Which fuel works best

[rattles]

Had my car in for a small service yesterday at a local Porsche specialist [non dealer]. He asked which fuel I had been using because there were a couple of fuel related faults showing when he did the system tests. I have used Shell pretty much exclusively since I bought the car.

He also said that when he dyno tests cars he gets different results depending on which brand of gasoline [98 octane unleaded] is in the [same] car. His research shows that Mobil and BP are giving the best results and are burning cleaner. He does not sell gas. He prepares his own racing Porches so can get back to back tests on his own engines.

Anyone have any opinions re this.

[JP66]

Interesting....I too have been using only Shell V-Power since I got my car, and I'm at 2300 miles. I'm also interested in what others have to say.

[1999Porsche911]

In the States, all the brands are almost exactly the same for each grade. You can, however, have dirty tanks at a specific station, but, everything being equal, I don't believe you could measure much of a difference between non-racing fuel. (93 octane and below)

Rattles: your guy is not measuring performance with street gas, but is using a 98 octane which is more of a racing fuel.

Edited April 6, 2005 by 1999Porsche911

[Lizard1]

recently, when I took my wife's BMW in for service, the service advisor noted that there was alot of carbon buildup and asked if we had been using supreme(93 octane)? car is 18 mos old with 14K miles.

we had been using 93 octane from Chevron and he stated that BMW is now recommending ~90 octane b/c the higher octanes are causing alot of carbon buildup and throwing codes

can this really be true? are we in reality hurting our Porsche engines by running higher octanes?

[rattles]

In the States, all the brands are almost exactly the same for each grade.  You can, however, have dirty tanks at a specific station, but, everything being equal, I don't believe you could measure much of a difference between non-racing fuel.  (93 octane and below)

Rattles:  your guy is not measuring performance with street gas, but is using a 98 octane which is more of a racing fuel.

<{POST_SNAPBACK}>

Must be different here, regular unleaded is 92 octane, premium is 95 or 98, all from the pumps at most gas stations.

He was comparing 98 Shell with 98 BP or Mobil.

The drivers manual for my 99 996 C2 says 98 Ron/ should be used, 95 can also be used but the knock sensors will adjust the timing. Maybe its different in US cars.

I also felt the same as you, most good brands are going to be very close, I'm sceptical when people say this ones better than that but he says his dyno tests show a difference. Theres nothing in it for him.

[1999Porsche911]

In the States, all the brands are almost exactly the same for each grade.  You can, however, have dirty tanks at a specific station, but, everything being equal, I don't believe you could measure much of a difference between non-racing fuel.  (93 octane and below)

Rattles:  your guy is not measuring performance with street gas, but is using a 98 octane which is more of a racing fuel.

<{POST_SNAPBACK}>

Must be different here, regular unleaded is 92 octane, premium is 95 or 98, all from the pumps at most gas stations.

He was comparing 98 Shell with 98 BP or Mobil.

The drivers manual for my 99 996 C2 says 98 Ron/ should be used, 95 can also be used but the knock sensors will adjust the timing. Maybe its different in US cars.

I also felt the same as you, most good brands are going to be very close, I'm sceptical when people say this ones better than that but he says his dyno tests show a difference. Theres nothing in it for him.

<{POST_SNAPBACK}>

Sorry...didn't see that you were not in the States. Isn't the octane rating over there calculated differently than here. I think you use the research octane (RON) rating and we use the motor rating (MON) 96 RON equals 92 MON.

[rattles]

In the States, all the brands are almost exactly the same for each grade.  You can, however, have dirty tanks at a specific station, but, everything being equal, I don't believe you could measure much of a difference between non-racing fuel.  (93 octane and below)

Rattles:  your guy is not measuring performance with street gas, but is using a 98 octane which is more of a racing fuel.

<{POST_SNAPBACK}>

Must be different here, regular unleaded is 92 octane, premium is 95 or 98, all from the pumps at most gas stations.

He was comparing 98 Shell with 98 BP or Mobil.

The drivers manual for my 99 996 C2 says 98 Ron/ should be used, 95 can also be used but the knock sensors will adjust the timing. Maybe its different in US cars.

I also felt the same as you, most good brands are going to be very close, I'm sceptical when people say this ones better than that but he says his dyno tests show a difference. Theres nothing in it for him.

<{POST_SNAPBACK}>

Sorry...didn't see that you were not in the States. Isn't the octane rating over there calculated differently than here. I think you use the research octane (RON) rating and we use the motor rating (MON) 96 RON equals 92 MON.

<{POST_SNAPBACK}>

yes, its RON here 98 RON = 88 MON 95 RON = 85 MON

[Kiko]

Europe -- RON

USA ----- AKI (Anti-Knock Index)

98RON approx 93 AKI