# Price of gas



## liquid stereo (Feb 26, 2003)

Here in the Twin Cities, the price of gas went up by $0.20/gallon this weekend. Premium (91) is now $3.49/gallon. My response - commuting via bicycle begins on Wed. and will take place three times per week.
Do you have plans to change your driving habits?


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## archiea (Nov 29, 2006)

*Re: Price of gas (liquid stereo)*


_Quote, originally posted by *liquid stereo* »_Here in the Twin Cities, the price of gas went up by $0.20/gallon this weekend. Premium (91) is now $3.49/gallon. My response - commuting via bicycle begins on Wed. and will take place three times per week.
Do you have plans to change your driving habits?

commuting in LA is not that mush of an option. In San francisco it is, and thats a good thing: premium gas is now over $4. I fell so... european....



_Modified by mark_d_drake at 3:08 PM 5-14-2007_


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## kghia (Nov 16, 2006)

*Re: Price of gas (liquid stereo)*

I make sure to stop in a city on the way home from work where gas is 20 cents cheaper.
Of course, here it is still only $3.09-$3.26 a gallon for premium
William


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## ChicagoVW (Sep 10, 2006)

*Re: Price of gas (kghia)*

I'm paying $3.59 in the suburbs, but the gas station closest to my house is $3.95. Can't bitch though, when I was in Amsterdam in December I paid $6.74 a gallon for diesel.
Alex


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## pdog (Mar 13, 2007)

*Re: Price of gas (ChicagoVW)*

Hi everyone, how about filling up in the UK, price varies by a few pence but on average petrol (gas) is about £5 a gallon, roughly 10 dollars.
Paul


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## oktasha (Apr 23, 2007)

*Re: Price of gas (pdog)*

Dang, so to get gas for an EOS in Europe I guess that you have to be basically rich, huh? In America, it almost feels like you have to be rich to get gas -- or at least it seems that it is getting to be that way.
Tasha


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## ravennarocket (May 4, 2007)

*Re: Price of gas (archiea)*

Well, price here in Canada starts at $1.07/liter (about $3.75US/US gallon( and that's for lowest octane. Archie, why blame Canada? Thank goodness we have reserves to provide long term assurance that middle east countries don't continue nudging prices even higher!


_Modified by ravennarocket at 9:41 PM 5-14-2007_


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## oab97 (Feb 18, 2007)

*Re: Price of gas (oktasha)*

Yeah, and my amazing high-tech direct injected Eos got a whopping 17.8mpg on its last tank of gas. Woohoo, a model of efficiency.








Since everybody else in world is already accusing the U.S. of meddling in the middle east so we can steal oil we might as well make them all right, steal Iraq's oil and bring the price of gas down. I'd rather deserve the blame we're getting then get it for no reason.


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## darien (Oct 28, 2006)

*Re: Price of gas (oab97)*


_Quote, originally posted by *oab97* »_Yeah, and my amazing high-tech direct injected Eos got a whopping 17.8mpg on its last tank of gas. 

I am curious to know if your EOS is manual or DSG. My EOS is DSG and I live in West Houston near Memorial City mall area, and I usually get about 27/28 mpg. I drive in the Highway and City equally. And yes, I only used the Octane 87 gas from Costco as well. However, my EOS has about 7.2K miles now, the only thing I can say is, give it some time, your EOS will give you good mileage.


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## WolfsburgerMitFries (Jul 4, 2005)

*Re: Price of gas (oktasha)*

It gets tiring hearing people attempt to compare apples to oranges. In Europe, cars run on petrol, which is a higher octane fuel that's used as a vehicle for all sorts of additional taxes that pays for education, infrastructure, and *Health care*. In the USA, gasoline is a lower octane, lower quality vehicle fuel that is not as heavily burdened by taxes, nor does it pay for health care. You simply cannot compare fuel prices in Europe to fuel prices in the USA anymore that you can configure a car on a European website and attempt to translate the total price from Euros to Dollars.


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## aflaedge (Jun 27, 2006)

When gas prices go up I drive the speed limit. This weekend I drove 300 miles and my avg mpg was 38. Course I did the speed limit everywhere but dayum. My car thinks it can get 540 miles per tank now.


