Thanks for the reply. For 8hp, I was about to pick up the phone and order one of these, as I am running basically your old exhaust setup (Nismo w/Y pipe, HFCs).

 

Awesome. Remember - my #s are with stock cats installed.

 

Update:
"Those goals were to make a few extra ponies and lighten the car up a bit for the track and autox."

Original car weight and power (when purchased USED): 3180#, and 250rwhp/237rwtq

After tune (MD [lighter] exhaust, rear gutted, cats installed): 3060#, and 259rwhp/242rwtq

After re-tune (NISMO headers swapped for ported stockers, more weight reduction, test pipes installed): 2920#, 266rwhp/250rwtq, but look at the tq/hp pick-up from 3-5k RPM.



You can read about my reduction from 3180# to 2920# (and not done yet) on the last few pages here: https://my350z.com/forum/engine-and-...your-z-34.html

 

the car sounds great.

I wouldn't have expected the MD exhaust to make more gains if the tune was bad... it kind of sucks the before/after was compromised due to that, but regardless it was an improvement.

 

Those are great numbers Scott. That area at 3-4 got great improvements. Doesn't really matter for you but I wonder what contributed to that drop at 2500. What were your intentions by going back to the stock headers, aren't they heavier then the nismo?

Btw, never asked Rob, but do you know if his dyno runs are ran under load or not?

 

Thanks! I asked Rob about the slow ramp at low RPM, and he said he likes to apply the pedal smoothly down low rather than just stomp on it. I put the stock headers back on to fund the goodies to make this a safer track car. I forgot to weigh the stock headers, but I bet their weights are within the noise of each other. I spent hours porting the casting marks on them, and given the data available, the NISMO headers on a stock engine don't give much in the way of gains.

As for Rob's dyno, I didn't know that they couldn't be run without being under load. . .His dyno is so new, so I'm sure it follows the same as the other Dynojet Research systems.

 

Thanks for the info, i'm sure those few extra HP gains from the Nismo are completely insignificant compared to how much you lightened your car. Not trying to be the devil's advocate but I don't think it matters if he does apply the pedal smoothly or not, the dyno is plotted over RPM and not elapsed time. I'm thinking it must be related to something else.

Yeah his dyno machine is pretty new and it's a higher model one that allows him to preload or not the machine when performing a test. If I recall correctly he does tune under load but I completely forgot whether the dyno he hands out are in which mode (it seems to me to be under load, but not 100% i'll ask him this week). I'm asking this since it will make a big difference for capturing the effect of rotating mass. I did some testing on a mustang dynamometer with my car and got some pretty interesting results when I lightened my rotors and changed rims.

 

Updating this thread with new/additional dynos after tuning for ART pipes with Osiris.

 

Nice stuff Scott. Do you think the top end gains was related at all to the switch over to Osiris and some better tuning because of better tuning as well as vtc?

 

Scott,

Is it possible you could email me the run files? I can put it into excel for a A minus B plot to bring out the deltas.

 

Possibly, though I'm not certain. Rob spent a long time tuning the car previously with my test pipes to maximize the power and torque curve. He spent an equal amount of time with the Osiris tune since we were basically starting over.

I'll ask Rob if he can get the data for those files so we can do the delta plots.

 

Nice. Thanks for the comparisons.

 

Might be adding these soon. I want a dyno graph just like that.