The Definitive 300ZX Brake Swap – Justifying The Upgrade

Why do this swap?  What are the benefits?  The primary purpose is to improve the overall braking performance.  This is accomplished by installing larger rotors and calipers.  The Nissan Z32 300ZX provides the 240SX enthusiast an OEM option that is considerably less expensive than aftermarket kits.  When I originally wrote about this brake swap in 2002, the only cost effective route was to buy used parts.  Now we have sources like RockAuto.com that sells re-manufactured calipers at prices lower than used calipers cost over a decade ago.  Other options available today include e-brake adapters, 5-lug conversion hubs, braided SS lines for the front and back to name a few.

This section will illustrate the physical difference between the original 240SX brake hardware and the 300ZX brake hardware and include my overall impression of the swap.

One thing to note, this swap can easily be completed on a 4-lug setup by ordering re-drilled rotors.  Before you go out to buy parts, you need to decide which front calipers you would like to have, or which calipers you may already have. Here is information and pictures regarding the difference between calipers prepared by Asad Aboobaker:

The following is a comparison of some different Z32 300ZX brake calipers. The “26mm Aluminum” calipers were used ONLY on 1990 non-turbos. They used a 280mm x 26mm rotor. The “30mm Aluminum” calipers were used on 1990 Twin-turbos and ALL 1991-1992.5 300ZX’s (both turbo and non-turbo alike). They used a 280mm x 30mm rotor. The “30mm Iron” calipers were used on ALL 1992.5-1996 300ZX’s (both turbo and non-turbo alike). They also used the 280mm x 30mm rotor. Of course, the easiest way to tell aluminum from iron is to use a magnet, but I hope this helps some people trying to figure out what they’ve got/are getting if buying with just a picture for info.

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Inside view of the three caliper options.
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Rotor Gap in the 30mm Iron Caliper.
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Note the different widths between the marked areas on the calipers as well as the overall width difference.
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The rotor channel has the same width on the 30 mm aluminum and iron calipers however the iron caliper casting is narrower near the bridge bolts. The total width of the calipers (distance from the mounting ear to the outside face of the caliper) is the same for both the iron and aluminum 30 mm calipers.
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Notice the well-defined small heatsink ridges on teh aluminum calipers and the “scalloped” out areas on the iron caliper. Again, note the width difference in the castings between the bridge bolts on the 30 mm calipers.
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The casting in the region of the pistons of the aluminum calipers has the two “circles” connected in a sort of dog-bone shape. The iron caliper has two well-separated circles. Also notice the small “SUMITOMO” casting on the face of the aluminum calipers.
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Note the “SUMITOMO” casting on the inboard side of the iron caliper as well as the aforementioned heat-sink ridges and casting differences in the piston region.
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The aluminum calipers use a threaded steel insert pressed into the caliper for the caliper mounting bolts. The iron calipers are threaded directly into the casting. Also note the different shapes in the body of the caliper.
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26 mm aluminum caliper rotor channel gap.
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30 mm aluminum caliper rotor channel gap.

The front brakes start out as a 9.8″ vented rotor and single piston caliper.  The 300ZX offers an 11″ rotor with a massive 4-piston caliper.

Outside comparison of front 240SX caliper vs 26mm 300ZX Caliper
Outside comparison of front 240SX caliper vs 26mm 300ZX Caliper
Inside comparison of front 240SX caliper vs 26mm 300ZX Caliper
Inside comparison of front 240SX caliper vs 26mm 300ZX Caliper
Stock 240SX Rotor compared to the 26 mm 300ZX rotor
Stock 240SX Rotor compared to the 26 mm 300ZX rotor
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26 mm caliper vs 30 mm caliper. It’s easy to see the difference between the two 300zx options. Ultimately, if weight is a factor, utilizing the aluminum 26 mm setup will save you a few lbs.
Badly abused stock 9.8″ front rotor
Front 11" 300ZX rotor (same diameter for 26 mm and 30 mm rotors)
Front 11″ 300ZX rotor (same diameter for 26 mm and 30 mm rotors)

The rear brakes start out as a 10.2″ non vented rotor with a single piston caliper.  Upgrading to the 300ZX equipment rewards you with an 11.6″ vented rotor with a separate drum e-brake and a 2 pistons caliper.

Inside comparison of rear 240SX caliper vs 300ZX
Inside comparison of rear 240SX caliper vs 300ZX
Outside comparison of rear 240SX caliper vs 300ZX
Outside comparison of rear 240SX caliper vs 300ZX
300ZX rear rotor
300ZX rear rotor
Roughly 11.6" vs the stock 10.2" rotor
Roughly 11.6″ vs the stock 10.2″ rotor

Impressions

I can say, without a doubt, that the swap made a significant improvement in braking performance! I never had a chance to compare stock to swapped on a race track but it is clear that the swap provides the foundation that will provide as much braking as anyone would need.  Pair this swap with a set of aggressive pads and the car will be ready for anything.

I also had a chance to experience the caliper and rotor upgrades prior to swapping the master cylinder.  I didn’t have one ready when I did the first part.  Using the stock 240SX master cylinder with the 300ZX brakes results in a very spongy pedal.  The master cylinder upgrade resolved that issue and improved brake feel better than any other part of the swap.

The next section will cover the front brake installation.  Click on the link below to see the complete series.

The Definitive 300ZX Brake Swap Series