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## liquid stereo (Feb 26, 2003)

*Re: Price of gas (WolfsburgerMitFries)*

(1) I'm not so sure the gas is so different. Is it really more than +1 octane more over there? I don't think so. Same engines, same compression ratio, very similar power rating (DIN, BHP, KW).
(2) As for the the cost, don't forget to include the cost of our fantastic military when including the cost of gasoline/oil.
(3) The dumbest thing the U.S. government does is not tax the hell out of gasoline/oil. A significant tax is the best way of ensuring that we find a way out of the oil-dependency morass. 

_Quote, originally posted by *WolfsburgerMitFries* »_It gets tiring hearing people attempt to compare apples to oranges. In Europe, cars run on petrol, which is a higher octane fuel that's used as a vehicle for all sorts of additional taxes that pays for education, infrastructure, and *Health care*. In the USA, gasoline is a lower octane, lower quality vehicle fuel that is not as heavily burdened by taxes, nor does it pay for health care. You simply cannot compare fuel prices in Europe to fuel prices in the USA anymore that you can configure a car on a European website and attempt to translate the total price from Euros to Dollars.


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## mark_d_drake (Aug 17, 2006)

*Re: Price of gas (liquid stereo)*

Please let's not start a Political discussion here, no matter how much you may agree / disagree with the viewpoint stated.
TIA
Mark


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## Sandalman (Aug 11, 2002)

*Re: Price of gas (liquid stereo)*


_Quote, originally posted by *liquid stereo* »_Do you have plans to change your driving habits?

No, I don't. I have a 4mi commute, which means a tank of gas lasts me over a week, even with driving hither and yon throughtout Houston's sprawl during the weekends. 
Even if I filled up once a week, I don't think I would change anything. A fifty cent change in the price of a gallon of gas makes a 13gal fillup $6.50 more expensive. That would mean a net affect on my monthly budget of $30. I can absorb that by eating out or drinking less often, which I find preferable to changing my driving habits.


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## WolfsburgerMitFries (Jul 4, 2005)

*Re: Price of gas (liquid stereo)*


_Quote, originally posted by *liquid stereo* »_(1) I'm not so sure the gas is so different. Is it really more than +1 octane more over there? I don't think so. Same engines, same compression ratio, very similar power rating (DIN, BHP, KW).
way out of the oil-dependency morass. 


So far as I know, "premium" here is 92-93 octane, and over there its 98 octane.


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## liquid stereo (Feb 26, 2003)

*Good question*

This brings up an interesting point. Namely, at what point do buyers (us) decide that something must change? And by something I mean anything - driving habits, off-setting of price increases (eg. drinking less), etc. My commute is fairly short - 3.5 miles - but I must admit I don't like being made to feel like I have no control.
The last round of fuel increases (Summer 2005?) really made me think of fuel economy. In a nod to self-indulgence, I decided to get the Eos. I would have gladly purchased the most anemic engine VW could have harnessed to it (with the exception of the tractor-like 2.5 I5). Three of my colleagues have TDIs, and they have commutes which are very similar to mine and get 45+ mpg. Part of my rationalization for getting the Eos is knowing that I would not be driving it much. My SO will soon be getting a new car to replace her 13 year old Camry and I'm hoping it will be TDI Jetta Wagon.
http://www.carmagazine.co.uk/f...age=1
In the meantime I've got the bicycle http://****************.com/smile/emthup.gif


_Quote, originally posted by *Sandalman* »_
No, I don't. I have a 4mi commute, which means a tank of gas lasts me over a week, even with driving hither and yon throughtout Houston's sprawl during the weekends. 
Even if I filled up once a week, I don't think I would change anything. A fifty cent change in the price of a gallon of gas makes a 13gal fillup $6.50 more expensive. That would mean a net affect on my monthly budget of $30. I can absorb that by eating out or drinking less often, which I find preferable to changing my driving habits.


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## ravennarocket (May 4, 2007)

*Re: Good question (liquid stereo)*

I believe there is a difference in the US and UK octane rating systems. The US method is known as AKI and the UK is RON, and there is approximately a 4 to 5 point difference in the two systems (eg. 93 AKI US = 98 RON UK) The inside of some EOS filler caps shows the rating in both standards.


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## WolfsburgerMitFries (Jul 4, 2005)

*Re: Good question (ravennarocket)*

That's the cloudy area I'm not sure of. In the USA there are 2 octane specifications, *Research* and *Motor* method. The octane rating listed on the pump is averaged between the 2, infact the octane rating stickers used to have the formula right below the octane number, it read (R + M)/2.











