

E85 is 85% ethanol. Unless you have a FlexFuel vehicle, DO NOT USE E85. It will ruin all the gaskets in your engine. I'm not aware that the Shelby Owners Manual supplement recommends E85. BE CAREFUL!

 

[Nataphen]

E85 is 85% ethanol. Unless you have a FlexFuel vehicle, DO NOT USE E85. It will ruin all the gaskets in your engine. I'm not aware that the Shelby Owners Manual supplement recommends E85. BE CAREFUL!

I'm very well aware of what E85 is. You should read up on these things before you make blanket statements. All that you need is a custom tune to handle E85. The engine and fuel system are ethanol safe, even for high percentages of ethanol. All non Flex Fuel vehicles state not to use E85 in the manual, and it's simply because they don't have the OEM programming to adjust for the fuel delivery.

It won't hurt your engine if you have a good custom tune for it. Lund already gained almost 40whp over stock on his GT350 just by switching to E85 and tuning for it. E85 will also keep your engine much cleaner than gasoline. The only downsides are a loss in fuel mileage, the lack of availability, and the fact that you shouldn't store a car filled with E85. Switch to gasoline for winter storage.

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