Fuel ????

[VWSM]

Hi every one this post is without prejudice,what is posted is not represented
by the manufacturer Volkswagen or any Other.

Bio Diesel:any thing over 8% may lead to stalling conditions at lower temperatures like 4-5 degrees celcius.
if your going to use farm diesel make sure it runs thru the filters before you
put it in your tank.do not syphon it out directly.nothing wrong with the
quality except it's illegal to use for non-agricultural business

octane:at our level 91 vs 87 makes no difference in power..at sea level it
is a big difference.91 octane and above thou have a better detergent
package to clean your injection system.
if your car is heavily modified then you use 91-94.prevents your engine
from knocking.but for the average joe use regular and enjoy the savings.

fuels containing ethanol will prematurally damage your fuel tank and injectors.
causes specific plastic or seals to break down.
great for winter starting thou.

diesel fuel try diffrent stations untill you find one that you like.some of the
fuel samples we have sent out have had animal and vegetable matter added
to it,but yet not stated it is bio-diesel.if you believe your car is smoking
excessively try a diffrent brand or station.lot's of people come to see me
and after checking the specifics it turns out to be fuel quality.

and you guessed it 99% are diesel owners.
anyone who wants some literature for fuel let me know and i believe i still
have some info especially on diesel.

[Aleks]

Re: Fuel ????

did I just see a reference to modded vehicles? you work at a dealership right? just kidding, I just noticed the "its not from VW" statement at the top...

Funny though, the best fuel in calgary is blended, and you state thats bad for seals and stuff eh? I've found all 91 oct in calgary is crap, and haven't found a 93 station yet......just 94 from husky...

[RedMile04]

Re: Fuel ????

So does this mean an unmodded 1.8t engine does not truly need to run on premium fuel like stated by vw. Just curious as I hope to finally get one later this week and its my only last concern; whether I can continue to run 87 (like my turbo volvo) or will I have to bump it up to 91?

[R_Ethug]

Re: Fuel ????

i'm pretty sure if put 87 in my S4 it'll work like poo

[Smonty]

Re: Fuel ????

Octane ratings deal with how slow the fuel will burn. A 91 octane will burn slower, cleaner and more completely than an 87. That being said, a friend of mine ran 87 in his A4 1.8T without any problems. But I dont see how atmospheric pressure would effect any octane ratings. Octanes aren't about performance anyway they are about preventing detonation. At sea level there is a denser charge of air in the cylinder which would lead me to believe that a higher octane will burn the charge more completely and give you better performance/less detonation.

[VWSM]

Re: Fuel ????

Octane ratings deal with how slow the fuel will burn. A 91 octane will burn slower, cleaner and more completely than an 87. That being said, a friend of mine ran 87 in his A4 1.8T without any problems. But I dont see how atmospheric pressure would effect any octane ratings. Octanes aren't about performance anyway they are about preventing detonation. At sea level there is a denser charge of air in the cylinder which would lead me to believe that a higher octane will burn the charge more completely and give you better performance/less detonation.

As explained to me it does not have to due with bar's of pressure but with
O2 content,the higher you go the less O2 you have.hence you waste the octane performance..
as explained to me in layman terms..
at the end use what ever works for you..experiment with fuels.if you can
save a dollar why not..
happy easter everyone..

[Smonty]

Re: Fuel ????

I'm no engineer and like you said 87 or 91 made no difference in my friends A4. I guess it only really matters when you get into 11+:1 compression ratios. Happy easter to you as well.

[B5]

Re: Fuel ????

.................................... That being said, a friend of mine ran 87 in his A4 1.8T without any problems. ..................

Interesting, but I usually see this on a 1.8T fuel-door “Fuel requirement: Premium unleaded (91 octane) recommended for maximum performance”.

[kuhli]

Re: Fuel ????

2001 VR6 didn't start properly on 87. As a result the 03 has only over seen 91...I'm not so sure about your comments...

[RONDAL]

Re: Fuel ????

yay lets here it for uninformed posts woooo hoooo.

you go right ahead and put 87 in all your cars. 91 is a REQUIREMENT for high compression cars. otherwise these cars will just not run period. Its not made to clean the car having a higher octane, its made to slow the time of ignition so the piston can get all the way down, otherwise you have predetonation in the cylinders.