_Modified by WolfsburgerMitFries at 10:53 PM 5-14-2007_


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## liquid stereo (Feb 26, 2003)

*Re: Good question (WolfsburgerMitFries)*

An easy way to answer it is this: VAG 2.0T engines in the U.S. makes use of 91 Octane and nothing higher. What is the number recommended in Europe?
That's an equivalency http://****************.com/smile/emthup.gif

_Quote, originally posted by *WolfsburgerMitFries* »_That's the cloudy area I'm not sure of. In the USA there are 2 octane specifications, *Research* and *Motor* method. The octane rating listed on the pump is averaged between the 2, infact the octane rating stickers used to have the formula right below the octane number, it read (R + M)/2.


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## ravennarocket (May 4, 2007)

*Re: Good question (liquid stereo)*

Here is a link to a Honda blog that discusses the difference:
http://hondaswap.com/reference...59435/
Not sure it sheds full light, but confirms that US (and Canada) rating system results in lower number for same octane level. Also, I noted Australian site that described UK/Australian 98 as being equivalent to US 93. Cheers,


_Modified by ravennarocket at 9:39 PM 5-14-2007_


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## oab97 (Feb 18, 2007)

*Re: Price of gas (darien)*


_Quote, originally posted by *darien* »_I am curious to know if your EOS is manual or DSG. My EOS is DSG and I live in West Houston near Memorial City mall area, and I usually get about 27/28 mpg. I drive in the Highway and City equally. And yes, I only used the Octane 87 gas from Costco as well. However, my EOS has about 7.2K miles now, the only thing I can say is, give it some time, your EOS will give you good mileage.

It's DSG. I've never had a car (I've had 7 now) where my mpg was so far outside the percieved norm for the vehicle. I've tried varying my driving habits and driving like granny only seems to make a 1-2 mpg diffrence. It's unfathomable to me how all fo you are getting 10+mpg better than I am on a regular basis. We'll see how much the engine "loosens up" over time. In the meantime I'm glad I drive less than 20 miles per day and even at 17mpg I only have to fill up every week and a half.


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## liquid stereo (Feb 26, 2003)

*Re: Price of gas (oab97)*

Another statistic, I'm getting between 25 and 28mpg, with a 60% city, 40% highway mix.
I hope improvement comes your way http://****************.com/smile/emthup.gif


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## ChicagoVW (Sep 10, 2006)

*Re: Price of gas (liquid stereo)*

I think there is a vast difference between "city" driving and "city" driving. If I'm in stop and go traffic in the densest parts of Chicago, where there are stop lights or stop signs at every block and I idle in traffic between them I get 13-15mpg. If I'm in the less dense parts of Chicago where stop lights are 1/2 mile apart I get 17-22mpg. Out in the suburbs I get 25-28mpg. Top down on my one road trip and I got about 30mpg.
Alex


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## kghia (Nov 16, 2006)

*Re: Price of gas (oab97)*

the rated mpg is 32 hwy, but only 23 city.
If you are only driving short distances, it should probably all be considered city.
If you are actually having to speed WAAAY up, and then waay done during the short distances, then you just probably have the worst mpg situation.
Myself, I am driving mostly a highway commute back and forth, but there is a little city at first and a little at the end.
When I drove a long stretch at once this weekend to visit my mother, I actually got 28-29+ mpg, and that going through the mountains. Being on a constant move along a highway weighed more in the process I guess.
William


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## Canadian Lurker (Nov 11, 2006)

*Re: Price of gas (ChicagoVW)*

So I just filled up tonight after running on fumes...partly hoping that the price would come down a bit and partly just too rushed to get it done sooner. Anyways, just paid $1.189 / litre for 52.277 litres for Premium = $62.16 (CAD) in total. 
That's roughly $56 USD for the fill up with 13.8 gallons. This makes the price about $4.05 USD / gallon.








Enough to be noticeable, and to complain about it around the water-cooler or on Vortex, but realistically, not enough to change anything.
JJ


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## PanEuropean (Nov 3, 2001)

*Re: Price of gas (WolfsburgerMitFries)*


_Quote, originally posted by *WolfsburgerMitFries* »_ In Europe, cars run on petrol, which is a higher octane fuel that's used as a vehicle for all sorts of additional taxes that pays for education, infrastructure, and *Health care*. 

