Hi everyone, I'm locking this thread. Topic has been completely discussed and everyone has shared their opinion, and I believe this thread now contains a wealth of information on what octane rating to run!!!...as there is nothing left to argue or discuss lets move onto something else!

 

Nice one Matt, now you made this a 6 page thread

 

If this becomes a 6 page thread it probably won't be because of Matt.

 

Here's how I see it:

(Cliff notes version): You can't really hurt an 87-octane recommended engine's performance by using a 91-94 octane fuel in it, but you can cause performance degradation (if not worse) in a 91+ octane recommended engine by running 87 in it.

(Longer version):
-I've never heard that using too high of an octane in a modern engine will cause any mechanical or performance issues, as long as the ignition system is up to igniting the air/fuel mixture.

-I've read/heard/personally experienced that using lower-than-recommended octane reading causes performance degradation. As has been discussed, mixture and timing are adjusted to keep the knocking/detonation to a minimum. However, a stock computer can only adjust things so far, and I'd be concerned with causing issues by doing this long-term. I'm not saying it will definitely happen, but it could be in the realm of possibility.

This is why my Touareg has never seen anything less than 91-proof.

As far as manual versus fuel filler: I'd go with the higher of the two. You can't really hurt it by going with the higher octane, but you could by going with the lower.

Matt

 

actually in bones defense the manual is incorrect and conflicts with the filler door...it says use 87 AKI (equivalent to RON+MON/2 or 91 RON)....the flap says use 91 RON+MON/2 (eqiv. to 91 AKI or 95 RON).

Like the weight distribution sticker I'm following the decal on the vehicle vs the manual in this case

 

So, you don't think the manual states right there 87 Octane is OK?

Yes, the filler flap....THE Filler Flap...Like I said WAY BACK!

5 pages is right Matt.

 

AKI=Anti Knock Index

I can't believe this thread has gone into being five pages long. We've already beat this topic to death at least seventeen times.

Bottom line: If you value your warranty, follow what's on the fuel door. Otherwise, do whatever you want. Just don't cry if your engine gets damaged and VW denies a warranty claim.

/thread

Matt

 

I think the paragraph titled Caution pretty much explains it all....

 

What's 87 AKA ? (Anti Knock Additive?)

 

Yes, I mentioned the Fuel Filler Door Reference as well. Maybe review my previous post?

 

Read your own manual, is it different then the page posted? If not then it clearly says at the top that you need to refer to the sticker for fuel recommendation.

 

It needs 91 octane to perform the best.
With lower octane you will be retarding your timing to prevent knocking. The result is less power and not as good a mileage thus pissing out the $5 savings on a tank of gas

 

As stated earlier....My FIRST Full tank of SUPER coming up soon.
I can't imagine any better performance however higher MPG would be great.

You guys are going to spoil me...No going back I'm betting...!

 

I did see your earlier posting but I don't have any conflicts between my manual and the fuel filler door...I don't doubt it though, my manual and hitch decal conflict on weight distribution use and maximum tongue weight so it wouldn't be the only conflicting data that's for sure.

101 at the pump was before my time, but I remember my first street motorcycles in the late 80's (I couldn't afford a car in high school..well at least not a fast one!) we used to go fill them up with the 110 octane avgas at the local airport (ie: the type of airport where everyone flies their private Cessnas)...we thought we were pretty cool getting the 110 octane and we were positive we were making huge horsepower!!!!!!

I wasn't being a donkey when I said run whatever makes you happy...I was serious. If you don't notice the difference they why bother spending the extra on 91?...if you're not getting knock then....?

 

Vw does have a new statement that says it will not Cover damage caused by using poor quality fuel.The other factor is the cleaning agents in the fuel,lower fuel grades have less or none of them resulting in,poor starting,rough running engine,poor performance,so with a compression ratio of 11:3/1,use high octane gas.

 

You can provide this data officially?

 

Hey NorthVan! Well unfortunately we are still shopping around. Work got so bad that we were cut down to 30 hrs. per week and I had to take a temporary pay cut, so jumping into another car wasn't in the cards. Now we are back to normal operating hours and things are starting to look better. I'm still driving the trusty 'ol Rover. we have looked at alot of cars this passed week, so we'll see if she makes a decision soon. It's hard because I always compare everything we look at to the Touareg, and we all know there is nothing like it!!

 

I feel for you, my business is down about 20% but we are holding our own. Haven't had to cut hours of the staff, just keep banning OT for now.

Good Luck with the car shopping, there are some great deals out there.

 

Alex, nice to see you visiting, what car did you replace your Toureg with?

 

If there is something that simple to drastically increase MPG's that much don't you think that every car manufacturer would already have that installed on all vehicles?

 

Don't take the above too seriously.



You know they also have a pill that you can put in a gallon of water to turn it into gasoline. And don't forget the carburetor that gets 200 miles per gallon. Oh well, go and see. Fuel saving gadgets - a professional engineer's view and Fuel saving gadgets - a professional engineer's view.

