Using an Aftermarket Clutch Line

The factory No. 27 pipe in the illustration (Pipe B, Clutch 46961-SL0-000) runs along the floor through a hard-to-reach area, making it very difficult to install later. For this reason, I used an aftermarket braided hose together with the No. 26 pipe in the illustration (Pipe A, Clutch 46960-SL0-010).
Kinokuniopen_in_new also offers custom-order hoses to your specifications, but rather than work out the correct length, I decided to buy the AT→MT Conversion Clutch Lineopen_in_new sold by RFY.

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RFY AT→MT Conversion Clutch Line

1. This clutch line connects directly to the hose on the release-cylinder side, so the clutch damper is automatically eliminated. However, because the clutch-hose bracket (No. 31 in the illustration) attaches to the clutch-damper bracket (No. 38), the damper bracket is still needed to secure the hose to the body.
   T3TEC sells a Clutch Hose Bracket (Part No. T3R-46968)open_in_new that allows the hose itself to be secured to the body for a cleaner installation.
2. These are only the parts related to the clutch master cylinder, but the master cylinder itself is the only component supplied as a partially assembled unit; all the other items are supplied as individual parts.
   This is not limited to this area: even individual bolts come in separate bags, which makes identifying all the purchased parts quite a task.

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Clutch Master Cylinder Parts

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Coupe vs. 02R Shift Levers

1. I bought the 02R shift lever (shared with the Type S), a commonly used swap because of its shorter design. The Coupe version (54101-SL0-000) is on the left, and the 02R/Type S version (54101-SL0-010) is on the right.
   Comparing the two, the 02R/Type S version simply has a longer threaded section; otherwise they appeared identical.
   The Coupe version has since been discontinued and superseded by the 02R/Type S version, so the latter is now the only choice.
   The 92R uses an unusual arrangement with a tapped hole in the shift lever and an integral stud on the shift knob. Since this prevents the use of aftermarket shift knobs and offered no major advantage for my purposes, I did not choose it.

Prices as of January 2010

There were two shift control cables with different part numbers: one for the 5MT (54310-SL0-023) and one for the 6MT (54310-SL0-033). The 5MT cable has since been discontinued and superseded by the 6MT version.
Either can be used without issue, but the 5MT cable can be adjusted for length at both ends, whereas one end of the 6MT cable has a fixed length. Apparently, improved manufacturing accuracy allowed one end of the 6MT cable to be fixed, while the 5MT cable can reportedly be adjusted more precisely at both ends to achieve lighter shift operation.

1. I bought a used shift cable removed from an ACURA NSX on eBay. More NSXs were sold in the U.S. than in Japan, so inexpensive used parts were commonly available on eBay at the time. The purchase price was $199. With the strong yen at the time (¥85 to the dollar), that worked out to just ¥16,915.

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5MT Shift Cable 54310-SL0-023

Using an NSX-R Clutch Pedal

1. I bought an NA1 NSX-R clutch pedal. Its pivot point, actuation point, and assist-spring mounting position are all the same as the Coupe pedal, but the pedal pad itself sits about 20 mm farther back. Because clutch travel changes depending on whether the clutch damper is fitted, I used the NSX-R pedal, whose pedal position is suited to a damperless setup.
   There are two NSX-R pedal versions, for the NA1 and NA2. The NA2 NSX-R version (35710-SE3-A01) adds an arm for the stopper that actuates the inhibitor switch. Since the inhibitor switch is not needed, I used the NA1 NSX-R version (46910-SL0-J00).
   There are two clutch-switch types: a 3-pin Coupe version and a 2-pin NSX-R version. To retain cruise control, two signal outputs are required, so I chose the 3-pin type (36760-SM4-003).

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Assembled NSX-R Clutch Pedal

1. The half-shaft assembly must be replaced with the MT version because the bracket is positioned differently on AT and MT cars. The shaft itself differs only slightly in length and appears reusable, but because the bracket is not available separately, the complete half-shaft assembly must be purchased.
   At the time, inexpensive used units removed from ACURA NSXs were readily available, so I bought one on eBay for $110, or ¥9,350 at the exchange rate then (¥85 to the dollar).
2. When the half shaft arrived, it looked thinner than the MT versions I had seen in books, so I measured it. The shaft diameter was 30.5 mm, the same as the AT version (the Japanese-spec MT version is 34.5 mm).
3. The bracket is stamped “MT,” so it is intended for MT installation.
   Several photos of 5MT ACURA NSX half shafts showed the same thinner design. I do not know whether this is related to gearing, but it appears that ACURA NSX MT cars use the same shaft diameter as the AT version, unlike Japanese-spec cars.

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ACURA NSX MT Half Shaft

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ACURA NSX MT Half Shaft Diameter

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ACURA NSX MT Half Shaft “MT” Mark

Reusing the AT Drive Shafts

1. The right-side (driver-side) drive shaft has the same part number for AT and MT cars, but the left-side (passenger-side) shaft uses different part numbers, and the service manual specifies the MT shaft as 6 mm shorter than the AT shaft.
   Replacing the left shaft with the MT version would be ideal, but many conversions have retained the AT drive shaft without apparent problems, so I did the same.
   The AT drive shaft installed without any problems, and nothing felt out of place afterward.

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Drive Shaft Reference Measurement Point

Factory Twin-Plate Clutch

I also considered an aftermarket clutch, but because the clutch is not easy to replace if I did not like it, I wanted to choose carefully. The factory unit is still a twin-plate clutch with ample capacity, so I bought a used factory clutch and flywheel set and replaced only the clutch discs with new parts.

1. Because it is a twin-plate clutch, a proper splined alignment tool is required.
   Used mainshafts that could serve as an alignment tool were not readily available, and the factory Clutch Alignment Shaft (07MAF-PR80100) had also been discontinued and was difficult to obtain, so I bought the ScienceofSpeedopen_in_new Clutch Alignment Toolopen_in_new made by ScienceofSpeed.
   It is made of plastic, but at $12.40 it was reasonably priced.

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ScienceofSpeed Clutch Alignment Tool

Two Mounts Have Different Shapes

1. Mounts are wear items, so used ones are not generally recommended, but I happened to find a set in good condition and used them.
   AT and MT cars use different part numbers for all three mounts, but the front-side engine mount rubber (50820-SL0-000) differs only in rubber hardness; its mounting dimensions are the same.
   For a conversion using the minimum number of parts, only the differently shaped transmission mounting rubber (50805-SL0-010) and rear engine mounting rubber (50810-SL0-010) are required.
   
   Someone previously compared vibration levels between the AT and MT mounts, and their report concluded that the AT mounts used harder rubber than the MT mounts.
   Since the AT transmission itself is considerably heavier, that result seems reasonable to me.

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NSX Transmission Mounts