Whoa, careful there. How fuel taxes are used varies greatly from country to country. For example, in Switzerland, there is a law that states that fuel taxes may only be used for the purpose of maintaining the road network, and for no other purpose at all. This partially explains why the Swiss have good roads and also very low fuel prices when compared to all other European countries. However - there are 26 different countries in 'Europe' (if we define Europe as the EC and candidate states) and I bet there are 26 different ways that fuel taxes are used.
In Canada, fuel is taxed by both the federal and provincial governments, and to the best of my knowledge, the revenue just gets tossed into the general operating fund - in other words, it is not earmarked or restricted in any way.
Michael


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## PanEuropean (Nov 3, 2001)

*Re: Good question (liquid stereo)*


_Quote, originally posted by *liquid stereo* »_An easy way to answer it is this: VAG 2.0T engines in the U.S. makes use of 91 Octane and nothing higher. What is the number recommended in Europe?

Sean:
A caution - the difference in fuel octane (anti-knock resistance) specified for similar engines in different countries may vary significantly because of emission or other certification standards differing between countries, not only because of the different measuring index for anti-knock resistance.
In simple terms, and with sufficient accuracy for any discussion we would conduct here in the forum, you can convert an American anti-knock rating to a European anti-knock rating by simply adding 4 to the American rating - or subtracting 4 from the European rating. That method is more than accurate enough for any motor fuel that is sold to the general public at gas stations in either Europe or North America.
But - you might find that what appears to be the same engine (for example, a 1.6 liter engine in a small car) might have different anti-knock requirements in different countries (even after allowing for the conversion of the anti-knock ratings) because the engineers want to obtain different performance from the engine in different countries. 'Performance', in this context, could be emission levels, mileage ratings, acceleration, or any combination of factors.
Michael


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## PanEuropean (Nov 3, 2001)

*Re: Price of gas (liquid stereo)*


_Quote, originally posted by *mark_d_drake* »_Please let's not start a Political discussion here, no matter how much you may agree / disagree with the viewpoint stated.

I am going to echo Mark's warning, and ask all of you to respect it.
If you want to discuss any of the following:
- function of the engine
- composition of the fuel
- engineering issues related to the engine or fuel
- specifications related to the Eos
by all means do so. These are technical issues.
If, on the other hand, you feel the urge to discuss anything that is even remotely related to:
- ecology
- war
- carbon emissions
- environmental issues
- save the planet
- nuke the whales
- governments
- religion
- politics
- taxes
- ethics
- why you can't find a good 5¢ cigar anymore
then click right here: The Car Lounge to switch forums and go to The Car Lounge, where I am sure that you will find hundreds of other people who are just aching in their heart to discuss those topics with you.
*This specific forum - the Eos forum - is restricted to technical discussions only. That's the rules! *







Remember: Opinions are like anuses- everyone has one. Go to the Car Lounge if you want to compare yours with anyone else's.


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## PanEuropean (Nov 3, 2001)

*Re: Price of gas (PanEuropean)*

Apropos of the price of gas in general - I just finished driving from Scottsdale, AZ to Toronto, Canada during the last 7 days. The price of 91 octane fuel ranged from about $3 a gallon to about $3.50 a gallon. I did a little bit of math and figured out that the car consumed $10 of fuel every hour (every 65 miles).
Michael


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## swordfish1 (Jul 22, 2006)

*Re: Price of gas (WolfsburgerMitFries)*


_Quote, originally posted by *WolfsburgerMitFries* »_It gets tiring hearing people attempt to compare apples to oranges. In Europe, cars run on petrol, which is a higher octane fuel that's used as a vehicle for all sorts of additional taxes that pays for education, infrastructure, and *Health care*. In the USA, gasoline is a lower octane, lower quality vehicle fuel that is not as heavily burdened by taxes, nor does it pay for health care. You simply cannot compare fuel prices in Europe to fuel prices in the USA anymore that you can configure a car on a European website and attempt to translate the total price from Euros to Dollars.


At the end of the day though, it does merit a comparison. It matters little what the taxes on fuel pay for or the octane level. The point is if I want to get from A to B, I'm having to pay $10 per gallon for that privilege.


