CLK55 - unleaded or super unleaded?

[Wannabe]

Hi,

I'm thinking of buying a second hand CLK55 (2001 model).

Can anyone tell me whether they will run on "standard" unleaded or does such a vehicle demand super unleaded.

Also, while I'm on the subject, I'd appreciate anyone who has one, or who has had one, telling me the sort of mpg they get/got.
I know the official combined consumption is supposed to be around 23.7mpg.

Thanks.

Wannabe.

 

[guydewdney]

my CL 420 does 20 - 21 mpg on unleaded and 22-23 on super....it will run fine on normal, and the 23 mpg sounds about right, assuming you dont boot it everywhere...

 

[nickg]

When I bought my 2nd hand SL60 AMG a couple of months ago, I only found out that it had to have super unleaded when I had a flick through the handbook.
My car came with the standard SL handbook plus an additional one specifically for AMG models.
This may well be the case for the CLK55.
My advice would be, if you want the car, forget about fuel cost and just enjoy it. Otherwise you spend half your time watching that damn mpg needle.......
Super unleaded works out about 6% more expensive than regular (assuming that regular costs 80p/l and super 85p/l.
Let's assume that you spend £100 a month on fuel. Over the course of a year, super would cost you an extra £72 - not a lot in comparison to everything else it'll cost you.

On fuel consumption, obviously my SL is a different car, but similar in concept. I don't think I get anywhere near 23.7mpg. On a rough estimate I reckon I get around 18-20 on average.

 

[portzy]

I dont know if this would be helpfull as I dont have an AMG anything but, I have used ordinary unleaded on my 200K for the first few months then went to full fat 'Optimax' from then on. It's worth it, believe me. You may only get another mile or so per gallon but the engine 'feels' a whole lot happier. I read somewhere that ALL modern engine specs are based on the use of super-unleaded anyway so......

Portzy.

 

[Anders]

I think the CLK55 is similar in requirements to the C43 - which is 95 RON minimum (UK = normal unleaded?).

The compression ratio is not that high with 10:1, so it should be fine on this. However, I do normally run it on 98 RON (super), as it seems to improve fuel economy with about 5 % which off-sets the higher cost.

 

[saorbust]

I owned a CLK55 AMG - it did about 28-30 mpg over motorway distances - you could get 300 miles out of a tank. In town, and driven hard - well different story but you could probably get at least 250 miles out of a tank.

I always used Optimax or BP Ultimate. I seem to remember it being a requirement. Make sure you get the full spec AMG - it should be fully loaded. If its silver, with black leather PM me the VIN no - it might be my old one ! (only 150 or so of the 208 series made it here).

Clarky.

 

[GRAV888]

Let's assume that you spend £100 a month on fuel.

More like £100 a week in my E55

 

[RichieRuss2000]

I have a CLK500 which is probably quite similar and I can get about 30MPG when taking it really easy... typically combined around town you can get 23-24MPG... amazingly at a steady 110MPH you can also return about 24MPG which is much better fun on the right continental road...

 

[Benzowner]

Unleaded, super unleaded, cleaner diesel, ultimate diesel. imo what a load of tosh. I think its a sales ploy of the giant fuel providers to get more of your money. The difference of 1 or 2 mpg could be the result of better driving less harsh braking. The extra performance one can "obtain" by using these fuels is only at the top end, where most of us never go. £100 per week or month per car at a 6% increase, geese. You accountants out there, if your company could increase its profit by 6% by changing a name. The fuel companies have, excuse the pun, got us over a barrel.

My rant over,

 

[C240Sport97]

I tried Optimax for 3 tanks and gave up .. really can't tell any difference to performance

Unleaded, super unleaded, cleaner diesel, ultimate diesel. imo what a load of tosh. I think its a sales ploy of the giant fuel providers to get more of your money. The difference of 1 or 2 mpg could be the result of better driving less harsh braking. The extra performance one can "obtain" by using these fuels is only at the top end, where most of us never go. £100 per week or month per car at a 6% increase, geese. You accountants out there, if your company could increase its profit by 6% by changing a name. The fuel companies have, excuse the pun, got us over a barrel.

