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| Current best dyno power figure: |
| 218.7 kw @ rear wheels |
| Current best quarter mile: |
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15.0 seconds @ 98mph |
| Advertisement: |
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| Current best dyno power figure: |
| 218.7 kw @ rear wheels |
| Current best quarter mile: |
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15.0 seconds @ 98mph |
| Advertisement: |
The front brakes on S13s are a little underdone, even the SR20DET equipped cars which have the largest discs of the lot. While the S13 cars have only single piston front calipers, most others in the Nissan family have much larger four piston front calipers on thicker dics. With the ease in which the turbo variants can gain power the factory brakes quckly vecome weak link in the overall performance. Luckily it is quite a simple proposition to upgrade to these items for various cars.
Nissan Car Front Brake Comparison
Below is a table featuring the most commonly considered models and their front brakes. Thanks to James for supplying most of the data in this table. I will look into adding more models in the near future.
Car
Number of Pistons in Caliper
Caliper Material
Disc Diameter
(mm)
Discs Thickness
(mm)
Stud Pattern
(PCD)
S13 CA18DE(T) / SR20DE
S13 SR20DET
S14/S15 SR20DET
R32 GTS-T Type M
Z32 300ZX
R33 GTS25T
4 Stud or 5 Stud
As can be seen on the table above the main problem with converting an S13 to the better brakes of another model is that the S13 has a 4 stud pattern where as everything else has a 5 stud pattern. Therefore it must be decided whether to retain the 4 stud pattern or convert to 5 stud.
Converting to 5 stud requires the changing to the hubs from the model the brakes are coming from, and to allow a bolt on other suspension components from that model are also required. Therefore this makes the process a little complex but has the advantage of being more thorough. No discs have to be redrilled and a wider range of wheels are vailable in the 5 stud pattern.
Retaining 4 stud is easily the simplest way to upgrade the brakes, as it is just a case of redrilling the rotors from the new set to 4 stud and they should almost bolt on. The only other work required is to shorten the banjo bolt of the S13 3-4mm. Alternatively new dics can be purchased from someone like DBA that are blank, allowing a fresh 4 stud pattern to be drilled.
Caliper Clearance
Another trouble often found is that most of the wheels available in 4 stud are he incorrect offset to clear the bulkier calipers, requiring spacers to be fitted. 5 stud wheels have a habit of having a good amount of room behind the spokes for the 4-spot calipers, another advantage to making this conversion. Sometimes where the brakes are very close to clearing but just foul the embossed Nissan lettering on their outer surface can be machined off to save a few millimetres.
My Choice of S14 Brakes
I was originally after a set of R33 calipers to go over new DBA blanks drilled to 4 stud but when these late model S14 brakes where available for $200. When I was being quoted for just the calipers only the prices were around the $400 mark. So clearly the S14 brakes were too good to pass up.
Disassembly of S13 Front Brakes
This process is quite straight forward and can be attempted by anyone with some half decent hand tools.
First remove the wheel. Seen here are my 20mm bolt on spacers that have to be the safest type of spacer available. They bolt on the studs from the hub and then have their own new studs that the wheels bolt to. Here is a good shot of the factory S13 SR20DET brakes.
The calipers unbolt via the two sets of bolts on the rear side. One is 14mm and the other is 17mm head size. Once both are removed the calipers will slide straight off the disc. Now in the centre of the disc are two small threaded holes. Screw a spare bolt in one of these and the discs will become free from the hub and slide off. Too easy!
S13 SR20DET and S14/ S15/ R32/ Z32 Disc Comparison
Shown below is an original disc compared to an S14 discs. Backing up the figures in the previous table it can be seen that the discs are the same diameter but the S14 discs is noticably thicker. This adds a bit of weight as well from the increased material. Should be excellent for avoiding brake fade causing heat sink however.
S13 SR20DET and S14/ S15 Caliper Comparison
The S13 brakes use a two part caliper as they are only a single piston caliper. Therefore the two halves must be engineered so that they squeeze equally on both sides despite the piston only beingon one side. Here it is clear to see he single large piston from the S13 caliper versus the four pistons on the S14 item. The advantages here are a greater and more even spread of braking force accross the pad and the rotor. Also note the open ends of the S14 calipers allwing greater air circulation around the pads and pistons and also greater ease in changing the pads.
As the two piece mechanism of the S13 calipers is quite bulky and complex, the wider S14 item still seems to wight the same amount. I would imagine then that R32/ Z32 alloy calipers (identical otherwise) would be substancially lighter and assst removing unsprung in the suspension. I dummy fitted the S14 caliper in place and it lines up perfectly (still over the S13 disc though). I can see only one small section of the protective backing plate behind the hub that will need to be trimmed.
