Well over the last few weeks (10) ive filled my car (full fill) up 3 times with premium and 3 times with Normal unleaded.

Each week i did around 250kms'ish, not once did i use a highway only the usual stop start residential area driving..

Someone said that Pulp lasted longer... well sorry to say that after 6 60L fills each time my car got to 460km's it was flashing empty... So for my 3L auto PUlp or Ulp gives me the same mileage yet one costs more.... so i dont think its worth the extra 4c a litre!. sorry if im stating the obvoius but i actualy believed that pulp would last longer, it doesnt i wished it did.... there scentific fact number one brought to you by the letter j.

So pulp should only be used for.. what reason then?

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Greetings All.

PULP will be better for cars with engine management such as Greddy E-manage or UNICHIP and the such....
Simply, with a car tuned for it, it would get more power, and more milage from it, economy wise it would be better.

Cheers,
--Tonba
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I use PULP once every 2 months or earlier if fuel prices are down, but only reason being to clean the fuel lines :)

What fuels were you using? Generally on Optimax I do get about another 50km's from it. Performance though wouldn't be different. The fuels themselves aren't any more powerful. You only get more performance from having your car tuned to using them because they are more resistant to causing knock etc when the timing is advanced. It's the advanced timing that gives the performance boost. That and better fuel mapping.

The last tank of Optimax however only got me 550kms before the fuel light came on. It also didn't feel like it was running as smooth as normal. The tank after however is BP regular 91 and it's nice and smooth and I think more economical. We'll see.

many ppl get misled by the myth that there is some mystery secret ingredient in PULP, or premium petrol that gives more power and better fuel economy. it's all a big scam by petrol companies to get you paying more. first up, the research octane rating, or better known as RON is really, just the resistance to knock, or pre-ignition. so what happens when you put RON91 petrol in an engine that specifies RON95 minimum? well simple, the RON91 being less resistant to combustion than RON95, ignites prematurely due to excessive pressures and heat in the cylinders. this is why when you use 'lower grade' petrol (ie ULP) in performance engines or an engine that is not designed for lower octane ratings, you lose power. when the air-fuel mix is ignited and how it is ignited is all pre-programmed into your engine managment for maximum punch. so when ULP ignites before the piston reaches top dead centre, obviously you don't get the expected 'max punch' because some of the energy was already lost when the piston was on its way up. to cap it off, when you are using PULP in an engine specified for ULP, you really are just paying extra for the extra refinement process and ingredients that does nothing significantly beneficial for your engine. some countries' (e.g. singapore, japan, parts of europe) premium grade petrol are very well refined and have good quality additives that ensure clean and efficient combustion. i can't say the same for petrol sold in australia though. that's why you see some car manufacturers having to 'de-tune' the engine of some of their performance cars before they can run on the poorer gasoline quality here.

I think for highway driving you will recieve some extra km's form PULP. When i filled up with PULP in the magna for city driving it did get me an extra 20km, but that is debatable. I believe it is all a mental thing wen it comes to putting premium in your magna, as truthfully, it gives it little if nothing in terms of performance and economy.

I use premium fuel only because l do about 150 to 180 klms per week, so the extra cost is not an issue. I can't say that l notice any real difference in consumption which runs generally around 16.5L/100.

I would like to say to any members who let their fuel tanks run low, l was advised by a service manager of a large Melbourne Mitsubishi dealer to NEVER let the tank drop below half full. Something about the fuel pumps location within the tank and it being prone to failing if the tank ran too low on fuel. I don't know if he is right or not but he was quite emphatic about it.

Well I am a fan of PULP, i definately get more kms than ULP but my car is tuned with it though with my greddy. PULP is the only fuel i use, i dont do much highway driving and my consumption stays around 10-11L/100km, 11L is when im thrashing my car a lot too.

I was just thinking about this stuff the other day. When we first bought the car we were advised to only use Optimax once a month to help clean out the engine. After using Optimax for 5 tank fills in a row we reverted back to the regular out of curiousity only to find out fuel consumption was more or less the same with very little difference in power so now we only use Optimax once a month. It really gives me the S#%@! when you see these ads on T.V. with all there Bull!$%@ claims.

Normally, just use what the min RON the manufacturer recommends if your car is stock as it has been tuned to run most efficiently on that RON. Like the above thread, If u have an aftermarket ECU that is tuned to run the car on another RON, then do it... if not, there is really no point in doing that.

CHEERS
Nick

I would like to say to any members who let their fuel tanks run low, l was advised by a service manager of a large Melbourne Mitsubishi dealer to NEVER let the tank drop below half full. Something about the fuel pumps location within the tank and it being prone to failing if the tank ran too low on fuel. I don't know if he is right or not but he was quite emphatic about it.

:doubt: my car hardly is ever over half a tank (i dont got 60 buks to fill her up) been that way for 7 months now havnet had any problems with it

I only ran higher RON in my car when I advanced the ignition timing. Simply as a precaution, and it worked well. I once used ULP and I noticed it wasnt going as well as it was...so back to PULP and it was great.

But if you did that to a stock magna, it wont make that much difference.

I would like to say to any members who let their fuel tanks run low, l was advised by a service manager of a large Melbourne Mitsubishi dealer to NEVER let the tank drop below half full. Something about the fuel pumps location within the tank and it being prone to failing if the tank ran too low on fuel. I don't know if he is right or not but he was quite emphatic about it.