My rant over,

 

[Robby]

Super unleaded and all of those high octane fuels only make any difference at all if your car is set up for it, or has the necessary sensors to realise you are using higher octane fuel and take advantage of it.

And down here, unleaded is around 80ppl and super is around 90ppl. In my old escort I got about a 5% increase in fuel economy using it, and it did feel better.

However, that was a 4 pot 1600cc escort with a manual transmission. In a 2.6litre 6 pot mercedes engine hooked up to an automatic transmission, the whole plot is less sensitive anyway, and theres enough power there without having to buy special petrol.

That said, I may run some lead additive through. This old engine is supposed to like some lead once in a while.

 

[R2D2]

Those who have been around here for years know I have been testing Optimax for ages. I do a month or two on it and then a month or two off and have done for several years.

I have now done maybe 20,000 mile like this and can report that Optimax definately makes a big difference in my car. My C200 is superchipped and has a K and N air filter and was tuned on a dyno using three different superchip programs. It was tuned to run on Optimax.

Run on 95 ron fuel my car has never bettered 30.4 mpg and its worst was 19mpg. Run on Optimax my best ever was 34.5mpg and my worst 24mpg.
Remember this is tested over 18 months or so not a couple of tank fulls.

The mpg is only one factor though, because MY car sounds much better and smoother on Super fuels than Normal fuel. It has become such a marked difference that my poor long suffering wife can now tell by listening to the car if its running on Optimax or not. (Do you think that constitutes cruelty to her that I make her listen?)

Anyway on My car it makes a big difference and if I know I'm doing a long run or a track/testing/showing off day then it has Optimax in it.

What I can't answer is does it only make a difference because my car was tuned to run on it?

 

[Benzowner]

I have now done maybe 20,000 mile like this and can report that Optimax definately makes a big difference in my car. My C200 is superchipped and has a K and N air filter and was tuned on a dyno using three different superchip programs. It was tuned to run on Optimax.
QUOTE]
You have stated that your car is tuned to run on optimax. You are therefore bound to get an adverse reaction by running the engine on lower grade fuel. A normally tuned engine, I think will gain little or no advantage on running higher octane fuels without retuning the engine and re-chipping. If you can obtain more mpg, faster acceleration etc etc just by increasing the octane, then why arn't we all pouring octane boosters into our engines? Perhaps I'm getting old, but I can never understand that if you need your car to do 0 - 60 in 7 seconds or less, why not buy a car that will do that. Perhaps they should sell chips that slow cars down and return higher miles per gallon, and call them SMART

 

[R2D2]

"Perhaps I'm getting old, but I can never understand that if you need your car to do 0 - 60 in 7 seconds or less"

What about if I need a car thats smoother and drives better and gives better fuel economy................

 

[RichieRuss2000]

In the case of different fuels it is simply about advancing or retarding the engine timing to take advantage of them... Most modern Mercedes engines have a knock sensor which will automatically release the extra performance from these fuels and therefore it is worth using them if you really need the extra performance. I don’t want to scare anyone however chip tuning can lead to pinking, detonation, cracked pistons and a bust engine due to the inexperience of these tuners with your specific engine....

 

[nickg]

Unleaded, super unleaded, cleaner diesel, ultimate diesel. imo what a load of tosh. I think its a sales ploy of the giant fuel providers to get more of your money. The difference of 1 or 2 mpg could be the result of better driving less harsh braking. The extra performance one can "obtain" by using these fuels is only at the top end, where most of us never go. £100 per week or month per car at a 6% increase, geese. You accountants out there, if your company could increase its profit by 6% by changing a name. The fuel companies have, excuse the pun, got us over a barrel.

My rant over,

How did you know I was an accountant ???

Without wishing to labour the point, the 6% was illustrative and less relevant than the actual £££ difference. If you're going to buy a CLK55 then why worry about £100,£200,£300 a year in fuel costs.
No doubt you're right that these fuels make little discernable difference to the average motorist. I use super because the handbook tells me to and I'm much too busy enjoying my car to worry about a few extra quid on petrol.