# high octane gas ?????



## eddiefury (Aug 5, 2007)

So where can I find 93 octane gas?? or even higher, like say... 100 octane?? I'm in the Los Angeles area btw.

Would my 2.0 A3 like this? and if so, would it get used to it and hate me for going back to 91 octane?

i'm not chipped yet, but will do so in August.

thaaaaaanks!


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## JOSER2K (Mar 11, 2006)

I dont remember the streets but i think its on De Soto and Burbank in woodland hills 76 gas station has 93


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## eddiefury (Aug 5, 2007)

it doesn't do any harm at all to use 93 then go back to 91, right?

will my A3 even notice a difference? will I?


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## krazyboi (May 19, 2004)

Here on the east coast...we have 93 regularly


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## OOOO-A3 (Jul 20, 2004)

Greater than 91 in a stock A3 is a waste. 

Since you're in CA, when you get "chipped" you'll be set up for CA gas grades (i.e. you'll get a 91-octane program). Just run your local premium grade and get over it. 

And no, it won't "learn" your gas grade....


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## FreeGolf (Sep 18, 2003)

OOOO-A3 said:


> Greater than 91 in a stock A3 is a waste.


unless you have a 93 tune.


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## crew219 (Oct 18, 2000)

Get chipped, then run water meth and run a 93 octane tune with 91 octane gas. It's the only thing keeping me from going k04 right now.

Dave


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## Gtiupb2002 (Jun 4, 2007)

crew219 said:


> get chipped, then run water meth and run a *100* octane tune with 91 octane gas. It's the only thing keeping me from going k04 right now.
> 
> Dave


fixed :laugh:

No seriously the car is a beast with 100oct Tune.


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## crew219 (Oct 18, 2000)

Gtiupb2002 said:


> fixed :laugh:
> 
> No seriously the car is a beast with 100oct Tune.


Eh, too much timing pull for my taste.


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## trucaliber (May 13, 2009)

eddiefury said:


> Would my 2.0 A3 like this? and if so, would it get used to it and hate me for going back to 91 octane?
> 
> i'm not chipped yet, but will do so in August.


The higher the octane the higher you can boost without knocking. But it comes with a higher cost at the pump, and lower mileage on the highway. With a stock, non-chipped, setup you're not boosting enough to make 89 octane pre-detonate. Although I wouldn't risk putting any 89 in my car since 91 octane quality is much better, and usually the only octane without crappy ethanol getting into the mix.

Once chipped and using more boost your car will be able to enjoy 91+ much more than it does now.

I used to run 89 in my 02 GTP when I wasn't using the super charger. I'd always get +3-4 MPG, but it'd knock like crazy under boost... especially with hot summer air temps.


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## Sagild (Jul 23, 2008)

I have dynoed the difference on my car totally stock with our 99 RON and 95 RON - would be the same as your 93 and 91... The difference was 12 hp and 20 nm so even a stock car notice the difference. The ECU ind your car is very intelligent and will adapt to the fuel you fill on it within 20-30 km so there is no problem changing down the road. Even if you get a specific map to ron 100 octance you can put 93 on it - it wont run perfectly because of the timing settings, but it will run without problems...


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## guiltyblade (Jul 12, 2007)

i run 93 regularly, its not much more expensive on the east coast and makes me feel cool.


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## Uber-A3 (Feb 23, 2002)

Sagild said:


> Even if you get a specific map to ron 100 octance you can put 93 on it - it wont run perfectly because of the timing settings, but it will run without problems...


Unless it calls for more than 12 deg of timing pull, that is all the "intelligent" ecu will do. Try this then.. On a hot day with 100 octane map with 91 in the tank.. Report back please.


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## Sagild (Jul 23, 2008)

Uber-A3 said:


> Unless it calls for more than 12 deg of timing pull, that is all the "intelligent" ecu will do. Try this then.. On a hot day with 100 octane map with 91 in the tank.. Report back please.


I havent got the possibility to try it, first of all because we don't have 100 octane RON on the pumps in Denmark, we only have 99 octane RON and my car normally only touches this... last week i was about to run out and changed to 95 octance RON (which is your 91) and the car ran just as smooth as ever after 2 mins... The timing pull then adjusts when you drive full throttle for some runs, but there is no issue at all... Thats with a REVO map, and i have done it with my old APR map aswell...


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## VWAddict (Jun 12, 1999)

Note: RON... NOT (R+M)/2 by the way...


