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GTI Fuel Requirements

tfcGTI

Ready to race!
Greetings:

I am new and I will be buying a 2010 Carbon Steel 4 door, manual GTI in a couple of months. I am wondering what type of fuel is required? The sales guy says premium is recommended but not required. Is this true and if so what are the consequences of using regular 87 octane?

Thank you.
 

GlutenBoy

Passed Driver's Ed
Good question. When I had my Jetta Wolfsburg 1.8T I always put premium into it, but I always wondered if it was about fact or fear.
 

Stein357

Ready to race!
The ECU will retard the timing of the ignition and you will see a slight decrease in performance and fuel mileage.
 

s2kguy

Ready to race!
Auto dealers who have their own pumps generally have 87 octane only. I know the launch GTI I drove had 87 octane in it and it felt strong with no pinging noticed. Having said that, I try to fill my car that requires 91 octane with premium (93) and refill when I'm down to 1/2 tank with plus (89) to keep it about 91.
 

dthomas53

Passed Driver's Ed
Damn, for whatever reason this never occurred to me. What if I only fill up with regular? Will this degrade my engine over time? I'm not too worried about a little HP loss, but I don't want to get the car and kill it.

Any info is appreciated. :)
 

GlutenBoy

Passed Driver's Ed
That was pretty much my philosophy I had with my Wolfsburg and I don't think it will change with my new GTI.
 
I'd stay with premium as much as possible personally. The price spead isn't that much and you will get better performance. I take that as "87 is OK if needed". Here in the US, you will find at least 91 octane almost everywhere. The only scenario I've ever run into where it wasn't available was border towns in Texas and a couple of trips down to Mexico (Pemex can do whatever they please as they're a state-owned monopoly essentially). Modern knock sensors and ECU are wonderful but there's a limit and I'd question whether 87 octane is going to be OK long run in the GTI's motor.
 

fokker

Ready to race!
Engine is designed to be used with high octane fuel to allow for higher compression. However, if regular fuel is used, the ECU will retard the timing so as to not damage the engine.

So, feel free to use regular if you like -- but you're gonna have less power and more fuel consumption than with premium fuel.
 

koolgreen

Ready to race!
now how does the engine know it is low octane gas?
or is it just that it will adjust timing as it starts pinging creating stresses in the cylinders?
________
Outdoor Japanese
 
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zee

Go Kart Champion
now how does the engine know it is low octane gas?
or is it just that it will adjust timing as it starts pinging creating stresses in the cylinders?


It is the knock sensor's job to know the gas octane rating. See definition below.

answers.com said:
It allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor detects pinging. At that point the computer retards the ignition timing just enough for the pinging to stop.
A knock sensor assures that you're getting as much power and fuel economy as is possible from your engine
 

krische

vdubber in training
Honestly, using regular gasoline will give you less performance. Which means your mileage will likely decrease. Thus, negating any benefit of buying the cheaper gas.
 

grada89

Go Kart Champion
Honestly, using regular gasoline will give you less performance. Which means your mileage will likely decrease. Thus, negating any benefit of buying the cheaper gas.

Speaks the Truth.
 

gerard

Newbie
I would stick to the recommended fuel grade or better. Afet all, you did not buy a GTI and degrade it with low octane fuel. The ability to run such fuel is basically to enable you to continue to drive but with some performance compromise should the servo had no premuim fuel on hand.
 
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