Car
Car: Mercedes C43 AMG W205 (2019) – Max
Engine: 3.0 24V bi-turbo (V6) (M276E30)
Manufacturer data: 390 PS (385 hp) @ 6100 rpm – 520 Nm (383 lb.ft) @ 2500-5000 rpm
ECU: Bosch MED 17.7.3.1
Mapping (David): Ethanol conversion + slight performance optimization
Configuration: Stock
Fuel: Initial = UL 98 ==> Final = E85
PerfectPower Weighing
Date: Tuesday, May 13, 2025
Place: France (77)
Result: 1780 kg (3924 lb) with 1/8 of a full tank ==> 1823 kg (4019 lb) with full tank (66 L)
PerfectPower Results
Date: Tuesday, May 13, 2025
Place: France (77)
Software: PerfectPower Androïd 7.1.3
Hardware: Xiaomi MI 8 + RaceBox Mini 25 Hz driven by PerfectPower
Session plan:
- I) Initial config: Stock map + UL 98 (Power)
- II) Final config: David map + E85 (Power)
- III) Accelerations in semi-final config (E85 map + E85)
Report I-II: Two power measurements performed for the validation of the results of each config tested:
- In mode 2 (GPS only) for the initial config with UL 98, but in mode 1 (Accelerometer + GPS) for the final config with E85 because of the empty battery of the RaceBox at the end of the session!
- In Power Setup DIN / Losses calculation on parameters
- With 2 people on board (Cedric & David) and with 1/8 of a full tank (8 L) for the initial config with UL 98, and with half a tank (33 L) for the final config with E85
- In 3rd gear for the very first test then in 4th gear (official) for all the following ones, in manual mode from 2000 to 6200 rpm (rev limiter)
- With the WIXGEAR universal magnetic windshield mount even if it doesn’t matter in mode 2
- In both directions of the road then averaging of these two measurements according to the strict recommendation of PerfectPower in order to eliminate the effects of road slope and wind
Report III: One acceleration measurement performed:
- In mode 2 (GPS only)
- In Accelerations Setup “Normal” (stop when the user slows down)
- With 2 people on board (Cedric & David) and with 3/4 of a full tank (49 L)
- 25 s of acceleration to be sure of completing a 1000 m standing start (second reference acceleration after the 400 m standing start)
- With the WIXGEAR universal magnetic windshield mount even if it doesn’t matter in mode 2
- In one direction of the road, but this one is almost flat and no wind was blowing that day, which makes the times valid
Note 1: The E85 used for this tuning was actually verified E80!
I) Initial config: Stock map + UL 98
1) Power in 3rd gear
Official Result = Average of the two measurements
Comparison of results with manufacturer data for this engine (M276E30):
- Max Power: – 6.5 PS / hp or – 1.7 %
- Max Torque: + 7.5 Nm or + 1.4 %
These results obtained in 3rd gear are superbly balanced, very close to the manufacturer data (less than 2% difference) and well distributed, with the power slightly lower and the torque slightly higher, so they can really be used as a reference!
However, the very fast acceleration rate in this gear (3rd BUT on a gearbox that has… 9!) with less than 6 s of measurement time led us to carry out all the following measurements in 4th gear, which was better for the tuning, and to use the “new” results in 4th gear as a reference for the sake of homogeneity, especially since they are directly comparable to those obtained on braked dyno where the acceleration rates are NEVER as fast as here on the road in 3rd gear with such a car!
Note: In fact, we had performed these measurements in 3rd gear a few days before the tuning session to get our bearings with this car that had just been entrusted to us, especially with these modern automatic gearboxes where it is an obstacle course to get into manual mode!
2) Power in 4th gear (official)
Official Result = Average of the two measurements
Comparison of results with manufacturer data for this engine (M276E30):
- Max Power: – 4.1 PS / hp or – 1.1 %
- Max Torque: + 38.7 Nm or + 7.4 %
The results in 4th gear are even closer to the manufacturer data for the max power (from 1.7 % to 1.1 %), however small surprise for the max torque which is now higher by more than… 7 %, which is higher than the tolerance margin of +- 5 % for certification of the engine results, but we will explain this further down in the comparison of the 3rd / 4th results!