 

Anything higher than 91 octane in your Treg is a waste of money. Less than 91 and you lose performance and mileage for a few cents a gallon less cost; most have found that it is a wash and stick to the VW recommended 91 octane.

 

I was just stating I understood the altitude reference since I live at altitude as well and know it robs HP also. I don't feel the need to take more performance away by going with lesser fuel.

 

Yes Sir

I really want someone to convince me that while my engine is running well I still need to switch to higher Octane?

I'd love to be able to again pull up to pump and get 101 Octane for $.95/gallon and I KNOW our TOUAREGs would love 101 but it's not neccessary...IS IT?

 

I just added the altitude bit to remind all that the higher the altitude, the lower your compression ratio and the need for higher octane fuel (please, don't start complicating it with turbos and superchargers, humidity, sunspots, etc, etc).

 

(please, don't start complicating it with turbos and superchargers, humidity, sunspots, etc, etc).

Not wishing to complicate things... but... If you encircle your fuel hose with those special fuel magnets available from ebay; you will find that you can now get 44 mpg on the V8. The magnets will self align the fuel molecules to create the ultimate explosion in your cylinders. As a positive side effect, the ultimate explosion produces a super high temperature which will clean all the carbon out of your cylinders which will make even old engines run like new.

Surely the mpg increase from this wondrous device would offset the $6.00 per tank difference in buying premium gas. =;

 

Let's throw altitude into the Ron/Mon discussion and really stir things up

 

I am about at 4K here in Salt Lake and I run nothing but 91. I occasionally get some 93 in the tank if I want to travel to get it, but generally run 91. I don't want to take the performance hit with low octane gas when altitude does that for you already.

 

2005 V8

 

Bones, what year and engine do you have?

 

North America uses the RON+MON/2 system so 98RON is roughly the equivalent of 93, 95RON is roughly 91. All north american Tregs are to use 91 (except obviously the diesels).

 

You seem so sure of this and even VW writes conflicting data as I cited.

My real world use proves that the crappy 87 is functional and therefore acceptable. Maybe not when Summer comes I bet but for now...OK in that no detonation and that is the tattletale of sufficient Octane.

Any DATA regarding this?

It's all truly low Octane at the pumps.

 

According to ElsaWin:
V8, Engine Codes AXQ, BHX - 98RON (95RON in exceptional circumstances)
VR6, Engine Codes AZZ, BAA, BKJ, BMV, BMX, BRJ - 98RON (95RON in exceptional circumstances)
VR6 FSI, Engine Codes BHK, BHL - 98RON
V12, Engine Code BJN - 98RON (95RON in exceptional circumstances)

That's everything up to 2007.

I would run it on highest octane available.

Always.

 

Doesn't the 87 octane gas meet operational requirements?
No knocking or pinging = adequate Octane?

Maybe this won't be adequate during Summer months in Texas when Ambient Temp is 95+ degrees F.

In Manual, Section 3.4 page 32 it states several places 87 Octane...

On page 31 it states to go with what is on your fuel filler flap = 91 on my V8 model.

I wouldn't have thought it is as much $6 / tank to go with Super, more like $4 here.

I drive the $50K vehicle because I like it, my Wife likes hers also.

If 91 Octane fuel is absolutely needed...SO be it.

 

Doesn't the 87 octane gas meet operational requirements?
No knocking or pinging = adequate Octane?

Maybe this won't be adequate during Summer months in Texas when Ambient Temp is 95+ degrees F.

In Manual, Section 3.4 page 32 it states several places 87 Octane...

On page 31 it states to go with what is on your fuel filler flap = 91 on my V8 model.

I wouldn't have thought it is as much $6 / tank to go with Super, more like $4 here.

I drive the $50K vehicle because I like it, my Wife likes hers also.

If 91 Octane fuel is absolutely needed...SO be it.

SINCE PAGE 1 OF THIS ILLUSTRIOUS THREAD I HAVE SAID THIS.

I initially read the manual after first trip to gas pump and realized conflict.

My Wife and I ahve only run 87 cotane thus far and p[erformance is great. No Pinging....No knocking.

I can't wait to burn up the 1/2 tank of gas I currently have so I can fill with "SUPER".
I anticipate no increase in MPG nor do I suspect any performance gain however the only way I have to measure that is the seat of my pants and that's obviously not so accurate as other's arses are!

 

Don't take this personally, but if you're worried about $6 a tank then why are you driving a $50K(or more) car? You've paid for a premium vehicle, why cripple it to save a few bucks? I just don't get it.

 

91 RON+MON/2 is the minimum in North America. I remember hearing my V6 pinging after filling up on mid grade and towing thru Utah. I have never filled with anything lower than 91 after that. Besides, the lowered grade burn less effeciently and your milage will suffer. The 6 dollars a tank difference largely evaporates once you factor in the milage.