new to the site, and need some help

[rich96cobra]

Hey guys,

I am new to the site, and was hoping to find some experience performance guys.  I dynoed my 1996 ford mustang cobra.  It has a k&n filter, long tube headers, SCT program and high flow cats.  I dynoed 266 rear, stock is around 260.  I got something funny going on around 5600 rpms.  Thanks for any advice or help.

Can anyone give me some advice on where to start on why the zig zag instead of the normal straight line you normally get?

Thanks in advance.

Rich

[Thierry]

 Welcome to the site rich96cobra. Did you ask the dyno technician his opinion? A specialist will probably give you a better explanation than any of us here. There is probably many factors, like ignition or fuel that could explain it but I don't know much about this mystery 
 Also if you search Google, it will show many dyno results that don't have straight lines. It could be due to their machine and not your car. Let us know if you find out 
 Google image search.

[Bossnutt]

It kinda looks like the ignition is breaking down at higher rpms, but I'm not sure.

[Soaring]

Hopefully this article will answer your question.
http://www.johnsonenginetechnology.com/JETPAGES/dynoruns/howto.html