I had the stock HR headers, HR cats, and HR y-pipe from a 2008 350Z installed on my 2005 G35 6MT Coupe. Going into the install, I had a Z-tube, MREV2, and 5/16" iso-thermal spacer installed; other than those mods, the car was stock. I did a baseline dyno on a dynojet with these mods, the proceeded to have the HR headers, HR cats, and HR y-pipe installed. After this install, I proceeded to dyno the car again, and found that I had lost power (approx -5HP) and torque (approx -10TQ) at the low end , with slight gains (+5HP, +10TQ) in the high end. It turned out that I was running lean in the low-end (as expected), which was taken care of by the subsequent Osiris tune.

In summary:
Before install - Runfile_001 (baseline: MREV2, 5/16 spacer, ztube): 254.67HP / 246.99TQ
After install - Runfile_004 (HR headers, HR cats, HR y-pipe): 257.42HP / 241.91TQ
After a tune with everything installed - Runfile_015: 266.43HP / 254.41TQ

Do you guys think I could've achieved the tuned numbers without the HR headers, HR cats, and HR y-pipe?

 

interesting, I wonder how much you would have netted with juts the tune, minus all the HR parts

 

was ignition timing and cam timing changed?

 

Not sure. Is the ignition timing and cam timing normally changed as part of a full custom tune?

 

yes

 

Did your low end come back up after the tune?

 

Do headers really add anything on our cars? I am hearing yes and no.

 

They add close to nothing, it's more worth is for boosted cars. So the tedious labor, and cost of headers > worth it for power.

I didn't know the HR stuff fit on the DE minus the Ypipe, nice to know.

 

Maybe when i get a lot of money ill try it out

 

They do add power but most of the member including myself dont think its worth investing $600 - $1200on a mod that only gives 5-10 whp.

 

I agree they do add power and the only reason i did them on my car is because i got a rediculously low price on the headers and install on them.

 

yeah, the tune recouped all of the loss at the low end and added additional gain at the low end as well.

I don't think I would've done this if I didn't get the HR headers, HR cats, and HR y-pipe for dirt cheap. Since I didn't compare the tuned performance before and after the exhaust mods, I don't know what I would've gained with just the tune by itself.

To get a true delta for the headers, cats, and y-pipe, the correct sequence should've been: Tune, install headers, cats, and y-pipe, retune.

 

Any video clips of how the exhaust sounds like now?

-Frank

 

Are these stock HR cats? I wonder if the bottleneck is hindering everything from preforming to it's maximum potential.

 

Is it louder over all?