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In lieu of my appearance on the green hell later this month, I thought it better to organize as many ponies as possible, so I had a chip tune done with a roller test before and after.

Disappointing.

The before only got to 387 horses at 5967 rpm. The operator blamed the fresh air installation, meaning they couldn't get enough air in the engine to get to the MB advertised 421.

They did add 21 bhp to the total and promised a free run once the dynostar was replaced at the end of this year.

I can only hope that these 21 horses will also be there in real life at the Ring.

Stats will follow.

Oh, and I haven't noticed any extra performance, yet.
 

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Premium Member 2006 SLK55 AMG
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Was that at the wheels, or compensated?
 

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Who did the tune?
The only one I could find was Kleeman but at 1200Euros (+VAT!) I felt it wasn't worth it for 20bhp or so.
Russ
 

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The before only got to 387 horses at 5967 rpm. The operator blamed the fresh air installation, meaning they couldn't get enough air in the engine to get to the MB advertised 421.

They did add 21 bhp to the total and promised a free run once the dynostar was replaced at the end of this year.

I can only hope that these 21 horses will also be there in real life at the Ring.

Stats will follow.

Oh, and I haven't noticed any extra performance, yet.
As in the next post, question to be asked: BHP at flywheel or WHP at wheels? If the former, then get the calculation they used as this is very low indicating something radically wrong. If the latter, then the 387 is high - either shows perfect tune throughout, or it is the figure with the new chip. 55 chassis dyno figures are usually somewhere around 360+.

This is not at all bad - 360 or 390 at the wheels, IF all went onto the tarmac would give a 1300kg car blistering performance! Unfortunately not so with the SLK! Unless this 387 is calculated at the flywheel, I would urge you to comcentrate in getting the chassis right so that the maximum can get to the tarmac - get the geometry spot on (go the full hog and add some adjustable arms etc) and use the widest, most worn out tyres possible. This where your better times will come from.

I do get annoyed o some other threads where the demand is power, power and power! 'i want a twin turbo V8' - why? 50% of the power will just be useless! The other annoying part to this is the scourn poured on the SLC43 'because it is less powerful' without giving any thought to what is happening to this power. 'The SLC43 is not a proper AMG' nonsense! it is maybe more of an AMG than the 55! - it is AMG who designed the engine mounts for it and redesigned the front suspension to stay on the ground better, resulting in better handling and consequently better track times, wherever the track might be.

Anyway, how did I end up on this..! Back to the post, ask the dyno people exactly what the 387 is and how they arrived at it. If flyweel - get the engine checked quickly! If wheels, fine tune the suspension and tyres - take a couple of runs, but some with a weight strapped into the boot to gauge the difference.

You say you have not noticed the extra 21. Assuming the engine is good and it is genuinely there, it will be difficult to notice such a small increase in road driving, but you should feel the car a bit livelier, no? Unless you drive the same track day in, day out, you will not see the effect properly. Bear in mind race preparationists tweek a bit here and there, take it onto a track and monitor where acceleration and braking point change by fractions of a metre, come back, do it all again, so only they will notice a few extra bhp.
 

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Discussion Starter #9
55 chassis dyno figures are usually somewhere around 360+.
Chassis dyno figures? I figured (!) that if MB promises 421 a commercial test would provide something in that range. 40 horses missing is way too much in my book. (before the tune)

This is not at all bad - 360 or 390 at the wheels, IF all went onto the tarmac would give a 1300kg car blistering performance! Unfortunately not so with the SLK! Unless this 387 is calculated at the flywheel, I would urge you to concentrate in getting the chassis right so that the maximum can get to the tarmac - get the geometry spot on (go the full hog and add some adjustable arms etc) and use the widest, most worn out tyres possible. This where your better times will come from.
I figured that too. So I'm looking into a KW3 suspension eventhough I now have the AMG adjusted suspension. (option 486)

