I used mid-grade most of the time on my V8. No issues. Never used regular and once in a blue moon I used premium.

 

The Touareg is a premium SUV. Not a mid-grade SUV nor a regular SUV.

PREMIUM ALL THE WAY!!

 

No tellin' what previous owners may have run thru a used T1 or T2. But if you're lookin' at a new T3, I'd stick with premium. Better yet, buy a diesel.

//greg//

 

Better yet, buy a diesel.

That's the right answer!

 

There was a thread that I thought I read on here once, wherein a member drive from somewhere in canada to colorado and back. One way he used premium, and the other way regular. After all was said and done, the final tally was that the difference was around 3 pennies per gallon. The Treg got better fuel mileage with the premium, negating alot of the price difference, and it also, according to him, ran smoother and accelerated better.

For myself, I only run premium, and try to get pure gas without ethanol, because I do notice a decrease in mileage with ethanol.

It is a premium, high revving engine and runs best with gas to match it.

 

When I first bought mine I ran a couple tanks of regular through it. The only thing I noticed was upon startup it would "hobble" for a moment. The electronics are equipped to adjust for octane to prevent knocking. However, I didn't like the hesitation and am paranoid about giving the warranty company any reason to void, so I've run premo since.

 

Engine is designed to run Premium otherwise it would say to run something less. The sales guy would certainly tell you running something less is fine because he just wants you to buy the vehicle. Technically the anti-knock sensors will pick up the premature detonation that will occur with a lower octane and adjust timing and fuel mixture. This reduces the engine performance and MPG. At the end of the day the engine management will adjust to protect the engine... I'm pretty sure, if it was recommended to run Regular, VW would have put that in the manual instead of Premium. Or get a TDI. I can go almost 600 miles on a tank of diesel and get 27MPG driving in the mountains between 5700 and 12000 feet above sea level.

 

In reality, I can tell you I have a 2004 V8 and have always run premium and done maintenance by the book. Never had an issue with the engine although once in a blue moon it will do somehitng that will make my heart stop and then go away. So far it has 145,000 km's on it. My Uncle however has putting regular in his 2004 V8 since he bought it. He has 260,000 Km's on it. It pulls just as good as mine, but you can tell when you drive it there something different. I dont know if its the age, the gas or the fact he drives it harder, but in terms of things breaking.. so far nothing. His maintenance isnt by the book like mine, but I guess you could says he gets it done.

 

An update to the regular versus premium gas "experiment" that I talked about before about my uncles 2004 V8. The engine died last night at 265,000 km's. The shop looking at the Treg said it was related to low oil pressure.

 

I run the premium. If I'm putting in about 15 to 20 gallons at a fill the cost difference is 3 to 4 dollars. That is worth it to me that I may avoid any problems.

 

Premium vehicle = premium fuel.

If you worry about an extra dollar or three per fill, then I hate to say it, but can you really afford a Touareg?

 

if you run the required octane then you get full power, if you run regular then the knock sensors will retard the timing and you'll get less power but no knock.

If your knock sensors fail or cannot compensate for the low octane with timing, then you will get detonation (diesel-ing) diesel engines are built for detonation (its how they run) but gasoline engines are not...detonation is a good way to put a hole in your piston and grenade an engine. Not saying it will happen but it can.

Running higher octane than required is a waste of money...if it asks for 91 anything over and above 91 is useless.

 

This. ECU knock control strategies pull timing and may even add fuel. This increases net fuel consumption. It is at best a wash, possibly an increase in total fuel cost. Run the minimum the manufacturer specifies, unless you're chipped (generally advanced timing, leaner mixtures) and/or running higher boost on a turbo car (non-issue for gas Touaregs, but my Scooby FXT never sees less than 93, since it's far from stock).

if you run the required octane then you get full power, if you run regular then the knock sensors will retard the timing and you'll get less power but no knock.
Running higher octane than required is a waste of money...if it asks for 91 anything over and above 91 is useless.

 

i run 93 octane most of the time because most stations have the choice of 87,89 or 93. Once in awhile I find a fourth option of 91. Can I presume that going back and forth between 91 and 93 is not a problem?

 

I think it is ok. Around me, if it is rated 93, it has 10% Ethanol in it, and if it is 91, it is generally non ethanol. With the 10% ethanol, you are losing some power due to its characteristics anyway.

