Regarding drive train losses, the value one obtains will vary depending on the dyno, but since dynojets are highly consistent from shop to shop, I like to go by them for estimating this stuff...

Based on multiple dynos from at least 9-10 different Z's, with SAE correction, this is what I've found:

Average power for 370Z or G37: 273 +/-5

Average power for Nismo version: 290 +/-5

Drive train losses for both AT and MT appear to be between 16.5% and 17.5%

You get a few outliers here and there; lower values appear to be associated with few miles on engine, suggesting incomplete break-in and compression may go up later on, resulting in higher power figures (unconfirmed).

Higher outliers could reflect everything from weather fluctuations to the ECU being unusually charitable with the max timing it allowed on a given run.

Also, you get some variance due to the gear dynoed in, with slightly higher readings associated with dynos taken in 5th vs. 4th.

Only other major factor is that lots of folks like to report STD corrections, which I find tend to skew optimistically for N/A cars.

Again those values are the average (arithmetic mean) based on a realtively small sample, with more data the numbers may be updated slightly (please send me drf's!!!! :D ).

I thought the correct gear to do it was in 5th for the 1:1 ratio?

It is, but untuned 7AT's will hit the limiter and need to dyno in 4th, so most drf's from the auto or based on 4th gear runs.

Also, 4th puts less wear on the motor... mine was not very happy going 170 mph on a 98* F 90% humidity day just to try and see 2-3 more lbft of peak torque :icon14:

Anyway, the difference is really small in output between 4th and 5th -- literally only a few whp/tqs. You can dyno in either just fine, and get accurate and virtually identical values, although technically 5th would be the correct one in terms of gear ratio.

Speaking of tunes, can you program in a launch control limiter in the Uprev software?

Damn, you're making 339 to the wheels on a mustang dyno in NA form? That's impressive.

As far as I know -- no.

^^^^ Mustang's do NOT always read lower than Dynojets.

It all depends how they are calibrated. Load bearing dynos can be calibrated differently from shop to shop-- they are NOT always heartbreakers.

That number is much higher than you typically see on a dynojet (weight of drum accelerated is fixed, thus the only major x factor is correction used, so dynojet values from shop to shop tend to be highly consistent), thus I would say it is not to be taken as a low reading.

I guarantee you on a dynojet (and some mustangs) lower numbers will be achieved.

Again, Mustang dynos are NOT always more conservative than dynojets.