As you gain altitude you can go down octane points, i believe it is every 1000' you can go down 1 octane point. it is why you can get away running 91 octane here but need to run 94 at sea level. Putting the improper fuel into your 1.8T will allow it to run, but the stock ECU will retard the timing to try and sort things out. So while you paid for 180hp you definetly will not be making 180hp with crap fuel in your car.

[Khyron]

Re: Fuel ????

That's ultimately the point (though the numbers are off).

If you buy a 1.8T instead of a 2.0 you're probably doing it for more power. If you buy a CAI or a new exhaust, it's probably for power. So to then reduce that power to save 2 bucks a week on gas? Not me.

Octane is the rating of when the fuel will spontaneously detonate under compression. The higher the octane, the more it can be compressed, but it actually often burns worse, depending on additives. This is why putting 94 into a car designed to run 87 is absolutely pointless, other than perhaps the benefit of the detergents (buy a can of fuel injector cleaner instead), and will probably result in worse fuel economy.

Since the air is thinner up here, there is less air to compress, less chance of detonation, so you can use less octane. But it would be wise to have a vagcom to check for cylinder retard. If your knock sensors detect knocking, they roll back the timing - up to 15 degrees. So you could be driving around, thinking everything is great when in fact your running with the timing retarded to almost the maximum (12-14). Then when you really do have a problem, there is no room to roll back any more and bad things happen.

Not a mech, but that's how I understand it.

Khyron

[VWSM]

Re: Fuel ????

I think we need a mythbusters episode on this one.
i believe you can run 87 with no problem...at this altitude or higher.
i'll buy the burger's and buns.anyone has a suggestion for a mountain road or
test strip let me know.On highly modified cars i agree about higher octane.
this is for stock vehicles only.
1.8LT or 2.0 auto or manual and of course VR6
THIS IS NOT A RACING EVENT.
just a casual drive were we switch cars with diffirent fuels and have some fun..
this is a great site with alot of good input keep it up..
paul
i always love a challenge.

[Khyron]

Re: Fuel ????

Just borrow one of your 1.8T test drive cars and take it for a run with a vag com. You can't really tell by the ass dyno. If it shows timing retard, that's your answer. I turn up my boost/timing until I get 3-6 of pulling under max load which is 0 under normal cruising. That said, I agree that being at 3000+ feet does give us a huge cushion room compared to our sea level friends.

My issue with my old salesman was that he said you can run 87 period. He didn't qualify it as "in Calgary" or "at elevation". So if it was my mom, and she goes to Vancouver, she'd keep using 87, which would indeed be a bad thing.

Khyron

[RONDAL]

Re: Fuel ????

NO!

go read about gasoline and engines and then come back and talk to us. They have already done tests, and its already been proven.

I know for A FACT my buddies rabbit with high compression engine WILL NOT RUN on 89 here. It needs 91 and then it runs okay. Even then we toss in some octane booster to be safe.

Don't believe what you hear on the news when they say you dont HAVE to run premium, some cars are designed for high octane and without it will run badly. There is no debate about that, its fact.

[RONDAL]

Re: Fuel ????

for your reading pleasure:

If you've read How Car Engines Work, you know that almost all cars use four-stroke gasoline engines. One of the strokes is the compression stroke, where the engine compresses a cylinder-full of air and gas into a much smaller volume before igniting it with a spark plug. The amount of compression is called the compression ratio of the engine. A typical engine might have a compression ratio of 8-to-1. (See How Car Engines Work for details.)

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.

It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.

During WWI, it was discovered that you can add a chemical called tetraethyl lead (TEL) to gasoline and significantly improve its octane rating above the octane/heptane combination. Cheaper grades of gasoline could be made usable by adding TEL. This led to the widespread use of "ethyl" or "leaded" gasoline. Unfortunately, the side effects of adding lead to gasoline are:

Lead clogs a catalytic converter and renders it inoperable within minutes.
The Earth became covered in a thin layer of lead, and lead is toxic to many living things (including humans).
When lead was banned, gasoline got more expensive because refineries could not boost the octane ratings of cheaper grades any more. Airplanes are still allowed to use leaded gasoline (known as AvGas), and octane ratings of 100 or more are commonly used in super-high-performance piston airplane engines. In the case of AvGas, 100 is the gasoline's performance rating, not the percentage of actual octane in the gas. The addition of TEL boosts the compression level of the gasoline -- it doesn't add more octane.