Twin Splined NSX-R Mainshaft vs OEM 5 speed Main

[MJK]

Let me preface this by saying that this is probably a stupid question, but I can't seem to find the answer.
I ran across a post that seems to suggest that a 5 speed mainshaft part number 23210-PR8-A02 could be used in a 6 speed transmission to use a dual disk clutch. I already have an extra OEM 5 speed main shaft laying around (don't ask). So my question is, is there any point in buying an NSX-R mainshaft or do I already own one?

 

[heretic]

http://www.scienceofspeed.com/produ...ance_products/NSX/Honda/6spd_twinplateclutch/
:smile: I saw this too and wanted one as a spare...
I think you do have one indeed. Wonder what Chris thinks.

 

[Larry Bastanza]

They are not the same. Remember the original mainshaft holds 5 gears not 6.

The spline end is identical, but in the pic on SoS's site they are comparing an NSX-R mainshaft with a standard 6 speed mainshaft, not a standard 5 speed mainshaft.

You will need the NSX-R mainshaft if you want the dual plate clutch with a 6 speed.

HTH,
LarryB

 

[heretic]

Thanks LarryB
Your spot on...again:tongue:

 

[ScienceofSpeed]

As stated above, you need the specific NSX-R input shaft if you would like to use a double disc clutch with your 6-speed transmission. The 5 spd shaft can not accept the complete gear stack used in the 6-spd.

take care,
-- Chris

 

[MJK]

Thanks guys, I owe you (another) one!

Chris, I will give you a call when the time comes.

:smile:

 

[TURBO2GO]

What's the benefit of the dual disc clutch?

 

[ScienceofSpeed]

What's the benefit of the dual disc clutch?

Multi disc clutches allow smaller discs to be used. Multiple discs can have the same surface area of a larger single disc clutch. Smaller components allow the mass to be concentrated towards the centerline of the clutch reducing the rotating assembly's moment of inertia. Lower moment of inertia results in quicker engine response and less rotational loss.
http://en.wikipedia.org/wiki/Moment_of_inertia

There is a dramatic difference between the factory double disc and factory single disc clutch assembly in mass and moment of inertia. The single disc clutch in general is easier to drive while the double disc is better for performance - hence Honda's selection to use the double disc clutch in the NSX-R.

However, there are single disc clutches, like the RPS, which have lighter assemblies with a lower moment of inertia compared to the factory double disc clutch. Although the clutch is a single disc with a larger sized clutch disc, the whole assembly is significantly lighter and with less mass on the outer fringes of the clutch due to it's mostly aluminum construction.

cheers,
-- Chris

 

[titaniumdave]

A dual disk clutch can have a lower moment of inertia(smaller diameter) while having the same clamping force. In the equation to calculate inertia, the radius is squared, so the diameter of where the mass of the clutch is located has more effect than the actual mass of the clutch. A 28 lb, 9" single disk will take more energy to accelerate than a 28 lb, 7" dual disk clutch. This is also why flywheels are lightened on the outer most diameter.

This will allow the motor to rev more freely, using less energy and allowing more HP to flow to the rear wheels.

 

[Kitaka]

Having formal training as a Civil Engineer, this was a great explanation!

 

[TURBO2GO]

So whats the drawback? I mean should we all be upgrading to the lighter flywheel and the dual disc clutch? and by we I mean "me"... :biggrin: