Hi Guys
Out of curiosity, does adding fuel additives like Petrol Injector Cleaner or Octane booster improve the fuel consumption or engine life as they claim.
Though they even say that they improve the car performance which I really doubt.

Some like them some don't.
I sometimes throw one in a tank of fuel for piece of mind.

I use Liqui Moly Fuel Injector Cleaner (http://www.liqui-moly.com.au/products/fuel-additives/)

As far as I can tell, not on a relatively modern engine like the 6G75.
Better bet is to fill up with 98RON fuel (Shell V Power, BP Ultimate, Caltex Vortex etc) every fourth or fifth tank. The extra additives in 98RON clean your fuel system just as good as the additive.
The 6G75 also has a knock sensor, unlike the 6G74, so when you chuck 98RON in it will advance the timing a little and you'll get a small increase in power and/or economy.

Thanks for the info guys.
As an experiment I am using 100ml of the Repco Fuel Injector Cleaner with the Unleaded 91 octane fuel (full tank).
I have stats from only using 98 octane fuel and 91 octane.
Will be posting the results soon.

That is interesting and if that's the case why don't we use 98 all the time??
.. I note that Mitsubishi recommends 91 in my Manual for 2006 LS

The theory behind the benefits of using "injector cleaner" is to return the fuel injector to optimum factory spray pattern, with optimum spray pattern it will return your car back to factory FC rating.

If your FC has been consistent since day 1, then there will be no benefit or FC improvement at all but if your FC drop for no reason, then maybe a shot of injector cleaner will help in restoring it.

That is interesting and if that's the case why don't we use 98 all the time??
.. I note that Mitsubishi recommends 91 in my Manual for 2006 LS

Some of us do use 98 all the time.

My piggy back ECU is tuned for 98, that's the main reason I use it all the time.

But I'm pretty sure there are other 380 owners who don't have a piggy back who use 98 all the time.

The main downside and reason most people don't use it all the time is the cost, 15 or 16 cents per litre more than 91.

Another reason is that it's not available at every servo (especially out donga) and even where it is available there might only be one or two pumps out of 10 or 12 total pumps.

I currently use 98 all the time, but had recently (a few months back) been using 95 instead. I found there is no difference in power between the two, not that I can feel anyway. I have used E10 a few times and definately felt a lack of power with it, like towing a heavy box trailer. A few years ago I even ran a few tanks of Optimax Extreme/VPower+ 100 octane (United had a 100 too) and that stuff did feel a bit stronger overall but not worth the 20c increase over 98's already higher price. And it's gone now anyway.
This interesting test was on TV recently. They seem to run it every few years (have seen it before) but its good to watch if you haven't seen it.
http://au.news.yahoo.com/today-tonight/consumer/article/-/15967799/value-for-money-petrol/

Some of us do use 98 all the time.

My piggy back ECU is tuned for 98, that's the main reason I use it all the time.

But I'm pretty sure there are other 380 owners who don't have a piggy back who use 98 all the time.

The main downside and reason most people don't use it all the time is the cost, 15 or 16 cents per litre more than 91.

Another reason is that it's not available at every servo (especially out donga) and even where it is available there might only be one or two pumps out of 10 or 12 total pumps.

I only use 98 RON fuel for the cleaning and better economy benefits.
Also, twice a year throw a serve of injector cleaner through for goodmeasure.

I've never used an additive in mine. The injectors get cleaned when their due to be cleaned according to the service manual. As TreeAdeyMan said, some of us use 98 all the time. I fill up on Shell 98 sometimes twice a week because I drive so much. Car hasn't missed a beat on it.

I'd suggest using good fuel every few tanks at least which would probably be as good as additives...

Helpful comments all round. I know that filling a tank with 98 is very expensive compared to 91 but I have been convinced to be a bit kinder to my 380 and give it some 98 every few tanks. Regardless of whether it makes any difference to power figures or not, at least it may help to clean out the engine, and perhaps prolong its life a little.

Helpful comments all round. I know that filling a tank with 98 is very expensive compared to 91 but I have been convinced to be a bit kinder to my 380 and give it some 98 every few tanks. Regardless of whether it makes any difference to power figures or not, at least it may help to clean out the engine, and perhaps prolong its life a little.

91 thats padded out with e10 is a rip anyway, your fuel economy will suffer. for most cars, 95RON is best bang for buck fuel

Does it make a lot of difference if the ECU is tuned for the 98 Octane fuel while using the 98 Octane fuel?


Some of us do use 98 all the time.

My piggy back ECU is tuned for 98, that's the main reason I use it all the time.

But I'm pretty sure there are other 380 owners who don't have a piggy back who use 98 all the time.

The main downside and reason most people don't use it all the time is the cost, 15 or 16 cents per litre more than 91.

Another reason is that it's not available at every servo (especially out donga) and even where it is available there might only be one or two pumps out of 10 or 12 total pumps.

