Normal Or High Octane Fuel?

[celica_xr9145]

I used the search button but couldnt find anything.

With the world the way it is nowadays, im trying to get as many Km's as possible.

Obviously when filling up with premium, you get less fuel and less Km's.

The problem i got (not really a problem) is when i fill up with 'Normal' unleaded, my tappets go nuts when i accelerate.

Back in october when i got a tune up, the mechanic strongly recommended i filled up with high octane fuel, what i wanted to ask is why?
When i did take it in the spark plugs were soaked in oil but i dont think that had anything to do with it.

Is it safe to run on 'Normal' fuel with the tappets rattling?
Obviously i dont want to ruin the engine but i want to get more Km's for my money.

Its not a problem, just after some opinions/advice.

What do you think and what do you use?

[Mr.Phreak]

Obviously when filling up with premium, you get less fuel and less Km's.

I would've thought a full tank was a full tank, regardless of rating, and some people have reported better mileage with 98, so while it may cost them more at the pump, they'll go further with it. Although I haven't tested the theory personally, because debates about economy make me want to stab people.

[xsspeed]

Obviously when filling up with premium, you get less fuel and less Km's.

I would've thought a full tank was a full tank, regardless of rating, and some people have reported better mileage with 98, so while it may cost them more at the pump, they'll go further with it. Although I haven't tested the theory personally, because debates about economy make me want to stab people.

yes, full is full, you just pay more for it

I have not done a 'test' myself but have seen evidence of them done in oz, compating ULP to PULP, they were getting so many more kms on PULP that it was cheaper per km to use it.

Plus supposedly cleaner burning etc etc

[Bling]

You sure its the 'tappets' making the noise? Could be detonating with the low octane fuel. I know mine is rancid on anything other than 98. But yeah, I don't know how fuel can be related to any noise other than detonation.

[fivebob]

The problem i got (not really a problem) is when i fill up with 'Normal' unleaded, my tappets go nuts when i accelerate.

That's not your tappets (you don't have any but that's beside the point), it's your engine detonating

[celica_xr9145]

detonating? that doesnt sound, so in that case its better to run on premium?

Also, i think i might have worded it wrong, i meant more fuel for your $20 if you see what i mean.

[Alex B]

Do not run a 3s-ge on 91. They go like ass and ping their head off. If your worried about gas milage then buy a corolla or something.

[celica_xr9145]

Do not run a 3s-ge on 91. They go like buttocks and ping their head off. If your worried about gas milage then buy a corolla or something.

its not that im worried about gas milaege, but if i could get more milaege out of it, its a plus.

So its not just my 3sge that does it then?
If thats the case ill keep it on premium

[xsspeed]

yeah I always use 98 in our 3sge beams

[Bling]

Also, i think i might have worded it wrong, i meant more fuel for your $20 if you see what i mean.

False economy really, sure 91 gets you more fuel per $20, but detonation kills engines. I know which is better 'value' fuel

[celica_xr9145]

Also, i think i might have worded it wrong, i meant more fuel for your $20 if you see what i mean.

False economy really, sure 91 gets you more fuel per $20, but detonation kills engines. I know which is better 'value' fuel

Thats a good way of putting it, really 91 is not an option then

[rollaholic]

its not detonation, its pre-ignition or 'pinking' as it is known by some

use 98

[MR2BOY23]

Don't run your car on 91, I had the same sort of symptoms when I used to fill up with 91 I got lots of pinging noises and it ran like shit

I started using BP 98 and Gull biofuel.. I can tell you the 98 lasts longer and my car runs so much better, I never put anything else in it

[sergei]

You will certainly get better fuel economy out of modern engine/engine control with higher octane.
Even old 3S-GE is relatively high compression and certainly is designed for high octane.
Don't put cheap stuff, it works out the same if not better with high octane.

[iOnic]

its not detonation, its pre-ignition or 'pinking'

.... There's a difference?

[sergei]

its not detonation, its pre-ignition or 'pinking'

.... There's a difference?

Both are high speed shock waves created by spontaneous ignition under different condition.

[iOnic]

I know that....that's why I was curious as to why someone can say "it's not detonation, it's pre-ignition or pinking".....all three terms refer the same thing

[Crampy]

I did a test with one of my old AE82 FXGTs. Back when there was 91 and 96 octane gas. I put $20 of 91 in it and measured the kms travelled, then did the same with 96. I did it a number of times to confirm and was consistently getting more kms with the 96, even though I was getting less volume of fuel.

The car ran a lot better with the higher octane stuff too, as most Japanese cars do.

[fivebob]

its not detonation, its pre-ignition or 'pinking' as it is known by some

It is detonation, pre ignition is caused by hot spots in the engine firing off the charge before the spark plug fires, totaly different thing and far more destructive than detonation.

Pinking is detonation, well it was the term that was always used to describe detonation in days gone by.

This form of detonation is usually observed when the engine is in to high a gear and the engine is trying to accelerate. The ignition is too advanced for the conditions, and because it's rotating slowly the charge is more dense, and therefore more prone to detonation than would normally be the case when peak pressure is reached at the desired position of approx 22°ATDC.

[cat007]

hmmm

what about older cars/vehicles? I'm tempted to put 98 in the Hiace's 4Y and then adjust the timing a little more advanced....