Regular ULP or 95 RON Premium only? 2004 147 2.0 Manual

[kenigma]

Hey Alfa lovers

Tried to search the forum for previous posts on this but nothing came up... Sorry if it's a repeat.

My 5 door 147 is recommended to run on 95 RON premium only. I only recent bought this car after 5 years without owning a set of wheels. I was shocked when I filled up the first time at $1.47/l for premium and nearly died when I had to fill up the second at $1.53/l!

Anyway, will there be long-term damage or negative side effects of running on regular ULP? (I wouldn't go as far as E10)

At these prices I don't think I want to drive all that much...

Cheers!

[ANG156]

Always ran my cars on 98 octane vpower. Find it very good. Sure it costs more but i remember when my dad did all the main seals and gaskets in his 164 3 litre, the motor was spotless inside. Its on 330,000kms atm and still going strong. Thats enough evidence for me to keep using that fuel. I just remind myself of this experience and the fact that it takes 5 mins to fill up compared to hours and big dollars to repair if something goes wrong. Regular is still good but vpower gets my vote. BTW have you got a copy of this saturday's age drive guide? Interesting article on fuels with 98 octane still better than e10 or e85 for litre per 100km. enough said

[Stuart Thomson]

If you use the regular unleaded the car will ping.  If the engine doesn't have a knock sensor (someone here will know, or contact the Alfa dealer) the detonation will cause damage.  If it does have a knock sensor the engine will retard the timing until you don't get pinging, at which stage the performance of the engine will have deteriorated to the extent that you will notice.  Bite the bullet and fill up with 95 or 98, your car will love it and actually use a lot less fuel, if you run the numbers, just the higher density of the PULP fuels usually makes up for the price difference, if you take into account the possible extra maintenance that using regular ULP, it's a no brainer.  For a 60 litre fill at an average of 15c a litre more for PULP equals $9 a fill.  I'll bet you waste $10/week elsewhere and don't complain about it.

Cheers
Stuart

[Ray Pignataro]

Stuart is it still beneficial to run a lower octaned engine eg falcon or commodore on the 98 octane?

[John Hanslow]

Kenigma, use as per Alfa owners manual 95RON and as Stuart says, you do not want to damage the engine.

I always use 98RON (usually BP) and have done even on my wrecks on wheels (pre alfa days)  and why - because the engine is just more responsive and runs better.  The Alfa was designed for it so use the best you can afford.  Note that you do actually get better performance and economy with higher octane but not enough to match the price differential.

My question is what oil has been used and who is servicing it as (handbook again) you have to use the correct oil too.  So many people have had issues with cheaper service options.

[Stuart Thomson]

Stuart is it still beneficial to run a lower octaned engine eg falcon or commodore on the 98 octane?

Probably not so much Ray, although you'll reap the benefits of the higher density fuel, the engine map is probably not optimised for the higher octane fuel, so won't advance the ignition.  Importantly though, it won't hurt.  I have read that many people claim higher mpg when using higher octane fuel, but this is really affected by driving behaviour more than anything else, so the placebo effect has to be overcome.  By this I mean that people, usually subconsciously will drive "leaner" when they have more expensive fuel in the car, the only way to tell is on a dyno.

Cheers
Stuart

[wankski]

lads...

lets get something straight.... 98, 95 and regular 91 relates to the OCTANE in fuel. Octane is LONGER chain than what is mainly buirning - the chief constituent of fuel HEXANE!

the longer chain octane helps delay pre-detonation of the lighter hexane.

pls, 98 does not lead to better running unless as previously stated the engine map/piston compression is designed to require 98 (high compression, advance timing)

The 156/147 is designed to run on 95RON. doesn't matter if its the E10 stuff (i run it) or otherwise... Don't kid yourself - 98 is mainly marketing. Having said that, there are cars that require 98.... porsche, ferrari - maybe some bimmers like the m5 etc

Petrol is already one of the best solvents known to man...

[Craig C]

The only thing I've got to add is that on a few occasions where I have had to use 91 I have then had trouble with my oxygen sensor.  I don't know what the link is or whether it is a coincidence but having had to replace it a few times I go out of my way to make sure I get the 95 or higher.

[Stuart Thomson]

lads...

lets get something straight.... 98, 95 and regular 91 relates to the OCTANE in fuel. Octane is LONGER chain than what is mainly buirning - the chief constituent of fuel HEXANE!

Uhh, wrong, wrong and wrong.

These are typical mythconceptions about fuel
The Octane rating of fuel is not a chemical measure, although inferences as to the probable octane number from a fuels mixture can be made from a knowledge of the makeup of the fuel.  The system is based on n-heptane being zero (totally unbranched seven carbon hydrocarbon chain), iso-octane (2,2,4-trimethylpentane) defined as 100, not a measure of the amount of octane in the fuel.  It is determined experimentally with a calibrated test engine with variable compression and timing.

