Optimax

Neil Barker · 2003-08-22T19:09:27+00:00

I have a Stilo Abarth and today decided to fill it up with Shell Optimax to see what, if anything, happened. OK, it had approx 1/8th tank of normal 95 RON unleaded in there when it was filled up, so it won't be 'neat' Optimax.After approx. 20 miles driving, I parked my car and came back to it a few hours later.I then drove off, down country lanes, to see if I could begin to detect any improvement.Well, err, not exactly - this may be totally co-incidental with something else, but my engine's performance at the top-end has dropped off and when accelerating hard, it feels what I can only describe as 'strained' - it doesn't sound the same, either. It almost feels like the engine is misfiring at high revs, producing a drop-off in power.I can only put this down to one or more of the following:-1) My engine doesn't like the unleaded/Optimax mix - whichwould eventually improve as it becomes neat Optimax withsuccessive fill-ups. Perhaps the ECU is confused ? Ignition timing out as a result of this confusion ?2) I have something wrong with my car which is causing this.I was concerned, so I called out the AA - he'd never seen a Stilo Abarth before and took it for a short test-drive to see if he could detect anything. He remarked on how quick the car seemed, but given that he'd never driven one before, he had nothing to compare it against. He checked my car's computer with his laptop and found no error codes.I took my Stilo for an Italian tune-up for 40 miles (as much also to burn off some Optimax) and it doesn't have the performance it used to - when accelerating from 70MPH, it would rapidly go past 100 and keep pulling. Now it feels like it's hard work.I'm puzzled as to just what to do here.

Aug 22, 2003 22 Replies

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Pete Smith 22 years ago

I've only got personal, empirical data to go on, based on my driving a Mk

5 Escort and a Mk2 Mondeo.

If you remove the battery, the ECU takes half an hour or so to re-learn all of its settings. Until this point, performance is down, and the engine tends to stall.

If you drive it in a spirited manner, it seems to "get used" to it, which leads to "poor" economy, not particularly good low speed driving, but fun high speed driving.

Similarly, if you drive like a pensioner, it gets used to it, and needs a bit of thrashing before you can drive in the manner of paragraph above.

Just my 2ps worth.

Pete.

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sro 22 years ago

Got to ask - how are you measuring these changes and to what accuracy ?

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Neil Barker 22 years ago

By experience and 'feel' / car's petrol gauge / amount dispensed at pump.

Things are just about back to normal now - I'm really surprised that Optimax was such a negative experience in my car. I'll never touch the stuff again.

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