And so... my (not so triumphant) return to proven power for a fresh summer baseline (no tune, K&N panel filters + cobb smooth tubes) and then a re-dyno with the take off Nismo exhaust (H-pipe from factory car rather than Y pipe off of S-tune).
Commentary and conclusions to follow...
First -- dynos of K&N + tubes, November vs. Agust. And, as would be expected, the baseline numbers are woeful relative to my boast worthy results taken back in November.
Behold the ugly effects of more ambient heat (gets worse when you see the dyno for the exhaust...)
And here we are with fresh (but saddening) baseline vs. with shiny new exhaust...
A more charitable version using the far more generous STD correction (again, unless you are running boost, where SAE will tend to severely underestimate power, STD for a NA car is basically like pulling on your penis until it hurts before measuring... use SAE ya fukin' bastards!)
Now... as to (tentative) conclusions (other than the heat and humidity are cruel and I look forward to re-dynoing in November).
I think the Nismo take off exhaust (as Sh0velman predicted? I think it was he) does seem to make a bit more power than the S-tune exhaust. I am hesitant to make this claim because the S-tune exhaust was added AFTER test pipes, and this Z still has the tree hugging factory cats... and there are also certainly to be diminishing returns as we add additional bolt ons...
Still, gains with Nismo take off were in the 3% - 3.5% range whereas S-tune gains were closer to 2.5% to 3%. We're squeezing apples and citrus fruits a bit here, so my verbal preference for the take-off version over the S-tune is very tentative.
I'll say this: If you can grab the take off for under $400 bucks, its a deal and a steal given that I rarely see the S-tune version offered for less than $500. So, from a bang for the buck standpoint, I have to give the slight win to the take-off Nismo.
More dynos (with hopefully happier results) coming soon... soon as the MFCSing summer in FL winds down
EDIT: Side note -- if indeed its just the temps assbuggering my numbers (seems to be the only logical cause), then I predict values just shy of 300 or a wee bit higher in November, and closer to 305 with a tune. (***EDIT: Still pretty hot here. Got nowhere near 300 until after the headers were on... oh well. It's the delta that matters, not the absolute value... sigh***).
Now I just have to decide if I want to install the PPE headers... ughh... it aint gonna be cheap (ran into some $ troubles last year, so they never went on), and once they're on, they're staying on... they continue to collect dust on my couch. Sigh.