FSI got problems using less than 98 octane?

[Fluffy]

Hi guys,

 

there is alot of discussion why Czech auto brought in the MPI instead of the 1.6 FSI which is in the golf V.

 

1) less power and less fuel efficiency when using 95 instead of 98. True, because i get the same problem with my regular 1.6SR. the car is smoother, has better mileage with 98 than 95, so i don't see why the fsi is any different.

 

2) Fsi so must use 98 octane?

I have come back from US and most of the VW and Audi there are 2.0T FSI versions, including the Audi A4 2.0T fsi i got as a rental.

 

The problem is, they don't have 98 fuel, in fact, they don't even have 95 fuel. What they have as the highest is 91.

 

We don't see them having problems with the fsi engines so i don't see why fsi can't use 95 fuel. Yes, they have lower power, etc, but that also happens to regular engines too!

 

I know europe and japan have low sulphur fuel, but i don't think US does and neither do we .....

 

 

attached pic of US fuel pump at Chevron i took this with my hp:

Edited September 5, 2006 by Fluffy

[Drive]

Correct me if I'm wrong but here we use RON as classification, in US I think different.

[Tzeench]

Hi

 

I think it is the sulphur content rather than the octane level.

 

Petrol here has higher sulphur content compare to UK/US which will wear FSI engine faster.

 

 

My 2 cents

Edited September 5, 2006 by Tzeench

[Weihui]

Maybe due to the fact that FSI engine requires higher octane fuel to prevent pre-detonation? I remember reading from some articles saying that Mitsubishi GDI engine requires higher octane fuel too in order to achieve better FC and prevent pre-detonation. Correct me if I am wrong

[Koolaba]

Hi Fluffy,

 

If you pop open the fuel tank caps of any VAG model (excluding those in the US market) equipped with FSI engine and another model equipped with MPI engine, you will see the following details on refuel requirements on the inner side of the cap.

 

FSI equipped models

RON 98 (95)

 

MPI equipped models

RON 95 (91)

 

The numbers in bracket refer to the petrol RON requirements if and only if the higher recommended RON petrol is not available.

 

When you refuelled the Audi A4 2.0TFSI in the States, have you noted the details stated on the fuel tank cap? Most likely, the ECU has been detuned in order to suit the US market.

 

In the following extract from the Octavia II catalogue published in Austria, there is a note which goes like this:

(Reference from http://www.skoda.at/files/docs/catalog/73.pdf page 52)

 

Bei Verwendung von Benzin mit niedrigerer Oktanzahl kann es zu einer leichten Verminderung der Leistung kommen.

Translated: With the use of petrol with lower RON will result in the reduction of power.

[Falc]

USA use a different octane measurement as us, their 91 is about our 95 i think.

[Falc]

I think more like the ECU controls the timing so that timing is retarded when lower quality fuel is used. But i have seen a few USA dynos of stock 2.0TFSI - 170-180ish whp compared to 200bhp quoted. 10-15% drivetrain loss only for the dsg. Sounds very reasonable to me.

[Swwpl]

Check this out. Think US uses MON rating.

 

http://www.btinternet.com/~madmole/Reference/RONMONPON.html

[Falc]

No they use PON. It's in the link u posted, you never read?

 

"In America the service stations use the Pump Octane Number or PON rather than RON"

 

So it's correct, 91 there (PON) is 95 RON here.

[Fluffy]

didn't get to fill up the Audi, had to return it as the GPS was missing, got a crappy Ford Taurus instead...... the only available GPS installed car at that time....sigh....

 

and if 91 PON is 95 RON, then 95 RON is okay for fsi ?

Edited September 5, 2006 by Fluffy

[Falc]

Ai ya, such a waste, else u can really trash that 2.0T.

 

95 RON should be ok for FSI, since it's ok for TFSI.

[Skip]

I have tried both 98 and 95 RON on my B6 Passat 2.0FSI, didn't notice any significant difference in performance. In fact 95 seems to return a slightly better FC than 98 .. haven't tried them long enough for a conclusive comparison though..

 

I owned a Mit Lancer GDI before, fed it with 95 RON for 3.5 years without any problem too...

 

These are just my own experience with direct injection engines... try it at your own risk..

Edited September 5, 2006 by Skip

[Fortress]

This topic got to do with oil company. They take away the chemicals in the fuel, and sell it with "great" additives etc...Basically, you said about economy, sometime you feel that some fuel of the same octane is better than others and sometime don't.

 

The reason is because, the content of the fuel, has 5 properties/range, from light to heavy and the light one helps to give you power and heavy gives you economy. And depending on the cost and availability basically in Singapore only 1 supplier, the additives are added to give 98 etc, octane. Of course they add a little more of each range for the higher Octane.

 

My little understand, which to my advantage is that I drive according to the fuel that gave me the economy said previously.

[Renegade]

attached pic of US fuel pump at Chevron i took this with my hp:

 

Dude...don't you know you're not supposed to be using your hp at the pump?

[Fluffy]

bro, i didn't call, i use the "cam" function duh! ...... good one, bro......

[Magfocus]

..but your HP was still on right?

[Fluffy]

err........got to switch off hp when pumping gas ah?? whoa, didn't know that

[Magfocus]

I mean just leave it in the car lah..