There is an interesting article in the latest C&D issue which implies that dyno testing will become less reliable with certain new model cars and many others in the future. The reason is that sensors that measure things like water temperatures in the block vs. the radiator, underhood air temp, over bumper airflow, etc., will cause the engine to electronically decrease power under typical dyno conditions (usually by running rich). The example used is a Dinan M5 that had an 77 hp higher hp result when an industrial fan was used to blow air at the radiator and an open hood vs. running with a closed hood and no airflow. Judging by the numbers most people post, I figure that this does not apply to our cars but I'm curious if anyone has ever experienced any similar inconsistancies when dynoing one of our generation cars?

I would post a link to the article but I cannot find it on the C&D website yet. It is in the May 2004 issue a few pages before the review of the new A-Spec (with which, by the way, they managed to achieve a quarter mile time only .2 sec behind the new 545i 6speed in the same issue)

 

most reputable dyno shops use an industrial fan to prevent the engine from reducing power.

 

That's good to know. I have never been but I probably will after I get headers.