Super Unleaded 98ron - wow!

[L John]

Virtually every motoring organisation worldwide that has run side by side tests has found virtually no benefit to running 98 RON fuel as opposed to 95vRON fuel.

Is this on engines designed for 95 or 98 RON?
If the OP's car was designed for 98 and he's been using 95 before changing to the correct fuel then I take back what I said.
My understanding was the thread was about using 98 when 95 was the supposed to be the regular fuel.

 

[Uncle Benz]

I'm saddened to see that the original poster hasn't been on since 27th june, and his last post was the first in this thread.

Of course, he could have just been throwing in a grenade before walking away...

 

[Capra]

I'm saddened to see that the original poster hasn't been on since 27th june, and his last post was the first in this thread.

Of course, he could have just been throwing in a grenade before walking away...

This debate wouldn't put me off, it's an open forum, and everyone here is a lot nicer than some of the forums I've been a member of over the years.

 

[L John]

As Capra says, it's a debate between members and a good discussion. There's support on both sides and even if it's placebo it's worth using.
Many products are sold to us on expectations and they get repeat sales even if the products are no better than a cheap version, e.g. headache tablets.
It always makes me laugh when I see adverts on TV that say something like 87 out of 94 agree, they never do a large number and it's often a strange number, why not 100?
My guess is they ask people if they agree and as each one is logged they see if it sound good, when they get to 94 and the next 6 say they found no difference, they decide to only give the stats up to the 94th person.
I've seen ads with out of 104 people... Surely they would have stopped at 100 or carried on well past 104?

 

[gizze]

If an engine is designed for 98 it will run best on that fuel, pretty obvious really. The M3 is designed for 98 isn't it?

If an engine is designed for 95 there should be no knock and so there should be no need for the electronics to retard the timing. In this case 98 wont do much in the way of performance gains.

But there are a lot of people saying to the OP that it is all in his head, it is not.
On the German site it said his car is to use Super Plus Benzin, as was my 350, as is your 350.
It is only the UK who don't list it under the spec. and also seems that Mercedes UK and every "tech" you speak to at dealerships are as clueless about why we have higher octane fuels as many of the posters on here, and say "Ahh, there's no point, doesn't make a difference". Which is complete nonsense.

I had it on a rolling road, there was a 25hp drop in power on 95, you can feel it in the throttle response, it is far from subtle. I spent weeks researching this a couple of years ago, I'm not talking shite. Haha

 

[Craiglxviii]

There seems to be some rather patronising, and incorrect, answers to the OP on this thread.

I had my E350 on a rolling road as I believed that it was only set up for 95ron, however, after filling up with Shell 98 for a couple of tank fulls as my EML had come on after using Sainsbury fuel, it genuinely felt much more responsive. I put Shell 95 back in and sure enough it felt flat in comparison.

So, rolling road test.
After a few tanks of Shell V Power it read 301hp. Then took it back again and after a tank of 95ron and 284hp.

I had this before with my 335i, it would constantly lose around 30hp on 95ron compared with 898ron. Someone did some tests comparing fuel and they got the same results. Think it was maybe Evolve Tuning, it was 10 years ago now, but can probably find the threads somewhere like e90post.com with a search. Lots of naysayers and sniggerers on there too.

In the end I found some of the old details for the S212 350 (M276) on one of the time machine archiving websites of Mercedes.de.
This, unlike the UK site/spec, said that the E300, E350 and E500 should use Super Unleaded, but can retard the timing when 95ron is used.

So it is not a placebo OP, these cars have knock sensors and maps for when you use 98ron.

If the car IS mapped to optimise on 98 then it will see a performance increase on 98. If it ISN’T so mapped then there may be a very slight improvement in response, but EVERYTHING ELSE “noticeable” will be due to Placebo Effect.

In my last job I sat on a fairly major OEM team that (amongst very many other things) studied the Placebo Effect, specifically with regard to “performance mods” on cars. K&N air filters and 98RON were the two most popular due to cost/ accessibility. Both produced almost identical results; placebo effect resulted in 99% of “improvement” (quite often there was none, just a slightly different response or sound) for 99% of the time. Quite often, dependent on the vehicle model these mods resulted in performance degradation and quite often in unpredictable ways.

 

[rorywquin]

I had it on a rolling road, there was a 25hp drop in power on 95, you can feel it in the throttle response, it is far from subtle. I spent weeks researching this a couple of years ago, I'm not talking shite. Haha

My car is set up for 98.

I was in Ireland for two weeks running on 95 (max available) and I have to say the car was definitely not as responsive as usual. I noticed it was mostly when wanting to accelerate slightly (eg traffic has slowed to 55 and I was getting back upto 60) and the car was not as responsive as I am used to.

