Does anyone agree/disagree with this?

I put a tank of the stuff in because I couldn't get hold of Optimax and I had heard good things from a number of people about it.

I must say I was shocked how poor it is. The RON octane number may be higher but it is still a crude supermarket fuel.

After about a mile (so just long enough to run the fuel through to the engine) the car was noticeably more lumpy in response while the engine and exhaust note was brash and crude compared to how it normally sounds.

I put a tank of Optimax in it today after (finally) finding some at a local garage and within another mile the car was running sweet as always again.

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JDM ST205 (286bhp and 281lb/ft)
JDM ST202 (Finally sold )
1982 Pontiac Trans Am 5.7L V8 (See my website)

Umm how odd, you must have used old standing fuel..


did you reset the ecu.

I know it does vary in performance, that’s for sure..

Old and new

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Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.

My jdm is better on tescos 99 than optimax Paul,and as said before all the fuels come from the same refinerysso maybe Jon is right old stock.

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TERRY

94 Silver ST205 JDM 280bhp
gone but not forgotten

I use Sainsburys Super Unleaded & find it better then Optimax in Krude.

I heard that Optimax is hard to get hold of as the major store for this fuel went up in smoke a few weeks back (Wasnt that the place where they cremated George Best?? )

I recently tried the Tesco 99 RON fuel after a tank full of 95 RON and you could feel the difference but whether this was just because I felt more relaxed about using more than 0.5bar boost I dont know

Although the Tesco fuel may come from the same refinery I'm pretty sure the additives are different e.g. toluene, detergents etc. Why else would they rate it 99 RON not 98 RON like Shell with Optimax.

Anyway Optimax is back in stock so I'll stick with that until such time as people do a comparison of Tesco 99 against Optimax including a top end strip down.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

That's what most people have said before. "Tesco is just as good and cheaper".

I am aware that my experiences are highly subjective but the car really hated it (before and after ECU reset)

I cannot beleive that Optimax and Tesco 99 come out of the same barrel. They may come from the same refinery but that means nothing. You'll get 3in1 oil, plastic and a whole host of things out of the same barrel of crude oil but they won't run your car

Is it confirmed somehwere that Shell make Tescos fuel for them then? Even if they do I would expect them to keep the best for themselves.

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JDM ST205 (286bhp and 281lb/ft)
JDM ST202 (Finally sold )
1982 Pontiac Trans Am 5.7L V8 (See my website)

hmm, must get round to testing thsi fuel and looking at teh knock readings on the Power FC.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

what about fuel economy..???

ive heard people are getting very bad fuel economy (worse than usual!!!) using 99 ron tesco's stuff, and i have to say that the economy isnt great when i use it...

must get around to trying some optimax.!!! to compare.

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1998 JDM ST205

My GT Four History:
Black 1992 JDM ST185 GT-Four, Grey 1990 UK ST185 GT-Four


My celica website

Oh yeah, forgot about that part too.

I got 240miles from a full tank of tesco 99 but i normally get 290 from the same amount of Optimax!

That's not a saving in my book!

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JDM ST205 (286bhp and 281lb/ft)
JDM ST202 (Finally sold )
1982 Pontiac Trans Am 5.7L V8 (See my website)

Interesting, I get circa 230 from Optimax, but circa 260 from Sainsburys super...

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ST205 WRC #0002249

holy super tanker - that is one lead boot or one sick O2 sensor m8. I typically see 260-300 on short runs. (erghh buggering about with Power Fc the last tank for mapping and forgot to switch o2 feedback back on and got 180 miles )

230 on stock ecu sounds frightening m8.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

I usually get about 250 on a tank on all short runs thats abot 21.5 to the gallon.Goes up to 30 mpg on a run,the best I have done is 400 on a tank.

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TERRY

94 Silver ST205 JDM 280bhp
gone but not forgotten

Hummmmmmmmmm Now im worried, I struggle to get 280 on motorway runs (Not going above 80 Mph).

Could my running rich at the RR day the other month be a sign??

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ST205 WRC #0002249

I normally get 300 miles from a tank which ends up being about 58 litres by the time I fill up. Last tank however got me 340 miles with a light foot and 2 longish runs.

Record worst tanks are joint between Donington Park and Nurburgring trackdays where the average was 60 miles per tank.

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GT4DC Events Co-ordinator
1996 ST205 UK

Krude, running rich on a rolling road is perfectly normal - especially with a standard ECU.

Your O2 sensor could be on its way out, or caked in carbon and not reading correctly. The O2 sensor is used to adjust the Air/Fuel ratio when not on boost, so is only used for motorway cruising and light throttle.

Something for you to think about. IIRC Dennis Heath wrote a little article on how to test the O2 sensor for correct calibration. You need a multimeter. Ask Google for the guide URL because I can't remember it myself.

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Sprint ST165 aka "The 500BHP Sledgehammer" #6 in the Toyota Sprint Series. GT3071 1.9bar