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Fuel - Premium or Regular?

62K views 84 replies 59 participants last post by  yrktreg  
#1 ·
Does anyone notice a big difference in gas mileage and performance when you do not use premium fuel?
 
#2 ·
Yes, because the engine and its management system changes the performance of the engine.
 
#4 ·
I use regular, and have no issues with power or MPG.
I have used premium once and noticed more power off the line and about 1 MPG better.
Considering the cost, I don’t think premium is worth it unless you’re towing something.

Of course others will tell you different. It’s been debated a lot on this forum.
 
#6 ·
Yep theres a diffrence. When i go to Czech Rep., on the highway in Germany i usually have a speed of 180Km/h.
With regular 95 octane - i get +- 20l/100km
With premoum 100 octan - i get +- 16,5l/100km
Theres a diffrence, the engine seems to be more reactive and better response.
Im saying a better MPG is worth the extra Eurocents... :pelvic_thrust:
 
#8 ·
jlbunting said:
I use regular, and have no issues with power or MPG.
I have used premium once and noticed more power off the line and about 1 MPG better.
Considering the cost, I don’t think premium is worth it unless you’re towing something.

Of course others will tell you different. It’s been debated a lot on this forum.
I have noticed pinging under load with mid grade. I have never since put and BUT premium in my V8.
 
#9 ·
I never thought it was worth the risk either, so I use nothing but premium. In fact with the exception of only a couple of cars all mine that I have ever owned required premium.
 
#10 ·
Premium or Regular

Thanks for the comments. I personally feel I get better MPG's when I use Premium. I notice a big difference in power also. When I used regular fuel I really had to put my foot in it to get it moving therefore canceling any financial gain in using regular.

I agree that using Premium is best for the engine also. I talked with a VW Tech and he said regular will not hurt the engine but I would rather play it safe.
 
#11 ·
Premium or Regular

Thanks for the comments. I personally feel I get better MPG's when I use Premium. I notice a big difference in power also. When I used regular fuel I really had to put my foot in it to get it moving therefore canceling any financial gain in using regular.

I agree that using Premium is best for the engine also. I talked with a VW Tech and he said regular will not hurt the engine but I would rather play it safe.
 
#13 ·
I just found this information on Carbibles.com. Just thought it could help with this discussion.

Octane and gas mileage
Here's a good question : can octane affect gas mileage. The short answer is absolutely, yes it can, but not for the reasons you might think. The octane value of a fuel itself has nothing to do with how much potential energy the fuel has, or how cleanly or efficiently it burns. All it does is control the burn. However, if you're running with a petrol that isn't the octane rating recommended for your car, you could lose gas mileage. Why? Lets say your manufacturers handbook recommends that you run 87 octane fuel in your car but you fill it with 85 instead, trying to save some money on filling up. Your car will still work just fine because the engine management system will be detecting knock and retarding the ignition timing to compensate. And that's the key. By changing the ignition timing, you could be losing efficiency in the engine, which could translate into worse gas mileage. Again as a practical example, my little tale above about our trip to Vegas on low octane gas. (Whether you want to believe some bloke on the internet or not is up to you). On the low octane gas on the trip down, we could barely get 23.5mpg out of the Subaru. Once I was able to fill it up again with premium at the recommended octane rating, we got 27.9mpg on the way back. A difference of 4.4mpg over 450 miles of driving.
Doing the maths, you can figure out that by skimping on the price during fill-up, you may save a little money right there and then, but it costs in the long term because you're going to be filling up more often to do the same mileage. My advice? Do what the handbook tells you. After all it's in the manufacturers better interests that you get the most performance out of your car as you can - they don't want you badmouthing them, and in this day and age of instant internet gratification, you can bad-mouth a large company very quickly and get a lot of publicity.
 
#14 ·
Just a little more proof we need to keep using Premium:

Octane and power
It's a common misconception amongst car enthusiasts that higher octane = more power. This is simply not true. The myth arose because of sportier vehicles requiring higher octane fuels. Without understanding why, a certain section of the car subculture decided that this was because higher octane petrol meant higher power.
The reality of the situation is a little different. Power is limited by the maximum amount of fuel-air mixture that can be jammed into the combustion chamber. Because high performance engines operate with high compression ratios they are more likely to suffer from detonation and so to compensate, they need a higher octane fuel to control the burn. So yes, sports cars do need high octane fuel, but it's not because the octane rating is somehow giving more power. It's because it's required because the engine develops more power because of its design.
There is a direct correlation between the compression ratio of an engine and its fuel octane requirements. The following table is a rough guide to octane values per engine compression ratio for a carburettor engine without engine management. For modern fuel-injected cars with advanced engine management systems, these values are lowered by about 5 to 7 points.