 

Arrgh! Say it isn't so. I only see 93 premium around my area. Midgrade is only at 89. I tried both and noticed the difference in response time on the road with the midgrade but better MPG (20.5), yet slightly less MPG with the Premium 93 (19.5) but better response time. The prices are slightly higher for 93. Need to seek out stations with 91 and no ethanol. Someone mentioned Shell in another thread.

 

I have asked this question to a race car driver friend of mine -- same guy who recommended my TDI to me -- and he will tell you, unless the engine is a true premium engine like a Porsche, Ferrari, etc. -- use regular unleaded.

 

What is the definition of a "premium" engine anyways?

The title of this thread should not even belong on the Touareg forum.

Excellent advice by others up top.

 

That's gonna draw some criticism from the non-race crowd here. I've always viewed the fuel selection as a matter of engine compression. Low compression; low octane. High compression; high octane. Mid-grade; for those that can't make up their minds. Compression ratio on a Jetta is 9:1. Regular gas. Compression ratio on a Touareg is 12:1. Premium gas.

Perhaps your friend didn't realize that the Touareg 3.6FSI is a high compression engine. So is the super-charged 3.0 in the Touareg hybrid.

//greg//

 

That's gonna draw some criticism from the non-race crowd here. I've always viewed the fuel selection as a matter of engine compression. Low compression; low octane. High compression; high octane. Mid-grade; for those that can't make up their minds. Compression ratio on a Jetta is 9:1. Regular gas. Compression ratio on a Touareg is 12:1. Premium gas.

Perhaps your friend didn't realize that the Touareg 3.6FSI is a high compression engine. So is the super-charged 3.0 in the Touareg hybrid.

//greg//

Great advice. Hence going higher octane the designed is waist as nick noted above. I use Vpower with no ethanol. It's false economy as mpg goes up with regular.

 

Because octane measures a fuels resistance to combustion...the octane need comes from compression ratio, piston crown design and head design. If you do modifications such as running a thinner head gasket, milling your head, or installing high compression pistons you are raising your compression ratio and hence increasing your octane need.

as you know diesels ignite their fuel mixture via heat of compression, in the old diesel days that was done via compression ratios of 22:1, with modern CRDs (that atomize the fuel) its more like 16:1....take a modern gas engine, a high output one will run a 12:1 compression ratio, it needs 91 octane such that it doesn't knock (which is really dieseling, its the mixture lighting up before the spark)...

tuning an engine via software changes nothing when it comes to heat of compression - so no need to change octane rating...all it does is richen the fuel mixture and messes with the timing a bit. Rich mixture = bad for emmissions, which is why most vehicles are tuned super lean (lotsa air, not so much fuel). Since a rich mixture will resist ignition more than a lean mixture (more fuel to ignite, the mixture is "wetter") your octane requirement should technically drop - not increase.

So recap octane measures a fuel's resistance to ignite - that's it. It doesn't mean 94 octane is more powerful than 87, or that its cleaner, or that its better, it just means that 94 will be more resistant to igniting under heat of compression than 87 will.

heat of compression is how a diesel engine runs, it is also what can destroy a gas engine.

 

Ok. I understood and agree. But perhaps I should have thrown this example in the mix as well. A 87-91 BMW with a low by today's standards of 8.8:1 compression with its inline 2.5L six, is required per mother ship to take min 87AKI regular unleaded fuel. However, when you chip it with either of the most popular choices(comforti or dsylva) to gain a measly 15-16 peak HP at best, 91 octane is suddenly required, otherwise it will ping, and trust me that it will. Those Motronic units also had no knock sensors might as well point that out if it means anything as far as the final answer to my question might be concerned.

It is really the above known example versus the Touareg example I threw in the previous post, that the question was really being based on.

 

I will stir the pot some more ...

Consumer Energy Center - Information for the consumer about Saving Energy from the California Energy Commission / transportation / consumer tips / REGULAR VS PREMIUM

REGULAR VERSUS PREMIUM GASOLINE
Regular Gasoline Has As Much Merit As Premium Gasoline
"Put a tiger in your tank," says a classic advertising tagline. In today's motoring world, what kind of fuel grade will have the power to place a beast in your gas tank?

