E39 M5. Which Fuel?

[welshy]

Hi all.

Just accquired E39 M5 and would like to know thoughts on fuel.

This isnt regarding performance or saving money. Previous owner has always used Shell Optimax and he had a garage just down the road from his house.

He did say it HAS to run on optimax but surely this cant be true. Happy to use super unleaded at all time but the nearest Shell garage to me is over 25 miles away. thing is (get this) I wouldnt mind if I lived in the sticks but I live in the middle of fking Plymouth!! How is this possible?

Car has Powerflow BB and cold air intake system.

Cheers all

Happy days

[Quinten]

Check your fuel flap, the answer is on there

RON98 is recommended, which afaik no fuel in the UK offers, but I've always filled up with super unleaded/vpower/nitro+/momentum but a little bit of regular in between should not hurt at all...

[welshy]

Just checked and for one awful moment i thought it said DIEsel.....arghhh imagine!

How long you had your M5? With your extensive posting have you come across ppl saying about using ONLY optimax?

More than happy to use any RON+ petrol. Only plus side on only using Optimax is i have to drive through a tunnel (windows down, sunroof open, sports button on, to saviour the noise!

Cheers for the reply bud.

[Patrick Bateman]

Any super unleaded.

[belleair302]

Regular unleaded and on every third tank for for the super stuff!!!

[scarecrow]

Had my 02 M5 for three years now and run it on normal 95.
Have tried successive tank fills of super plus and can't tell any difference in either performance or economy.
The S62 V8 isn't really that highly tuned at about 87bhp per litre so maybe it is not needed?

Edited by scarecrow on Thursday 24th October 22:53

[Patrick Bateman]

S62

I'd bet a dyno would say otherwise.

[scarecrow]

Patrick Bateman said:

S62

I'd bet a dyno would say otherwise.

No 420bhp at fly with both (give or take)

[Quinten]

I've had mine for 3.5 years and I've never heard of the requirement for optimax. Unless it is in a high state of tune/supercharged, the previous owner may have been misinformed himself

[scarecrow]

Patrick Bateman said:

S62

I keep doing that! S62, S62

[drivin_me_nuts]

I drove 160k on mine and concluded that if there is any difference in performance, drive, response between the asda special or the sacred juice of the high octane fuels, it's so marginal as to be insignificant.


I concluded that the best fuel was the cheapest.

[Patrick Bateman]

I'm quite surprised at that, I know it's not the most highly strung M engine but still thought there would be a difference considering it's still high performance.

[MattOz]

I always ran mine on SUL. Which SUL didn't matter, but for the most part it was Sainsburys Super with the occasional visit to Shell or BP.

Honestly couldn't tell the difference between the vendors, but suppose that they should be much of a muchness anyway.

[tjlazer]

I get better mileage with super and it's not exactly going to hurt to use the best. Given the extra miles any cost saving with standard is negligible.

[MGR]

I've not got an M5 but I can't tell any difference between asda cheap stuff and optimax in my E36 M3, or the other S54 engined M cars I've owned. It also says 98+ on the filler cap of those.

[av185]

I have run an E39 M5, 3 E46 M3s, 3 911 Carreras, a 458 Italia and a 911 Carrera GTS on 95 Ron from different petrol stations, including supermarkets, during the past 10 years with no problems whatsoever.

Recently I have also tried Tescos 99 for two or three consecutive fill ups on several of these cars with no noticeable performance or economy changes.

[Stinkfoot]

All of my old E36 M3's ran really poor on standard unleaded when tried. The M5 has only ever had super unleaded and I would not dream of putting standard unleaded in it.

[TheAngryDog]

I run mine on either shell vpower nitro or Tesco momentum. BP ultimate if I can find neither

[welshy]

Cheers all for your input. Do about 5K per year so I think it'll be Super Unleaded but wont worry about the odd tank of normal.

Shame as the drive from Plymouth to Trulefoot Roundabout isnt a bad one.

[Adam3441]

My step dad managed to fudge up his fuel filter in his Merc CL600 (V12 Bi-Turbo) using supermarket fuel. How he didn't melt a piston I'll never know. It was misfiring with the throttle floored due to a clogged fuel filter.

This put me off ever using cheap petrol in an expensive engine. He was probably just unlucky but in my M5 I always look out for BP / Shell / Texaco.