I was wondering what was going on until I realised that it must be the fuel. As soon as I got back to using 98 (undiluted by 95), it was business as usual.

Not a placebo and not my imagination........

 

[Capra]

My car is set up for 98.

I was in Ireland for two weeks running on 95 (max available) and I have to say the car was definitely not as responsive as usual. I noticed it was mostly when wanting to accelerate slightly (eg traffic has slowed to 55 and I was getting back upto 60) and the car was not as responsive as I am used to.

I was wondering what was going on until I realised that it must be the fuel. As soon as I got back to using 98 (undiluted by 95), it was business as usual.

Not a placebo and not my imagination........

This isn't the point, your car is setup to run on 98, so going into 95 will of course make a difference. It's when cars are designed for 95 and claiming that there is a difference when using 98.

 

[gizze]

If the car IS mapped to optimise on 98 then it will see a performance increase on 98. If it ISN’T so mapped then there may be a very slight improvement in response, but EVERYTHING ELSE “noticeable” will be due to Placebo Effect.

In my last job I sat on a fairly major OEM team that (amongst very many other things) studied the Placebo Effect, specifically with regard to “performance mods” on cars. K&N air filters and 98RON were the two most popular due to cost/ accessibility. Both produced almost identical results; placebo effect resulted in 99% of “improvement” (quite often there was none, just a slightly different response or sound) for 99% of the time. Quite often, dependent on the vehicle model these mods resulted in performance degradation and quite often in unpredictable ways.

The point is, many cars from the factory have a map for 98ron, it detects it and loads the map.

Of course if they are not set up for 98 it is pointless and you will not see a gain.

 

[gizze]

This isn't the point, your car is setup to run on 98, so going into 95 will of course make a difference. It's when cars are designed for 95 and claiming that there is a difference when using 98.

But who has claimed that?

Mercedes Germany say that the E350, E400, E500 need 98ron, it is only Merc UK that say it doesn't. Or rather doesn't mention it for some reason.

 

[Capra]

But who has claimed that?

Mercedes Germany say that the E350, E400, E500 need 98ron, it is only Merc UK that say it doesn't. Or rather doesn't mention it for some reason.

What, using 95ron when the motor is setup for 98ron?

 

[gizze]

No, who has said that they have seen an increase in power using 98ron in a car that is not set up for any more than 95ron?

 

[Craiglxviii]

I think this is one of the cases where we all actually agree, so no need to argue

 

[Botus]

This isn't the point... It's when cars are designed for 95 and claiming that there is a difference when using 98.

there WILL be a difference.... it may well feel smoother and it WILL be slower

 

[LostKiwi]

Not actually sure what you are saying?

Are you saying you don't believe the manufacturers that they have knock sensors and set up many of their cars for use with higher octane fuel?

Here is a rolling road of the M3 on 95 and different super unleadeds...

View attachment 44279

A I said, a lot of ignorance being spouted in this thread.

As there is on so many car forums about this subject. The above test was done by Thorneymotorsport back on the old M3 forum as loads of owners were saying the same thing on their. Then when they did the test everyone started using 98 and were all converts.

BMW N52 3 litre straight six is a great engine to test it on, NA and really sings when run on 98, drops from around 230hp to 205hp which is really noticeable on a NA engine, but the biggest difference is how much quieter the engine sounds, it purrs like a sewing machine when run on 98 and can sound a bit tappety when run on 95, everyone noticed that too.

Go back to the second post in this thread.

You're not telling us anything new.

 

[rorywquin]

This isn't the point, your car is setup to run on 98, so going into 95 will of course make a difference. It's when cars are designed for 95 and claiming that there is a difference when using 98.

There were several posts with people saying they don't use 98 because it is expensive, makes no difference, is a marketing con etc. My point is that if the car needs 98 then using a lower octane will make a difference (negative).

 

[gizze]

Go back to the second post in this thread.

You're not telling us anything new.

It was more in response to those saying...

There were several posts with people saying they don't use 98 because it is expensive, makes no difference, is a marketing con etc. My point is that if the car needs 98 then using a lower octane will make a difference (negative).

And to be honest, many were mocking the OP, I was explaining why he was correct in his findings.

 

[LostKiwi]

It was more in response to those saying..

Then why quote my post questioning my responses?

 

[McDonald]

The manual for my car says, 'Use premium unleaded petrol with a minimum octane rating of 95 Ron for all petrol engines except the SL600.'

 

[Capra]

There were several posts with people saying they don't use 98 because it is expensive, makes no difference, is a marketing con etc. My point is that if the car needs 98 then using a lower octane will make a difference (negative).

I agree.