protoj

So what's the next step for you on this? Still waiting to hear if you're going to do custom headers?

Cam duration doesn't have a universal lift measurement location, sadly. Brand cam duration is based on "where this company measures from, and sets their own standard for all cams", so a bit of a subjective art to it. A bit weird, but true. Many companies will swear this way or that is the best way for measuring duration. I think lift is a more valuable measurement. JWT and Tomei are both top notch, you can't go wrong either way. Personally, I went with the JWT cams because I know and trust those guys and their long term experience working alongside Nissan / Nismo factory racing programs and trade secrets, especially regarding the VG / VQ platforms. I'm sure you'll have good results either way once the cam timing gets tuned in. Currently, your dyno graph looks solid and a good start. Very curious to see how things look after tuning, especially over 6k rpm. Keep us posted!

Also what was the reason behind switching to Tomei cams from the JWT? Weren't the JWT's more aggressive? Or did you go to a non-solid lifter cam profile?

Looking good! Are they still drawing up a custom set of headers?

The Hyper has always had one of the top flowing designs, at the expense of a more polarizing aesthetic style of twin can. Yes, regarding the headers, that's been a huge issue, right? The original Stillen headers were decent at the time, but with only poor quality copy rip-offs only existing these days it's no wonder people have lost faith in the performance benefit of them. We need a new design that has been properly researched and engineered to help extract a bit more from this engine. Interestingly enough, I've never seen a longtube style available for this car w/ it's own mid-pipe cat/de-cat section. I guess the shorty designs are more popular to adapt to already owned cat/decat sections.

Great post! Very interesting. So I've been dealing with similar concerns on my build as well before I decided to tear things down and make some changes. I have also been in talks with a local performance custom exhaust builder and discussed with him my concerns with the typical aftermarket header setups available for these cars. Is the same shop going to do the research for you or are you taking it to another company? I would be interested in testing some stuff as well or can provide further data if necessary for my race car NA 300ZX slicktop. Our projected power ceilings are not so dissimilar. My machinist shop and I are currently still in the build phase for the new setup.

Swinging through and checking up on your progress! Everything still behaving as expected? What's the word on the tune? -Cheers

Those codes are all pointing at a related issue. A/F ratio falling out of range, heater elements within the O2's out of temp range, EGR sensor or exhaust gas temp falling out of range, etc. There is a few areas to consider... Was any work recently done to the car that may have triggered this? When was the last time you replaced the O2 sensors? Check the O2 connectors and wiring to make sure one of them hasn't contacted the exhaust or melted. Any exhaust leaks especially before the cats? When was the last time you performed an induction service and cleaned the intake, TBs, IAC, etc? The EGR and IACV love to get carbon buildup over the years and can affect flow, similarly can happen to the vac lines to the factory wastegate control solenoid. You mentioned the car felt like it was still running well, so no idle RPM fumbling, hanging, stumbling, etc? Are you running an aftermarket boost control solenoid or OEM? Sorry for the load of questions, but need a bit more to go off of to help point you in the right direction. Even though the vehicle has considerable low mileage, it's still 30 years old. If it's kept in a garage it tends to handle the elements better than sitting out in the external environmental conditions and will need more routine maintenance and care regardless if it's being driven or not. (i.e. 60K / 120k maint w/ timing belt)

Ah, no that's rough! Sorry to hear that. Something preventable always feels the worst. I am sure extra care will be taken on the rebuild to avoid this type of thing happening. An expensive mistake for sure, but don't be down on yourself too much about it. Stuff happens. Now you / they know for next time and can build it better! Any changes while it's apart or sticking with same setup?

Getting ready to tear one of my projects back down and it reminded me of your project. Did you receive word back on the failure?

Any update on what the issue was?

T-belt slip? Tensioner not set correctly? They can be a pain sometimes to get just right within that range. Hopefully nothing involving physical contact of the rotating hardware. *wink

Oh man, that's sad news to hear. Keep us in the loop when you know more. Appreciate the updates! Hopefully it's something minor that can be fixed easily. Best of luck!

Any news regarding some results and a tune? I am currently in the process of two NA builds, one of which will be higher HP. Always curious seeing other like minded individuals results and work. I'm excited about your build, so keep us posted!

Nice looking Z! Welcome to the club.