100 octan gas

[valjo]

i would like to ask what kind of gas are you using in yours s2? in manual it is recomidented to use 98 octan gas. There is also 100 octan gas available in my country, so should i use it? what should be difference?

[Erikb]

I dont think you will notice a big difference. I believe you have to rewrite your chip to notice some real difference.

[robo]

I dont think you will notice a big difference. rewrite your chip to notice .

You will notice big diffrence if you jump from 98 to 100 shell racing as long is its true v-power. 100 shell racing from germany is owsome but identical petrol (so called 100 v-power) in Poland is like 94 octane petrol or more like diesel.

[MidnightBlueS2]

i would like to ask what kind of gas are you using in yours s2? in manual it is recomidented to use 98 octan gas. There is also 100 octan gas available in my country, so should i use it? what should be difference?

Hi !

I use 98 octane on a regular basis here in Belgium and the engine runs great on it... but I also go to Germany from time to time and I always fill up with either Shell V-Max 100 octane or Aral Ultimate 100.

Can I tell there is a big difference on hard acceleration, no, but there's no denying that the engine runs silky, silky smooth when fed with 100 octane. Even less engine noise, seemingly better low end torque and even smoother idling than a purring kitten

It's good stuff and well worth the extra cents !

HTH,

David

[dan_b]

In the UK we can now get 99 Octane petrol, which is nice. Along with others here, I've started using that on a regular basis and with a few tanksful through the engine I've noticed an improvement in throttle response and a bigger feeling of full boost coming on more quickly. Purely subjective of course as I've not had the car rolling roaded and a before and after comparason done, but I do remember that there was a thread where someone had done that, and there was something like 20bhp difference between 97 octane and Optimax (98 octane)?

I was of the understanding that the Motronic ECU has adaptive capabilities so that if you run higher octane, the ECU can advance the timing, yielding more power...

[valjo]

I was of the understanding that the Motronic ECU has adaptive capabilities so that if you run higher octane, the ECU can advance the timing, yielding more power...

if that is true and if that is working in practise too it is great! i realy have to fill up my car with 100 octans next time!!

[renoks]

...yep., but can you imagine that in Ireland, the best what can you find is texaco 97 octane witch is not better than ordinary 95 (just price 30cnt plus!!!! than 95 ) and you will be very lucky, if you will find petrol station wich sells that kind of petrol. I live in third bigest city of IRL and here is just only ONE petrol station with 97 and not even daily..

[philS2]

when i put optimax or some 99 octane it does'nt retard.but with 95 it does(because Minhea set it up that way).i don't think you'd get 20bhp between 97 and 98 would you?maybe 95 and 99.just seems toomuch or am i underestimating fuel potency?

[Audi_CQ]

when i put optimax or some 99 octane it does'nt retard.but with 95 it does(because Minhea set it up that way).i don't think you'd get 20bhp between 97 and 98 would you?maybe 95 and 99.just seems toomuch or am i underestimating fuel potency?

How does the ECU know what octane it is

[newsh]

With low octane fuel engine pinks, ECU detects knock and reduces boost to avoid detonation and subsequent damage. If knocking continues it will throw in a bunch of extra fuel too.

[Audi_CQ]

With low octane fuel engine pinks, ECU detects knock and reduces boost to avoid detonation and subsequent damage. If knocking continues it will throw in a bunch of extra fuel too.

OK, but does the ECU try to advance ignition until knock is detected everytime it's started? A stock engine is mapped for 98 isn't it? Can't imagine that there are much use in 100 if boost isn't increased