I do get annoyed o some other threads where the demand is power, power and power! 'i want a twin turbo V8' - why? 50% of the power will just be useless! The other annoying part to this is the scourn poured on the SLC43 'because it is less powerful' without giving any thought to what is happening to this power. 'The SLC43 is not a proper AMG' nonsense! it is maybe more of an AMG than the 55! - it is AMG who designed the engine mounts for it and redesigned the front suspension to stay on the ground better, resulting in better handling and consequently better track times, wherever the track might be.
Ramble: OFF. <g>

If wheels, fine tune the suspension and tyres - take a couple of runs, but some with a weight strapped into the boot to gauge the difference.
after the KW3 upgrade (which needs to be fine tuned by a German pro on the track, which makes all the difference in the world) I can look into getting more rubber to the tarmac. Naturally the current PSP3 are great for day-to-day but not something you want on a track day.

You say you have not noticed the extra 21. Assuming the engine is good and it is genuinely there, it will be difficult to notice such a small increase in road driving, but you should feel the car a bit livelier, no?
My sentiments exactly. 5% increase can only be felt 'on the limit', not puddling along. Sure the car feels smooth but I also switched from regular to premium (well before the tune, premium is difficult to get to nowadays in NL) and that also made the car feel smoother especially in cold start situations.
 

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Discussion Starter #10
Here you are - a set of these will see your extra 21 go straight to the tarmac...
4 X Michelin Slicks Track Tyres 25/64-18 | eBay
Only 200 GBP. A bargain nowadays! Thank you Brexit. :grin:

First things first. Chip tune, Xpipe instead of the second cat. Replace primary cat with high flow ones. Install KW3. Look at more rubber.

Heck I should have bought a 911!
 

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Premium Member 2006 SLK55 AMG
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First things first. Chip tune, Xpipe instead of the second cat. Replace primary cat with high flow ones. Install KW3. Look at more rubber.
Usually people do the exhaust mods first, because the Chip Tune will be able to better utilize the changes. Did you tell the chip tuning company that you had those mods in mind? (will they re-flash to accommodate?).
 

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I had a chip tune done with a roller test before and after.

The before only got to 387 horses at 5967 rpm. The operator blamed the fresh air installation, meaning they couldn't get enough air in the engine to get to the MB advertised 421.

They did add 21 bhp to the total and promised a free run once the dynostar was replaced at the end of this year.
Was that at the wheels, or compensated?
Dunno. Can I tell from the graphs they've supplied or do I have to get back with them?
At the wheels. Graphs attached. Notice the slippage of 86% in red in the top left (sorry, it's in Dutch ...)
Did you get back to them, to confirm the numbers are at the wheels? Usually dyno numbers are indeed at the wheels, but if so they wouldn't care about comparing to the MB 421 number. There are also fairly large variations between types of dynos used, although I'm not familiar with dynostar since it's not too popular in the US as far as I know.


Chassis dyno figures? I figured (!) that if MB promises 421 a commercial test would provide something in that range. 40 horses missing is way too much in my book. (before the tune)
Like the other guy said, 387 is a massive number if stock (or with just an intake) wheel hp. The R171 SLK55 is lucky to get 270 whp stock while it is listed at 355 flywheel hp.

What gear did you run the test in?
 

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Just to clarify: MB put a V8 5.5L engine in a car - any car, but in this case, an SLK. The BHP of that engine is at the flywheel. This is the 421 figure that is often mis-judged. The engine then sits on mountings, has an torque converter box with heli-cut gears attached, then driveshafts to a diff that is sitting in mountings and then more shafts out to the wheels. All these add-ons sap up power along the way, so that by the time useful power hits the road you are way down on the 421. Anything up to 20% loss can be expected with an auto box. So you now have your 387, but more, much more gets lost because the car just cannot cope with it, and here is why Ferarris and Porsches lead the way. So much is put into the running gear to use every ounce of power that is given to the wheels that the others cannot afford to do.

Now, you put the car on a dyno. It cannot measure accurately the flywheel BHP, only the HP where the wheels hit the rollers, commonly known as WHP - wheel horse-power. This is your 387. Other blogs I frequent have 55s showing around 360 at the wheels.

