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I've been dumb and haven't created a thread for the Z I've been building for STU competition, but better late than never, right? Let's catch y'all up to now.

March 2018
Flew up to "sunny" Rochester, NY to pick up a 2-owner 2008 350z Base manual in San Marino Blue Pearl with 45k miles on the clock. Owner was obsessive about it - the car was as immaculate as a 10 year old car can be, with the usual shitty paint on the door card and a few scuffs on the waterfall cubby door. Importantly, the PPI showed no rust on the underside - the car was a summer only car, and only if it wasn't raining. Very definition of a Sunday driver. Oh, little Z. Your life awaits!


The very next weekend
Off to Black Lake for the CCR Novice School! Things learned: the stock wheel and tire combo is seriously awful. To quote my instructor: "You know what you're doing, the tires are letting you down." I swore to my wife I wouldn't upgrade the car for a year. Yeah, that's gonna last...



Bonus pic
My dad, always underdriving, finally hit a cone! Picture taken to preserve the memory of poor slalom cone #4. RIP in peace - I had to fish you out from being wedged on the belly pan. Good times, good times.



April 2018
Oops. Hotchkis FSB with Whiteline endlinks. Enkei RPF1 in 18x10.5 wearing Bridgestone RE71R in 275/35/18.

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Here's the video from the Z's first event at Black Lake:

And Brainasium, where I discovered that 275 tires would rub in the front on full compression:

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May 2018
Kinetix upper camber arms installed and aligned for -3 Front, -3.5 Rear, 1/8 toe OUT at Front, 1/8 toe IN at Rear. No more rubbing! Open diff, however, is a major letdown. You can hear the inside tire talking a ton on the run.

June 2018
Yeah, I'm bad at the "don't modify the car this year" thing, and in went the OS Giken diff and Z1 differential bushings. Turn in and mid-corner push was so much better, you can now really steer the car with the throttle at apex to adjust corner exit. Additionally, you can truly feel the differential working and the inside tire gaining grip and pulling you towards apex. If anyone is wondering, buy the OSG - it really will change how you drive at the limit.




UCAC
Day 1:
Day 2:

SilverGLE

iTrader: (3)

Man, I love that color...! That Z is too clean to live a life of RACE CAR!

I myself have/had an 04 base that I did mild STU prep for. Got the itch to go mo' faster and bought a cheap 08 that was absolutely rough around the edges. Been swapping parts and finalizing the details.

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July
Bristol time! Couldn't figure out the surface, car felt super slidey the whole time, including spinning twice in the same run on Day 1. Got pretty frustrated; felt like I went backwards in a lot of ways at this event. But on the plus side, the car looked great.



Even if the runs were kinda ****.


Driving home with all 4 race tires in the car netted me a new hand accessory when a minivan stopped short and the rearview mirror mount was snapped off the windshield. Oops.

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July
Time spent with the missus so she wouldn't divorce me. No racing.

August
New exhaust day! Z1 single exit. Note: the fitment with the OE hangers sucked. I had to figure out different options for both the muffler and the connecting pipe. Luckily, Amazon had my back. FYI - if you install the exhaust with a finned differential cover, there really isn't much room for the pipe to hang between the extra length of the fins and the lower control arms on the driver's side.



Bonus pic of the Z waiting in line.

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September
Traveling. Nothin' to report.

October
North Carolina Autocross Championship. Felt like I drove well on Day 2, still didn't chart where I should have due to picking up two cones on my fastest run on Day 1. Clean run would have put me in 3rd, as it stands I was 4th by a tenth to a prepped STi.

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Winter '18
The Z sat for a bit while work and family life got crazy. Man, I really hate the holidays. Harumph. But January rolls around and all of a sudden you're only two months out from the first event, time to get cracking!


In speaking with a number of people, I weighed the options for the Z's new suspension. The front has Kinetix front camber arms, so I went with the same in the rear just for completeness' sake. Z1's eccentric lockout bolts were also used, but what about shocks and springs? The "standard" answer is Penske, Ohlins, Koni Truechoice, or MCS. But KW? For an autocross car?

Yup.

There's a couple of reasons to go this way for the Z, so let's go through them. First, when working through a new suspension setup, I wasn't sure what I wanted for a spring rate and needed a place to start. Rough math suggested that 1000 front and 750 rear might work pretty well, but you have a number of highly competitive cars (with alien drivers) were running as far up as 1200 fronts, with some builders thinking that 1000 or higher rears might be a good way to set the car up. Those people have also won jackets, so they probably know what they're doing, unlike me. But they're also building cars for drivers who know what they're doing with twitchy, knife-edge cars and I don't, so there's that. But hey, isn't there that NASA Spec class for our car?

Enter KW and the Nissan contingency racer program. See, they'll sell you all kinds of go-fast parts for your Z as long as you put big stickers on your car. One of which is custom-valved KW Clubsports for 800 F, 600 R. That's not too far off our target, either. Hmmm. Should make the car easier to drive than 1200 F setups, even if the ultimate limit of grip is a little lower. If we want to move up the rates, KW says the dampers will handle our target numbers AND we get to see how the car handles something stiffer than stock? Win-win!

Installation was actually really easy, so if you're thinking about doing your own suspension, I highly recommend you do. I had all four corners out of the car inside of 2 hours of mostly screwing around trying to figure out how everything went together and came apart. I could probably do the whole car inside an hour, now that I know what I'm doing.




