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Peter Mount
22nd June 2008, 01:24 PM
Hi

I've just been buying the normal unleaded petrol for my small car.

Would I get enough better fuel economy to justify buying a higher octane petrol like Caltex's Vortex 98 or Shell's VPower?

leon
22nd June 2008, 01:51 PM
Nope. All marketing mumbo jumbo. I use the 98 stuff as I run a tuned turbo motor that has been mapped to run on 98 octane only.

Unless your car requires and or contains maps to run on the better stuff it is a waste of money. You might possibly eek out a few km's extra, but not enough to warrant the extra 10c per litre.

I've found from personal experience that when you start running these fuels ( that contain all of the detergents after previously running the normal stuff), it dislodges crap from your fuel system and blocks the filters. If you decide to run on these fuels, change your fuel filter after a week or so. It will be full of crap.

Hamsmyth
22nd June 2008, 01:54 PM
I run my old car ('78 Peugeot) on Premium Unleaded. It just runs so much better and I can feel the difference. It justifies the cost from my experience. However I'd imagine every car would behave differently and there is no blanket rule for its use.

ozron
22nd June 2008, 01:58 PM
Anyone had a positive experience using one of the ethanol blends from Liberty? It's usually several cents cheaper and it is slightly more environmentally friendly. I've tried it a few times but haven't noticed much of a difference in my Magna.

laprius
22nd June 2008, 02:51 PM
I've been running my XR6 turbo on UNited's 95 ron ULP+eth for over a year now never a knock never missed a beat and cheaper than normal unleaded :)

mac_man_luke
22nd June 2008, 02:58 PM
I run my car on BP ultimate 98, the extra cost does not bother me (dont do many kms), it runs nicer and the fuel system stays cleaner.

I find the best thing you can do is be consistent, imo EFI cars run the best when run on the same fuel all the time.

meinrosebud
22nd June 2008, 03:06 PM
Use 94 Octane with 10% Alcohol... you will get less pings but not necessarily more kilometers. If your engine is not tuned for 98 or 100 octane you're wasting your money. Ford Turbo Sixes are built to use higher octane fuels.

shiny
22nd June 2008, 03:26 PM
All depends, cars with high compression ratios will need higher octane to avoid pinging, see Compression ratio - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Compression_ratio) and as mentioned above older cars that used to run on leaded will need the high octane or an additive.

If it just a little run about then just try a tank full and see if makes any difference. :thumbup:

Peter Mount
22nd June 2008, 03:33 PM
If it just a little run about then just try a tank full and see if makes any difference. :thumbup:

That sounds like a good idea. I'll just see what happens when I fill up the tank with it.

Al Aero
22nd June 2008, 03:39 PM
98ron Premium fuel here, BP or Mobil.

Stay well clear of Shell Optishit or whatever its called now, its watered down, inconsistent mix of detergents, idle ruining crap fuel.

Btw, running a seriously modded 2002 Saab 9-3 Aero and have never had a pinging issue with BP or Mobil.

a.

arkenstone
22nd June 2008, 03:42 PM
Another vote on the BP 98ron stuff.

Back in the day my piece of shit 86 astra would get a near 10% economy increase from it and my current car (1990 S Class) while tolerant of pretty much anything has a whole lot more balls if it's on the good stuff.

I avoid Ethanol blends (don't trust the way it absorbs water) and stick to the 'premium' fuels, as I believe the extra $6 per 80 litre tank or whatever more than worth it.

wabbit
22nd June 2008, 03:53 PM
I use the 98 stuff as I run a tuned turbo motor that has been mapped to run on 98 octane only.

Thanks for saving me typing as much lol. Same petrol for the same reason :)

PurpleLogix
22nd June 2008, 04:03 PM
Our pug needs 95 ron. Anything else and it goes like a dog. Calais (5.7L) ECU has been edited and I only use 95 or higher, The calais gets a further 50km more on higher grade fuel.

Optogamut
22nd June 2008, 04:40 PM
I'll chuck in the ethanol blends when it's there, can't tell the difference.

bartron
22nd June 2008, 04:52 PM
All depends, cars with high compression ratios will need higher octane to avoid pinging, see Compression ratio - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Compression_ratio) and as mentioned above older cars that used to run on leaded will need the high octane or an additive.

If it just a little run about then just try a tank full and see if makes any difference. :thumbup:

^^^important read...

