What James is trying to convey Is this.
Our cell moves between 25 and 40 thousand Cubic feet of air per minute from outside the cell, through it and back out again, turning the whole cell over for fresh every 4 seconds. This is done so that the cell remains at the SAME temperature as the outside ambient temp, so if its 26c outside, it's 26c in our cell. You can see this in the video where the air probe is on the cell wall a foot from the engine bay. with a 500bhp engine screaming away plus exhaust, transmission, tyres and retarders all pumping out huge heat only a couple of feel away, the cell temp and air temp remain the same as outside... 26c.
So yes, if its 26c outside on Wednesday but 38c outside on Thursday, the mapping will be done in different conditions technically, but it wouldn't make any odds temperature wise if you did It on the road or in our cell as our cell is maintained at exactly the same temperature as it is outside my workshops front door. This remains the same for any testing by anyone and is exactly the reason the correction standards exist. An engine really DOES produce different power on different days, in different weather and even in different towns and countries.
This is why I have invested so much time and money in the cell itself (far more than the cost of the dyno) because without serious airflow, a dyno's repeatability is pretty damn poor and that's no good to me as we use it for far more than just power runs. I need to simulate hills and fuel economy improvements as well as diagnostics on weird and wonderful faults, and for that I need it to be as close to a real road as possible which is why it's taken me so damn long to get one. The investment in dyno alone would never have made me happy - I needed a custom built cell to go with it and make it all work properly.
This is why OEM's calibrate the cells in fully automated climatic chambers where they can take the car from Saudi Arabia to the North Pole in under 2 minutes. They can also simulate rain in the same cell to test the effects of humidity and more mundane stuff like wiper control etc. will find a vid, it's awesome. NOTHING anyone can do is as accurate as OEM'S development cells.
Last edited by Stu @ M Developments; 13-07-2013 at 06:02 PM.