What fuel do you use

[Styria]

Just to get back to less exoting posts. Ever since the old Super Petrol was discontinued, I have been using Ron95 petrol, with an occasional 'sprinkling' of 98 grade. Just recently, I decided to take GB to a 'real' mechanic just to get the old girl checked over by someone 'that knows'. I had been a little concerned about fuel consumption (fairly high), and wasn't sure about vacuum leaks, mixture, a fast idle etc. etc.

Everything checked out perfectly, believe it or not, which relates to ignition timing, fuel/air mixture showing 0.5% of CO, no vacuum leaks etc., but he did not put a tune-up machine onto the engine. He thought that the engine was perfect, which totally surprised me. There are two matters I would like to elaborate on. Firstly, he mentioned that GB should be run on Ron98, and no less. His argument was that, basically, the high octane rating relates closely, and best, to the old Super Petrol.

Secondly, the reading of 0.5% - years ago, I was told that, with a slightly worn engine, a reading of 1.5% to 2.5% was acceptable, and almost preferable. That was as long ago as ten years (I have since-in 2010-carried out a valve grind and de-coke) and I am slightly worried that the low percentage is due to lean running of the engine which, of course, could be detrimental to engine life. The Technical Data manual specifies 1% to 2% when NEW (I presume). Are there any opinions from members, and how can I increase the percentage ? When richening up the engine, it starts to run unevenly - as it is at the moment, the slow idle is just about perfect. Regards Styria

 

[SEL_69L]

The design of fuel is an impirical black art. The formulation of it changes from season to season, location to location, for some very good reasons.

I use 98 octane fuel exclusively.
NOT because it is better for high performance engines; I believe the 6.9 engine isn't. Actually, with the lower compression Australian market 6.9 engines, the use 98 fuel isn't justified.

My reasoning has to do with the extra fuel system cleaing properties associated with 98 octane. I have read brochures from Caltex, BP and Shell explaining these specific advantages.

That means that I don't have to consider using injector cleaning products where the solvents would be more aggressive in a 30year old fuel system.

For the same reason, I would never consider using any modern fuel that contained alcohol, with it's different family of fuel additives, irrespective of it's octane rating, in any older car.

From what I can figure out, the tank storage life of most fuels is not more than six months.

 

[Michel]

I use 98 exclusively on all my Benzes without exception and concur with SEL_69L on the cleaning properties...

 

[abl567]

I only use 98, even in my mower since my local fuel outlet no longer stocks normal unleaded and I refuse to use ethanol blends

 

[Tony66_au]

As most of you know I run fairly strict fuel consumption records and being in a country area I am limited to fuel outlets available and nothing after 10pm.

I found that I get the best mileage using 91 ron Caltex which also contains cleaning additives and I average between 8.1 and 9.6 km per litre in my M102 powered Wagon.

I did initially try E10 from freedom and Liberty outlets and actually got marginally worse mileage, as low as 6.9 Km per lt.

For a while I ran Caltex premium and I still only achieved the same figures as I did on 91 ron.

The local BP chain afforded me lower mileage on both 91 and 98 (Ultimate) averaged over 4 or 5 tanks.

As yet I havent done enough driving in any of the W116's to provide mileage.

 

[BenzBoy]

I use only 98 in everything. I got caught short in Kilmore and had to use E10 - the ML was sluggish and most unhappy.
When Shell made Optimax 100 with ethanol I used it in the Spirit and the motor sang like a bird. Ethanol does not worry me but low octane does.
Regards,
Brian

 

[260ebenz]

Interesting topic guys.

Said before I use BP 98 in the 260E have done so for the last 4 years.

The cost of 98 is $1.70 at local BP would it be okay to use Octane 95 when filling up the 260E?

A Current Affair last night featured Servo's in Sydney Shell & Caltex closing off there Octane 91 fuels and people who wanted to fill up could only use Premium fuels that is very cheeky of Shell & Caltex to do this!

Did anyone see this on TV last night?

 

[hoddo]

My 450 runs best on 98 so thats all I use..
Tim the difference between 95 and 98 is usually only about 5 cents a litre.. thats $3 extra on 60 litres. Why would you bother with 95 in the 260?

 

[260ebenz]

My 450 runs best on 98 so thats all I use..
Tim the difference between 95 and 98 is usually only about 5 cents a litre.. thats $3 extra on 60 litres. Why would you bother with 95 in the 260?

Fair enough Hoddo will stick with 98.

