| That's not to say this was done on purpose or that this is the case, but the numbers are suspect. I gleaned these from some other forums a while back and I know parts of it have been confirmed. Food for thought that you might want to try a different place. Not so much to verify the semi-outrageous number but more to be sure your car is actually running properly. It's a tool afterall. Dyno Manipulation
There are various ways to manipulate the dyno result depending on what type of dynos. For Dynojet for e.g., there is some 'systems parameter' such as the drum mass and drum bearing's coefficient of friction that can be manipulated to affect the result. But these are difficult to manipulate and usually only the distributor is able to change it. Certainly it can't be changed for individual runs without the sharp-eyed owner noticing it. However, many tricks can be done without directly altering the machine. Things like leaving the straps looser than they should be. You'd be surprised how often this is done to squeak out more power to please a customer. It's more than you'd think. On some dynos, the rpm is calculated / interpolated by clicking on a button when the tachometer of the car reads say 3000rpm. The dyno computer then grabs the current drum rotation rate and then uses the rate of drum rotation to calculate the approximate engine rpm during the actual dyno-run. This is not applicable to Dynojets since a pickup is used to read the actual spark signals so the rpm readings of the dynojet is actually more accurate than the car's tacho. If the pickup doesn't work, then the dynojet software plots power according to car speed instead. Data can be fudged both ways too. One of the more 'effective' tricks used is the dyno operator can use less than full throttle. This is the most common 'trick' to get lower than actual power reading. This is why the formal dynojet procedure instructs the operator to check to make sure there is no floor mat or other obstructions preventing full throttle travel. Certainly only the dyno operator him/her-self will know if the throttle was pressed all the way and given that most dyno runs are operated at 3rd gear, one can cheat for a lower than expected result by going say 3/4 throttle and the engine will still happily rev all the way to redline. The trouble is the dynojet reads engine rpm but do not extract MAP sensor or TPS readings so we know if the run went all the way to redline (the plot will show anyway) but we can't determine if the run was on WOT or not. Other smaller things the operator can do is to mess with tire inflation, overtightening the straps or sometimes intentionally spilling some oil on the dyno drums. Weather conditions are also often used to correct for the actual run results. I notice the latest Dynojet software do not print it anymore but they used to have the 'correction factor (CF)' printed as notation for each run. So far, of all the runs I have seen (I can confidently claim to over 1000 dynojet runs to date), I have never seen it gone above 1.05 and never below 0.98. The temperature, air pressure and humidity sensors are located on the 'instrument stack' on a dynojet which is a stack of midi-sized aluminium cases usually put just beside the computer. They will check for the conditions once a few seconds and is supposed to be very accurate. You can blow a fan against the stack and fudge the result somewhat using this trick too.
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