I had the day off so I went to a performance shop with a new all wheel drive Mustang dyno.
It was low 80's and raining. First pull (3rd gear) only yielded 248 hp and 228 torque. Man o man sheeesh. Well after trying to do better we decided to do a 1/4 mile run. More problems. The traction control was kicking in because the tires were loosing traction on the rollers. He just couldn't stop it from happening. Then I pulled fuse 17 and 18. Then the dyno showed a 13.9 at 106.9158. That is the mph I get at the track with a 13 flat. The problem, no fat guys at the shop to sit in the trunk and loosing traction on the rollers. But the dyno operator pulled up the hp and tqe from the 1/4 mile pull which was 291 hp and 283 torque. AFR was 11.4. Still not what I thought I'd get. Now I understand all the back and forth about dynos! It's not so simple as strapping down and reading the printout. So who wants to guess what I really have considering it's a Mustang? I won't be torturing myself on a dyno again for a long time.

Les

 

Have you considered lowering the pressure in the rear tires before beginning the dyno runs?

BC.

 

You know, that didn't occur to me or the dyno operator. It seems they usually put a few fat guys in the back when burning on the rollers occurs. They were really nice and gave me all the time in the world on the dyno for $50.00. When I'm ready to try again, I'll lower the pressure and ask for the fat guy. The same afternoon they dynoed a 600 hp Subaru with no problems.

Les

 

I finally got around to scanning the dyno sheet so here it is.

 

You need to get a proper tune. A/F at 11.4 is running rich.....I'm at 12.5 right around where it should be.