Optimax Fuel

[Bibbs]

Fifth gear is a load of tosh anyway, obviously an import/tuned car designed to run on decent fuel will run better on higher octane! But it won't "gain power" over stock, it will merely not "lose power" for the reasons discussed when running sub specification fuel 

GT4 booster, sorry mate but you seem a little hazy on the facts. 

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The car was a stock UK scooby .. and wasn't tuned, they just drained the tank, re-filled and re-set the ECU. This was tested at Thor racing.

Went from 245bhp to 265, from 95 ron to Optimax (and load more torque than ultimate).

Stock is 245 aparently .. on 95 ron (as it says in the manual)

And the reason they didn't do 99 Ron? Cause it's only available in the south east of the UK.

[sotal]

As I posted the other week, you can actually lose power from higher octane fuels. My Motorbike (600cc - not efi) will actually lose power if you put a higher octane fuel in, It's made for 95RON fuel and states to only use that. If you put 97 or higher in it drops from 105bhp to around 90bhp which is quite significant.

Me and Mikeb had a bit of a discussion about it and decided that cars with EFI will have knock sensors which will adjust for it but I still think you should run your car on what it was made for. If you bought a UK car it's going to be made for 95RON, maybe some real performance cars will benefit but I wouldn't dream of putting it in a yaris or anything similar

[Karma Supra]

So you are telling me the reccomended fuel for a scumbaru turbo is regular unleaded??? <_<

Thats pretty :censor:ed up as even N/a mercs are set up for 98+!!!!

[GT4 BOOSTER]

a performance car that can utilise the extra ron will gain added bhp , those not geared up for it wont get any gains what so ever performance wise

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I especially like "gain added bhp" straight out of the magical additive advert in the back of max power!!

Fifth gear is a load of tosh anyway, obviously an import/tuned car designed to run on decent fuel will run better on higher octane! But it won't "gain power" over stock, it will merely not "lose power" for the reasons discussed when running sub specification fuel

GT4 booster, sorry mate but you seem a little hazy on the facts.

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those were my words , i dont read max power , never did or will , maybe its you thats hazy on facts mate - imports mapped on 100 ron will respond better than on 95 ron and they DO gain power i own 1 , its what they were designed to run on.the 5th gear test was simply aSKING whats best between , 95 ,bp ultimate and optimax .the findings of which were conclusive that on a motor geared up for it will perform better. :D

[Karma Supra]

Imports do not GAIN power... they merely don't LOSE as much ;)

[Jesus]

Like Bibbs said... my car was designed to be run on 100RON... the nearer I can get fuel to 100RON will determine how close it runs to its potential. As Karma said, the lower grade you go, the further you are from what is was designed for and hence lose power. If the car was designed to run on 100RON in Japan, and you bring it over here and use 97, 98 or even 99RON, you're not making the most out of your car. Your car doesn't gain horsepower, it just gets closer to what it would have been running in Japan on better grade fuel that it was designed for.

If the car wasn't designed to run on 100RON, like a Yaris, then higher octane fuels will offer little in means of performance.

[GT4 BOOSTER]

it still gains bhp over 95 ron running it on 98 or 99 ron.which is what i was saying.

[Bibbs]

Like Bibbs said... my car was designed to be run on 100RON

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Even the S2k is designed for it .. higher compression and an extra 10bhp apparrently ..

[MIP]

You probably do have to reset the ECU though, couldn't just go from 95 to 97 or 99 and expect a power gain. I imagine once the ECU has retarted the timings to whatever level using the knock sensor, its not gonna advance them again.

[GT4 BOOSTER]

thats correct MIP and when its done full of optimax when in comes the turbo spool it flies