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

GAD Tuning LTD

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Hello members,

Had a stunning SL350 in for Stage 1 remapping.

While we let the car get rid of a bunch of heat on the dyno while also running diagnostics and all of our pre checks on fluid levels, Dif, visual inspections, tyres, tyre condition and pressures etc.....

Equipped with the Bosch ME9.7 management system which is also found in the W204 C63 AMG we can either perform and Bench READ of the ECU or if a stock file is in the database then a VIRTUAL READ is performed.

So this vehicle was quite heavily down on power, we tried different gearing and also lock out modes to see what the car was most happy in and all modes and gears showed the same results. While monitoring everything the vehicle was more than happy so customer wanted us to proceed.

After many runs, logs and sweep tests with multiple tweaks to the software we gained an extra +30bhp and +43nm of torque.

Below are shots and plots

https://www.gadtuning.co.uk/

https://www.gadtuning.co.uk/rolling-road-essex/

For any enquiries please feel free to pop us an email to info@gadtuning.co.uk or call direct on 05603 67 21 09

Many thanks

Anthony @ GAD

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Mercedes SL350 C4PHJ Stg1 Jpeg.jpg
 

fabes

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Hi Anthony

Which engine did this have in, was it the M276?
Both the before and after bhp are considerably below factory figures....

Why?

Issue with the car or do these engines lose a lot of power over time?

Impressive torque curve improvement from low down though on an n/a engine
 

LostKiwi

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Hi Anthony

Which engine did this have in, was it the M276?
Both the before and after bhp are considerably below factory figures....

Why?

Issue with the car or do these engines lose a lot of power over time?

Impressive torque curve improvement from low down though on an n/a engine
M272 I believe.
 

flowrider

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Hi Anthony

Which engine did this have in, was it the M276?
Both the before and after bhp are considerably below factory figures....

Why?

Issue with the car or do these engines lose a lot of power over time?

Impressive torque curve improvement from low down though on an n/a engine
Most factory figures for power and torque need to be looked at in the same way as mpg, normally better than real life.
 

LostKiwi

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Most factory figures for power and torque need to be looked at in the same way as mpg, normally better than real life.
Also factory figures are taken at the crankshaft. Dyno figures are a guesstimate based on what's measured at the wheels (after all the losses incurred by transmission etc).
 
OP
GAD Tuning LTD

GAD Tuning LTD

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  • Thread Starter
  • Thread starter
  • #7
Hi Anthony

Which engine did this have in, was it the M276?
Both the before and after bhp are considerably below factory figures....

Why?

Issue with the car or do these engines lose a lot of power over time?

Impressive torque curve improvement from low down though on an n/a engine
Am really not sure my friend car was more than happy from logs that's why customer said to proceed. Also tried different gearing and ramp rates all came out pretty much identical so can eliminate the dyno as far as calculating crank numbers as had a BMW M3 BMW book at 425bhp and did 424bhp calculated crank and also a 595 Abarth 180bhp factory did 181bhp so that ruled the dyno out.

Its like we have mentioned before a lot of the time customers are interested in big number tuners are interested in deltas.

Many thanks
 

thebiglad

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Also factory figures are taken at the crankshaft. Dyno figures are a guesstimate based on what's measured at the wheels (after all the losses incurred by transmission etc).
I think you'll find that with most vehicle mfrs the figures they aren't even at the crankshaft. They are a set of theoretical calculations - not measurements - based on engine specs, so completely meaningless when compared to actual rolling roads results.
 

crippo2

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Am really not sure my friend car was more than happy from logs that's why customer said to proceed. Also tried different gearing and ramp rates all came out pretty much identical so can eliminate the dyno as far as calculating crank numbers as had a BMW M3 BMW book at 425bhp and did 424bhp calculated crank and also a 595 Abarth 180bhp factory did 181bhp so that ruled the dyno out.

Its like we have mentioned before a lot of the time customers are interested in big number tuners are interested in deltas.

Many thanks
This is our SL. Initial concerns about apparent power shortage were more than removed on driving the post mapped car home & Mrs cripp2 little short of ecstatic.
There is much more usable mid range get up and go, and the slight hesitation often evident on low rev pickup is gone, to be replaced by a smooth clean acceleration.

So well done to GAD - a very positive result for a very acceptable cost.

One thing still intrigues me about the possible power loss is that hitherto I have generally used standard 95 grade supermarket fuel, now to be replaced by premium.

My question is: is it really worth buying Shell (or other named fuel brands) for their alleged cleaning and lubrication improvements rather than supermarket fuel. Some say (eg Honest John in the Telegraph) that more thought goes into the premium fuels anyway but shell etc is best.
thought please,
 

Blobcat

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This is our SL. Initial concerns about apparent power shortage were more than removed on driving the post mapped car home & Mrs cripp2 little short of ecstatic.
There is much more usable mid range get up and go, and the slight hesitation often evident on low rev pickup is gone, to be replaced by a smooth clean acceleration.

So well done to GAD - a very positive result for a very acceptable cost.

One thing still intrigues me about the possible power loss is that hitherto I have generally used standard 95 grade supermarket fuel, now to be replaced by premium.

My question is: is it really worth buying Shell (or other named fuel brands) for their alleged cleaning and lubrication improvements rather than supermarket fuel. Some say (eg Honest John in the Telegraph) that more thought goes into the premium fuels anyway but shell etc is best.
thought please,
Unless your car is set to run on higher octane it won't make a difference

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.

