C55 baseline dyno run
04-10-2014, 06:35 AM
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2010 E63AMG
C55 baseline dyno run
Greetings from sunny South Africa (howzit to the other SA AMGers here!). I have a 2005 C55 AMG with 51K miles that I am about to start modding. I took it to the dyno at RGMotorsports in Randburg for a baseline measurement today.
The results are in the attached graphic (noted in kW not bhp). Test conditions were air temperature of 68 degrees F, barometric pressure of 1031.16 and an elevation of 5174 feet. Depending on how you cook it, it comes out to about a corrected 300 horsepower to the wheels. Another C55 on the same dyno came in at about 187 kW peak so mine seems to be doing OK. Of note is that unlike other dyno charts I have seen for this motor is that the power does not seem to decline as hard at 5500 rpm and also there is a bit of a sag in the midrange. Unfortunately, I mistakenly fuelled up with 93 RON gas (roughly equivalent to 89 octane in the US) prior to the test - that could explain the midrange stumble and may have cost the peak number a little bit.
I plan to do some exhaust mods in the near future and will be removing the speed limiter for the purpose of a top speed run at Kalahari Speed Week this year.
The results are in the attached graphic (noted in kW not bhp). Test conditions were air temperature of 68 degrees F, barometric pressure of 1031.16 and an elevation of 5174 feet. Depending on how you cook it, it comes out to about a corrected 300 horsepower to the wheels. Another C55 on the same dyno came in at about 187 kW peak so mine seems to be doing OK. Of note is that unlike other dyno charts I have seen for this motor is that the power does not seem to decline as hard at 5500 rpm and also there is a bit of a sag in the midrange. Unfortunately, I mistakenly fuelled up with 93 RON gas (roughly equivalent to 89 octane in the US) prior to the test - that could explain the midrange stumble and may have cost the peak number a little bit.
I plan to do some exhaust mods in the near future and will be removing the speed limiter for the purpose of a top speed run at Kalahari Speed Week this year.
04-10-2014, 03:51 PM
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"Corrected"
Hi L8 apex, in this case I am referring to correcting for altitude - 5174 feet. The factor used was something like 1.143. You can find calculators online that will give you the number based on air temp, barometric pressure and more. None of this implies a high level of precision about the results but they are mostly consistent with other stock C55s.
04-10-2014, 06:44 PM
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not bad, the gas probably kills your numbers a bit too... my car feels very
alive with 93 octane and i never put anything less in her.
alive with 93 octane and i never put anything less in her.
04-10-2014, 07:43 PM
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Thanks, I certainly understand that more octane won't increase performance magically without a tune... I was more eluding to the fact that running less octane than recommended for our performance engines will affect power and in fact can even cause engine damage because the car is more prone to knocking and that blip in power may even be evidence of timing being pulled because of it.
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04-11-2014, 07:47 AM
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04-11-2014, 01:25 PM
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2002 C32 AMG, 2013 GLK 350/4, 2015 E63S AMG Wagon
Not sure about SA but for the US market, the ECU baseline is set to 91 octane. You can change that default to 93 using STAR and the baseline timing will get adjusted accordingly. The main reason are the states like CA where 93 octane is mostly unavailable.
04-11-2014, 02:05 PM
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Do you have to take it to a MB dealership to change the default or can i do that myself? Is STAR the program used to change it through the OBDII connection?
04-11-2014, 05:24 PM
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STAR is the diagnostics computer program used by MB dealers. You can also purchase it on ebay or from other sources. If you don't know what you are doing, it can be a very dangerous tool. So, using STAR under: Control Units > Drive ME-SFI 2.8 > Control Unit Adaptations > Correction Programming > Ignition > Correction Value of RON you will see a drop down menu with "base value", "93", "91" and "89". From the factory the ECU is set to "base value" which means the ECU will "learn" the quality of gas you are using and will adjust accordingly. When I said that the baseline is set to 91 octane, I mean that this is the mid point for the ECU to begin optimization. If you look inside your gas cap, it will say that 91 is the recommended gas. Here is the area of debate/confusion. The STAR system specifically mentions RON values while in the US the gas is rated using (RON+MON)/2 (also known as AKI). So, did the Germans screw up and used the wrong unit of measure on the screen while meaning to say AKI? Or does setting your ECU to "93" RON mean that you can run on less than 89 AKI?
So, to make the long story short, the base MAP will learn and adjust to the gas that you are using. There is an optional MAP in the ECU that is optimized for 93 AKI or RON?, that can be enabled using Star. If it is AKI, then this should only be done if you never go near regular because it does not allow the system to retard timing sufficiently when the knock sensor detects the initial knock. If it is RON, you don't want it since you should use the best gas available and in the US it is usually 91 AKI or 93 AKI.
04-11-2014, 06:26 PM
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This subject is a bit messy. But since you asked, here is what I know. STAR is the diagnostics computer program used by MB dealers. You can also purchase it on ebay or from other sources. If you don't know what you are doing, it can be a very dangerous tool. So, using STAR under: Control Units > Drive ME-SFI 2.8 > Control Unit Adaptations > Correction Programming > Ignition > Correction Value of RON you will see a drop down menu with "base value", "93", "91" and "89". From the factory the ECU is set to "base value" which means the ECU will "learn" the quality of gas you are using and will adjust accordingly. When I said that the baseline is set to 91 octane, I mean that this is the mid point for the ECU to begin optimization. If you look inside your gas cap, it will say that 91 is the recommended gas. Here is the area of debate/confusion. The STAR system specifically mentions RON values while in the US the gas is rated using (RON+MON)/2 (also known as AKI). So, did the Germans screw up and used the wrong unit of measure on the screen while meaning to say AKI? Or does setting your ECU to "93" RON mean that you can run on less than 89 AKI? So, to make the long story short, the base MAP will learn and adjust to the gas that you are using. There is an optional MAP in the ECU that is optimized for 93 AKI or RON?, that can be enabled using Star. If it is AKI, then this should only be done if you never go near regular because it does not allow the system to retard timing sufficiently when the knock sensor detects the initial knock. If it is RON, you don't want it since you should use the best gas available and in the US it is usually 91 AKI or 93 AKI.
