I am wondering if any of You have tried a portable Mustang Dyno?

I tried one this weekend and was very disapointed with how the Dyno worked. My T-72 in My 3rd gen is insane fast and I still have to do alot of fine tuning.

My first run i was running water injection and the car would nut even spool at all so I took it off and went for a drive and again the car felt great. By the time I got back there had been a few modified big blocks that only made about 250 RWHP and I thought there must be something wrong. So I got on the dyno again and turned the boost up a bit. Again I could barly spool and was starting to misfire at about 7000 and only 17 PSI just where I should be pulling veryhard. I run 20 PSI on the street.

I made a whopping 285 RWHP???? which was enough to take home the hard ware for the most HP for the day with about 30 cars running.

Now I had My car dynoed last year and made 380 RWHP and this year the car is making a TON more power. It felt like I was pulling a travel trailer.

Has anyone else had any experience like this on these portable dynos? I think the Guy had the wrong settings and did not know what the hell was going on.