Dave M UK

iTrader: (4)

I hear Tesco are offering 99 RON super unleaded on a trail basis in the south east.

The question is- what is best for a 2001 classic or imprezas in general,

Is it possible to put super unleaded in even if i have half a tank of optimax, whats the crack??

Do you need a ECU reset every time you use either of the 2??

I always thought super unleaded was an ageing grade of fuel, even though its got a higher RON rating than premium unleaded, info please

Dave m uk

ZEN Performance

In order of preference:

Optimax
Tesco 99 (maybe even joint 1st?)
97RON SUL
95RON UL
Diesel
Paraffin
Boot Polish
Soup
Water
BP Ultimate 97 RON

lee65

New_scooby_04

iTrader: (4)

Optimax seems to be the preferred diet of Scoobies
Mixing petrol won't don't any harm, esp if its two SULs
The Ecu adjusts automatically and quicky in later classics and new age cars, so no need to rest.
Better the RON, the better your car will run - and superior protection against knock.

Ns04

scooby_matt

The Chief

I actually find Esso Supreme pretty good and to be honest to me anyway it feels better than Optimax

DABALLS

is the BP realy that bad!!!!!!!

ZEN Performance

really that bad.

All the other 97RON sul products are almost on a par with Optimax in my experience so far. BP ultimate is noticabley worse when it comes to det suppression.

Paul

Lee 2.0T

Thats the last time I use BP Ultimate...been running on that for months now...seems to run ok though....

Might have to travel the extra 2 mile and fill up with Optimax....Probably be worth it by the sounds of it...

wah

Wish I had known that when I last saw you Lee I would have slapped ya round the head

Si

Trap2Terrorist

iTrader: (3)

I run mine on Texaco HighOctane (97RON) and it's definately smoother and more responsive than BP Ultimate. I'd use Optimax if it wasn't a 25 mile round trip and don't have access to Tesco99.

I've only tried Esso Supreme twice and both times my CEL light flashed for 30 seconds within a short period of time from filling the tank.

Possibly coincidence but enough to put me off ever using it again, although it was from the same garage on both occasions so another factor in my "scientific" assessment .

ZEN Performance

On the newer factory ECU you will probably not notice a difference as it will hopefully dial out any knock. Where we see the results is in the mapping, and what needs to be done to allow for various fuels. Or in cases where a car is mapped for one type of fuel, the owner has some knock feedback (knocklink or perhaps a OBD scanner like a SECS) and the change in fuel grade is quite noticable.

Paul

powercrazed

Just read a fuel test feature in Banzai magazine. Cossie YB engine on a dyno, fuel tank draine and refilled with 5ltrs of each fuel in turn. All readings taken at constant 6500rpm, 2 bar boost and ignition value of 13degrees advance. After each run, ignition was advanced as far as possible and new figures taken.
Results:-
Supermarket unleaded 95ron 512bhp/417lb ft. (could not get 13deg advance, only 10.75deg)

Tesco 99ron:-13deg adv 521/421 (13.75 deg adv 523/423) 17bhp/6lb ft increase over 95ron

BP Ultimate 97ron:-13deg adv 530/428 (15deg adv 537/434) 25bhp/17lb ft increase over 95ron

Optimax 98ron:-13deg adv 537/434 (16deg adv 547/442) 35bhp/25lb ft increase over 95ron

Nathan

ZEN Performance

That is surprising, or at least the Tesco 99 not doing so well as the BP. In my experience so far, the Tesco 99 allows more advance than I would expect, and perfoms on the rollers well too.

At lower loads and speeds the timing difference between 95ron and optimax can be as much as 9 degrees in my experience.

Paul

JJstiuk

Well my sti dets on bp ultimate even with millers cvl octane booster, when using shell super plus i hardly get a flicker with knock link, same with sainsburys sul i always use millers cvl turbo too and have an ecutec remap...

Adam M

Paul,

serious question, have you tried BP ultimate recently? As in since they reblended it but didn't advertise the change substantially enough for people to know they had done it?

If not, then give it another try, you might be surprised.