Changing gears from 4th to 5th ( did put my foot down )while getting in the freeway and at 60mph I noticed that my speed stayed at 60 but my RPM just kept climbing…

Is this the beginning of my clutch going out?

 

It would help to know how many miles are on your Z, or at least how many since your clutch was last replaced? Without that, I'd simply guess yes.

 

Bought the car in January and it now has 115k miles on it- got it from a used car dealer so no idea as to when and if the clutch was last worked on….

seems to shift fine through all the gears if driven slowly, but as soon as I accelerated hard from 4th to 5 th gear - the speed stayed at 60 and the rpm just kept climbing til I backed off the throttle.

 

My bet would be yes. When you replace it, I would also do pivot ball, clutch fork, and slave cylinder

 

Pretty common, time to replace it

 

Put it in 5th around 3k and floor it. If it slips then the clutch is slipping. Clutch can be done on jack stands in about 4 hours. Get a lot of extensions. This is the clutch I went with on my Z with ~ 300whp 335wtq https://www.ebay.com/itm/13265692549...QAAOSwy2Ncw5F-

Didn't break it in and I have been beating the hell out of it.

 

Clutch almost without a doubt. I've experienced the same sensation from a failing clutch in the Z. For the briefest of moments I thought my rear tires were losing traction when the RPMs shot up.
-Icer

 

Are you truthfully using this non expensive clutch kit? Did you mount this to your original Dual Mass Flywheel?

 

what year is your nissan I know that the 03s had stamped forks, might be bending in higher gears, most likely clutch

 

Yes, I bought this off eBay for about $60 shipped. I installed it with the factory dual mass stock flywheel without refinishing and just lightly sanded it with 400 grit paper. I am running a godspeed turbo kit @6psi. I also forgot a pressure plate bolt when installing and haven't had any issues. I always shift very hard from 1st to 2nd

The number on the "stage 1" clutch disk is just an oem replacement disk. The pressure plate number didn't seem to get me any info online
I also skipped the top driver's side bolt on the tranny because it's a PITA to get to