optimax

[swansea v6]

Hi I have an imported Mazda MX-3 v6 which I have always run on optimax, mainly because I have heard some horror stories of damaged engines when other imported cars have been run on regular lower octane petrol. Last week I had to fill up at a non shell garage which didnt have super unleaded. Ever since the car has felt much rougher. It doesnt like being revved like it used to, it is almost like it is missing along the rev range and also it takes a little bit longer to start, whereas before it always started on the first turn of the key. I have just had a major service where the leads were changed for magnecor ones and all the fluids and plugs were changed. Surely this missing cant be because of the lower octane petrol, or can it??????

[tuttle]

When you re-fill with the 'good stuff' see if these symptoms disappear. Tho if you've just had the plugs/leads changed it may be worth re-checking for good clean connections & that the plugs are gapped right & in the correct temp range.

[gofasterrosssco]

I put a tenner of 'normal' 95 RON into my imported MR2 as an experiment, to see if there was actually any difference. Wasnt a huge difference really, but it did feel a wee bit less smooth and was less willing to rev like the symptoms you describe. Im sure that the ecu will retard the timing a bit to account for the lower grade fuel. I wont be trying it again thou............

[swansea v6]

Filled up with optimax again yesterday and all the rough running issues have gone away....I don't really understand as I thought my mx 3 didnt have a knock sensor so the ecu wouldnt be able to adjust/compensate for differing octane petrols?? any ideas

[tuttle]

I think nearly everthing post 1990something now has some form of knock sensor/timing retarder.Glad it was just the fuel tho.

[swansea v6]

Yea glad its back to running sweet again, take it I better keep coughing up for optimax.........

[MR.COATES]

I've been mainly using Optimax. Did try the new Texaco High Octane (97) but was totally unimpressed with that.

Would love to try the Tesco 99 RON but it's still very much a saaarf only thing at the moment.

[tuttle]

Check here for locations/updates on where you can get Tesco 99RON-we got it in 1 Bristol station,Brislington, now!
www.greenergy.com/products/99_octane_locations.html

[DamienCBR]

i use super unleaded in the bike, i tend to get better mpg and power. The mpg is better because obviously you get more power lower down on the acclerator. Don't bother in the car though.