The graph you attach is fine, but I would have expected more separation between the blue and red curves. This though can be down to a number of things and not worth worrying about here. No two dynos are the same and there are tricks of the trade to make figures look better than they are.
 

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Discussion Starter #14
Usually people do the exhaust mods first, because the Chip Tune will be able to better utilize the changes. Did you tell the chip tuning company that you had those mods in mind? (will they re-flash to accommodate?).
They have a partnership or some kind of deal with the exhaust (and KW3) installer. Crooke tuning, very well known name around here. I did tell them about my plans but haven't got a firm we'll adjust accordingly, only the promise for a free ride when the new equipment comes in (Q4-2016 or Q1-2017). You're right in that more elegant way would have been to do the exhaust first. Shame.
 

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Discussion Starter #15
Did you get back to them, to confirm the numbers are at the wheels? Usually dyno numbers are indeed at the wheels, but if so they wouldn't care about comparing to the MB 421 number. There are also fairly large variations between types of dynos used, although I'm not familiar with dynostar since it's not too popular in the US as far as I know.

Like the other guy said, 387 is a massive number if stock (or with just an intake) wheel hp. The R171 SLK55 is lucky to get 270 whp stock while it is listed at 355 flywheel / chassis.

What gear did you run the test in?
I had it confirmed, it was wheel horses.
I wasn't (allowed) to be in the room where the testing took place but the graph shows 4th gear which seems unlikely. (bottom middle) I would expect 6 or maybe 5.
 

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I had it confirmed, it was wheel horses.
I wasn't (allowed) to be in the room where the testing took place but the graph shows 4th gear which seems unlikely. (bottom middle) I would expect 6 or maybe 5.
2012 SLK55 still have the 7-speed, correct?

5th gear (1:1) would make a little extra power compared to 4th
 

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Said it b4, chip tunes are bs UNLESS you have additional mods that require tuning. Why spend the amount of money these peep want for unnoticeable gains? Do the actual hard part swapping then tune to match, otherwise a waste of money.
 

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Any way you look at it 360/390 hp is a lot power put to the wheels ! How the car handles it is another story indeed . I am a hp/torque addict lol I must confess .0:)

Geo
 

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In lieu of my appearance on the green hell later this month, I thought it better to organize as many ponies as possible, so I had a chip tune done with a roller test before and after.

Disappointing.

The before only got to 387 horses at 5967 rpm. The operator blamed the fresh air installation, meaning they couldn't get enough air in the engine to get to the MB advertised 421.

They did add 21 bhp to the total and promised a free run once the dynostar was replaced at the end of this year.

I can only hope that these 21 horses will also be there in real life at the Ring.

Stats will follow.

Oh, and I haven't noticed any extra performance, yet.
Have you driven the ring before ? If not the last thing you need is more power , just be careful when you go , there was a French couple killed this weekend in a terrible accident .
Good luck and enjoy it , I'm there in a couple of weeks .
 

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Just my 2 cents worth for the 'average' 172 / 55 owner looking for a quick fix upgrade. I have recently been looking around for some ECU tuning also; I am certainly no mechanic but I having called around a number of well established 'tuners' around the GTA in the last month, I really can't justify spending nearly $4000 Cdn, which is what I have been quoted by two locations for a Renntech ECU upgrade, to gain anywhere between 20-30hp and a few lbs/ ft of torque which would get lost by the time it gets to the road.

Calling around there doesn't seem to be an awful lot of demand or off the shelf parts to upgrade this engine, around here anyway :frown: Although I am sure that by the time you've added a few more 'bits n pieces', headers etc, and spent another 10-15k or so it might all be well worth it if you are using the car on the track a lot.

Does anyone know what the max gains are for this engine? And what has to be done to achieve it?

For the average owner like myself 415hp (as measured here in NA) is enough to have in your back pocket when needed, especially given the ridiculously low speed limits on the highways here in Ontario, and the fear of having the car impounded for 'racing' when your 50kph over the max speed limit of any road.......not that I would ever do that intentionally>:D
 
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