I only use Tesco 99 (T99) in the S5. If I need to fill up and no Tesco is close then I fill up on Shell V Power, but I find that the S5 prefers the T99. Pick up just seems smoother on the T99. I can't tell the differnce performance wise between V Power and T99 but you can if you use the cheap stuff, which I did once when I had to fill up at an ESSO and the best they had was RON 97.I've just had it pointed out to me that Tesco do a RON 99 fuel which might well go well with the S5. Anyone tried it out on their machine yet?
Any other recommendations for RON 98/99 fuels which work well with the car?
Just for your reference there have been many independant tests on higher octane fuels to prove if there is a difference or not, here is a link to one of the UKs more repectable tuners with the results from their tests: http://www.thorneymotorsport.co.uk/tuning/Fuel_Test_Results_Update.shtmljust know that unless your ecu has programming specifically centered around it, running higher octane fuel won't have any actual difference on anything other then your wallet.
The engine should have no compensation to do as the fuel will burn as the timing has been designed... compensation is only really needed when lower RON fuels are used and the knock sensor adjusts the ignition timing to avoid knock problems.
Correct, while the ecu will retard the timing for lower octane fuel (when detecting pre-ignition) it will not work the other way around.
The time and expense taken to tune an engine at an octane level unavailable and unknown to the majority of owners makes it a very low priority on a manufacturers list.
Ah 1 out... I knew I should have looked. Personally I pay little atttention to this stuff and just put BP Ultimate in it. as I get Premier points from BP.
if someone can provide me evidence of a stock, non-altered ecu that compensates for higher then premium octane fuel then i will be impressed. Until then, I stand buy my statement that it's a waste of money.It depends entirely on the ECU. It was discussed in some detail on other forums i've been on in the past (Some tuning forums and Alfa Romeo forums). Believe it or not, some ECUs will adapt over time to compensate for the higher 99RON fuel, the ECU in effect, "learns" that the car is using a higher RON fuel, even if it was first programmed to run on 95.
So it can work the other way around if you have the correct ECU and use it for long enough for it to "learn".
Here you go: Independant test, with dyno results to prove that higher RON fuel makes a difference, in both an old unmodified MR2 and an M3 CSL.if someone can provide me evidence of a stock, non-altered ecu that compensates for higher then premium octane fuel then i will be impressed. Until then, I stand buy my statement that it's a waste of money.
Here you go: Independant test, with dyno results to prove that higher RON fuel makes a difference.
yep, I'll give you that -on a limited production, track focused M3 CSL with a TUNED ecu. That does not mean that the same is true for all vehicles.