Question I have a Vortec V2 H.O. system for my 2005 gt. The problem I'm experiencing is the tune falls on its face after tunning on the dyno. Example: Installed at 11.9a/f @ 442rwhp...cool! One week later to check for leaks, problems, dyno, etc. Dyno: 10.2a/f @ 409rwhp... wow, rich. Dialed back in at 11.9/442...ok cool.

That was 1/11/06. Now, today I dyno at 9 something a/f @ 347rwhp! It was so rich it droped off my print out scale. What the hell!!! They did lean it out again to 11.9a/f but i'm only at 413rwhp now. [:@]
Is this just a bad tune from diablo/vortec? Any advice please!!!

Thanks
Mauiboy


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Not sure it can be blamed on Diablo if it is being readjusted by someone at the dyno.

Might be completely off base here especially considering that I have not seen a Vortech in person. But is there any change/rearrangement/addition in any way to vaccuum lines. Specifically the line going to the fuel pressure regulator. I have seen ( first hand unfortunately ) installers connect the vac line for the fuel pressure regulator to the brake booster vaccuum line instead of the manifold and it cause strangeness.