Anyways, Back on topic...

Max55AMG, I highly recommend you go get a full injector cleaning service done. An injector cleaning will clean out your injectors, fuel rails, and even the valves & combustion chamber. You can easily regain some of your lost HP with this service and it only costs on avg $150-200. I would start here before you do anything else.

 

Let's just say its worth trying. I believe 4th gear is the 1:1 gear and yes, you should be in dyno mode.

 

Or you can try to get a can of Seafoam and save about a $100...

http://www.seafoamsales.com/

 

Seafoam does help, but it is not nearly effective as the full injector cleaner service because simply due to the fact that it ties directly into the fuel rail itself. I am a big advocate of seafoam, its still the best over the counter injector cleaner but its just not as strong as BGs injector cleaner service.

However if you run high concentrations of seafoam (like 2x cans in 1/4 tank of gas, then run it hard) you should be able to get much of the gunk out of the system (although not all). Even after seafoam treatment, the injector cleaning service will still make a big difference.

 

I'm picking up what you're putting down!!!

 

Drivetrain loss, and how dyno numbers are calculated, are both on topic.

The OP asked about his dyno results...wondering where his last 23 horsepower are. There are many possible answers to this, including one that his car is operating normally. But certainly trying to understand the characteristics of the dyno he used is within the realm of other possible answers, especially if the horsepower number was arrived at though a coast down on the dyno. If this is true then drivetrain loss corrections will not answer his question. If it did not measure flywheel horsepower, then the correction factor discussion is again one of the possible answers.

 

My car is putting down 366fwhp pre K&N's. Using 15% Drivetrain loss. But I have a tune.

In all honesty. I would not worry about your dyno numbers. If you are in a dead heat with a C6 LS2. Your car is running fine.

 

15% is way too conservative even for a dynojet, all Mercedes autos will be between 18-22% depending on the dyno brand

 

well at 18percent then...I am making around 380hp and 438wtq?

Seems abit excessive.