Compression ratio Octane
5:1 72
6:1 81
7:1 87
8:1 92
9:1 96
10:1 100
11:1 104
12:1 108

I think the V6 has a compression ratio of 12:1. Does that mean we should be using 101 octane?
 
#15 ·
12:1 is really high. But yes, its best to be using 100+ octane for this car. I think we get better mileage from it. But it is a pain in the butt to order these type of fuel in canada. Anything beyond 96 is considered racing fuel, you cannot get it from the pump, you can order it, but you need either a shop or have a valid race car license
 
#17 ·
We used to have 100-octane (104 RON) at the pumps here in Vegas. When premium (91 octane (R+M)/2 (95 RON)) was at $2.40 a gallon, it was $4.25 a gallon! I'd hate to fill up a Touareg with that stuff! It did do well in my 2-stroke pre-mix for my old dirtbike, it seemed to burn cleaner and the engine ran more smoothly on the 100-octane gas.

Overall, though, I'd run what's recommended. 91 to 94 would all be good, 100 may be overkill, but it would be interesting to see what the 100-proof would do to fuel economy and performance.

Matt
 
#42 ·
We used to have 100-octane (104 RON) at the pumps here in Vegas. When premium (91 octane (R+M)/2 (95 RON)) was at $2.40 a gallon, it was $4.25 a gallon! I'd hate to fill up a Touareg with that stuff! It did do well in my 2-stroke pre-mix for my old dirtbike, it seemed to burn cleaner and the engine ran more smoothly on the 100-octane gas.

Overall, though, I'd run what's recommended. 91 to 94 would all be good, 100 may be overkill, but it would be interesting to see what the 100-proof would do to fuel economy and performance.

Matt

You know what is sad - here I go dating myself - but I used to buy 100 - octane in the mid 70's to early 80's for less than $1.50 for my 74 Super Beetle!!
 
#19 ·
Vegas Matt said:
We used to have 100-octane (104 RON) at the pumps here in Vegas. When premium (91 octane (R+M)/2 (95 RON)) was at $2.40 a gallon, it was $4.25 a gallon! I'd hate to fill up a Touareg with that stuff! It did do well in my 2-stroke pre-mix for my old dirtbike, it seemed to burn cleaner and the engine ran more smoothly on the 100-octane gas.

Overall, though, I'd run what's recommended. 91 to 94 would all be good, 100 may be overkill, but it would be interesting to see what the 100-proof would do to fuel economy and performance.

Matt
At the Deltasonic car wash I used a few weeks ago in Niagara Falls, NY they sell 100 octane for over $5 a gallon. I stuck with 93 for $2.83 ;)
 
#22 ·
Seriously why mess with this. here premium costs 20 cents more per gallon. We burn about 40 gallons a week so that is $8 a week, about $35 a month. If that ruins you financially, buy a jetta tdi and sell the treg.

PS a new engine costs $12000. I see the $35 as an insurance policy
 
#23 ·
Keep the Touareg and buy a Jetta TDI. This move brought my fuel economy average from 17mpg to somewhere in the 30s (the TDI gets about 55MPG).

I never bought the treg assuming it was a mileage queen..its just like most of us in college -keep primed with plenty of liquids :)
 
#29 ·
Keep the Touareg and buy a Jetta TDI. This move brought my fuel economy average from 17mpg to somewhere in the 30s (the TDI gets about 55MPG).

I never bought the treg assuming it was a mileage queen..its just like most of us in college -keep primed with plenty of liquids :)
I have a Touareg to drive it. I would refuse to drive a jetta for mileage.
I solved this money wise to buy a used treg, so I can spend the difference of a new one on gas;)
 
#26 ·
I had a 2002 Passat 1.8T Wagon that we traded for our Touareg. Not enough experience with the Reg, but the Passat performed markedly better with Premium than Regular. I did the math, and in '03 dollars the cost of regular vs. premium was a wash. I got better milage and performance with premium. The extra cost was made up by an increase in MPG. I didn't know at the time, the computer de-tuned for regular. I assume the same is true for the Touareg.