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## Sagild (Jul 23, 2008)

RON vs MON vs AKI

Here you can find the relevant comparison i am using in my above posts.

http://en.wikipedia.org/wiki/Octane_rating


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## OOOO-A3 (Jul 20, 2004)

OOOO-A3 said:


> Greater than 91 in a *stock* A3 is a waste.





FreeGolf said:


> unless you have a 93 tune.


:what:


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## tdotA3mike (Feb 5, 2009)

OOOO-A3 said:


> :what:


also notice my MPG drops with 94 in stock mode, compared to 91 V power. I think that might have more to do with sunoco/petro canada gas though.


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## skotti (Sep 27, 2005)

First- I' m not professing to be an expert on fuel.
I live on the East coast- 93 is the 'norm' for premium- but at low-end stations (no-name gas, WaWa, Sheetz...etc) the premium is 91, and a bit cheaper.
I notice a definite change in my gas mileage-a decrese- if I fill up with 91 instead of 93.
Also, while I don't put any additives in my tank (I'm thinking I should start putting in the Techron stuff from Chevron- I don't have Chevron gas nearby)- I think there would be some benefit to going with a brand such as Chevron with the additive- 93 octane.

Would like to hear more opinions on fuel additives, etc in this thread (sorry for thread-jacking).


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## FreeGolf (Sep 18, 2003)

OOOO-A3 said:


> :what:


:thumbup:


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## SilverSquirrel (Jul 24, 2006)

FreeGolf said:


> :thumbup:


here in my neck of the woods (New England) 93 runs about a buck exta per tank over 91, so thats what i go for. Tried 91 a few times, and never noticed much difference in mileage. My butt dyno noticed a little less power, but that is not backed up with any number data. 
thats with the 3.2 NA motor..


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## FreeGolf (Sep 18, 2003)

every car i ever owned, i always put 94 in until sunoco discontinued it and we only have 93, so they all get 93. i just dont get the point of buying a high-end car (eg: audi, bmw, mb, etc.) then complain about the gas you put in it or the maintenance etc. it's life. you want to reduce cost? buy economic cars. pretty simple...


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## crew219 (Oct 18, 2000)

FreeGolf said:


> every car i ever owned, i always put 94 in until sunoco discontinued it and we only have 93, so they all get 93. i just dont get the point of buying a high-end car (eg: audi, bmw, mb, etc.) then complain about the gas you put in it or the maintenance etc. it's life. you want to reduce cost? buy economic cars. pretty simple...


You do know that higher octane doesn't mean higher quality right? 

There's really no point in running a higher octane fuel if the ECU is not calibrated to run it. If the car calls for 10 degrees of timing, and 91 octane results in 0 timing pull, 93 octane will have very little benefit (and often less energy content).

Dave


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## VWAddict (Jun 12, 1999)

...almost invariably lower energy content, in fact.

Miles-per-gallon should -if anything- be fractionally LOWER -_not_ higher- with higher octane gasoline.

Today's blends call for a small amount of ethanol in ALL grades, not lower-grades-only, as suggested earlier.

In fact, since Ethanol _per se_ has a HIGH octane rating (E85 for example is VERY high octane) then gas companies tend to use as much as they can in higher-octane blends...

....which is a real bummer, because Ethanol has such a low energy density that you have to use MORE of it for the same power.

So your MPG goes DOWN -not up- with higher octane blends.

Higher octane means retarded detonation; if your car is in stock tune, there is NO call for it. It might burn less completely, it might leave a varnish/glaze, there's all sort of things it might do.

But there's one thing it WON'T do; it won't give you more power. The BOOST/Tune gives you more power. High-Octane fuel gives you more problems, and costs more.

Anyone who thinks that filling a stock car with higher-than-necessary octane rated fuel gives more power or better economy is deluding themselves.

Keith


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## FreeGolf (Sep 18, 2003)

i am certain all the gas suppliers are not selling 91/93/94 for custom tuned cars and there is certainly a benefit of running it... in any event, this debate has been around long before this forum and will be around long after. i personally prefer to purchase 93 regardless of tune or stock.


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## MisterJJ (Jul 28, 2005)

crew219 said:


> You do know that higher octane doesn't mean higher quality right?


That depends. First off... by "quality" I would assume you are talking about additives. In most areas all gas stations use the same base gas but the "branded" stations have certain beneficial additives added, making their gas better "quality".