91 thats padded out with e10 is a rip anyway, your fuel economy will suffer. for most cars, 95RON is best bang for buck fuel

im finding at least in my town, servos have all but stopped selling 95, so that the choice is now either 91 or 98.

im finding at least in my town, servos have all but stopped selling 95, so that the choice is now either 91 or 98.

Same here

Interesting. Drove from sydney to melbourne and visited many different servos. All had 95

From what I can gather by the "research article" by Grubco, it makes sense to either fill 98 octane fuel or the 91 octane fuel!

I currently use 98 all the time, but had recently (a few months back) been using 95 instead. I found there is no difference in power between the two, not that I can feel anyway. I have used E10 a few times and definately felt a lack of power with it, like towing a heavy box trailer. A few years ago I even ran a few tanks of Optimax Extreme/VPower+ 100 octane (United had a 100 too) and that stuff did feel a bit stronger overall but not worth the 20c increase over 98's already higher price. And it's gone now anyway.
This interesting test was on TV recently. They seem to run it every few years (have seen it before) but its good to watch if you haven't seen it.
http://au.news.yahoo.com/today-tonight/consumer/article/-/15967799/value-for-money-petrol/

I remember seeing that show. Test was a bit simplistic as they didn't test all the fuels in all the cars with all the drivers

ie it didn't take into account differences from car to car and in driving styles

As Telpat16 implies, The Today Tonight test is completely invalid. The only way to do this properly is to run each of the petrol cars on each type of petrol and also repeat several times so each driver drove each car. The variation in fuel economy between identical cars can be startling, especially when the engines are new. If this was published in a scientific journal, the methodology wold be crucified. Typical poor current affairs journalism.

I currently use 98 all the time, but had recently (a few months back) been using 95 instead. I found there is no difference in power between the two, not that I can feel anyway. I have used E10 a few times and definately felt a lack of power with it, like towing a heavy box trailer. A few years ago I even ran a few tanks of Optimax Extreme/VPower+ 100 octane (United had a 100 too) and that stuff did feel a bit stronger overall but not worth the 20c increase over 98's already higher price. And it's gone now anyway.
This interesting test was on TV recently. They seem to run it every few years (have seen it before) but its good to watch if you haven't seen it.
http://au.news.yahoo.com/today-tonight/consumer/article/-/15967799/value-for-money-petrol/

United sell 100 octane, its 98ron with a dash of 10% ethanol to bring the rating up. My car goes hard on it, but it drinks like its going out of fashion. Also found out im not allowed to use any ethanol fuel in my car so only tried 2 tanks over the past year. With it, my car made 12kw atw more than all the other models present at a dyno day

I remember seeing that show. Test was a bit simplistic as they didn't test all the fuels in all the cars with all the drivers

ie it didn't take into account differences from car to car and in driving styles
Yeah, also looked like one of the cars was going faster from start. They didn't mention speed limits did they?


As Telpat16 implies, The Today Tonight test is completely invalid. The only way to do this properly is to run each of the petrol cars on each type of petrol and also repeat several times so each driver drove each car. The variation in fuel economy between identical cars can be startling, especially when the engines are new. If this was published in a scientific journal, the methodology wold be crucified. Typical poor current affairs journalism.

Just a quick result that they can package and show on the TV. They'll do it again in 6-12 months.

After using the Unleaded 91 octane fuel with the Petrol Injector Cleaner dint really help in terms in improving the fuel economy.
At the moment I am using shell v-power fuel (unleaded 98 octane) with octane booster. Let's see if it helps anyhow.

Hi guys,

After reading all your consistent advice about using the right fuel, I have stopped filling up with E10 and have been using 95 and 98. I don't have any technical means of determing what benefits the change has provided. However, the car appears to be slightly quicker and smoother. Of course this may just be my psychological reaction to the advantages that have been put forward, but I won't be using E10 any more regardless...Anyway my mechanic who has been in the business for over 30 years says that you shouldn't use E10 in any vechilce older than 3 to 4 years despite what the car manufacturers say. He has seen too many examples of engines suffering a whole range of problems from prolonged use of E10. It's good to know that there is a site like this with people who have the same vehicles who know every nut, bolt and weld and have had the same experiences.
Thanks.Kevin

Also when you think about it the price difference between 91 and 98 is negligible only a few dollars. dont grab a bottle of coke when you go to the servo and get the 98 instead.
same deal with the fuel discount dockets. save 4c a litre and on a 60L fill you only save $2.40... is it worthsaving the dockets and carting them around with you...

never mind . . .

I was given a few 8c dockets and they save almost $5 (on 98) which is pretty good.

From the "experiment" so far I can't see any improvements with the addition of octane booster or fuel additives.
Personally I would recommend using the 98 octane fuel, if not all the time, majority of the time.