I just had my 07 550 dyno-ed. It pulled 255 hp. This seemed low so we got another used 550 out of the dealer's lot and it pulled 278 hp. With 360 hp at the engine I should be at 280 minimium and certainly not 20+ hp down from a similar car tested in identical conditions. I am trying to find who stole my horsepower and what I need to do to find it. Has anyone else had a similar situation?
Great questions. Thanks. Here's the poop: Mileage- 24k Oil- factory changed every 5K Fuel- Shell premium only No codes showing. I am stumped.
What about the the other vehicle? mileage, etc. Same wheels, tires (a stretch but just curious). Also what kind of dyno, and were the conditions for the runs exactly the same? Temp? Humidity? operating temp of the vehicles, etc?
I will dig up my dyno and scan the graph in tomorrow. If anyone is still interested in this. My pull was about 290 hp. The dyno machine itself also has a lot to do with it as well as temperature.
There are a million variables, like others have said. The brand of dyno makes a difference too as I've heard that Mustang dynos tend to be more optimistic than others.
Maybe this will help I think anyone interested in this subject should read the information on Dyno testing at the following link. I can also say it has been my experience that factory built engines tested back to back on "real" state of the art electric engine dynomometers where the only difference is the engine and where proper corrections for atmospheric conditions are recorded vary less than 2%. http://www.dinancars.com/bmw/technial-info/dynamometer-testing-and-the-modern-bmw-engine
Good article that covers a lot of the variables associated with Dyno testing. Having done many dyno runs on my Supercharged E36 I can attest that there are so many factors involved and they do indeed impact the numbers significantly. I have also performed the runs on more than one brand/type of dyno with much different results. For someone that is just trying to get an idea of what gains (or losses) have been found from a modification I think the key is to get as many of the variables as consistent as possible, Same Dyno, same fuel, same humidity, same temp, same level of operating temps, same fans/cooling, etc.
It would seem he took most of the obvious variables out (like the dyno equipment itself) by immediately putting a like kind car under the same conditions through the same equipment... Any follow up to your original post and findings?
