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is 93 the highest octane you can get in the US? back in the UK i used 99
 

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is 93 the highest octane you can get in the US? back in the UK i used 99
My Sunoco guy has 100 octane, I used a 1/2 tank after he installed my LT headers, K&N drop and Zoomers exhaust- runs awesome !

Tech heads have guidance on how 100 octane may affect the engine pieces?
 

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Octane which is higher than the engine can take advantage of may actually reduce performance, since it is much harder to ignite.

It won't hurt the engine, but running 100 octane in a 392 with mild bolt-ons probably won't provide any additional power over 93 octane. Unless the 100 octane fuel has more oxygen content, which is an entirely different matter unrelated to octane. Oxygen enriched fuel definitely adds power.
 

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Fuel me once, fuel me twice...

I always put in 93 oct when possible, sometimes 91 if nothing else available. I keep a bottle of Torco in my trunk in case I am somewhere that is out or doesn't have premium. That has only happened once, with the previous SRT8.

(yes, I know that Torco has evil chemicals in it. :werd: LMAO!!! I only use it when octane is below 91, so once a year would be average, 2x a year would be extreme for me. I have read hours worth of pros/cons, and I feel ok about the spare usage.)
 

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funny, looked at the manual last night while loading the Sirus update and saw 91 octain is minimum octain for the 6.4. I run 87 in my 5.7 hemi with no problems but I don't race it.
 

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We run 91 or higher, but more importantly with no ethanol! Ms Red is an 09 SRT8 but is not quite stock anymore. Depending on the driving plans, we also add Torco.
 

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just wondering, has anyone done any research using 93 plus a quality octane booster? I just got my gwe auto, was wondering if the upward trend in power would continue with octane levels of 93+....thanks :scratchhead:
 

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sorry for the redundancy, Herminator! I suppose reading might eliminate some of the questions prior to posting!

I use 108 octane mix with my 70 cuda and 69 z28, but cr's are 11.5 and 12.5 respecively.

imo, octane boosters are generally a waste of money.
 

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It's amazing the machines that were thundering around so long ago! I was only born in 1970, so I wasn't even born early enough to realize how things were before the "Big Change". I mean, prior to reading this topic, I never even knew there was a such thing as 90 octane regular back in the old days. :eek: I knew of a thing called "leaded gas" prior to when everything went unleaded, but that's about it.
 

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i worked at a full service texaco station in high school when they were still around, we only had two grades, regular and ethyl, that name still brings a laugh. i don't remember the octane levels, but my 70 road runner liked it!
 

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Doesn't "ethyl" imply alcohol? That would be yet another surprise to me, that supreme grade was actually a high alcohol blend. :eek: Anybody else have more background on this to add?
 

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Ah, that makes more sense!
 

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Here's a real interesting passage from that link:

"The use of TEL in gasoline started in the US, while in Europe, alcohol was initially used. The advantages of leaded gasoline from its higher energy content and storage quality eventually led to a universal switch to leaded fuel. One of the greatest advantages of TEL over other antiknock agents or the use of high octane blend stocks is the very low concentrations needed. Typical formulations called for 1 part of prepared TEL to 1260 parts untreated gasoline. Competing antiknock agents must be used in greater amounts, often reducing the energy content of the gasoline.

When used as an antiknock agent, alcohol will cause fuel to absorb moisture from the air. Over time fuel humidity can rise, leading to corrosion in fuel lines. Whereas TEL is highly soluble in gasoline, ethanol is poorly soluble and that solubility decreases as fuel humidity increases. Over time, droplets and pools of water can form in the fuel system creating a risk of fuel line icing. High fuel humidity can also enable biological contamination, as certain bacteria can grow on the surface of the water/gasoline interface, forming bacterial mats in the fuel system. TEL's biocidal properties helped prevent fuel contamination and degradation from bacterial growth."


It really underscores how much modern gasoline has been gimped compared to the "golden era" gasoline (in the interest of air quality concerns, of course). TEL was like the "magic tweak" to straight gasoline to bump octane w/o diluting the energy content of gasoline. The modern stuff we have now is plagued with a direct trade-off/compromise between octane and energy content (plus we are forced to pay through the nose to foreign govt's for it because of our lack of will to develop domestic sources).
 
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