Petrol costs

[Rave]

Smoother running at low revs I can believe, engines are prone to knock at low revs. Still, the point I'm trying to make is that you shouldn't trust your own senses to make an objective judgement, because it's basically impossibly- you know that you've put expensive petrol in your car, so you want to believe that it's automatically better. It's the same thing as people swearing that putting a £500 cable in between their CD player and amp makes a huge difference to the sound, when in fact if you put a blindfold on them they can't tell the difference between that and a cable which cost a pound.

The point is that Optimax doesn't contain any more energy than normal petrol, it just burns in a more controlled way; unless your engine can automatically detect that it's using good petrol (by having a knock sensor) there's no way it can actually be making more power.

Rich :¬)

[Lowe]

The point is that Optimax doesn't contain any more energy than normal petrol, it just burns in a more controlled way; unless your engine can automatically detect that it's using good petrol (by having a knock sensor) there's no way it can actually be making more power.

Correct - but there are other ways of making the engine more efficient: Clean all the carbon out of it.

Optimax and newer SUL have cleaning agents which help remove deposits through the engine. Whilst not necessarily giving you MORE power, it will ensure you don't lose any - and in the case of a badly choked up engine help free some of it up, and with sustained use get you back to what the engine SHOULD be pushing out.

Also, you'd be suprised how many cars have knock sensors. Hell, a standard R5 GTT has a knock sensor that can change the ignition, and how old are they now? I have no doubt that your MR2 has one.

[Rave]

My preferred method of making sure my engine has no deposits in it is to take it for a high speed blast. Doesn't look like the 4AGE has a knock sensor, although apparently they added one to the 4AGZE. Seeing as you're a knowledgeable chap Lowe, do you know the answer to my earlier question about advancing my ignition timing a smidge to get more go out of normal 95RON unleaded?

[Firelord]

Agreed Rave cos when I first put optimax in I was like wtf its made no difference but after 3-4 tanks and long runs I started to notice a difference with the way the engine performed under load and it got better

Whilst the difference is probably tiny for those who don't do many miles its not for me when I do quite a lot of mileage and if it means that town drivings a little easier i'm all for it

[Firelord]

Optimax and newer SUL have cleaning agents which help remove deposits through the engine. Whilst not necessarily giving you MORE power, it will ensure you don't lose any - and in the case of a badly choked up engine help free some of it up, and with sustained use get you back to what the engine SHOULD be pushing out.

See this is what I think has happened, I prob had a build up of carbon deposits causing the flat spots etc but when run with higher rated fuel its cleared it and what seems like more power but in essence just running the engine as it should at its given capacity

[Lowe]

See this is what I think has happened, I prob had a build up of carbon deposits causing the flat spots etc but when run with higher rated fuel its cleared it and what seems like more power but in essence just running the engine as it should at its given capacity

The higher rated fuel wouldn't of made much difference to cleaning - it's the additives that do the cleaning, not the higher RON. Just wanted to clear that up, but that's probably what you meant.

[Firelord]

yeah glad you understand what I mean

[Lowe]

My preferred method of making sure my engine has no deposits in it is to take it for a high speed blast. Doesn't look like the 4AGE has a knock sensor, although apparently they added one to the 4AGZE. Seeing as you're a knowledgeable chap Lowe, do you know the answer to my earlier question about advancing my ignition timing a smidge to get more go out of normal 95RON unleaded?

You'll probably find that it was set up to run best using 95 RON. Personally I don't have much knowledge about the Toyota lumps - excuse my ignorance, but are they fuel injected or carb?

If they're FI, then your ignition is probably controlled by the ECU in which case it'll be a time for a cheeky remap - otherwise known as a chip. That's how Superchips etc get their power gains, they tinker with the ignition to advance it slightly, and ensure it's fuelling properly. The only way you'll get the best from it is to take it to a rolling road and get it set up, but without a reprogrammable ECU you'll find that tricky. I doubt the standard ECU is reprogrammable.

The other problem with going down the "tuned to the max" approach is, if you're stuck for fuel and have to get supermarket crap then you'll be in a world of pain - the car will pink itself to death in the worst case. I have this problem since my car can only run on a bare minimum of 97RON, and I always carry a sealed bottle of uber octane boost around incase I'm really, really stuck.

[mnet674]

79.8 here for supermarket skank (its only a 1.0 it doesn't mind), notice that extra value 0.1p cheaper than standard! That 3p on the 30 litre fillup makes all the difference to my finances you know!

[Stringent]

76.9 at my local shell, although prices vary between 76.9-78.9 around here. I would stick Optimax in my engine if it came down a bit more, its 85.9 at the moment.

[thedrj]

Liverpool and there abouts for UL (1.1 doesn't benefit much from the good stuff)....

Dodgy independent - 86.5 > 95.7 (depending on the weather and which one)
Shell (outside work) - 76.9
Texaco (on the way) - 81.9
Asda (on way back from work with a little diversion) - 76.9
Total (very near the g/f) - 78.5
Tesco (near the g/f) - 77.9 (but 5p/l discount with £50 worth of shopping...so me and the flatmates go together and I reap the benefits with a full tank of fuel - making it 72.9)

There used to be a petrol station up the road from me which never showed the fuel price, so we figured it went up as you put the fuel in!

[Butuz]

Well - i ahve been through a few tanks of Optimax now, and i am getting better fuel economy than with the tesco supermarket crud i was using before.

With Tesco petrol : 235-240 miles to a tank
With Optimax 270-280 miles to a tank.

I wasnt expecting that!!!

Butuz