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How bout those gas prices?

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I'm run and am going to continue to run 87 octane because my car is designed and programmed to run 87 octane. Some cars require higher octane, for people that do, they should run the higher octane. But the majority of vehicles in the US only require 87.
 
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Use what you like, I really don't care. I'd guess your car runs just fine on 87. The engine de-tunes to accommodate the swill, running less efficiently and producing less power and worse gas mileage. It's a win-win choice for you.

It does, although the ignition timing adjusts according to load and fuel octane automatically, so under serious load (especially at low RPMs) I might lose 5 or 6 hp or 1 or 2mpg, but while cruising it makes no difference, at least in a new engine.

I have a very long road trip next week, so am going to test the MPG 87 Vs 91, I'll let you know - I'm pretty curious myself.

I still think the 'swill' comment is funny... it panders to the marketing. The difference between 87 and 93 octane has nothing to do with the purity of the gasoline or it's quality, simply the trimethylpentane and heptane mix. Most people who yack on about octane ratings don't even know what they are.
 
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Does that mean, that because the lowest (commonly available) RON we have here in the UK is 95, that we're all petrol snobs? ;)

I had to put in 98+ (there was even a little sticker on the inside of the filler cap saying so) in my old Evo 8 or it would have screwed the engine up. Not my choice, Mitsubishi's.

Thankfully I got rid of that, or I'd be paying upwards of £1.55/l for 99 RON juice.
 
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Does that mean, that because the lowest (commonly available) RON we have here in the UK is 95, that we're all petrol snobs? ;)

To convert RON Octane to AKI Octane, you multiply by 0.95. So 95 RON is approximately 90 (US) Octane.
 
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I still think the 'swill' comment is funny... it panders to the marketing. The difference between 87 and 93 octane has nothing to do with the purity of the gasoline or it's quality, simply the trimethylpentane and heptane mix. Most people who yack on about octane ratings don't even know what they are.

True. Octane is a misunderstood beast. People saying it makes their car faster, are generally experiencing what their motor was actually capable of all along. It's not an enhancement beyond that, which was somehow bestowed by the magical high octane gas. Generally, it takes about 100 to 500 miles of varied driving for a vehicle to even readjust parameters in the PCM to different fuel anyhow. I suspect in most cases, filling up with 93 octane has a placebo effect more than anything else.

My view is a bit skewed I guess as I like to tune engines for fun and occasional profit. For me, there is no point in tuning an engine if it isn't running 93 octane as a baseline. The difference in the power and efficiency that some engines can produce running on higher octane fuel (to me at least) is quite amazing. Air/fuel, duration/advance can be pushed much further with the elbow room that higher octane brings to the party. My air/fuel bars are flatter the higher the octane. I'd run the 110 octane race stuff if I could find it for less than $9-11 a gallon with any regularity.

Stock 2008 5.7L HEMI advertised as 345hp (at the crank)
Added RDP CAI before test; tuning via Diablosport CRM software.
87 octane untuned rear wheel 296hp (Dynojet) 26mpg MDS active
87 octane tune rear wheel 307hp (Dynojet) 27mpg MDS disabled
Add 180 degree thermostat for tuning
93 octane tune rear wheel 324hp (Dynojet) 29mpg MDS disabled (Roughly 380hp at the crank if measured as advertised)
Add a mild cam and we go to 349hp, JBA & Corsa exhaust 368hp, polished/ported heads... but that's a different thread... ;)

The gas doesn't magically make it faster by itself, but merely allows you to make the engine more efficient if you choose. Many cars have some advanced tuning metrics built in and require the higher octane sauce to make use of it. Many also have higher compression or are non-naturally aspirated which also require increased octane to both prevent detonation, and to cycle larger than normal advance curves based on the driving conditions.
 
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The gas doesn't magically make it faster by itself, but merely allows you to make the engine more efficient if you choose.

Excellent post, and the above is a neat quote that sums up the reality of the situation nicely. Those numbers were pretty interesting.

I have done zero tuning or modding of my current car, but want to get a CAI (APR do a nice carbon fibre one) that doesn't void the warranty. I keep meaning to call VW about it and see if they'll get antsy about it. I love the sound more than anything (had one on my GTI back in the UK, loved the growl).
 
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Gas at the supermarket 1 mile down the road on Monday was $4.04/gal. (my better half bought groceries on Monday) On Tuesday, it was up to $4.15 when I filled the car I drive 99% of the time. But, for buying groceries there, you get a $0.04 discount per gallon.

However, I have a Mobil speedpass, and there was an offer for $0.15 off per gallon for 60 days or 100 gallons, whichever comes first in my e-mail. I signed up for it. I checked the price at a convenient Mobile station, and it was $4.19/gal. So this discount gets me $0.07/gal. lower than the other one. Yeah, I'm doing it, until I hit 90-some gallons. I check my mpg on every tank, so keeping track, even with two vehicles, won't be difficult.
 
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We're well into the $4+ range here in LA

Most stations are around $4.35 for unleaded 87 (regular), and I've seen $5.09 for 93 (premium) at a couple places. Shocking, especially here in LA where driving is pretty much a requirement, both for simple grocery runs and commuting (typical commutes can easily be 25-35 miles, and often in nasty MPG-robbing traffic). I fully expect it to be into the $5+ range in a lot of places by summer. Sigh.
 
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Stock 2008 5.7L HEMI advertised as 345hp (at the crank)
Added RDP CAI before test; tuning via Diablosport CRM software.
87 octane untuned rear wheel 296hp (Dynojet) 26mpg MDS active
87 octane tune rear wheel 307hp (Dynojet) 27mpg MDS disabled
Add 180 degree thermostat for tuning
93 octane tune rear wheel 324hp (Dynojet) 29mpg MDS disabled (Roughly 380hp at the crank if measured as advertised)
Add a mild cam and we go to 349hp, JBA & Corsa exhaust 368hp, polished/ported heads... but that's a different thread... ;)
sweet! I'm thinking on getting my engine tuned for more HP and better mileage its a 5.6 L.
 
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I'm in Florida at the mo and it just cost $40 to fill my (rental) Ford Focus sedan. That's about £27.50. At home (in Leicestershire, England) it costs about £60 - £70 to fill my Mercedes C220 diesel. Both are automatic but my C Class outperforms the Focus in every respect including economy - 32 mpg vs 52 mpg.

I wish fuel was this cheap back home.
 
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We're at $4.12 in central New York, was $4.16 over the weekend.
 
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Bouncing between $3.59 and $3.69 for 87 octane in Minneapolis suburbs. It's about 10 to 25 cents more in the Metro areas.
 
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US $4.959/ US gallon here at the pumps
Canada $1.30/L
I have my Dads business's bulk fuel card so I can tank 10/cents per Liter cheaper than other people at the pumps :)
 

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