Volkswagen Passat Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #1
Is it really worth the extra dollars per tank. 87 ws 94. The difference is 10 cents a litre in Canada. Its a 50Litre or so tank..so five bucks. My wife recently read an article that with today's engine's...not necessary...More of a cash grab for oil companies and people thinking higher octane is better for performance and engine runs cleaner...Now really! What are your thoughts.

andiman from North...Home of Winter Gas...laced with gas line antifreeze.
 

·
Registered
Joined
·
243 Posts
Do a search. This topic is beat to death on a regular basis.

About half say it doesn't matter and they have used low octane for 500K miles with no harm/loss of power.

The other half says that it will ruin your car and it will die a quick sudden miserable death.

The truth, my friend is somewhere in between. Not you, me or a thousand experts will ever determine the real answer.
 

·
Registered
Joined
·
2,281 Posts
Warranty work traced back to the use of bad fuel and refuse would end this debate. But I haven't heard of any warranty work being refused because of improper fuel octane. I don't think the dealer has the ability to test the octane of the fuel in your tank. It would be up to the owner to fess up to using less thane premium.
 

·
Registered
Joined
·
189 Posts
Recommends 91 is different then REQUIRES 91. They can't deny warranty work for fuel octane. The dealer or manual nevers uses the term 'requires' only 'recommends'. Therefore, you can't be held liable. On the other hand, you can go back to the gas station for bad fuel. This happened to my brother-in-law and they fixed his car. You must keep acurrate records tho.
I use middle '89' gas, mainly because the gas prices keep going up!
 

·
4th Gear (Wax on Wax off)
Joined
·
4,974 Posts
Yes do the search ... on top of it all the Control unit based on the knock sensors etc. retards the timing thus reducing power and at the same time reducing milage .. so in the end ... false economy.
 

·
Banned
Joined
·
3,535 Posts
I don't think it is bad for your engine , but you will definitely loose performance and economy since the mixture cannot be compressed as much.
Think about that :
Why race cars use high octane gas?
The could save a lot of money if 87 worked for them.
 

·
Banned
Joined
·
3,535 Posts
retards the timing thus reducing power and at the same time reducing milage .. so in the end ... false economy.
Correct if im wrong .
I always tought the you retard the time for higher octane ( more time for gas to be compressed)and therefore getting more power.
 

·
4th Gear (Wax on Wax off)
Joined
·
4,974 Posts
1.8Tabamoura said:
retards the timing thus reducing power and at the same time reducing milage .. so in the end ... false economy.
Correct if im wrong .
I always tought the you retard the time for higher octane ( more time for gas to be compressed)and therefore getting more power.
With higher octain you can run more advance at higher compression with less fear of pre-ignition ( Knock)
 

·
Registered
Joined
·
2,281 Posts
Problem with knock sensors is they have to detect a knock condition for a predefined amount of time before they retard the timing. This may be milliseconds 50 "knocks", or hundreds of knocks. This may or may not have ill effects on the engine. Only way to find out would be to run a virgin engine on 87 or 89 octane for a few thousands of miles and tear it down.

Every other discussion has on this has also stated the price difference per tank is a couple dollars. Generally less than 5 dollars. One less latte, drink at the bar, or pack of cigarrettes a week and you have made up the difference.
 

·
4th Gear (Wax on Wax off)
Joined
·
4,974 Posts
rpaller said:
Problem with knock sensors is they have to detect a knock condition for a predefined amount of time before they retard the timing. This may be milliseconds 50 "knocks", or hundreds of knocks. This may or may not have ill effects on the engine. Only way to find out would be to run a virgin engine on 87 or 89 octane for a few thousands of miles and tear it down.

Every other discussion has on this has also stated the price difference per tank is a couple dollars. Generally less than 5 dollars. One less latte, drink at the bar, or pack of cigarrettes a week and you have made up the difference.
Good point .. Also a knock ( pre-detonation) means your hammering the rod bearings by firing on the top end of the compression stroke in essense trying to force the piston / crank down the same way it was just coming up.
 

·
4th Gear (Wax on Wax off)
Joined
·
4,974 Posts
D.Passat00 said:
what if it's chipped? would you need to run 91?
I think you will find if its chipped you will need to or even more.
 

·
Registered
Joined
·
5,753 Posts
Run the 91, 92, 93 or the highest in your area (mine is 93). It's worth the extra cost.

My owners manual for my 2 cycle lawn equipment recommends the use of 89 or higher octane. They claim that it'll reduce the buildup of deposits, etc.

I run 93 in everything.
 

·
Registered
Joined
·
5,335 Posts
Andiman,

Your wife is correct in stating that many of the claims made about higher octane gas are completely bogus. i.e."Makes your engine run cleaner", "Unleash the full power of your engine", etc. That is completely true for engines that are not designed to take advantage of the slower explosion provided by higher octane. There are not any additional detergents in higher octane gas, as your fuel injectors could care less what the octane is.

However, if the engine timing is designed to spark earlier (like the Passat), higher octane will give you more power in a car w/ adjustable ignition timing (like most cars with a distruibutorless ignition), and will prevent engine damage in a car without it. (Spark knock = bad)

The manual for my '04 1.8T states that the car will run without damage on 87 and higher octane, but the engine will not deliver it's best performance, and fuel economy may suffer.

SirWired
 

·
Registered
Joined
·
7,583 Posts
http://caranddriver.com/article.asp?section_id=4&article_id=3604&page_number=1

Here's the executuve summary:
"Our tests confirm that for most cars there is no compelling reason to buy more expensive fuel than the factory recommends, as any performance gain realized will surely be far less than the percentage hike in price. Cheapskates burning regular in cars designed to run on premium fuel can expect to trim performance by about the same percent they save at the pump. If the car is sufficiently new and sophisticated, it may not suffer any ill effects, but all such skinflints should be ready to switch back to premium at the first sign of knock or other drivability woes. "

My emphasis added.
 
1 - 17 of 17 Posts
About this Discussion
16 Replies
11 Participants
Altair 4
Volkswagen Passat Forum
Passatworld is a forum dedicated to Volkswagen Passat enthusiasts to discuss mods, Quattro, Turbo Diesel, reviews and more!
Full Forum Listing
Top