Getting the shocks back in, however, was a slightly different experience...

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Installing the new suspension
The fronts were super easy. Unbolt old ones, bolt in new ones. Had both done in roughly an hour. Again, could carve off probably 15 minutes off that after doing it the first time. Here's what they look like in the car.


NOTE: The fronts use a 6" spring with a 1.5" (compressed) 100lb tender. This is functional, and works just fine. No issues at all.

The rears, however, ship with all this hardware.


Now lookie what we got here. A tender spring (same 1.5" compressed 100 lb), a 1.5" spacer, and an 8" spring. I spent half a day dealing with this nonsense, and here's what the combinations look like.

8" spring rear with tender spring

8" spring rear with spacer
Neither of which will let the car get to our desired ride height of 5" at the pinch weld. The closest I could get them was about 5.5" with the ride height adjuster fully slammed. That may work for some, but this is racecar. SO I pulled the tenders and the spacers, ending up just using the 8" spring without additional help of any kind. For those that have been around the block once or twice on these cars, you'll know that the spring length when the car is off the ground is insufficient to capture the height adjusters, and so can fall down or lose their placement, meaning that when you raise and lower the rear end you have to be pretty careful to put them back as you're dropping the car back down. This is a pain in the ***, but clearly how the car is supposed to work in this configuration.


This is correct.
Figuring this out took two friends and a number of exchanged messages. Wasn't that fun.

Here's the car on its suspension for the first time - be warned, if you go from stock to this, get your car aligned first thing. It drove like it was freaking drunk, with 1.5" toe in on both sides after I set the ride height where I wanted to start the corner balance at. I honestly thought I'd ****ed something major up. Nope, just the stupid alignment. Hooray.

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Suspension Part 2
On to adjustment time! I had the car initially aligned after putting in the new suspension, and with the Kinetix front arms could only get to -3.1 F camber. Well, it'll have to do unless I decide to swap out for the Z1 arms. I'd have preferred to get to -3.5 F, but let's drive it this way for a season and see how it does. After rendering the car driveable, I took it to my buddy's to hop on his corner scales and corner balance the thing. Here's where we started:



That works out to, without me in the car, 3130 lbs. I haven't done some of the weight savings that the class allows yet, so figure I can pull another 100 lbs out when all is said and done.

Here's where we ended up, with some ride height adjustment to get us to roughly 4.75" at the pinch weld.



Perfect! First autocross is in a few weeks, let's see how the car handles then. For now, it's as set up as I can get it without a test and tune event.

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For the record, here's the final alignment specs.

SilverGLE

iTrader: (3)

That's interesting that KW uses such a large spacer for the base of the rear spring... Pretty sure that's several times larger than what BC uses, and I don't think BC includes a helper spring for the rear.

Did you modify your FUCAs for more neg camber? I had Kinetix & then picked up some "blemished" Z1 arms that I had trimmed at the balljoint spot.

I believe my 04 DE was about 3193 when I put it on scales. No clue what my 08 weighs.

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RE: FUCA modification, yeah, ground them flat to the weld to get down to that much negative camber. Interestingly, when we lowered the car the camber didn't really change in the front, either. I don't have any pictures of the ground FUCAs, I'll get one if I remember next time I rotate the tires.

RE: KW spacer - here's a picture of the lower spring seat in the car without the spacer so you can see what it was like normally. I don't mind the way the bottom is done, but the tops are just, well, lazy. There's no capture into the body that appears designed in. I think if I had access to a full lift I could probably bend the top seat tabs around the height adjuster to hold it securely versus just using them as a positioning guide, but that is nowhere in KW's notes about it. When I redo the suspension bushings in the off season I'll likely tackle that, but that presumes I'm keeping the Spec Z suspension into the '20 season and I'm not certain of that yet.

I bought the KWs because they're a great "try it and see if it works" before jumping to 8300s or another custom-valved setup (KW actually offers a Motorsport option) and if I hate it I can get most of my money back out. 800/600 is a little soft for what I want to do with the car, but I might be able to get 1000/750 or even 800/800 depending on what I'm willing to tolerate for rebound and compression at those rates. If not, I should be able to unload the whole kit for ~2k and have had a race suspension for a season that I didn't sink 5k+ into.

SilverGLE

iTrader: (3)

Gotcha.

Yeah, I went with Z1 FUCAs because they had more neg camber out of the box. Once the BJ mount is ground flat, the shop was able to eek -4.2 out of the front with ease, probably -4.5+ if they were really trying. I had them take it to -3.5, as I do drive the car some on the street, but mostly to/from events.

I'm nowhere near where I'd need to be to justify $5k suspension on a car I paid $6k for less than a year ago... I'm running DGRs w/ 15k/10k (840/560). My rear springs match the stock lower seat, but narrow to regular "coilover diameter" springs up top, where the height adjustment is. My upper mounts don't really clip into place, either, and I did consider bending the tabs. May try that when I actually convert the rear to a coilover spring.

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Heard. I wanted to try the Spec Z suspension for exactly this reason - they were half the price of a "true" competitive suspension. Figure I'll see how it works as-is for a season and re-evaluate.

SilverGLE

iTrader: (3)

^ Yup. First the driver mod, then the high-$$$$ suspension and other go-fast bits.

Having said that, I'm sure you've seen that Jerry his selling is red 08... Wish I had $15k on me right now!