Dear AMG friends,

Can you please help me to understand the Dyno results below?

In theory, the C55 has 360hp or so... How come this one below only has 301
I understand that it's possible to have less that what AMG said but that seems like a lot

Thanks so much!
btw I am going on a dyno tomorrow so I don't want to get a hearth attack if I am reading the results wrong lol


http://www.dragtimes.com/Mercedes-Be...lip-10306.html

http://www.dragtimes.com/Mercedes-Be...no-Sheets.html

While it could be a true degradation in power through issues (loss of compressions/sealing/low spark, etc), I think you may be thinking flywheel horsepower directly translates into a dyno that shows horsepower to the wheels. Depending on the dyno itself, this could be true since some account for drivetrain drag and account for it in the results. However, not all dyno's or dyno operators do this, so they may just be showing the results as the true wheel hp.

Don't worry about it too much. A dyno's main purpose should be to establish a baseline and then go from there with your modifications and/or tuning plans.

Damian

DG83 C55 is correct, each dyno varies widely on their results. Also, 349 hp that the C55 comes with is at the crank and a dyno usually reads hp at the wheels. The transmission causes a loss of hp when transmitting hp to the wheels from the engine. I think the loss is around 12-15%. So if a stock C55 is suppose to have 349 crank hp, then the loss of hp to the rear wheels by the transmission would be 52hp(349X.15). So then the C55 should have around 296 wheel hp.

Here's a link I found about a tuner's dyno, but they claim that drivetrain loss is 25%, which I think is super high, but maybe that's what their dyno reads.
http://dyno-comp.com/tuning.php

Remember a dyno doesn't mean much, it's just a loose baseline on how much whp you are making. Each dyno can vary from day to day, from machine and machine, and can be manipulated by the user. Taking your car to a track will show you how it does and if you are really making the hp numbers you're thinking.

If you're C55 is suppose to be making 440 crank hp, then it will be making around 374 wheel hp, which is a 66 hp drivetrain loss(15%).

That's my dyno #.. lol

These cars loose quite a bit of power through the drivetrain, more than most cars. Automatics also loose more power than manuals. Most of these cars seem to dyno at 275-300whp when stock.

ok so my car with the new exhaust which is making less hp and the problem with the airbox is making 347ps and 488nM. Thats about 400ps correct? I will need to fix the airbox and change back my exhaust but i guess its not too bad

The general accepted consensus is there is a 15% drivetrain loss of horsepower. As stated above the dyno is recording the horsepower at the wheels but the manufacturer’s horsepower number is at the crankshaft.

Automatic transmissions continually show a larger drivetrain loss than do manual transmissions as do steeper rear end gears, etc...

I would say your 301 rear wheel horsepower is pretty much right on track of where it should be done. Personally I would save the money from going back to the dyno as you won’t see any measurable increase.

Also in play is the type of dyno. A mustang dyno will always show a lower horsepower number over a conventional dyno. The reason is a mustang dyno places more stress on the vehicle which correlates more to real world numbers. Dyno queens will stay away from these types of dyno as they simply want the largest number but you’ll find most racing teams on the other hand will rely on the mustang dynos

I´ve heard up to 20% drivetrainloss in our 5-speeds gearboxes...

You also need the right software for less backpressure,
preferably individually done for just your engine and 98 RON.

Here is one videos of my ride on the Dyno.
You can hear the new exhaust


For those of you who went on a dyno.
Do you have to be in Dyno mode on the C55 screen?
I am asking because Vath told me maybe the engine was to hot and since only the rear wheels were turning the throttle wasn't fully opened?

I put mine in dyno mode both times.