Well, back to Proven Power to dyno the new Zed :tup:

The weather was perfecto (SAE CF was 1.0) -- so conditions were ideal for a "true" set of measurements (by comparison, my old Z's baselines were taken at temps over 100* F, and all measured values were a good bit lower across the board, even with a more generous CF that attempted to account for the hotter temps).


Below are the best runs, all taken in 4th gear with oil temps between 180* - 195* F. Other runs hovered within 2-4 whp of the highest runs, but I can post them as well if folks wish to compare and contrast in obsessive detail.



First, bone stock vs. Cobb smooth tubes and humble K&N panel filters. Excellent gains for such an inespensive and easy to install mod.


http://www.the370z.com/members/jordo...-k-n-panel.jpg



Behold the detailed comparison to see where big vs. small gains were picked up throughout the rev range. No tuning as yet. Just the tubes and filters.

http://www.the370z.com/members/jordo...ed-comparo.jpg



Last, my "bragging rights" dyno, so called because it uses STD correction, which invariably overestimates gains on NA cars (it is more appropriate for FI cars given that no CF takes changes in air temperature due to compression into account...).

http://www.the370z.com/members/jordo...ights-dyno.jpg


Qualitatively, I'm a pretty liberal guy by nature, but when it comes to quantitative measurement, I lean conservative -- thus, I prefer SAE estimates (a bit stingy) for NA cars over STD (a bit overly generous), but here they are anyway as legitimate (if overly optimistic) numbers for consideration.


Headers, CBE, and tune coming soon :tiphat:

Martin tuned it?

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At the moment, that is without any tuning.

Cooler weather is definitely helping out here, although I consider the more conservative SAE values more representative of what the car is actually putting down. STD values tend to be high for NA cars.

Also, those are the best runs. Successive runs were about 2-4 whp less as oil temps skewed closer to 200+* F.

If we want to be really (conservatively) fair, I'd say treat my reported SAE numbers as x -3 and that's what the car is consistently putting down with these mods under these conditions.

Expect those values to plummet by as much as 10% or more when summer heat and humidity returns to FL tho... :(

Did you ever get the PPE's installed?

Project got put on hold until July -- still definitely happening, but not for a little while :(

EDIT: no, no, I'm full of ****. I was broke and so they spent the year taking up space on my couch as a conversation piece (the conversation being "Hey, don't sit on my ******* headers!")

Should grab a few local members and try to tackle it now :P Lure them with the promise of beer and Women!

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...) :ugh:

http://www.the370z.com/members/jordo...you-summer.jpg




And here we are with fresh (but saddening) baseline vs. with shiny new exhaust...

http://www.the370z.com/members/jordo...o-take-off.jpg




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!)

http://www.the370z.com/members/jordo...ion-std-cf.jpg



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 :shakes head:

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.

Just for grins, I thought I'd compare a tuned dyno (later re-tuned for more a bit more power) of my 2010 Z vs my 2011 Z given that I happened to have two with very similar ambient temps (over 95* F!).

Note that the lower peak values dyno (2010 Z - titled "Summertime baseline") includes some tuning with uprev (tweaked AFR and ignition advance), smooth tubes, K&N filters, test pipes, and the S-tune exhaust (w/Y pipe). The humidity is nearly twice as high...

The higher peak values dyno (2011 Z - titled "K&N Nismo catback") has stock AFR and ignition timing, smooth tubes, K&N filters, FACTORY CATS, and the Nismo take-off exhaust (w/H-pipe). It also has lower humidity helping it a bit.

Air temps and air pressure are about the same. Same dyno, same shop (Proven Power, above ground dynojet).

Below are the values both SAE corrected (compensates a bit for different humidity as much as anything) and also uncorrected.

In the immortal words of Arte Johnson, "Very interrrrrrrresting...."

Interpret as you will.

Detailed comparison, SAE corrected.

http://www.the370z.com/members/jordo...off-summer.jpg

Just comparing when hp and tq are (about) equal, no CF.

http://www.the370z.com/members/jordo...ncorrected.jpg

I dunno -- it's still inconclusive, but I'm thinking the S-tune exhaust kinda sucks as compared to the Nismo take off. Given how similar values were until higher in the rev range (with SAE correction), I'm not really convinced that the Nismo take off is simply benefiting from dynoing on a day with less humidity...