I find the mass populace seems to equate more=better therefore 98 ron must be better tham 94 ron etc.

The octane rating is just an indicator of how hard it is to burn the fuel. If you put 94 ron in a high compresion engine then you will get pinging which means the fuel is being compressed so much it ignites under pressure before the spark plug fires (essentially, this is how a deisel works). High compression engines need the fuel to not do that, hence why some cars genuinely need 98+ ron fuel.

Rule of thumb, if your engine isn't pinging on unleaded then there's no need to move to premium or any of the higher octane fuels. If you want to clean your engine then try a tank of it or use one of the engine cleaning additives but it's not something you need to do all the time.


But if you want a cheap way to run a car (cheap until everyone starts doing it)....convert a diesel to run on woodgas :)
zi7Yf8-sAxM

Currawong
22nd June 2008, 04:59 PM
Avoid Shell, always. Their fuel is awful. If you want a free octane boost, drop a couple of naphthalene moth balls in your tank after a fill. I have no idea if it's good for your car or not, but it definitely works.

iMic
22nd June 2008, 05:40 PM
You'll find decent boosts also if your engine is equipped with a knock sensor. This will allow it to advance the timing on higher octane fuels.

I'm running a modified Mitsubishi Magna TR 1991, 2.6L 4 cylinder with a knock sensor, and by running it on 98 in stock form the performance boosts from 98kW to 102kW, 212nm to 220nm of torque. In modified form the figures are higher but I have yet to dyno it and find out the exact figures.

For engines without a knock sensor it can help them in some cases as we found on a Chrysler PT Cruiser, but it was mostly because the engine was optimised for the fuel.

ozron
22nd June 2008, 06:52 PM
You'll find decent boosts also if your engine is equipped with a knock sensor. This will allow it to advance the timing on higher octane fuels.

I'm running a modified Mitsubishi Magna TR 1991, 2.6L 4 cylinder with a knock sensor, and by running it on 98 in stock form the performance boosts from 98kW to 102kW, 212nm to 220nm of torque. In modified form the figures are higher but I have yet to dyno it and find out the exact figures.

For engines without a knock sensor it can help them in some cases as we found on a Chrysler PT Cruiser, but it was mostly because the engine was optimised for the fuel.

Hey iMac600. I'm running a Magna TS SE 1994, also with 2.6L 4 cyl @ 240,000km. How much did it cost to get the knock sensor installed and exactly what are the benefits?

Also which brand of 98 do you use?

Ruotian
22nd June 2008, 07:10 PM
My bmw e46 318i specifies ron 91, I run 95/premium and it gives 50 kms more (from ~550km to 600 - 620km) per tank.

The engine works so much smoother. I'll stick with premium.

Ruotian

Redman
22nd June 2008, 07:18 PM
I have an everyday VZ Holden Commodore and have ran Caltex Vortex 95 Octane since day1. I get around 8.6-9.1 lts/100kms.
The Holden "specs" say 9.5 Hwy and 11 around town.

hoony
23rd June 2008, 12:57 PM
Depends on what you car is made/tuned to run on... I've got an evo which just loves 100RON fuel, but if I put the same in my motorcycle it would make no difference, in fact it would probably be bad.

But wow - Evo + 100RON = :D:D:D:D:D:D:D:D:D:D

delux
23rd June 2008, 01:15 PM
if your car is made ot run on regular unleaded then stick with regular unleaded. theres a chance you will see a postive result but its just as likely you will see a negative result as your car is not tuned to run on that type of fuel. and at 15-20 cents a litre more expensive i doubt you would see a saving in your pocket at the end of the day anyway.

delux
23rd June 2008, 01:19 PM
Hey iMac600. I'm running a Magna TS SE 1994, also with 2.6L 4 cyl @ 240,000km. How much did it cost to get the knock sensor installed and exactly what are the benefits?

Also which brand of 98 do you use?

your car is already fitted with one, check your user manual towards the back and you will see it states the different power and torque figures than can be achieved using premium fuel.

Aladdin
23rd June 2008, 03:38 PM
Anyone had a positive experience using one of the ethanol blends from Liberty? It's usually several cents cheaper and it is slightly more environmentally friendly. I've tried it a few times but haven't noticed much of a difference in my Magna.

Note that ethanol blends increase fuel volume consumption (more litres of the stuff for the same distance).

This will offset the savings generated from a cheaper cents per litre price compared to non-ethanol (i.e. normal) petrols.