Two powerful heuristics to increase drivability and improve performance are copying the MBT tables over to the similar base tables and changing the manual wastegate duty cycle table.
Some things to note
- The MBT or optimum spark tables and base tables have slightly different axis
- Ensure that you copy the tables to the similar table and use to the appropriate axis
- Manual Wastegate Duty Cycle
- Using AMG style is a good starting point but note differences in axis
- I would reduce the low RPM cycle slightly and increase some of the higher RPM cycles slightly
- Please note the differences in AMG and non base MB
- Base MB wastegate is basically just a linear boost
- AMG tries to increase response and takes note of the decel and shift patterns
- There is some room to improve the AMG tables but if you push too hard you may throw a "ESP not available" induced limp mode
You can often adapt AMG tables to similar non-AMG engines. Once I have dug into the tune file and compared against AMG, I began to realize Mercedes are somewhat meant to be tuned and out of the gate are a solid platform to start from.
There are a few things to note:
- AMG and non-AMG engines often have slightly different axis values
- These need to be adapted
- There is quite a bit of gain to be had by loosening up the "torque limiting" functions of the ECU
- These ECUs are sometimes defined as Torque Limiting ECUs
- Items like driver demand tables adapted to AMG are often smoother than Mercedes
- After loosening the Torque limits my 0-60 times dropped to 4.1 s from 4.17 s
- They are also much more consistent
- Some torque tables do serve somewhat as ESP aggressiveness
- Stock Mercedes ESP is somewhat too aggressive to me
In this video I discuss the process of unlocking a Mercedes ECU with HP Tuners.
A few important things to note:
- An internet connection is needed when flashing
- Not necessary to remove ECU
- First read and write is very long
- Subsequent changes are quick
- No credits are needed for VCM Scanner only writing
- Once you use HP Tuners you cannot go back to My Genius files without modifying/resetting the ECU
I've often read the term pre-tune checklist on various posts across facebook groups, forums, etc. One of the items that you may want to consider is replacing your Mercedes battery, regardless of how it tests if it is over six years old. There are two batteries on many late model Mercedes. This article is about changing the main battery, if you would like to see more about changing the auxiliary battery on a Mercedes, please see here.
DIY Ease Score 2-3
(out of 10 being like a re-timing/transmission rebuild, something possible but perhaps hard for DIY)
10mm socket plus 6 inch plus extension.
Why Replace a Good Old Battery?
Replacing your an older Mercedes Verta battery is important for many reason I don't understand. However, in general modern cars use a lot of electrical load for the amount of voltage they were designed for and they are very sensitive to having a working voltage that they like. And while they may crank and run a variety of mercedes elecrtical sub systems may not work optimally if the presented voltage is on the low side of what is anticipated. If the alternator is struggling to charge an older battery it is entirely possible that under the increased stress of a tune may present errors with injectors and spark plugs as well as ECU and TCU, etc.
What did I just write?
On my range rovers lots of weird little electrical gremlins were actually the beginning of being able to tell a battery was going. And it is still true today. Often things like the radio may not seem to have as much head room, or perhaps brakes feel squashy, HOLD doesn't engage as well. Things like that.
H8 Upgraded Battery Size installed into a Mercedes C218. >10% Increased Capacity
Updating the battery isn't very difficult. You will most likely need a 6" extension, a 10mm socket and a 13mm socket as well as a towel.
The battery slots in one direction which needs to be matched. The batteries themselves are slightly heavier than expected. Make sure your hood is open beyond the normal opening, but to the often available on Mercedes, service opening straight up position.
My car felt better right away. For example changing the battery provided a
Updating a battery, for whatever reason, in my car made the brakes feel much tighter with more consistent pedal feel, earlier.
This is just an example I would guess of the change of running on a 7 year old battery to hopefully something newer.
With the introduction of the turbocharged Mercedes Engine line up beginning with the v12, v8, and v6, it was realized that there were more impactful gains to be made from simple ECU tuning than in the past.
The levels of ECU tuning were no longer 10-30HP and quicker response, but 80-100 more HP. This new level of power can of course reveal weaknesses in the drivetrain, up until the point where it is clear that the turbos are a bit too small... That is of course another topic. I will also write about some of the common issues that are encountered with ECU tuning.
Some of the popular options for ECU tuning are to buy a salvage ECU and have it cloned and tuned, to purchase a hand held tuner, or to have the car brought to a dyno and custom tuned based on the data from the pull.
Some of the popular providers are Renntech, Weistec, OE Tuning, Eurocharged, and AMS. As of 2020 the most aggressive 93 octane M278 tunes will yield approximately 585-hp.
As another data point an e85 tunes with Down Pipes in a M157 will in practice put down 684 HP to the wheels.