Racing Fuel (110 Octane) Question

fire_4_effect

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i was wondering if it would be alright/safe to run 110 octane in a tuned cobra (tuned for 91/93)... the reason is, my town just got racing fuel on tap and i'm eager to try some! :rockon: thx!
 

Sinister04L

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Yep it'd be a waste of time. Going that high over what you're tuned for will actually make you run worse. Putting in a little gas to bump your octane up for safety's sake is fine though. Sometimes you can get crappy pump gas.
 

fire_4_effect

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thx for the quick responses guys... what if i mix 91 (80%) and 110 (20%) during a fill-up? sorry guys, i'm just like a fat kid in a donut shop right now! LOL!
 

boostftw05

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I use to put 116 in my evo at the track and bump the timing up quite a bit, but I do all my own tuning/datalogging so that makes a difference I guess.
 

thomas91169

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if its C10 its leaded and will foul your o2's but thats after long-term usage.

Mixing a bit in a tank thats 3/4 91 to get yourself a nice buffer should be fine. Ive never heard any issues mixing leaded and unleaded.

Ive ran 100octane pump (unleaded) on 91 tune when i know im going to do spirited driving (IE corner carving up a mountain with altitude changes) to give myself a nice safety zone as far as knock/predetonation goes, especially when it comes to higher altitudes and less oxygen up high.
 

fire_4_effect

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if its C10 its leaded and will foul your o2's but thats after long-term usage.

Mixing a bit in a tank thats 3/4 91 to get yourself a nice buffer should be fine. Ive never heard any issues mixing leaded and unleaded.

Ive ran 100octane pump (unleaded) on 91 tune when i know im going to do spirited driving (IE corner carving up a mountain with altitude changes) to give myself a nice safety zone as far as knock/predetonation goes, especially when it comes to higher altitudes and less oxygen up high.

i appreciate your input. i guess it wouldn't hurt if i mixed a little at each fill-up :coolman:
 

thomas91169

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now a little at each fillup, if leaded 110, will foul out your o2's over time. The amount of time I have no clue.

Ive yet to see anyone have any issues with leaded C10/C16 after a few track uses though, but if youre running the shit on a daily youll be investing in o2 sensors about the same rate as spark plugs.
 
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OhIIICobra

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If you are going to mix something for the sake of raising octane once in awhile, buy some Torco Accelerator. 32 Oz in 10 gallons makes 104 octane. It won't jack up your oxygen sensors. The only side effect is reddish plugs after many uses. But if your tune isn't going to utilize the extra octane you'll still be pissing money away.

When I had a 93 tune in Oklahoma I would use it to make 93 because all I could get was 91.
 

thomas91169

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But if your tune isn't going to utilize the extra octane you'll still be pissing money away.

think of it as an insurance policy.


Say you get your car tuned in the summer. Come winter the cooler air (denser=more oxygen) starts to lean out your tune. You go for a night of freeway runs and with just 91/93 on a tune for just that, you start to get a slight bit of knock/predetonation up in the top of 4th, fine for the first few runs but the 3rd run you get compounded heat soak and end up taking the car through 4th and into 5th......your pistons expand, your rings cry for mercy as they are pummeled with 2000+psi flamefronts from predetonation, your 7 and 8th cylinders red hot due to poor coolant flow and leaner burn from manifold design. With a splash of 100 or better, you can increase the octane rating and help stave off some of that knock/predetonation.

you'd be surprised how much environmental variables affect your tune. And since your tune was based on a summers day in a controlled environment, your tuner took no consideration for the winter night you were out there pummeling the competition all the while your tune went from a bit on the safe side to over the edge.
 

CobraBob

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For the negligible gain, if any, you'd get IMO it isn't worth doing. 91/93 octane fuel is expensive enough. If you really want to play around with the 110 octane get a separate tune and maybe use it at the track.
 

pho_phizzat

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if its C10 its leaded and will foul your o2's but thats after long-term usage.

Mixing a bit in a tank thats 3/4 91 to get yourself a nice buffer should be fine. Ive never heard any issues mixing leaded and unleaded.

Ive ran 100octane pump (unleaded) on 91 tune when i know im going to do spirited driving (IE corner carving up a mountain with altitude changes) to give myself a nice safety zone as far as knock/predetonation goes, especially when it comes to higher altitudes and less oxygen up high.

You dont need the higher octane with the higher elevation.

That is why in the mountain states there is no 93 avalible the highest you can buy is 91.
 

fire_4_effect

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If you are going to mix something for the sake of raising octane once in awhile, buy some Torco Accelerator. 32 Oz in 10 gallons makes 104 octane. It won't jack up your oxygen sensors. The only side effect is reddish plugs after many uses. But if your tune isn't going to utilize the extra octane you'll still be pissing money away.

When I had a 93 tune in Oklahoma I would use it to make 93 because all I could get was 91.

sounds like the temptation of trying a gallon or two is out the window... i'll probably stick to my tune rating at 91/93. thx for all the inputs on this subject guys... fist pound! :beer:
 

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sounds like the temptation of trying a gallon or two is out the window... i'll probably stick to my tune rating at 91/93. thx for all the inputs on this subject guys... fist pound! :beer:

you can easily run c16 but your going to have to run the car in an open loop, which is solely off the MAF as the o2 sensors are removed.
 

thomas91169

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You dont need the higher octane with the higher elevation.

That is why in the mountain states there is no 93 avalible the highest you can buy is 91.

You sure its due to elevation?

Sea level here and we dont have 93......I was in vegas and only saw 91 as well. I think 93 is just based on availability.
 

pho_phizzat

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You sure its due to elevation?

Sea level here and we dont have 93......I was in vegas and only saw 91 as well. I think 93 is just based on availability.

I was always under the impression that was the reason but looks like I have some digging to do. I will have to find out.

EDIT:
[ame]http://en.wikipedia.org/wiki/Octane_rating[/ame]

United States: in the Rocky Mountain (high altitude) states, 85 AKI is the minimum octane, and 91 AKI is the maximum octane available in fuel[citation needed]. The reason for this is that in higher-altitude areas, a typical naturally-aspirated engine draws in less air mass per cycle due to the reduced density of the atmosphere. This directly translates to less fuel and reduced absolute compression in the cylinder, therefore deterring knock. It is safe to fill up a carbureted car that normally takes 87 AKI fuel at sea level with 85 AKI fuel in the mountains, but at sea level the fuel may cause damage to the engine. A disadvantage to this strategy is that most turbocharged vehicles are unable to produce full power, even when using the "premium" 91 AKI fuel. In some east coast states, up to 94 AKI is available [1]. In parts of the Midwest (primarily Minnesota, Iowa, Illinois and Missouri) ethanol-based E-85 fuel with 105 AKI is available [2]. Often, filling stations near US racing tracks will offer higher octane levels such as 100 AKI[citation needed] . California fuel stations will offer 87, 89, and 91 AKI octane fuels, and at some stations, 100 AKI or higher octane, sold as racing fuel. Until summer 2001 before the phase-out of methyl tert-butyl ether aka MTBE as an octane enhancer additive, 92 AKI was offered in lieu of 91.
 
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x NOODLES x

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I ALWAYS add 1-2 gallons of unleaded 110 which we have here locally. Expensive, yes. But its insurance for when I decide to hit the juice.
 

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