Clutch Options
When changing the clutch it is best to also have the flywheel machined. Some people sand the flywheel by hand in an attempt to remove glazing, and to some extent this works, but it does not address the problem of the flywheel surface no longer being flat. Watching a flywheel being machined is an educational experience, you wouldn't believe how deformed this big solid casting manages to get over 15 years or so - there's a lot of metal removed before the tool starts making a continuous cut. You won't get any warranty on a clutch if you don't machine the flywheel.
Many clutch kits do not include the spigot bush, so make sure you've got one before you tear the gearbox out on Sunday (then again, you still have to wait for the flywheel to be machined). Changing the clutch is also an excellent opportunity to change the gearbox rear seal, at $5 or so, you'd be silly not to. Spend a few bucks more for a neoprene seal if you like, longer lasting.
While you're at it, also cast your eye over the slave & master cylinders. They might need re-kitting/re-building. The slave cylinder especially, when you push it back in, you might find the seal isn't sealing like it should, as it's now touching a different part of the shaft.
The RB30E has a 12"/300mm flywheel which is compatible with the mighty RB26DETT, so you can buy clutches from Japan that cost twice as much as your car. (Although for later RB26 clutches you'd need one of these push/pull adaptors.)
The Factory Clutch[edit]
The sad tired factory clutch that has worn down to the rivets and brought you to this page:
File:Clutch factory.jpg File:Clutch factory pp.jpg
It has a continuous friction surface, a sprung centre, and sprung facings. Six bolts attach the pressure plate to the flywheel:
Xtreme Clutch Adelaide[edit]
An Australian company providing clutch kits, hydraulics, hoses and other components for the R31. For the clutches, there's an organic clutch, a ceramic clutch, a six puck clutch, and multi plate clutches for high HP applications.
KNI24001
Factory Replacement
KNI24001-1A
- Disc Type: Sprung.
- Friction Material: Organic.
- Stage: 1.
- Recommended Use: Street.
- Clamping Force % Increase: 25%.
- Torque (Nm) Inc FOS: 380.
- Torque (ftlbs) Inc FOS: 280.
KNI24001-1AX
- Disc Type: Sprung.
- Friction Material: Organic.
- Stage: 1.
- Recommended Use: Street.
- Torque (Nm) Inc FOS: 620.
- Torque (ftlbs) Inc FOS: 460.
KNI24001-1C
- Disc Type: Sprung.
- Friction Material: Ceramic.
- Stage: 2.
- Recommended Use: Performance Street.
- Clamping Force % Increase: 25%.
- Torque (Nm) Inc FOS: 570.
- Torque (ftlbs) Inc FOS: 420.
KNI24001-1CX
- Disc Type: Sprung.
- Friction Material: Ceramic.
- Stage: 1.
- Recommended Use: Performance Street.
- Torque (Nm) Inc FOS: 750.
- Torque (ftlbs) Inc FOS: 550.
KNI24001-1B
- Disc Type: Sprung.
- Friction Material: Ceramic (6 Puk).
- Stage: 2.
- Recommended Use: Track.
- Clamping Force % Increase: 25%.
- Torque (Nm) Inc FOS: 570.
- Torque (ftlbs) Inc FOS: 420.
KNI24001-1BX
- Disc Type: Sprung.
- Friction Material: Ceramic (6 Puk).
- Stage: 2.
- Recommended Use: Track.
- Torque (Nm) Inc FOS: 750.
- Torque (ftlbs) Inc FOS: 550.
KNI24001-1R
- Disc Type: Sprung.
- Friction Material: Ceramic (6 Puk).
- Stage: 2R.
- Recommended Use: Track.
- Clamping Force % Increase: 120%.
- Torque (Nm) Inc FOS: 870.
- Torque (ftlbs) Inc FOS: 640.
KNI23530-2G
- Disc Type: Solid.
- Multiplate: Twin.
- Friction Material: Organic.
- Recommended Use: Performance Street.
- Torque (Nm) Inc FOS: 1200.
- Torque (ftlbs) Inc FOS: 890.
KNI23530-2B
- Disc Type: Sprung.
- Multiplate: Twin.
- Friction Material: Ceramic.
- Recommended Use: Track.
- Torque (Nm) Inc FOS: 1830.
- Torque (ftlbs) Inc FOS: 1350.