I think it's just a much better design than the S-tune exhaust.

Thoughts?

Good thing I like talking to myself :p

Ran some more calculations using this nifty link Relative Horsepower Calculator

Based on that, it appears we would expect uncorrected values to be only about 1.3% lower for the higher humidity run -- but they are much lower than that (around 3.5% lower).

Assuming my rationale and subsequent maths are right, this further supports my tentative conclusion that the untuned catted Z simply makes more power with the Nismo take off than a tuned catless Z with the S-tune exhaust when conditions are equal (meaning, the difference between them cannot be accounted for based on ambient conditions alone).

Moral of the story and recommendation when searching for a bang-for-the-buck exhaust: Pass on the Nismo S-tune, buy the Nismo take-off.

Additional implication of these data: H-pipes > Y-pipes.

PPE headers are on the car!

Dyno graphs and detailed commentary coming soon -- so far, on a below ground dynojet (different shop, but I'll go back to Proven Power for more dynos later): 290ish baseline (K&N panel, smooth tubes, Nismo take off, OEM cats), 315 with addition of PPE in place of OEM cats! (***EDIT: STD values were given to me -- SAE is lower***).

That's a nice +21 whp (without any tuning) to peak power (a gain of just under 10% from current baseline), so hopefully a bit more to be milked later.

More on this later tonight or tomorrow :tup:

How do you like the sound change? You should Def see a bump in power after it's tuned. Nice jump in power if we are comparing against two dynojets.

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Haven't heard it yet -- I've been out of town and will be getting the car today.

Yep, it's not the above ground dynojet at Proven Power, but the baseline and post-PPE numbers I noted above are both from the same in-ground dynojet at the same shop within a day or two apart.

I should have the car back later today and will post lots of details (graphs, commentary) later :D

Getting car shortly. Unfortunately, I'll have the drf's tomorrow, but allegedly 315 whp!

More tomorrow! I'll comment on sound at least later tonight.

EDIT: Much more power. Must retrain my foot. Breaks loose way too easily now.

Sounds fantastic! I'll see about a video or something later.

EDIT #2: Yeah, its definitely got a good bit extra oomph! Sounds great -- not much louder, but way deeper tone. A little bit of rasp and hiss here and there, but really, really mild. Definitely no worse (and maybe a lot better) than resonated TP's and nowhere as raspy/hissy as either a bigger Y-pipe or unresonated TP's.

Very, very happy with this!

Tuning next week, but will have initial baseline and post header dynos to share sometime tomorrow.

Well, for those who give a poop: I have not yet gotten the drf's, so no exciting before and after graphs just yet... :(

I'm sure I'll get them eventually. I'll definitely have tons of graphs and commentary to share after next weekend, as I am scheduled to do some tuning at Proven Power (not firmly locked in, but 90% likely, anyway).

So, quantitative results will have to wait :(

As to qualitative results: Wow! It sounds AMAZING! I really have to struggle to hear any rasp or hiss -- actually, it sounds pretty much stock, albeit a bit louder and a lot more menacing (in keeping with observations from both Sh0velman, who had my exact set up, and SS Firehawk, who had a highly similar setup).

When I give it the beans it kind of sounds like Frankenstein's monster on a rampage with each up shift -- as in, "Fire bad -- mrarhhhhhh---rahhhhhh-rahhhhhh-rahhhhhhhh"

And a lot more pull in each gear -- it definitely picked up a good dose of low to mid range torque :rock: (***EDIT: Inconclusive on that just yet -- the initial dyno's say no gains until after 5252 RPM. Stupid butt dyno...***)

I love it! PPE built a really great header! Looking forward to sharing hard data and possibly some sound clips, anon :tup:

Glad to hear you're enjoying them. I'm happy I was able to keep mine with everything I did. They really do add it's own unmistakable signature sound to any exhaust.

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