Optimax

Your car does not have a knock sensor. According to the various bods on

and Optimax will makeabsolutely bog all difference to your car.There are, however, those thatwill refute this....

I've seen magazine photos of a stripped head before/after regular use of Optimax, and it made those dirty valves shine. I've also seen a dyno graph before/after, can't remember what engine though unfortunately, and there was an across the rev range boost of 3% in horsepower that was repeatable. A guy at work with a 2.0 Mondeo with a mpg readout has kept track of different petrols' performance on the same routes/same speeds, and Optimax was the best by

2mpg. My 2.0 Primera was a bit faster but mpg didn't change as far as I could detect (no mpg meter). I don't use it regularly, just occasionally for the cleaning properties. I wouldn't be surprised though if it didn't give a boost on some engines, there's a lot of variables at work here.

The problem with all of these 'anecdotal' claims for increased performance/mpg is that you will find dozens of motorists who will say the same after installing these uselss 'save petrol' devices such as lead pellets in a tube and magnets around a fuel pipe!

Kev

Its not exactly the same situation though as Optimax is a higher octane fuel and that alone will result in better performance. Whether the engine management system makes good use of this is another matter as is the question of the extra cost of the fuel set against any gains.

but back in the real world, I noticed that tesco petrol was the best from a performance point of view till optimax came along

I've checked on four 500 mile journeys using Optimax one way, 'normal' the other, and using the cruise control where possible. And at about 33 mpg, couldn't say there was a significant difference. In theory, the engine in my car is meant to be able to take advantage of higher octane petrol.

I have never rated Tesco fuel as being a quality product either diesel or petrol. The diesel fuel tended to cause smoke in our Citroen during acceleration and petrol caused pinking in the Vauxhall when going up inclines. Shell standard or Asda fuel is better.

Gio

I Agree. Asda fuel is just as good, tried optimax in my mondeo and couldnt tell the diffrenece. Is it really worth the extra couple of pence?

While my car can't/isn't/won't make use of the higher octane rating, I'm sure shiney valves/etc can only be a good thing, and may extend engine life and be useful for spark plugs/etc on horrid cold mornings?

If any of the above is true, then a few extra pence on a fillup is probably a good thing?

--Nick.

Yeah but I always find a leaky head gasket cleans the chamber really well ...

?

--Nick.

If you have a small leak to the coolant it sucks some in which decokes the head very well. It's really obvious which cylinders blown to the water jacket when you take the head off

By comparison every couple of months I use Optimax in my Mondeo for a week (drive a taxi so it's a lot of miles in a week!) just to 'clean things out'. I notice a big difference in performance whilst using the optimax, smoother acceleration and more power. Doesn't last long after I stop using the optimax though. Saying that adding STP fuel injector cleaner boosted performance until the next tank of fuel. I guess it's just the extra octane that gives the boost.

There's no point in using higher octane petrol than the engine mapping can adjust to.

I have a Scooby WRX Jap import that will only run on Optimax. I have found that I get 200 miles to a full tank of optimax (which is rubbish really) but if I use normal unleaded i only get around 150 miles to a tank. Performance is smoother with optimax aswell. I would recommend any owners of performance cars of any nature to pay a little extra and get the 98 RON whether it be Optimax or any other brand name like BP SuperPlus. Sccoby Floz.

Or you could read the manual and find out if it needs 98 octane, as many 'performance' jap market cars do. Not so with most cars designed to be sold here.

Optimax. I have

is rubbish

miles to a

recommend

extra and

like BP

octane, as many

Easier said than done. As surprise, surprise, jap cars come with manuals, service history etc, written in japanese. :-) That's if you get one. I didn't get one with my Celica GT4 turbo. AFAIK though, jap performance cars are designed to run on 100 octane, or very near it, which is freely available in Japan. So it's not surprising that they can take advantage of any higher octane UK fuel. My GT4 is quite happy running on super, but it does run marginally better on Optimax. RR sessions suggest about a 5% increase in the power output. Whether that difference gives increased MPG. Enough to justify Optimax's extra cost, I doubt. It certainly feels smother and nicer to drive, but I expect my right foot compensates for the likelyhood of any reduced fuel consumption. :-) TBH I'm not that interested in fuel consumption. If I were, I'd buy a more economical car. Mike.

Found the dyno link for Optimax in a WRX

Thanks. But as my car doesn't appear to have a knock sensor, will the cleaning effect of Optimax only do the engine good, even if it doesn't take advantage of the higher octane rating (and will the combustion cause any ill effects in my engine, it not detecting the rating?)

--Nick.