petrol RON 95 or 98?

[Owd git]

On a whim the other day I filled up my standard THP with 98 RON rather than the usual 95 RON.

The question is can I tell any difference?

The answer is I don't know for sure but the car seems to be going very well at the moment and I wouldn't take much convincing that there might be a tiny improvement in performance and possibly mpg too - but I expect it's all in my mind and there's no point in paying extra for 98 RON, or going to 'superfuels'

I found this on t'internet

Also, a few vehicles, such as the new BMW K1200R motorbike, can sense knock and adjust their engine tuning to take advantage of higher grade fuels. Another user commented that the 2004 BMW 330 also does this, according to the driver's handbook it makes 231 BHP on 98 octane and 221 BHP on 95. This ability is apparently widespread amongst German performance cars using Bosch / Siemens electronic engine controls.

I guess my question is........... does the DS3's BMW/PSA THP engine mangement software adjust parameters to make best use of different RON fuels?

[bohrhead]

I read a while ago that unless the car specifies that 98 is required, you are just wasting money.

[telephoneman]

On my old Lexus (LS400) I found that if I put 98 in it improved fuel efficiency on a run but not around town. However, when I calculated the cost/benefit it didn't stack up, even if I was going on a long journey. I haven't tried it with the LS430 and my DS3 is a diesel.

[Fabian]

On 95 fuel my DS3 THP has 162 HP and with BP Ultimate 98 the car has 170,9 HP so there is a good difference.
Also the car runs smoother.

One thing, they told me that BP Ultimate is Octane 100 here in Holland (Same as Germany)

[ZACK]

Ron ?

[Owd git]

On 95 fuel my DS3 THP has 162 HP and with BP Ultimate 98 the car has 170,9 HP so there is a good difference.
Also the car runs smoother.

Presumably you're not running the standard engine map Fabian?

[Fabian]

Yes I am!
My DS3 is completly standard besides the Forge intake pipes and the ITG airfilter.

[Owd git]

Yes I am!
My DS3 is completly standard besides the Forge intake pipes and the ITG airfilter.

Hmmmm - think I'll try another tank full then!

Anyone else got any evidence?

[gar074]

Ron ?

Accio, brain!!

[Stef]

It takes a few tankfuls for the car to adjust fully, the DS3R is supposed to run on it exclusively but I've certainly found improvements when running it on previous cars.

Stef

[Chris_Blue]

Ive tried both ULTIMATE and Standard unleaded in the DS3 and cant see any difference at all
Saying that its only ever been a tank full and never several on the trot
So is there a benefit to using higher rated fuel other than performance?
IE It burns better and keeps the engine cleaner

My last motor- Ford Focus 1.6- it made a real difference. Car really accelerated better in lower gears
So much so that i used ULTIMATE pretty much for the first 50,000 miles
CBLUE

[x6411]

As far as I know, at least on the DS3s, it would take a remap to properly take advantage of higher RON petrol. I've also heard it takes a few tanks worth of the higher RON petrol for the ECU to adjust itself at all to take advantage.. Not 100% on either of these 'facts' though

One thing I do do though is steer clear from supermarket fuels, as they apparently burn 'dirtier'..

[Czar]

With the THP (PSA) engines having a high compression ratio you will find they perform better when run continuously on premium grade fuels, 98 + RON, the higher the RON rating the better the fuel resists pre detonation, commonly known as knock or pinking for the old school among us, running such premium fuels allows the self adaptive ECU to make the most of this suppression of pre detonation (knock) with full adjustment of the vanos timing advancement, throughout the entire RPM range, whereas the cheaper 93-95 RON rated fuels, will pre detonate (knock) much sooner throughout the RPM range whilst you accelerate, and when the knock sensor detects this, your ECU retards the vanos adjustment timing, to counter balance the pre detonation (knock) in order to prevent engine/piston damage, so in essence if you want to really enjoy your DS3's performance, then give it the best premium grade fuel, isn't that the reason you purchased a hot hatch in the first place, to enjoy it's full potential ?

[Chris_Blue]

Well it has to be said Czar, you seem to know your RONs
On strength what u said will stick with ULTIMATE fuel and see what happens
What about supermarket high RON stuff. Is it just as good
CBLUE

[Gazza]

Tesco 99 ron for my DS3R or Vpower 98 ron