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## ravennarocket (May 4, 2007)

*Re: Good question (PanEuropean)*

Excellent explanation! Through all of this, we not be very good pontificators or politicians;but maybe we will understand octane ratings and fuel requirements a little better! Through it all, gues I'll continue to give my car the best available ... 93 in Canada.
_Quote, originally posted by *PanEuropean* »_
Sean:
A caution - the difference in fuel octane (anti-knock resistance) specified for similar engines in different countries may vary significantly because of emission or other certification standards differing between countries, not only because of the different measuring index for anti-knock resistance.
In simple terms, and with sufficient accuracy for any discussion we would conduct here in the forum, you can convert an American anti-knock rating to a European anti-knock rating by simply adding 4 to the American rating - or subtracting 4 from the European rating. That method is more than accurate enough for any motor fuel that is sold to the general public at gas stations in either Europe or North America.
But - you might find that what appears to be the same engine (for example, a 1.6 liter engine in a small car) might have different anti-knock requirements in different countries (even after allowing for the conversion of the anti-knock ratings) because the engineers want to obtain different performance from the engine in different countries. 'Performance', in this context, could be emission levels, mileage ratings, acceleration, or any combination of factors.
Michael


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## liquid stereo (Feb 26, 2003)

*Re: Good question (PanEuropean)*

True. I didn't think of the temperature/timing-emissions connection http://****************.com/smile/emthup.gif 
BTW, the Honda link that someone above included seems correct.

_Quote, originally posted by *PanEuropean* »_
Sean:
A caution - the difference in fuel octane (anti-knock resistance) specified for similar engines in different countries may vary significantly because of emission or other certification standards differing between countries, not only because of the different measuring index for anti-knock resistance.
In simple terms, and with sufficient accuracy for any discussion we would conduct here in the forum, you can convert an American anti-knock rating to a European anti-knock rating by simply adding 4 to the American rating - or subtracting 4 from the European rating. That method is more than accurate enough for any motor fuel that is sold to the general public at gas stations in either Europe or North America.
But - you might find that what appears to be the same engine (for example, a 1.6 liter engine in a small car) might have different anti-knock requirements in different countries (even after allowing for the conversion of the anti-knock ratings) because the engineers want to obtain different performance from the engine in different countries. 'Performance', in this context, could be emission levels, mileage ratings, acceleration, or any combination of factors.
Michael


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## PanEuropean (Nov 3, 2001)

*Re: Good question (ravennarocket)*


_Quote, originally posted by *ravennarocket* »_...Through all of this, we not be very good pontificators or politicians;but maybe we will understand octane ratings and fuel requirements a little better!

Geez, I wish. Honestly, I have never been able to figure out what the whole story is behind minimum octane requirements. I think that the effects of using a lower than specified octane fuel will vary quite considerably from engine type to engine type, and this is something we can't make generalizations about.
Case in point - the Phaeton. Owners of Phaetons with W12 engines have a choice of running on regular grade (87 in North America) or premium grade (91 in North America), and the owners manual states that the car will run just fine on 87, the only difference is that it won't produce full horsepower. Many of us have discovered that we don't need the full 420 horsepower to bring the groceries home from the local mall, so we use 87.
However - the owners of Phaetons with V8 engines don't have this choice. They are obliged to use super grade fuel (91 in North America), because that is the only grade that is specified on the fuel cap door sticker. We don't know what the effects of using a lower grade are - whether it causes emission problems, performance problems, decreased fuel economy, or tooth decay.
For what it's worth, there is quite a long (and in some parts, scholarly) discussion about fuel grades in the Phaeton forum. Here's the link: Fuel Octane Specifications for the Phaeton (includes TB 01-06-02, Fuel, Poor Quality). But, please, out of pity for this poor moderator, don't post anything to that thread. I don't think I could cope with the stress caused by having two octane threads running simultaneously in both of the forums that I moderate.








Michael


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## liquid stereo (Feb 26, 2003)

*Octane, engines, technology, and knock.*

I would be very surprised if there isn't a direct correlation between compression ratio and req./recommended octane level.
Personally, I believe the bit about engine temperature being higher (due to lower octane) is a red herring, at least under "normal" operation, but that's just my opinion. From a combustion point of view, the differences between the V8 and W12 are fairly minimal. Unless (a) one is FSI and the other PFI, or (b) the amount of mixing caused by the difference in valve layouts causes the combustion process in one engine to approach something like homogeneous charge compression ignition (HCCI). HCCI is great as there is no flame-propagation process. Instead of there being the traditional turbulent diffusion flame(s), the combustion process becomes more like a "pre-mixed" one.
Interesting links:
http://www.llnl.gov/str/Westbrook.html
http://www.me.berkeley.edu/cal/HCCI/
HCCI combustion:








Potential piston damage due to prolonged knock











_Modified by liquid stereo at 5:23 AM 5-16-2007_


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## cb391 (Mar 12, 2006)

*Re: Octane, engines, technology, and knock. (liquid stereo)*

Actually octane rating and compression ratios are intertwined. The higher the compression the higher octane that is needed. More compression generates more heat. Lower octane fuel does not work right under this condition. Instead of the spark plug igniting the fuel, the heat of compression ignites the fuel prematurely. This basically is what a diesel does. So theoretically a low compression engine should run slightly cooler because lower octane fuel requires less heat to ignite. Btw way if the 2.0 engine had no turbo it would probably be rated with 87 octane. If you check I believe you will find the W12 runs lower compression than the V8 in the Phaeton.
Andy


_Modified by cb391 at 1:33 PM 5-16-2007_


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## liquid stereo (Feb 26, 2003)

*Re: Octane, engines, technology, and knock. (cb391)*

That's what I was suggesting... I may have done so in a somewhat unclear manner.
Thanks http://****************.com/smile/emthup.gif 

_Quote, originally posted by *cb391* »_Actually octane rating and compression ratios are intertwined. The higher the compression the higher octane that is needed. More compression generates more heat. Lower octane fuel does not work right under this condition. Instead of the spark plug igniting the fuel, the heat of compression ignites the fuel prematurely. This basically is what a diesel does. So theoretically a low compression engine should run slightly cooler because lower octane fuel requires less heat to ignite. Btw way if the 2.0 engine had no turbo it would probably be rated with 87 octane. If you check I believe you will find the W12 runs lower compression than the V8 in the Phaeton.
Andy




_Modified by liquid stereo at 4:49 PM 5-16-2007_


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## solarflare (Mar 28, 2007)

*Re: Octane, engines, technology, and knock. (cb391)*


_Quote, originally posted by *cb391* »_Btw way if the 2.0 engine had no turbo it would probably be rated with 87 octane. 

Not necessarily true, compression ratio, which dictates octane rating, has to do with combustion chamber design, cylinder bore diameter, piston stroke length, ect. You can still have a high compression engine with no turbo charger so the question would be to find out if these parameters are different for the 2.0FSI non turbo engine. If they are the same it would require higher octane as well.


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## liquid stereo (Feb 26, 2003)

*Re: Octane, engines, technology, and knock. (solarflare)*

I believe the 2.0 FSI (normally-aspirated) requires a higher octane for emission reasons.

_Quote, originally posted by *solarflare* »_
Not necessarily true, compression ratio, which dictates octane rating, has to do with combustion chamber design, cylinder bore diameter, piston stroke length, ect. You can still have a high compression engine with no turbo charger so the question would be to find out if these parameters are different for the 2.0FSI non turbo engine. If they are the same it would require higher octane as well.


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## cb391 (Mar 12, 2006)

*Re: Octane, engines, technology, and knock. (solarflare)*

The 2.0 has a compression if I remember of 10.3 to1. That should be able to run 87. My Escape is 10.0 to 1 and does. If you get to 11.0 to 1 then you need to be running 89 or higher. The Turbo while it technically does not boost compression like the factors you cited, the end result is similar. The cylinder fills with a denser air/fuel mixture which has less ability to compress. When the mixture ignites it decompresses with much more force. Higher octane fuel helps control this process better than low octane so that it burns more than explodes. You could pull the turbo off a 2.0 and it would run on 87 only it would have about 140hp. As for pollution controls there might not be any or much difference.
Andy


_Modified by cb391 at 4:43 PM 5-16-2007_


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## liquid stereo (Feb 26, 2003)

*Re: Octane, engines, technology, and knock. (cb391)*

I'm referring to the 2.0 FSI (Europe-only) engine. Not the 2.0 PFI engine that was here in North America for a few years.
Are you referring to the same?