So to get your additives, buy branded gas. Now once you are buying branded gas, do you get better additives with the higher octane gas? The consensus seems to be that companies add the same additives to all grades of gas so it does not matter.

So... Buy branded gas at the octane level recommended by the manufacturer.

Personally, I switch between branded and unbranded gas because from what I've read, the additives in the branded gas are very affective at removing any stuff left by the unbranded gas and besides, the additives only help clean the injectors, not the valves, in a direct injection engine. (Although I also give my car a shot of Redline fuel treatment on occasion).

P.S. Minimum required grade doesn't always work best. With 87 octane in my Jetta 2.sl0w it would top out at around 80 mph going up a long hill in my daily commute and it sounded aweful doing it. With 89 octane it would hit almost 90 mph and sound much better. 91 octane didn't improve things further though.


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## Krieger (May 5, 2009)

now that i have WM, im running regular gas and getting all the benefits of my 93 octane tune. :laugh:


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## MisterJJ (Jul 28, 2005)

VWAddict said:


> ...almost invariably lower energy content, in fact.
> 
> Miles-per-gallon should -if anything- be fractionally LOWER -_not_ higher- with higher octane gasoline.


As long as you don't go below the minimum required.

You want the lowest octane gas THAT PREVENTS PREMATURE DETONATION. Once you start getting detonation the car will retard your spark and make the combustion process much less efficient. That's why you don't want to go below the manufacturers recommened octane and if you do you will likely get worse gas mileage.

Using higher grade than required won't get you any benefit unless you've got a tune to match.


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## FreeGolf (Sep 18, 2003)

MisterJJ said:


> Personally, I switch between branded and unbranded gas because from what I've read, the additives in the branded gas are very affective at removing any stuff left by the unbranded gas and besides, the additives only help clean the injectors, not the valves, in a direct injection engine. (Although I also give my car a shot of Redline fuel treatment on occasion).


about once a month i use either techron additive or the oem audi additive and alternate between the two. never had any issues, and cannot say it is because of this, but cannot say it hurt.


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## VWAddict (Jun 12, 1999)

MisterJJ said:


> As long as you don't go below the minimum required.


Indeed.


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## LWNY (Jul 30, 2008)

VWAddict said:


> Indeed.


I know people that has the Passat with the Audi 2.8 engine and they get the lowest octane gas they can find given that with the knock sensor, they can go cheap.

Stupid Consumer Report and its recommendation of the Passat, it brought in all sorts of people looking for appliance cars.


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## dmorrow (Jun 9, 2000)

MisterJJ said:


> As long as you don't go below the minimum required.
> 
> You want the lowest octane gas THAT PREVENTS PREMATURE DETONATION. Once you start getting detonation the car will retard your spark and make the combustion process much less efficient. That's why you don't want to go below the manufacturers recommened octane and if you do you will likely get worse gas mileage.
> 
> Using higher grade than required won't get you any benefit unless you've got a tune to match.


This is what I have always thought but I did read this article - 

http://www.europeancarweb.com/tech/epcp_1007_2010_volkwagen_jetta_proven/index.html

and the test is based on using Premium or Regular Unleaded in a Jetta 2.5L unmodified car and got better results using Premium. 

Because of the very limited test I don't think this proves anything but it does raise questions.


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## Sagild (Jul 23, 2008)

VWAddict said:


> ...almost invariably lower energy content, in fact.
> 
> Miles-per-gallon should -if anything- be fractionally LOWER -_not_ higher- with higher octane gasoline.
> 
> ...


And yet again: I have tested this on my own car and there IS a difference... The difference is MUCH bigger with af tuned car, but there was a difference in my car which was noticeable even at stock! It is always recommended to use higher octane with a turbo car... If you buy the 2,0 FSI audi/vw will advise you to use your 91 (our 95 octane), but when you buy a 2,0 TFSI they advice you to use 91/93 (our 95/98 octane)... I decided then to test the difference and conclusion was undeniable!


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## Sagild (Jul 23, 2008)

MisterJJ said:


> As long as you don't go below the minimum required.
> 
> You want the lowest octane gas THAT PREVENTS PREMATURE DETONATION. Once you start getting detonation the car will retard your spark and make the combustion process much less efficient. That's why you don't want to go below the manufacturers recommened octane and if you do you will likely get worse gas mileage.
> 
> Using higher grade than required won't get you any benefit unless you've got a tune to match.