My old man's KR is always below half lol...and he's had that for a long time, never had a problem.

It's bad if you let the car run out of fuel though

And 3rd gen owners with aftermarket ECU mods need to be careful because if it's tuned for RON 98 and you use 91 stuff and it starts knocking, then the computer won't retard timing as the engines don't have knock sensors.

I'd rather not.. but I can't help but fill up with Premium.. my hand just seems to gravitate towards that red handle (assuming I'm at a Shell) and that's that. Fuel economy is slightly better but otherwise the car runs that bit smoother, especially at idle. We don't get Optimax here and I think only one or two BP's might have Ultimate but I'm not entirely sure. Same goes for Synergy.. doubt there'd be any here, despite what the pumps say.

around town i dont notice much difference but on the open road i only use 1 full tank plus one notch between full and 3/4from melb to sydney and the same back ive gotten 700klms once on optimax on a sydney to melb trip and fuel light wasnt on yet but was just getting on the empty line but stopped for fuel just in case lol 3lt auto tf.

My experiences seem to be about the same as everyone elses. I don't get any noticable increase in performance from PULP.

What I have noticed though is the variability in the quality of ULP. Sometimes I fill up with ULP and the car is definately running worse than the previous tank of ULP. I guess with PULP the consistency is going to be better due to better refinement and your not going to get any of that stink'n ethanol in it.

So if a car is tuned to run on PULP and you have to put ULP in because there is no PULP available, what damage if any will this do to the engine?




.

My experiences seem to be about the same as everyone elses. I don't get any noticable increase in performance from PULP.

What I have noticed though is the variability in the quality of ULP. Sometimes I fill up with ULP and the car is definately running worse than the previous tank of ULP. I guess with PULP the consistency is going to be better due to better refinement and your not going to get any of that stink'n ethanol in it.

So if a car is tuned to run on PULP and you have to put ULP in because there is no PULP available, what damage if any will this do to the engine?




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if you use ULP in a car tuned to run on PULP, without knock-sensors to retard the timing of firing (e.g. magna cos it's already factory-tuned to run on the lowest RON rating), it will damage your pistons and cylinder little by little over time, depending on how hard you push the engine. for engines equiped with knock sensors, you just get cut substantially in power and the car goes much slower than normal.

Coincidentally a colleague just discussed with me an article in FastFours April04 edition that goes into the whole fundamentals of petroleum refinement + effect of fuel constiuents.

In a brief they have said:

- In a higher octane fuel, within each molecule of fuel the atoms of carbon/hydrogen are a more branched structure and hence have lower volatility.
- In a higher density fuel (Optimax) each molecule contains higher amounts of carbon/hydrogen which gives a higher energy content when that molecule combusts.

My feeling is that running high octane fuel basically is as a safeguard, and if your engine is equipped to adapt to higher octane fuels then you will get higher performance. If you don't have a knock sensor (3rd Gens) or custom engine management, you will not get a benefit except for maybe ridiculously hot days when you will prevent possible detonation (it happens, but not that often on a stock car). Optimax should give a mileage improvement on all cars.

Well for some strange reason my car gets less K's a tank on optimax then ULP. Ok so this test was conducted with only 4 full tanks emptied till the fuel light turns on, all for tanks full of fuel were purchased from the same servo, not an accurate test as too many varible change but still suprising never the less. And also my driving during that time didn't vary much, and it was mostlly urban driving with a bit of freeway (to work and back):

1st tank ULP 570 Ks

2nd tank OPTIMAX 480 Ks

3rd tank ULP 567 Ks

4th tank OPTIMAX 489 Ks

Interesting, I still put in Optimax every 4th to 5th tank purlly to clean out the fuel lines a bit.

And 3rd gen owners with aftermarket ECU mods need to be careful because if it's tuned for RON 98 and you use 91 stuff and it starts knocking, then the computer won't retard timing as the engines don't have knock sensors.


Where did you get this info from? EVERY other person ive spoken to in regards to this tells me my car (TJ Magna) definitly has knock sensors. My TR V6 also had em. Dunno who told you any differently

Where did you get this info from? EVERY other person ive spoken to in regards to this tells me my car (TJ Magna) definitly has knock sensors. My TR V6 also had em. Dunno who told you any differently

Every one I have spoken to has agreed 3rd gens don't run knock sensors :confused:

hmmmmm.. anyone out there no the true answer to this!?!?!?!??!?!

Just asked my friend at Mitsubishi spare parts; the 6G74 (3.5L 24V SOHC) definately does NOT have knock sensors.

well it wouldn't make much sense for mitsu to put in knock sensors cos it's gonna cost and the car from the factory is already tuned to run on the lowest octane rating petrol sold in the gas stations. in other words, it's already made to run on the cheapest petrol around so unless you can find even cheaper petrol that is less than RON91, you won't normally get knocking. and i don't think mitsu engineers put in much allowances, if any, for owners who want to mod their cars.

Where did you get this info from? EVERY other person ive spoken to in regards to this tells me my car (TJ Magna) definitly has knock sensors. My TR V6 also had em. Dunno who told you any differently

Yup, 2nd gen did as far as I know but 3rd gen don't. Dave pointed this out first and I've spoken to a few other mechanics.

this is from the TJ/KJ Series Repair Manual