What fuel?

[theaxe]

It's a no brainer running 98 - it's cheaper (since in the UK it costs about 5% more and gives you 10% better mpg)!!!

Agreed! I can't understand why people waste their money on 95.

Plus, with v-power you get double points..

[audijohn]

i'll be trying tesco 99 tomorrow...

ps. can the engine really get any better ;@)

Yes it will get better but after most of the first tank it used, from then on it will settle and improve.

[mrdeli]

thanks john

[t_urbo]

I have some Sunoco Gt Plus 109 RON if anyone wants some, cost £ 17.00 a Gallon.

[W8PMC]

I have some Sunoco Gt Plus 109 RON if anyone wants some, cost £ 17.00 a Gallon.

Have you used any in your RS4?? Was their a noticable difference??

Won't be trying it on mine, but genuinely interested if a gain was had?? I'd expect a huge gain in a modern turbo car with any decent mapping (from anywhere) though.

[t_urbo]

I have some Sunoco Gt Plus 109 RON if anyone wants some, cost £ 17.00 a Gallon.

Have you used any in your RS4?? Was their a noticable difference??

Won't be trying it on mine, but genuinely interested if a gain was had?? I'd expect a huge gain in a modern turbo car with any decent mapping (from anywhere) though.

Stock was 450 bhp, pump gas map was 600 bhp and the race map was 620 bhp according to GIAC who distribute the maps. I assumed they were probably 30-40bhp down in real terms.
So the gain in the turbo was 20 bhp, i could only run the race map when i had a full tank of it, the problem is it is highly oxygenated and burns hotter at full boost so after say a tank full you had to go back to super unleaded otherwise the plugs would need changing.

Im away for a month but when i return i will try a couple of gallons in the RS4 and let you know but i cant imagine it will improve any, knowing my luck it will go pete tong, but better then using it in the lawn mower!
Also it works out a tad expensive to run on.

[SR71]

http://forums.audiworld.com/rs4b7/msgs/57515.phtml

Interesting read.

[Mikeyboy]

I've only ever used standard 95 ron, is there really a difference with 98?

Its on the sticker on the inside of the fuel flap. Its in the manual and the dealer should have told you before you drove away for the first time. How did you not know that it was designed for 98?

I am always staggered that people don't check their manuals about the fundamentals of keeping the thing in good nick.

also any of the fuel grades like the 102 and 105 racing types will have little beneficial affect according to a guy who did a whole load of fuel tests for one of the magazines and since. He found that it ran about the same as the Tesco 99 which is about the best there is apparently. It seems the map just doesn't adjust enough.

[audijohn]

I've only ever used standard 95 ron, is there really a difference with 98?

Its on the sticker on the inside of the fuel flap. Its in the manual and the dealer should have told you before you drove away for the first time. How did you not know that it was designed for 98?

I am always staggered that people don't check their manuals about the fundamentals of keeping the thing in good nick.

also any of the fuel grades like the 102 and 105 racing types will have little beneficial affect according to a guy who did a whole load of fuel tests for one of the magazines and since. He found that it ran about the same as the Tesco 99 which is about the best there is apparently. It seems the map just doesn't adjust enough.

Tesco 99 is the one for me. Good price at the moment too.

[mrdeli]

Well the UK brochure shows 95 ron as fine. I have filled today with 99 Tesco - to early to feel any difference either in power or MPG, but if either or both improve, i'll stick to the higher grade.

[Dom81]

98+ is recommended, as per the fuel flap and all docs I've seen

95 is allowed, but I wouldn't call it fine

All performance figures are based on 98

[gw007]

I always fill mine up on V-Power, or BP Ultimate where I cant get any V-Power stuff... I havent found any other places local to me doing other petrol, i.e. Tesco 99... I heard Esso had their own stuff, 100 RON? and Texaco I think have some... I have had a couple of tanks of 95 RON in the RS4 when its the missus who has filled up and it doesnt feel too different, but would rather run on 98.

When I had my 996 C2 it was run on 95 RON the first few times, then I switched to BP Ultimate (97) and when I drove away from the petrol station the car had no life in it (felt like I had pulled away in 3rd) and it kept stuttering... I thought I'd knackered the engine up, but after a few miles the mapping seemed to have adjusted and it ran fine.

The only time in the 996 I switched back to 95 RON as I couldnt get any V-Power it was a rather dull drive! The car felt down on power and it was rather noticeable...

[Dom81]

V-Power is 98 RON (as you'd expect) but BP Ultimate is only 97

I tend to use BP as it's nearer home, but still think the name (and absence of obvious octane rating) is a bit of a con

[PetrolDave]

Here's my comparison between 95 and 99 in a B6 S4 ...

exiting a motorway junction near where I used to work there is a tight(ish) left corner onto a dual carriageway. From a standing start with 95 octane in the tank the corner was flat-to-the-floor. With V-Power or Tesco 99 there was no way I could take the corner with my foot flat to the floor. I would say that shows a significant increase in power in an S4 with higher octane fuel.

Don't see why the RS4 shouldn't show the same difference, but I don't work there any more!

BTW if you look in the hardback brochures for the RS4 it says 98 RON is recommended, and in the "small print" says "In emergencies, use regular unleaded with a minimum RON of 95". The key phrase there is "IN EMERGENCIES" ...

[tartan_rob]

In my experience:

B5 - V-power only, car was lumpy and sluggish on 95
B6 - made no differance at all
B7 - V-power only, car is smoother and feels nipier whilst having better economy. Don't notice a big drop in performance going to 95, notice a big difference going back to 98 or higher. Also, chrome tail pipes stay cleaner longer on V-Power.

(By V-Power I mean higher than 97 octane).