Hi! My name is DeWayne Logan from Logan Motorsports, and we are an SCT dealer. I was turned on to this site by the guys over at newcougar.org.
I noticed that there is some confusion about how dynos read and how they are calibrated. Taking power numbers without a grain of salt is dangerous, especially when you speak of Mustang Dynos. Mustang dynos can be calibrated 2 different ways, and you should realize that they are calibrated VERY often, at least they should be. Dynojet's also need to be calibrated, but only every 4-6 months, depending on usage. Some shops don't follow this very well however, and as a result skewed readings aren't as uncommon as you would think. If I were you I'd always ask to know when was the last time the dyno was calibrated, and also what correction factor was used. There is no excuse to still be using the old "std" correction factor, as everyone in the industry uses SAE at this point. You need to understand that dynos are just a tool, and that is why the tool is only as good as the person using it. Arguing over power numbers is trivial, it's power gains that are important to see.
Now, as for dyno tuning adding power. It cannot, and should not, be said how much power dyno tuning will add. There is no rule, but you need to understand that the way your car performs is more than just numbers. A good dyno tune will not only make sure the car is making power, but that it is doing so safely and efficiently. Dyno tuning quickens throttle response, and very often improves gas mileage as well. Dyno tuning is ALWAYS better than a mail order tune, because it is specifically tailored to your car, and only your car. It should be noted that automatic cars will seem to benefit more from either a mail order tune or a dyno tune, because the tuner should (a good tuner at least) optimize the transmission for maximum performance. This includes shift points, shift firmness, etc.
I didn't really mean to just jump in this thread, but if you have more questions about dynos just PM me. I'm not the be all end all for dyno information, but I have used them and I do own one, so I know quite a bit.