The neat looking purple Xtreme Pressure Plate:
Cushioned Sprung Organic Clutch:
Cushioned Sprung Ceramic Clutch:
Un-cushioned Sprung Five Puck Ceramic Clutch:
Un-cushioned Sprung Four Puck Ceramic Clutch:
Exedy/Daikin Clutches[edit]
Descriptions from Exedy:
NSK-6308 (~$150-200) This is a direct aftermarket replacement for the equivalent original equipment standard clutch. It includes a new cover assembly, a new organic lined clutch plate and a new release bearing.
NSK-6308HD (Heavy Duty) (~$250-300) This kit is suited to lightly modified vehicles. It includes a new cover assembly modified to provide an increased clamp load of approximately 30% over standard, a new standard organic lined clutch plate and a new release bearing.
NSK-6308HDB (Heavy Duty Button) This kit is suitable for amateur competition. For Example: Drifting, Drag Racing etc. It includes a new Cover Assembly, providing approximately 30% higher clamp load over standard, a sprung centre driven plate fitted with 5 ceramic buttons per side and a new release bearing.
NSK-6308SO (Sports Organic) (~$600) This kit is suitable for street and light horsepower track use. It includes a High Performance cover assembly, which incorporates a high clamp load diaphragm, nodular iron anti burst pressure plate casting and triple drive straps. A Premium Organic lined clutch plate incorporating uprated spring centre dampening and a new release bearing is included.
NSK-6308SC (Sports Ceramic) This kit is designed to accommodate the demands of higher power modified engines. It includes a new High Performance cover assembly, which incorporates a high clamp load diaphragm, nodular iron anti burst pressure plate casting and triple drive straps. A new high capacity sprung centre driven plate, with 3 segments of sintered bronze (ceramic) friction material fused to each side of the main plate, and a new release bearing.
Exedy Clutch Experiences[edit]
Exedy Standard Clutch
File:Clutch exedy standard.jpg
This clutch has slotted organic sprung facings, and a sprung centre. The pressure plate uses six bolts. I ordered it for a turbo engine, but they told me the part number for the NA engine was the same(??!!). It drove very nicely from new, felt like a brand new car. The pedal pressure was very moderate and the engagement smooth. It held the unmodified turbo power adequately, but wouldn't cope with clutch kicks or big power.
Exedy Heavy Duty Clutch
"I was not there for the installation of this clutch, so didn't inspect it. This clutch was installed behind an RB30DET that had a turbo big enough to ingest small animals. It didn't cope. The engine could spin the wheels in third gear at 100km/h. The clutch was lost in 4th and 5th gear, could not hold the engine's torque, and made a terrible smell as it gave up. Pedal feel was similar to factory. I felt this clutch was a bit pointless, obviously this wasn't the right application for it, but what would you use it for? It was a reasonable price increase over the standard clutch kit for very little performance increase." - P
"For an RB20DET with mild power upgrades, this clutch is great. On a car that is mainly used for street (although I have taken it to the drags once), I find the take up and pedal pressure to be more than acceptable, and have never smelt any burning at any stage. I don't dump the clutch or do burnouts, but I think this clutch would probably stand up to a reasonable amount of punishment before giving up the ghost. The question is asked in the above paragraph "What would you use it for?", I'd say either an N/A car that is worked or given hell, or a mild turbo car that isn't subject to a large amount of clutch punishment. Putting it behind a RB25 or RB30DET is definately not a wise move, this is a middle range clutch, and not built to handle massive torque. That's why Excedy build a range of much stonger clutches..." - T
Exedy Sports Organic Clutch
File:Clutch exedy so.jpgFile:Clutch exedy so pp.jpg
This clutch has slotted organic facings, and a sprung centre. The facings are not sprung. The pressure plate uses nine bolts. The pedal pressure is noticeably higher than stock. This is the biggest clutch Exedy recommends for the street, although the box says it is a race only clutch. Because the facings are unsprung, this clutch takes up quite sharply. When new it was quite shuddery. After a few hundred kilometres it became much smoother. It is supposed to be able to hold some big power, but I haven't got big power yet. However I am reasonably confident because the clutch feels much better than stock on hill starts. You have to feather the stock clutch slightly more on hill starts, and you can feel the clutch flaring and responding differently due to the heat build-up, but this clutch feels the same under all conditions - very strong.
Compiled by:
WKD-031, Prestagea, Jeebus, Harolto, Blue, V-Spec