Mercedes SL350 V6 Petrol Stage 1 tuning with Dyno time!!!

Blobcat

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Thanks to everyone who has commented on the apparent power performance of the M272 engine in our SL.

Whilst I tend to agree that perception at my level is everything in motorcar performance, there has been sufficient comment about possible engine defects to give me some pause for thought. So I decided I would speak about this to a long time motor engineer with a good knowledge of MB engines with several feet in the high performance engine camp – we are but 5 miles from Brackley.

His thoughts were reassuring to me.

Essentially the modern MB engine is very well protected by its electronic systems. A lack of reported engine codes is a powerful indicator that so far as the engine is concerned it is not unhappy, stressed or being pushed outside its parameters. No smoke indicates no internal oil blow-bye. OK EGTs point to an engine operating within its design (and control) parameters.

However 30k miles by us on 95 Ron supermarket fuel will produce some restrictions in engine performance and the electronic control systems will notice and adjust accordingly. Examples given were injector restrictions, top end/valve carbonisation and Catalytic converter air flow restrictions. His view was that one or more of these is the most likely culprit to the extent that there is one.

He suggested three things.

First use branded premium fuel – it costs more but is more carefully blended and contains additives beneficial to keeping engines in (and in moving them towards) good nick.

Second use an engine cleaner to clean the injectors, any internal carbonisation and Catalytic converter air flow restrictions. Use several cans of the elixir over a few months and drive spiritedly for each tankful

Third if the remap gives you what you were looking for – it does and full credit to GAD for that – then once you have made the changes (branded premium fuel & several cans of engine cleaner) just get on with life!

Finally one very interesting point, already touched on. We have a similarly engined 2008 CLK. We took it to Spain & Portugal earlier this year. Our journey covered more than 2k miles and we filled with Branded Premium fuel all the time (and now still do) Although my memory might be playing me false I am certain that the CLK is has significantly more performance now than before the trip. Coincidence or wot?

Thanks again for all the very helpful thoughts. I will update in a few months, possibly with another trip to the rolling road.
Best thing you can do for a car is drive it, long regular runs that gets everything to temperature. Short town work does nothing for them. My M272 just loves the drives I do with it, exhausts clean as a whistle and it goes like a scalded cat when I stamp on the loud pedal. Just done 20k in 11 months in it...
 

crippo2

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Maybe take the SL for a similarly long trip?
Good thinking, but we have way exceeded our travel budget this year!
Perhaps Scotland in September just to get some miles on Shell V power under the wheels
 

crippo2

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Best thing you can do for a car is drive it, long regular runs that gets everything to temperature. Short town work does nothing for them. My M272 just loves the drives I do with it, exhausts clean as a whistle and it goes like a scalded cat when I stamp on the loud pedal. Just done 20k in 11 months in it...
You may well be right on this. Normally I run the car in old codger mode, but in sport today with max loud pedal, I swear I felt the front wheels going light!
I put the car on STAR yesterday. No engine codes at all and to my limited knowledge of what the actuals are supposed to be I am content the engine is happy and its parameters are well within limits.
Have got some engine cleaner which I will use in a week or so to see if any improvement.
For me, however I am satisfied with the performance.
I have had a thought though & started a new thread in the engine section
 

Blobcat

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Good thinking, but we have way exceeded our travel budget this year!
Perhaps Scotland in September just to get some miles on Shell V power under the wheels
You can tuck in behind me, I'll show you where to crash...:rolleyes::D:p
I've done this hundreds of times and no ones been hurt (much):rolleyes::cool:
 

fabes

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My M276 is fed on supermarket fuel mainly (plus occasional Redex)

Am tempted to speak to GAD off the back of this post......
Must save some pennies:rolleyes:
 

rorywquin

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Good thinking, but we have way exceeded our travel budget this year!
Perhaps Scotland in September just to get some miles on Shell V power under the wheels

I'm watching the weather for a Scotland trip (NC 500) late September.....
 

JB95

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Hi Chris, I have the same SL as you (A 2008 SL350) and was wondering how the remap has been for you? I'm considering visiting GAD myself later this year to have a remap done as I would like to squeeze just a little bit more power and responsiveness from the car. I was also wondering if you'd noticed any change in MPG, not so bothered about MPG more just curiosity.

Regards

Jordan
 

crippo2

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Jordan
There is no doubt that the remap has dramatically improved performance. I had the car tested recently and we were at approx 300bph output. I use Shell premium and shortly post the remap ran a cycle of cleaner through the engine as well.
It is not just the power increase, it is the everyday improvement that makes the difference. There is no hesitation low down in the Rev/Power curve, it pulls very consistantly throughout the range.
The 350 enjoys revs and needs a more enthusiastic boot to achieve the real benefits.
Having said that the addition of flappy paddles also improves controllability hugely - think anticipation, something the auto box cannot do.
so was it worth it - certainly; would I do it again - absolutely
hope this helps your decision making process
Chris
 

JB95

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Hi Chris,

Thanks for that. I definitely will be getting my car remapped with GAD after your glowing review. I've had the car for 8000 miles now (it's had 4 previous owners and now done 60,000 miles) and 90% of the time fill up with Shell V-Power so it will be very interesting to see what it gets on the dyno before and after.

Thanks again for feedback, hope the car continues to bring a smile to your face.

Jordan
 

rorywquin

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The benefits (or not) of premium fuel are difficult to quantify - It's probably more of a feel good factor, if you feel your car is better for it then it will be.
Definitely cleaner burning - in the past I’d have to get Jet-A1 or kerosene to power my jet engines (RC aircraft) , these days the top manufacturers allow Shell V power (diesel) because it burns cleaner and does not clog the fuel nozzles.
 

JBell

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Finally one very interesting point, already touched on. We have a similarly engined 2008 CLK. We took it to Spain & Portugal earlier this year. Our journey covered more than 2k miles and we filled with Branded Premium fuel all the time (and now still do) Although my memory might be playing me false I am certain that the CLK is has significantly more performance now than before the trip. Coincidence or wot?

Nice long runs to clean the Cats out
 


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