The cheek of the big oil companies Shell & Caltex closing off the cheaper fuel so people have to use Premium instead surely that is illegal?

 

[Oversize]

I think we may've covered this issue before?? I'd use 98 because it's not much dearer than 95, but has more patronage. 95s likely to have been sitting in the tanks for a while (going off) and is more likely to be contaminated with water etc..... Plus if you want max oooomph....use the 98!!!!

I've been assuming fuel will go off after 3 months and have been trying to use it all before it turns nasty....

 

[Oversize]

Here's the other thread (Longevity of Petrol):

http://www.topklasse.org/forums/showthread.php?t=2574&highlight=fairmont+fuel+pump

 

[WGB]

I use 98 in my 6.9 and 450 (both euro's), 95 in my E500(98 makes no discernable difference), 91 in my Honda and Diesel in my Diesel.

I believe Aussi 116's with 8.0:1 compression (Vs 8.8:1 in a Euro) are supposed to run happily on 95.

AFAIK E10 isn't around here - thank God.

Bill

 

[mondo]

I have had for over 7 years a '77 280se. I tried a variety of petrol from 91 to 98 and although subjective, it definitely ran better and smoother on the 98.

That was until it got shortened recently by an errant P plater.

This necessitated the revival of my '74 450 sel Djet which I have been driving lately after 18 months of being in storage. Ran horrible to start with but my mechanic did something and cured the horrendous miss at speed (80 - 100 km/h) He said the trigger points were dirty.

Then it started stalling when hot and idling too slow. Without making any other alteration I filled it up with 100 octane ethanol "enhanced" fuel from United as it is cheaper than anything 98 fuel elsewhere.

This made a dramatic improvement all round eliminating the slow idle and stalling, running quieter and smoother than ever before.Fuel consumption has improved noticeably from "it must be leaking" to only terrible (4.8 km/l)I am unsure about the effects of ethanol over time but the engine seems to love the higher octane.

While recently researching info on how to fully restore a 450 for under $1000 I found on the w116.org site info about petrol. It said the engine should be run on 98 and if run on anything less then the ignition timing should be retarded by 1 to 2 degrees for each drop of 1 RON up to a maximum of 6 degrees. With a warning that such measures should only be used in an emergency and both performance and fuel consumption will suffer badly.

I will find that page and post the link shortly.

 

[mondo]

Ok, here is the Link I was referring to.

http://handbook.w116.org/Engine/107/M117_45/15-501.pdf

I may have overstated the case slightly but doesn't this make you think, ideally, use 98 octane and nothing less.

I realize fuel has changed over the years but octane is still octane.

Anyway, really enjoying the various discussions

Cheers

Mondo

 

[260ebenz]

I have been using BP Octane 95 when filling up the 300SE is that the correct fuel Octane for my car?

 

[mrkozzy]

re: Mondo.... "I filled it up with 100 octane ethanol "enhanced" fuel from United".

I'm on my 3rd tank of this 100 octane stuff from United and definitely the pick up of my 116 is better, by far. I even ran half a tank in the wifes Barina for fun! and wow!! (naughty I know)
The only tip I was given about the 100 ron, was getting the engine tuned to suit, if I was going to use it exclusively. Think I'll stay with the "V" power for the most, and just occasionally dip my toe in the water with the "United 100".

(Don't know if its my imagination but my local United seems to have inconsistant quality, whatever the petrol, ...........my 3 cars tend to always end up coughing and spluttering if I stay with their mix. I've mentioned to them, perhaps they should check for possible water contamination in their tanks, however I just know my suggestion falls on deafg ears.)

 

[BenzBoy]

United 100 is 10% ethanol. That is not necessarily a bad thing if your car is built to take it.
Yes, it does burn more easily and with more power but I would be concerned about the cleanliness and consistency of the fuel.
When Shell had V-Power + available, I used it and all engines I put it into ran more smoothly. Like United 100 it contained 10% ethanol but is no longer available.
My floor cleaner is 2% ethanol - it's just alcohol and nothing to be afraid of, unless you have incompatible rubber seals and lines.
Regards,
Brian

 

[Michel]

Where does one get United 100?

 

[BenzBoy]

Where does one get United 100?

From a United service station.
http://www.unitedpetroleum.com.au/
Regards,
Brian

 

[Michel]

From a United service station.
http://www.unitedpetroleum.com.au/
Regards,
Brian

I thought that would be the case, but I also believed United servos have all but disappeared from the scene as I haven't come across any recently.