The Banjo Bolt
Shown below is is the banjo bolt that needs to be shortened. Immersed inside the S13 caliper it is too long for the S14 entry point and subsequently needs to be shortened approximately 3-4mm.
Redrilling of the S14 Discs
The redrilling process is quite simple but great care must be taken to ensure good accuracy. After all these are the car's brakes, which is something no one to ever have fail. If the discs are redrilled incorrectly then the disc will be out of symmetry and balance and cause vibration at best.
Fortunately as the discs are both X x 114.3 stufd pattern, this means the holes are the same distance from the centre. In short one of the original holes can be reatined, meaning only three others need to be drilled. Make sure to orientate the disc so that you will be drilling through fresh metal and not any of the previous holes. Below is a picture of how I set up the discs to be aligned correctly.
Letme take this opportunity to thank John and Stephan from the workshop at uni, firstly for allowing me to use the facilities for non-course work, and secondly for taking some time to help me from the very busy end of semester rush. This process would surely cost at least $50 per disc for the drilling and machining so I have saved a great deal.
Alignment
The two discs are placed hat to hat with the 4 stud item on top, and then a plastic dowel is pushed inbetween the two matching holes to keep them aligned. I then pushed a scrap piece of tapering blue foam down the centre holes to give them a rough alignment and dampen any vibrations from the drill. Lastly a clamp is placed around the meeting points of the two hats and tightened so that they are held firmly in alignment.
Now drill the three new holes using the 4 stud pattern disc at a template. Check that the bit is centred in the hole before drilling to ensure accuracy. Next use a much larger drill bit and drill a slight indentation around the top of the holes as shown. This not only looks good but helps remove dags from the fresh holes, and assists when the disc is slid on to the studs.
Surface Cleaning
Usually here you would pay to have the discs machned to ensure trueness and surface quality. However, since the discs appreared to be in much better condition that my original discs I assumed they only needed the surface oxidization cleaned off. I've been told however that the uni lathes can accomodate the dics for trueness machining, but now was not the time as the workshop was very bus with people doing genuine uni work. I can always return to machine them in future if need be.
To clean up the surface I simply used some medium grit wet and dry sandpiper and lightly rubbed until the surface was shiny again.
Trial Disc Fitment
When I got home I was able to fit the discs on the hub to see that my redrilling work was accurate. I am happy to announce that I must have done a good job as both discs went on without dramas. The only problem is the clearance between the protective backing plate and the new thicker disc, which is to be expected. On the lower right hand it can be seen where the plate fouls on the disc surface. A few hits with a hammer should fix this I hope.
Trial Caliper Fitment
As expected the calipers bolt straight up to the existing mounts, and sit nicely over the discs. A small section of the backing plate will need to be trimmed as suspected but the angle grinder will make short work of this. Now all that is needed are new pads and I'm ready to bolt on the brakes for good.
Parts Dealing
A few things need to be explained before I continue. Firstly the brakes were never fitted to the black car, only after I got the grey 180. The grey 180 already had some R33 gtst brakes installed, but these are not mine to keep, so the other brakes had to replace them.
I managed to swap my S14 calipers for a set of lighter but similar Z32 300zx items as well, so now they will go on and I can compare the three sets in detail.
Further Comparison
Below is an image of the three sets of brakes. From left to right are the R33, S14 and Z32 calipers. On the bottom left are the larger R33 disc and on the lower right the identical size S14/Z32 disc. All the the calipers take the same brake pad, although you cannot mix and match the discs and calipers. That is to say that the smaller S14 or Z32 calipers will not fit the larger R33 disc.
Here the size difference between the Z32/S14 dics and the larger R33 disc can be seen. They are layed directly on top of one another, as to display the larger diameter but identical thickness.
We took the time to measure the weights of the three calipers, the results are shown in this table. It is obvious that the equal smallest S14 calipers are quite heavy. It might not seem like much more but when the mass corcerned is attached to the suspension like it is it makes a big difference to handling. The R33 calipers are superb in their light weight despite being the largest of the three. Definately the one to go for, although you will pay extra for it.
In this hot it can be seen that although the Z32 (left) and S14 (right) calipers have slightly different castings, they are basically the same design.
Fitment
The grey car already had its bajo bolts trimmed as well as the backing plates, so fitting the Z32 calipers and redrilled S14 discs was a breeze. You simply clamp the brake line to limit leakage, unbolt the caliper and banjo, and bolt up th new one. Bleed brakes and done!
Performance
Since I was downgrading from the R33 brake setup that had been the car for the first part of ownership, its hard to compare the Z32 setup to the stock SR20 setup. I think on the street its hard to take advantage of the bigger brakes, but when I next venture onto the track I think the extended limits will be revealed. Braking should be a lot more solid fora lot longer (further resistance to fade).