_Quote, originally posted by *cb391* »_The 2.0 has a compression if I remember of 10.3 to1. That should be able to run 87. My Escape is 10.0 to 1 and does. If you get to 11.0 to 1 then you need to be running 89 or higher. The Turbo while it technically does not boost compression like the factors you cited, the end result is similar. The cylinder fills with a denser air/fuel mixture which has less ability to compress. When the mixture ignites it decompresses with much more force. Higher octane fuel helps control this process better than low octane so that it burns more than explodes. You could pull the turbo off a 2.0 and it would run on 87 only it would have about 140hp. As for pollution controls there might not be any or much difference.
Andy

_Modified by cb391 at 4:43 PM 5-16-2007_


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## cb391 (Mar 12, 2006)

*Re: Octane, engines, technology, and knock. (liquid stereo)*

No. I was talking about using TFSI 2.0 as used here and removing the turbo. From what I have found out the FSI is a Euro engine that has 170 hp and 177ft lbs of torque. Its torque kicks in at 1750 where the TFSI starts at 1800 (according to the vw site I found). My guess there is a bore/stroke difference and possibly a different head/valvetrain. The FSI engine is likely a higher compression engine. The two engines could have slightly different displacements and still be considered 2.0L. As for thr PFI engine, i'm guessing that is a diesel from what I have seen so far on the net.
Andy


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## flubber (Sep 12, 2005)

*Re: Octane, engines, technology, and knock. (cb391)*


_Quote, originally posted by *cb391* »_No. I was talking about using TFSI 2.0 as used here and removing the turbo. From what I have found out the FSI is a Euro engine that has 170 hp and 177ft lbs of torque. Its torque kicks in at 1750 where the TFSI starts at 1800 (according to the vw site I found). My guess there is a bore/stroke difference and possibly a different head/valvetrain.

I think those specs are for the TSI engine, which is actually a 1.4L with a supercharger and a turbocharger. The 2.0FSI generates about 150HP.

_Quote »_The FSI engine is likely a higher compression engine.

But this appears to be correct. Looking at the specs on the Volkswagen Germany site, it looks like the compression is 11.5:1 and they recommend 95 RON.


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## BigFoot-74205 (Jan 26, 2006)

I own an Eos with the 2.0 FSI engine (150HP) and they recommend 98 octane fuel (that's what, 91 in US?) though 95 is allowed as well. I always fill up with at least 98 octane, often even with 100 octane (same price as 98 but not all gas stations have it).


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## PanEuropean (Nov 3, 2001)

*Re: (BigFoot-74205)*


_Quote, originally posted by *BigFoot-74205* »_...they recommend 98 octane fuel (that's what, 91 in US?)...

The quick conversion factor (good enough for the purpose of this discussion) is that you deduct 4 from European rating numbers to get the American rating number, or add 4 to the American number to get a European number. Because this is a 'quick and dirty' conversion, you can allow 1 unit for rounding in either direction. Thus:
98 in Europe = 93 in North America
95 in Europe = 91 in North America.
I don't think fuels with ratings lower than 95 are sold in Western Europe anymore, although I do recall seeing 91 in the Czech Republic and in Slovakia last summer.
Michael


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## BigFoot-74205 (Jan 26, 2006)

Michael,
Thanks for posting the NA octane ratings. And yeah, it's been years since 91 was available here.
Damir


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## chrisj428 (Feb 26, 2005)

*Re: (PanEuropean)*

NAR EOS 2.0T: 10.3:1 compression ratio
NAR Phaeton V8: 11.0:1 compression ratio
NAR Phaeton W12: 10.8:1 compression ratio
Keep in mind, these compression ratios do not take _density_ into account, only volume. So, when you add a turbocharger to the equation, while the compression ratio remains the same, the density changes.
I don't know the math, but I'd have to believe a turbocharger operating at full output would raise the "effective" compression ratio by more than a few points.


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## liquid stereo (Feb 26, 2003)

*Density is higher*

Thanks http://****************.com/smile/emthup.gif
This brings up some interesting points that can be clarified with the use of high-school physics and chemistry - P = rho * R * T, where R is the gas constant, rho is the density, P is the pressure, and T is the temperature.
(1) I don't think the operating temperatures are significantly different betweent the various engines as oils, cooling systems and fuels are the same. Therefore T=constant across the various engines.
(2) Turbo/supercharged engines achieve power levels of higher displacement engines because they simulate higher displacement engines by compressing the reactants. This means that P is greater in the turbocharged engines. With R and T being constant, this means the density is greater as well.
This is backed up by the fact that VAG beefs up the connecting rods and such in their high-output engines. The easiest example is/was the 180hp and 225hp 1.8T engines.


_Quote, originally posted by *chrisj428* »_NAR EOS 2.0T: 10.3:1 compression ratio
NAR Phaeton V8: 11.0:1 compression ratio
NAR Phaeton W12: 10.8:1 compression ratio
Keep in mind, these compression ratios do not take _density_ into account, only volume. So, when you add a turbocharger to the equation, while the compression ratio remains the same, the density changes.
I don't know the math, but I'd have to believe a turbocharger operating at full output would raise the "effective" compression ratio by more than a few points.