The answer, according to experts who study fuel efficiency in detail, is both regular and premium gasoline. And it would be a waste of money to favor premium over regular, especially in these times when gasoline prices are high, according to the experts.

Virtually nothing is gained by filling up with a premium or more expensive grade of fuel than the vehicle manufacturer has recommended, the experts say. And many of the same experts explain that drivers may not lose much performance from their cars by using a lower grade of fuel than recommended by the car manufacturer.

There is little difference in energy content of regular versus premium gasoline. They both contain about 111,400 British Thermal Units of energy per gallon.

The price difference, however, between the fuel grades is anywhere from 20 cents to 40 cents, depending on where you live in the United States. The experts' consensus goes against the long-held belief by thousand of drivers who fill up with premium only, or on every third or fourth trip to the pump. The idea is to fill up with premium every so often to clean out the engines or rev up the performance of older engines.

But according to the experts, this practice is like tossing quarters in a wishing well, since most engines are designed to operate on relatively low-octane regular unleaded gasoline.

Octane is defined as a fuel's resistance to knocking. There is no benefit if the octane is higher than what the engine needs. Engine knock occurs when fuel in a combustion chamber ignites before it should. This disrupts the engine's operation. But electronic knock sensors are now common and have nearly eliminated engine disruption.

The American Petroleum Institute says if you find that your car runs fine on a lower grade, there is no sense switching to premium. The Institute recommends following manufacturer's recommendation, but even those manufacturers say that it is more of a suggestion than a command.


For more about this subject, see the excellent article "Fact or Fiction?: Premium Gasoline Delivers Premium Benefits to Your Car Exploding the myth that premium gasoline delivers better performance in the average automobile" by David Biello on Scientific American's website at: Fact or Fiction?: Premium Gasoline Delivers Premium Benefits to Your Car: Scientific American ("But for standard cars on the road today, purchasing premium gasoline is simply paying a premium for a fuel that delivers no added benefits. "If you think you need it," Green says, "you're being very eccentric.")

 

To the above post^^^^^, yes you will not really feel (average Joe butt dyno) the decrease in HP by adding lower octane fuel than stated on your fuel filler door, but do be clear, that if you were to put your vehicle on a dyno, the HP would be less than the HP figure listed in the owners manual, due to timing retard by the knock sensors, to compensate for the lowering of standards by the end user, for what the product was initially designed around.

Just realized that is one long sentence , the heck with editing.

 

Bottom line is that the the manufacturer of the gasoline Touareg (VW) recommends PREMIUM fuel. If you want to go against the manufacturer's recommendation, go right ahead.

When you get a tune, one of the things done to increase performance is to advance the timing. To prevent detonation, high octane fuel is needed.

 

I just traded my V8 for a Hummer H2. Everybody asks how much gas does it use.
I say about 11.5 mpg on a gallon of 87 octane.
I also add that I used to have a midsize VW with V8 that consumed 14 mpg but requires 91 octane.
I you do the math it does not make much of a difference anymore in the cost per mile in the end.
With the VW I never was questioned, with the H2 I get questioned on a regular basis. I think about putting a hybrid emblem on my Hummer and say it does 20 mpg (downhill)

 

2006 V8. Here is my comparison. YMMV. Ethanol free gas is hard to find.

93 no ethanol - runs great.
87 no ethanol - runs ok. 10% less mpg.
93 w/ ethanol - runs ok. 10% less mpg.
87 w/ ethanol - runs poor. 15% less mpg.

 

ethanol is crap, less power + less mileage.

Great if you grow corn and sell it, otherwise its junk.

 

Without reading all the above posts, gasoline grade is the least of your problems when owning a Touareg.

 

Well, now that I have read the posts, the hate for ethanol seems a little unfounded. Aside from the political reasons, from a performance standpoint, the higher Octane content of ethanol, e85 specifically, allows an engine to rev higher. I know because I use it on specific tailor made tune for it yielding about 45whp and 25 wtq more than my shell 93 tune. There's a reason its referred to as "poor man's race gas".

Regardless, with the ethanol mixes, although they cause a reduction in power, they do allow the fuel to burn more knock-free than otherwise.

 

I just think it is false economy to go over or under manufacturer recommendations for octane rating.