PlainWhite350z

iTrader: (1)

So I purchased my 04 Z this past fall with 81k miles. I didn't have a detailed service history for the car. Although the clutch showed no signs of slipping on the test drive, I went into the purchase knowing that it may be close to being due for a clutch considering the miles. As my first rear wheel drive car, I babied it all through the winter in order to just get used to the way it behaves.

In March, I noticed the clutch starting to slip. Considering the fact that my prior 3 cars were all manuals and I have never had to put a clutch in any of them while I owned them, I figured I had it coming and couldn't really complain. Once the clutch started to noticeably slip, it got worse rather quickly despite being babied once again.

I considered the very popular JWT clutch and flywheel combo, ACT, SPEC, etc., as well as an OE combo. Since the car is my daily driver, and will be for the forseeable future, I wanted to avoid (or at least minimize) the chatter from a single mass flywheel. I couldn't justify the ridiculous cost of a new OE replacement.

I decided to take a chance on Southbend's Stage 1 Clutch/Flywheel combo (from Concept Z Performance) even though it's a less frequently chosen option. The clutch is designed very similar to OE, and therefore will behave similarly. The pressure plate is a bit firmer, and should hold a bit more torque than OE (rated at 435ft/lb). The flywheel is single mass and lighter than stock, but is a happy medium between the featherweight aluminum versions and the lead-filled OE dual mass behemoth. IIRC the JWT aluminum fly is about 14lbs., stock is about 31lbs., the Southbend is 24lbs.


Here is the OE clutch removed


Closeup of the worn down rivets


Stock flywheel


Hotspots? Hmm... little bit.


Southbend flywheel mounted


Clutch disc and pressure plate bolted up

Obviously, the clutch had been slipping for some time, since long before I bought the car. In babying the car, I wasn't pushing the car hard enough to make it noticably slip. My guess is that it was a contributing factor why the prior owner traded it in. With OE parts and paying for labor, the cost would be quite obscene I'm sure.

The install was very straightforward. I installed a new throwout bearing, pilot bushing, and pivot ball (all supplied with the kit). The kit also included a braided clutch line, which I passed on for now, as it will be easier to install when I do my HFC's (more clearance). While I was at it, I replaced the tranny fluid with Redline MT-85.

I am extremely happy with this setup overall. Pedal is not significantly stiffer than stock. Now that the clutch and fly have gotten used to one another, it grabs hard when needed, but is just as mild mannered as the stock setup. Does it chatter? As anyone will tell you, EVERY single mass flywheel will chatter in these cars. The chatter is very conditional, and extremely minor. I only notice it at all when shifting early into second with the rpm's very low. Driven normally, there is no chatter while moving, and to really hear it at idle, I've got to bury my face in the wheel well and listen really closely.

My apologies for the wall-o-text, and none of this is new information, but hopefully a fresh opinion from a recent install will help somebody else make the decision of which to go with. Next stop... install of the RJM clutch pedal bracket.

pbn85

iTrader: (2)

Just remember to break it in properly. I installed the JWT combo on my 07 recently am at 300 miles so far. I hear the break in period is 1000-ish miles. Just remember to break it in properly otherwise the setup won't last as long as it should. How's the mt85? Are you honestly noticing smoother shifts like others claim? How much did you end up using, and did you use a pump to get the fluid in the tranny?

jv350z

iTrader: (6)

Good info. I will probably need to do this in the coming year.

PlainWhite350z

iTrader: (1)

Southbend recommends the same 1k miles breakin. Think of it like bedding in new brake pads and rotors. At first, the beginning of the friction point when releasing the clutch was much lower than before, which I actually kinda liked. As I approached the 1k mile mark after install, the friction point slowly moved back up the clutch pedal's travel as the fly and clutch disc "wore into one another". I'd imagine driving it very hard or slipping the clutch a lot during that breakin period would create significantly more heat than after breakin.

As for the MT-85, I bought a 4pack and I can only find one partial quart left, so it looks like I used 3+ quarts. I didn't change the fluid to correct any shifting problems I was having, just as preventative maintenance. I would say it shifts a tiny bit smoother now, but only because the fluid in there was most likely showing it's age and losing some viscosity from the miles. It would probably feel the same if I had used OE Nissan fluid or any other OE spec off the shelf stuff. IIRC, we drained the fluid before dropping the tranny for the clutch install, then refilled it most of the way before reinstalling. Funnel and section of hose method I believe.