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## kghia (Nov 16, 2006)

*Re: (PanEuropean)*


_Quote, originally posted by *PanEuropean* »_The quick conversion factor (good enough for the purpose of this discussion) is that you deduct 4 from European rating numbers to get the American rating number, or add 4 to the American number to get a European number. Because this is a 'quick and dirty' conversion, you can allow 1 unit for rounding in either direction. Thus:
98 in Europe = 93 in North America
95 in Europe = 91 in North America.
I don't think fuels with ratings lower than 95 are sold in Western Europe anymore, although I do recall seeing 91 in the Czech Republic and in Slovakia last summer.
Michael

Michael's numbers should be correct-- the VW recommendation in my wife's Passat says 91 (R+M)/2 *OR* 95 RON.
So Eu. 95 RON == 91 (R+M)/2 N. Amer.
but as others have mentioned, 93 is becoming the standard many places. For instance, I have not seen 91 Octane (R+M)/2 _anywhere_ around NC, or in brief trips through VA, DC, SC, or in LA (Louisiana)
Some people report getting 91 in CA, but it seems like most of the East Coast has already moved to 93 as premium, then 89 & 87.
William


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## solarflare (Mar 28, 2007)

*Re: (kghia)*

I have only seen 91 at one station, a Sunoco in Arlington VA. They sell 4 grades there, which is not the norm around here (87, 89, 91 and 93) I usually gas up there as it's on my way to work and the 91 is a few cents cheaper then 93 to boot


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## cb391 (Mar 12, 2006)

*Re: Octane, engines, technology, and knock. (flubber)*

Thanks, Joe.
I stand corrected. I pulled the wrong info and it was the TSI. I still believe however that an Americanized version (TFSI minus T) could still be made to run 87 and still get 140hp (give or take). 
Andy


_Modified by cb391 at 12:40 PM 5-17-2007_


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## liquid stereo (Feb 26, 2003)

*Regional availability*

Here in the Twin Cities, 91 is the most available from the major gas stations. Some independent shops carry 92.
I wonder what is the percentage of cars being sold today (as opposed to on the road) that can take advantage of 92+ octane gasoline.


_Quote, originally posted by *kghia* »_
Michael's numbers should be correct-- the VW recommendation in my wife's Passat says 91 (R+M)/2 *OR* 95 RON.
So Eu. 95 RON == 91 (R+M)/2 N. Amer.
but as others have mentioned, 93 is becoming the standard many places. For instance, I have not seen 91 Octane (R+M)/2 _anywhere_ around NC, or in brief trips through VA, DC, SC, or in LA (Louisiana)
Some people report getting 91 in CA, but it seems like most of the East Coast has already moved to 93 as premium, then 89 & 87.
William


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## chrisj428 (Feb 26, 2005)

*Re: Density is higher (liquid stereo)*


_Quote, originally posted by *liquid stereo* »_This brings up some interesting points that can be clarified with the use of high-school physics and chemistry - P = rho * R * T, where R is the gas constant, rho is the density, P is the pressure, and T is the temperature.

So, now that we have the compression ratios of the engines and should be able to find with relative ease the psi output of the turbo at max boost on an unmodified car, is there a way to solve for the "virtual" or "effective" compression ratio on a turbocharged engine?


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## liquid stereo (Feb 26, 2003)

*Re: Density is higher (chrisj428)*

I'm not sure.
Compression ratio is typically defined by V2/V1, where V2 is the maximum volume of piston-cylinder and V1 is the minimum volume of the piston-cylinder. Ie. a geometric parameter.
I guess one could define V2 as the equivalent volume of the "charged" mixture at the lowest pressure. The lowest cylinder pressure being when the piston is furthest from top dead center. This would require knowing the pressure at that point.
I'm not sure how the maximum boost would figure in as there all sorts of losses. This is why most if not all turbo charged engines consume more fuel than their equivalent normally-aspirated engines. And by equivalent I mean in terms of power.
http://****************.com/smile/emthup.gif

_Quote, originally posted by *chrisj428* »_
So, now that we have the compression ratios of the engines and should be able to find with relative ease the psi output of the turbo at max boost on an unmodified car, is there a way to solve for the "virtual" or "effective" compression ratio on a turbocharged engine?


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