3) Comparison 3rd gear / 4th gear
Comparison of results in 4th gear / 3rd gear:
- Max Power: + 2.4 PS / hp or + 0.6 %
- Max Torque: + 31.2 Nm or + 5.9 % (!)
What immediately stands out is that while the results are perfectly comparable above 4500 rpm, before this rev we see an overboost effect in 4th gear (confirmed by our engine logs), which significantly inflates the results and provides a 6% increase in max torque!
So, in fact, the subject is complex because two major phenomena come into play:
- The turbo’s charge speed relative to engine speed depends on the acceleration rate: it decreases as the acceleration rate increases, and vice-versa!
- But the dynamic boost regulation strategy can also vary with the acceleration rate, but also of course with the gear engaged, for example to create an overboost in higher gears, or conversely limit torque in lower gears!
But in this case, the difference is such that we have an overboost effect in 4th gear that we do not have in 3rd gear, limited however to 4500 rpm, and as the engine results (measured in stabilized rev, but NEVER in dynamic!) are always homologated without overboost, this is why the results obtained on the road in 3rd gear are ultimately the most “realistic” if we want to compare them to the manufacturer data, BUT all this is only a question of reference since on the contrary, if you want to be able to compare them to those obtained on a braked dyno where the acceleration rates are always moderate (minimum 10 s measurement time) and where we generally measure at least on the 4th gear, then on the contrary you will have to carry out your measurements on the road in 4th gear! All this with this C43 AMG of course!
II) Final config: David map + E85
1) Power in 4th gear (official)
Comparison of the two measurements
Official Result = Average of the two measurements
Comparison of results with manufacturer data for this engine (M276E30):
- Max Power: + 22.0 PS / hp or + 5.6 %
- Max Torque: + 72.0 Nm or + 13.8 %
2) BEFORE / AFTER Comparison
Comparison of results AFTER / BEFORE:
- Max Power: + 26.1 PS / hp or + 6.8 % (!)
- Max Torque: + 33.3 Nm or + 6.0 % (!)
This comparison is simply amazing! Indeed, the performance improvement is simply spectacular, considering that we ONLY adapted the mapping to ethanol, with just a slight performance optimization requested by Max, the owner. However, we want to emphasize that we absolutely did NOT touch the supercharging, there isn’t a single gram of extra boost (as proven by our engine logs), and it was an absolute will on our part to preserve mechanical reliability on this car, which still costs tens of thousands of euros & dollars…
No, we “only” improved combustion efficiency by taking advantage of ethanol’s properties extremely favorable to performance (and even reliability, yes!) because we at PerfectPower know better than anyone -and this since the very beginnings of ethanol- how magical this fuel is, even if -at least in Europe- it is still highly controversial in 2025 (and very surprisingly by the sports world, it’s truly the height of irony!), but anyway, the truth always comes out eventually, and we actively contribute to it at PerfectPower!
And to further illustrate the performance achieved with this C43 AMG converted to ethanol with just a slight performance optimization (and once again without touching the supercharging), know that we are almost at the level of the engine results of a Stage 1 with Unleaded 98 announced by all the remapping websites (which probably all share the same file…) at 420 PS / hp and 600 Nm: that says it all about the extraordinary performance of ethanol, doesn’t it?
III) Accelerations in semi-final config (E85 map + E85)
Valid but unofficial result because only one measurement
Note 1: As stated in the chapter name, these results were obtained in a semi-final configuration with the map only adapted to E85, but not yet optimized for performance. We wanted to redo a measurement in the final configuration, but the measurement conditions at that time did not allow us to do so. Nevertheless, this “E85 only” map already gave interesting results with a power of 397 hp, 11 more than the 386 measured stock with UL 98, thanks once again to the “magic power” of ethanol! Know that this level of power increase (3 %) is perfectly usual with a correct ethanol conversion, especially with supercharged engines!
Note 2: We just have a doubt about the start because we didn’t feel a strong push right away but only about a second later, which is completely confirmed by our measurement with a bad 0 to 20 km/h time for such a car, especially in four-wheel drive (1.08 s)… Cedric, who was driving, confirmed to me that he pressed fully the accelerator from the start… but normally, we should have been instantly glued to the seat from the start (which this E55 AMG does perfectly!), so we can only assume that it’s due to an extremely soft start management by the gearbox ECU in the selected mode… however, if the opportunity arises one day, we will measure the accelerations of this C43 AMG again to be sure!