what effects would useing plain unleded gas in my 2001 jetta vr6

lot of arguement and contreversy amongst the troops, tired of arguing...if the "GO juice" makes it go...that's all that is needed...we aren't entering into a rally, and do not need all that performance...but cheap.

Because of the decrease in efficiency (MPG's) it's sometimes more cost effective to buy the higher grade gasoline. -- I had an Astro Van that was cheaper to operate (cost per mile) using a mid-grade gas.

as compressions get higher, one might think it's just that much closer to diesel compression like a gas 9:1 or diesel 25:1...which if diesel is OIL, and not full of volitiles, like higher octane fuels...like higher compression=lower quailty fuel...so having a 93 octane should be used with a relitavely low compression...one might think.

the cold air has streamed in, and cannot feel my fingers typing anymore- Arctic BLAST---hold onto your wooly-caps 'cause you're soon to get hit with an ARCTIC BLAST!

Bob you have it backward. 91 octane is for higher compression engines. 87 is for lower, it takes less compression to have it ready to ignite by the spark. There is more energy in a gallon of diesel than a gallon of gasoline. The higher the compression the more octane # is necessary for complete combustion .....that's why if it "diesels", like continues to run (albeit real rough) after you shut the key off it's being ignited by heat and compression alone and a higher octane corrects that, am I making any sense at all? Sometime I have a hard time getting thoughts out right...

it's all about hydrocarbon chains~

The 20cent/gal difference in price between regular and premium equates to about a $3 difference per tank-full. How about you give your well-engineered German machine the fuel it deserves and just drink one less latte or beer this week.

MK4 (1999-2004) VR6s have a slightly higher compression ratio compared to the MK3 VR6s (10.5:1 as opposed to 10:1). This is an even more compelling reason to run premium grade gas in your VR6. High compression engines require premium gas because the air/fuel mixture is compressed a lot before being ignited. Regular gas will ignite solely because of the immense pressure, as opposed to being ignited by the spark. When this compression based ignition happens (called pre detonation), it causes engine knock. Your engine's computer will compensate for this by pulling timing (and reducing power), but it can only pull timing so much. Not only could this damage your engine internals, but it also makes your engine become less efficient and the fuel consumption will suffer. Long story short, run the recommended 91 octane or higher, and it will pay off in the long run.