I ran my W210 and W211 on Shell for they're whole lives and never had any issues with their engines

I ran my W213 on supermarket fuel for 48K and never had an issue either - it wasn't my engine though

My R171 I'm running on supermarket fuel just because of price, I feel I should go back to Shell but I'm covering quite a lot of miles and the price difference near me is too large to justify
 

EXMERCTECH

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I’m a little confused.
It’s meant to have around 272 Bhp from stock.
It’s been remapped tweaked to 254Bhp.
And still has Less than factory spec.
You found 30Bhp sure the owners will notice a difference.
And as a tuner that’s a good result

I’m sure that SL has another problem lurking somewhere
You already said the SL was heavily down on power.

Could be worth checking compression and valve timing.
I sure there’s more potential out of that engine

What’s the history of the the SL
 

AnthonyUK

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My question is: is it really worth buying Shell

Try one full top up using V-Power. If you notice the difference keep using it otherwise your engine is probably fine with 95 RON.
On my older C240 it is probably sub-optimal after nearly 20 years and runs and pulls better on V-Power. No hesitation or pinking.
 
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Blobcat

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I’m a little confused.
It’s meant to have around 272 Bhp from stock.
It’s been remapped tweaked to 254Bhp.
And still has Less than factory spec.
You found 30Bhp sure the owners will notice a difference.
And as a tuner that’s a good result

I’m sure that SL has another problem lurking somewhere
You already said the SL was heavily down on power.

Could be worth checking compression and valve timing.
I sure there’s more potential out of that engine

What’s the history of the the SL

Not sure how old or which variant :
R230 SL350 02-06 M112 Engine 242hp
R230 SL350 06-08 M272 Engine 268hp
 

flowrider

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I’m a little confused.
It’s meant to have around 272 Bhp from stock.
It’s been remapped tweaked to 254Bhp.
And still has Less than factory spec.
You found 30Bhp sure the owners will notice a difference.
And as a tuner that’s a good result

I’m sure that SL has another problem lurking somewhere
You already said the SL was heavily down on power.

Could be worth checking compression and valve timing.
I sure there’s more potential out of that engine

What’s the history of the the SL
It depends on the engine which depends on the year. Your assuming an M272.966 engine.
 

crippo2

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I’m a little confused.
It’s meant to have around 272 Bhp from stock.
It’s been remapped tweaked to 254Bhp.
And still has Less than factory spec.
You found 30Bhp sure the owners will notice a difference.
And as a tuner that’s a good result
You are correct in that we do notice a significant mid range improvement/difference.
Interestingly we also have a similar engine in our CLK350. This car seems to have as much urge, albeit that you have to work a little harder to get to it, without a remap (so far as I am aware) as the tweaked SL.

I’m a little confused
I’m sure that SL has another problem lurking somewhere
You already said the SL was heavily down on power.

Could be worth checking compression and valve timing.
I sure there’s more potential out of that engine

What’s the history of the the SL
It is an early 2007 car with the M272 engine. We have owned it for 5 years plus. It came to us with 43K miles and now is just shy of 70k. We are the 5th Owners. Touch wood the car has been very reliable indeed.
there have never been any engine/transmission codes on STAR
It is serviced regularly with all fluids & filter renewed as appropriate.
The only thing I can say is that it is a little rattly on startup and is not the quietest I have heard on idle.
I do not believe it has led a hard life, certainly not in our ownership.

I have no desire to go down the rabbit hole of giving anyone (except the, just down the road, Mercedes F1 team) opportunities to pad their pension fund without a very clear diagnostic/remediation plan!
 

LostKiwi

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If Chris is happy does it matter what the reading us? The delta was very healthy. As I've already said much earlier, the actual numbers are pretty irrelevant, the delta on the day is what matters.
 

EXMERCTECH

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If Chris is happy does it matter what the reading us? The delta was very healthy. As I've already said much earlier, the actual numbers are pretty irrelevant, the delta on the day is what matt

Chris may be happy.
The reading are way off stock figures.
Yes we know figures vary quite a lot
268 to 302 for this engine.
But having a remap to restore lost power isn’t in my book curing the fault.
Rattly on start up and noises points me in the direction of possible a stretch chain.
Do they stretch on these 272 engines I’m not sure.
Hence why I said check the valve timing.

If Chris is happy to leave it as it then that’s fine.
I’ll get my coat.
 

Blobcat

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Chris may be happy.
The reading are way off stock figures.
Yes we know figures vary quite a lot
268 to 302 for this engine.
But having a remap to restore lost power isn’t in my book curing the fault.
Rattly on start up and noises points me in the direction of possible a stretch chain.
Do they stretch on these 272 engines I’m not sure.
Hence why I said check the valve timing.

If Chris is happy to leave it as it then that’s fine.
I’ll get my coat.
M272 doesn't stretch the chain, the balance shaft gears on the early ones were made form chocolate though
 

crippo2

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Chris may be happy.
The reading are way off stock figures.
Yes we know figures vary quite a lot
268 to 302 for this engine.
But having a remap to restore lost power isn’t in my book curing the fault.
Rattly on start up and noises points me in the direction of possible a stretch chain.
Do they stretch on these 272 engines I’m not sure.
Hence why I said check the valve timing.

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.
 


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