I have to this day NEVER heard of a 2,0 TFSI with a premature detonation causing the engine to break! The ECU (as i have said before) is so intelligent that it automatically adjusts... 

Talks about old jettas and old 2,8 audis have nothing to do with the FSI technology and the ECU controlling it... I follow a lot of tuned seat leon cupras, audi s3's and edition 30 gti's and so on... I am online on different forums across the world and there is no place i have come across a premature detonation caused by example a tuning for 95 octane with 89 octane on it...


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## MisterJJ (Jul 28, 2005)

Sagild said:


> I have to this day NEVER heard of a 2,0 TFSI with a premature detonation causing the engine to break! The ECU (as i have said before) is so intelligent that it automatically adjusts...


You are missing the point. Nobody is claiming that it will break your engine. As you said, it automatically adjusts. That adjustment causes a loss of horsepower and loss of gas mileage, negating any savings from the lower grade gas. Although an argument could be made that using the low octane gas will cause some premature detonation before the car can adjust and that could increase wear and potentially break something.


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## tdotA3mike (Feb 5, 2009)

VWAddict said:


> ...almost invariably lower energy content, in fact.
> 
> Miles-per-gallon should -if anything- be fractionally LOWER -_not_ higher- with higher octane gasoline.
> 
> Today's blends call for a small amount of ethanol in ALL grades, not lower-grades-only, as suggested earlier.


shell v-power at least 91 in canada has zero ethanol 

other stations like sunoco/petro canada use ethanol in all grades of their fuel.


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## tdotA3mike (Feb 5, 2009)

MisterJJ said:


> You are missing the point. Nobody is claiming that it will break your engine. As you said, it automatically adjusts. That adjustment causes a loss of horsepower and loss of gas mileage, negating any savings from the lower grade gas. Although an argument could be made that using the low octane gas will cause some premature detonation before the car can adjust and that could increase wear and potentially break something.


i say put what the factory minimum is.. if its 91 do not put anything lower then 91. my car has never seen anything lower then 91 and usually only sees shell( i get the best MPG from shell by far).


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## VWAddict (Jun 12, 1999)

tdotA3mike said:


> shell v-power at least 91 in canada has zero ethanol


Lucky Canadians.

Here in the US it's now federally mandated that all gasoline sold at street pumps must contain at least 10% Ethanol.

George Bush pushed that one through into law.

Bastard.


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## tdotA3mike (Feb 5, 2009)

VWAddict said:


> Lucky Canadians.
> 
> Here in the US it's now federally mandated that all gasoline sold at street pumps must contain at least 10% Ethanol.
> 
> ...


we do not have 93/94 at shell stations though  i think 87 has 10% and 89 has 5% at our shells


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## Sagild (Jul 23, 2008)

Here in Denmark we have Shell V-power 99 octane RON which has a max of 5% ethanol...

Sorry i understood you as to saying it would break your car, but i still dont follow you. You say that there will be a reduced milage and loss of horsepower when going down in octane? But i guess that means your supporting what i have written? That a higher octane would give an engine like ours more horsepower (like i have stated - and have tested on dyno) and that there is no problem going down in octane in the future, since the car would automatically adapt to make the best out of the new octane rating...


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## VWAddict (Jun 12, 1999)

Sagild said:


> that there will be a reduced milage and loss of horsepower when going down in octane?


That's an oversimplification, which omits enough information to the point where it is no longer accurate.

It requires the words BELOW THE REQUIRED OCTANE LEVEL to be accurate.

It depends where you're starting from. If you're significantly ABOVE the required octane rating to prevent/deter the onset of knock, then going down in octane rating is actually marginally beneficial. If you go BELOW the required octane number, then power and mileage DECREASES because the ECU has to retard timing to prevent detonation, and by doing so reduces power output.



Sagild said:


> ...since the car would automatically adapt to make the best out of the new octane rating...


There is a fixed LIMIT to how far the car can adapt; since the maximum amount of ignition retardation adaptation is limited by the combustion chamber design, and the timing point. It's also affected by air charge temperature, and other factors ALL of which combine to affect how much adaptation the engine can manage.

Oversimplification doesn't help proper understanding.

'Saying that the cart will just adapt' is an oversimplification which can lead people to just buy lower octane gas and think that there's nothing wrong in doing that... I really think it's a bad idea to promote misunderstandings like that.