There are many constituents of fuel, of the major ones in high octane fuel are toluene and xylene (why it smells so nice).  Although both Xylene and iso-octane are 8 carbon hydrocarbons, they bear as much resemblance as myself and Elle McPherson (both approximately the same age homosapiens).

Hexane (or at least n-hexane, the straight chained version) is a neurotoxin at even quite low levels (ask the Chinese iPhone assembly workers), there is virtually none in petrol.

the longer chain octane helps delay pre-detonation of the lighter hexane.

pls, 98 does not lead to better running unless as previously stated the engine map/piston compression is designed to require 98 (high compression, advance timing)

There should be NO detonation of the AF mixture in a petrol engine, pre- post- or otherwise.  The AF mix should burn, not explode.  Higher compression engines require higher octane fuels to stop the mixture "dieselling" or detonating without ignition just because of the compression.  If your car is designed to run on 95 it will run on 98, possibly better, because at 95 you are at the mercy of the petrol retailers selling junk fuel, 98 gives you some leeway.  The higher density of the fuel means more mass gets injected with each squirt from the injectors as the injectors are a volumetric measure, mass is related to the amount of carbon, which relates to the amount of exhaust gas and energy produced.  Hence you get "more bang for your buck".

98 and 95 probably have similar additives to prevent corrosion etc., so there's probably no difference in that regard.

The 156/147 is designed to run on 95RON. doesn't matter if its the E10 stuff (i run it) or otherwise... Don't kid yourself - 98 is mainly marketing. Having said that, there are cars that require 98.... porsche, ferrari - maybe some bimmers like the m5 etc

Petrol is already one of the best solvents known to man...

Water is the best solvent known to man, but it doesn't burn.  I don't get the relevance of the statement.

Cheers
Stuart

[John Hanslow]

Stuart, I think you have answered Kenigma's question (and a bit more too).

I think you deserve a beer tomorrow night for all of that .

Perhaps I should try out Shell instead of BP and compare.  Previously there was some comment that Mobile was just the best for the older 105's.  

I used to buy that Shell 100 as I thought it the best you could but, but really I was impressed with the competition style nozzle.  Did not notice any smoother running but you nerver know until you experiment a bit.

[Evan Bottcher]

Is this also wrong?  I've always understood that octane was a measure of how slowly the fuel will burn.  The slower the fuel burns the longer the force is applied to the piston and more of the fuel energy is converted into kinetic energy.  In order to take advantage of this requires ignition timing to be advanced, so that the mixture is ignited earlier, as the the flamefront will travel more slowly.  Pinging can either be pre-ignition (dieseling) or if the ignition is too far advanced and the flamefront is hitting the piston while it's still on the compression stroke.  Knock sensors are used to detect pinging, and advance or retard the spark to optimise the timing, making up for variability in fuel octane and environmental conditions.

This matches up with the old practice of turning up at the racetrack, topping up with high-octane avgas, and advancing the timing to match.  Or is that only for high-compression engines?

I don't claim the above to be true, interested in how far off the mark I am

[wankski]

well i  certainly got schooled on the chemical composition...   thanks stu for the detailed response... (damn, must be a chemist or summit).. boo.

that is precisely what I was going for w/ the octane rating... what is described as 'pre-detonation' or pinging... under compression - i didn't make the term up, maybe a 'lay-term' but effective enuff - determined by the engine design (and temp)... Obviously 98 works in 95 cars, but i don't get the junk fuel statement/sentiment. If that was so, then they'd also be selling 95 as 98 or maybe diluting it more with toluene (not that that has ever happened)  

as for the solvent line - it was in response that 98RON makes your engine spotless... i don't get that..

isn't benzine still in fuel? thought that was pretty bad...

[wankski]

also, with slightly delayed burn and more mass, what is the risk of some of it ending up in the pre-cats? the engine management isn't adjusting for it...

[diglad]

fascinating reading, thanks to all for sharing the knowledge...

[colcol]

In Victoria with the crazy prices that go up on a Saturday afternoon actually 12-15p.m., at Caltex this week, fill up on Saturday morning for $1-37 for 98 ron or Saturday afternoon fill up with 91 ron for $1-37, it is as simple as that, the 932 cars have knock sensors that sense vibrations and when the engines get close to knocking [pinging], that is uncontrolled combustion, the engine retards the ignition to stop the pinging, if you have good quality 98 ron petrol then it will advance the ignition just before it starts to ping, pinging can cause burnt pistons, valves and broken piston rings, but if you have an older car without a knock sensor then run it on the recommended fuel rating and listen for pinging which sounds like marbles rattling in a saucepan, you are likely to hear it labouring the car up a hill in a too higher gear, Colin.