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## Sagild (Jul 23, 2008)

I have only encouraged to buy higher octane in my posts! So my point is that you get more out of your car with a higher octane level.

As i have said several times i went from 99 octane RON to 95 octane RON which is both within the factory required octane level. My statement has been very simple: there is a significant difference between these two octane levels even on a standard car. The intake temperature and what not has a influence - off course!! but without changing the external factors as intake temperature and what not, there is a significant difference in running different octane on a stock car.

Conclusion: Run as high octane as you are willing to pay for and if you change your mind down the road, there is no issue at all by changing back to a lower octane level. You shall obviously (to me at least) not use a lower rating than adviced by the factory. That will be the same as putting a 12 volt battery to your 220 volt tv thinking it would work just as well...


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## VWAddict (Jun 12, 1999)

Sagild said:


> I have to this day NEVER heard of a 2,0 TFSI with a premature detonation causing the engine to break! .... snipped a lot of waffle


I'm not replying to this bait.

I never said that "the engine will break", and yet again you're resorting to massive oversimplifications.

If that's how you see life, enjoy it, but I can't discuss the subtleties with you, evidently.

Keith


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## Sagild (Jul 23, 2008)

OMG your replying to a post thats 10 posts old, which i already have demented 3 posts ago because i thought the author meant different... Read the posts before posting indifferent comments like that...

I have dynos supporting what i am saying, until now i am the only one posting in this thread who actually have professionally tested their answers to Eddiefury instead of just talking of what they think...


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## VWAddict (Jun 12, 1999)

Ohferfuxsake...

You write like you're the one true god. the only person who knows ANYTHING.

"...Professionally tested..."
"...Proven..."

Things are so black-and-white-simple to you. You reach a conclusion and present it as proven fact.

Good luck to you.


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## sabba (Oct 25, 2008)

Running anything over 91/93oct w/o proper tune is useless. And there are no gains to be made because I professionally say so....


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## Sagild (Jul 23, 2008)

LOL grow up and come up with something useful for the OP or go write in off topics kid...


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## sabba (Oct 25, 2008)

Sagild said:


> LOL grow up and come up with something useful for the OP or go write in off topics kid...


I did contribute, there is no way the ecu will advance more timing or boost to take adv of a higher octane gas. It just wish my ecu has the ability to tune itself...I wish...


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## SilverSquirrel (Jul 24, 2006)

sabba said:


> boost just wish my ecu has the ability to tune itself...I wish...


It does. Its called APR or GIAC etc...:screwy:


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## sabba (Oct 25, 2008)

Apr and giac .... Really?


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## SilverSquirrel (Jul 24, 2006)

sabba said:


> Apr and giac .... Really?


really.


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## sabba (Oct 25, 2008)

OP in order to take advantage of any fuel higher than 93oct on a stock car or a car with a "chip" you will need a specific tune. Don't waste your money on race gas as the ecu will not take advance of it.


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## Sagild (Jul 23, 2008)

Sabba my reply wasn't to you it was to vwaddict...

I agree with you that racefuel wont give you anything compared to normal high octane fuel... Plus: racefuel costs sooo much more than normal high octane...


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## sabba (Oct 25, 2008)

Race gas is $$$$ but the gains are impressive. It's also why many of us run pump gas plus water/methanol injection on a more aggressive tune. The ecu remains happy and does not "protect" the car by pulling timing or boost.


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## gCHOW (May 26, 2006)

saw 100 octane race gas at a 76 the other day and it was $7.99/gal.

f dat.


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## Sagild (Jul 23, 2008)

Octane 99 RON here in denmark cost just under 7 dollar/gal. and thats what i pay everyday


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## VWAddict (Jun 12, 1999)

Sagild said:


> kid...


You funny.

Wrong, but funny.


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## Sagild (Jul 23, 2008)

VWAddict said:


> You funny.
> 
> Wrong, but funny.


*ignore


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## Uber-A3 (Feb 23, 2002)

Sagild said:


> *ignore


Good advice for this thread in general

cliff notes:
1. A stock car does not require nor take advantage of anything higher than 91 octane
2. A car will run on a lower octane as long as the ecu doesn't call for more timing pull than is necessary to prevent damage but may have a negative effect on MPG and power output.
3. It's your car put whatever gas or fluid you want into the tank.
4. People like to turn technical discussions into vocabulary and language discussions.


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