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).
This page is a general introduction to the development of the chassis and suspension of my car. It contains really simple explanations of what various available suspension parts are and what they will do. Some sections may have a brief description of some installation tips. Like many the first items I had on the car were coilovers so why not start the page there?
Coilover Spring/Strut Assembly
Factory S13 suspension by technicality is coilover strut, but when people refer to aftermarket coilovers they mean buying units where the whole lot comes assembled together and matched in springrate/damping. Japanese coilover kits are usually rock hard compared to factory suspension, and deliver a bone jarring ride on anything less than a perfectly smooth road. On such a smooth road however, the handling difference is immense, with response, turn in and cornering speed greatly improved. There are other ways to get a car handling great, so remember that even though coilovers are very popular that other avenues should be explored.
My coilovers came on the green 180 and I’ve stuck with them since. They are Kei Office/Ergfolkei units, as seen on the Kei Office D1 car and various other promo cars. Kei Office is owned by Keiichi Tsuchiya, D1 judge, revered as the grandfather of drift. The spring rates are believed to be 9kg/mm front and 7kg/mm rear, which is definately in the stiffer variety. Damping is adjustable to 4 presets as well as height adjust without upsetting spring preload (top end feature).
The image below right compares a moree expensive coilover (Kei Office, left), versus a cheaper item (Tein, right). Remember Tein make more expensive coilovers too so don’t think I’m saying that all Kei Office coilovers are better. The first thing to otice is how much more robust the base of the Kei Office coilover is, with a larger diameter. Secondly and more importantly is the locking ring at the base of the strut, allowing ride height to be changed independant of spring compression. On the Tein unit the spring must be compressed to shorten height, and is limiting factor in raising the car will then be keeping the spring captive. The Kei Office coilover has none of these problems. The Kei Office item also has damping adjustment which the Tein does not. These are all things to look out for when buying coilovers.
Installation is simple. Simply unbolt the nuts at the strut tops (three front, 2 rear) and then the nuts at the bottoms (two at front, one large at rear). Coilovers can go in and out in about 5 mins once the car is jacked up.
The front camber tops are believed to be Project Mu and feature additional ride height adjustment from the engine bay. Very handy indeed. Camber tops allow the top of the strut to be slid inwards or outwards, giving an instant camber change. There is lots to be found on camber by searching the internet, no need for a big explanation here. Negative camber will compromise straight line grip but will come into play as the car leans over during hard cornering. I am currently running around 2.5 degrees of negative camber at the front, but will probably reduce this a little to increase straight line braking grip with more contact patch available.
Castor Rods/Tension Rods/Radius Rods
Known by many different names but with only one purpose. The item in question allows complete adjustment of the front castor alignmenmt setting. The more the castor the better in the general opinion, allowing sharper turn in and faster return to the straight position when letting go of the wheel. I am unsure of the brand of my castor rods but they are setup to run approximately 6.5 degress of castor.
Sway Bars
Sway bars are probably one of the biggest areas of improvement available in suspension tuning. Unfortunately it is something a lot of people forget as well. The switch to aftermarket Whiteline adjustable swaybars for me was sensational. Previously it felt as if the outer front turning wheel was being overloaded, running out of traction and thus limiting the cornering capabilities of the car. The swaybars seemed to keepo the car a lot flatter, spreading the cornering load more evenly and making the chassis feel a lot more stable. Bodyroll is reduced and overall the car feels a lot more chuckable.
I haven’t physically had to fit swaybars myself but the details of the job are easy to see. The front swaybars mount to be the control arm on both sides and have a secondary mount on the chassis. Simply unbolt these and change. The rear is a bit trickier, as the swaybar curves over the top of the exhaust. It is recommended then that the cat-back section of the exhaust be removed prior to installation. Similar mounts are found on the lower rear control arms with body mounts once again on each side.
Front mount and swaybar path:
Rear Mount and Sway bar path:
Strut Braces
Strut braces are very commonly fitted because they are cheap, simple and super easy to install. Simply park the car on level ground, undo the nuts on top of the struts, put the brace over the strut studs and replace nuts. Rear strut braces can be harder simply due to interior trim in the way, so take a lead from me and strip it all out anyway.
Strut braces are meant to increase rigidity of the car much like a roll cage. It is said that during heavy cornering the body of the car will flex and suspension geometry will change. A strut brace will go a long way to fixing this in theory at least.
Alloy Steering Spacer
This part is very simple. It replaces a rubber link found inbetween the steering wheel and steering rack with a solid alloy one. A small amount of play is removed giving a more solid steering feel and increased feedback. These spacers are quite cheap and worthwhile for the money. However fitment should be simple but isn’t, with only four nuts to be fiddled with. The best way to get at them is to move the move the fuel filter to the side and unbolt the bracket which holds it. You will definately need two people from here on, as attempting to undo the nuts only turns the steering wheel. So position a 12mm spanner against a solid part of the engine bay and have your helper turn the wheel in the correct direction to crack the nut.
The only other thing to do is to loosen the nut that secures the lower rod into the steering rack (lower right pic). This will allow the rod to slide up and down, thus giving ample clearance to remove the old rubber spacer and put in the new alloy one. Doing up the nuts should be much easier now as the new spacer won’t flex and move like the old. Don’t forget to tighten the lower nut near the rack and to put the fuel filter back in place.
Urethane subframe mounts (Pineapples)
These are a very cheap addition to the chassis, and many have delved because of this. Although I have them I know little about them, so this section will be limited. Pineapples are usually used to combat axle tramp, the sudden and severe vibration of the rear subframe in wheelspin conditions. I have heard mixed reports of whether or not they actually work, but my car very rarely suffers from axle tramp so make of that what you will. Someone feel free to email me more information on this subject and I’ll update this section with due credit.
Rear Upper Camber Arms
As the S13 chassis is lowered negative camber is introduced. This reduces contact patch and thus available traction, giving the Silvia/180sx platform the infamous tail out behaivour suited to basic drift. Sometimes you actually want traction, and sometimes you really need it. My rear camber was found at 3.5 degrees negative, and then was adjusted with the factory allowance to 3.0 degrees. Ideally it should be somewhere near 0.5 degrees negative, and closer to neutral if drag racing is on the cards.
Rear camber arms are needed to correct this, and dependin on how much adjustment is required, the other upper control arm may need replacement too. The rear strut will have to come out to fit the arms, so remove this first. The closest bolt is straight forward but may be very tight. The rear bolt has factory adjustement built in so is much trickier. One side loosons the nuts for the whole bolt, while the turning the other simply rotates the assembly to push the mount either closer or further from the chassis. What needs to be done is to for the first nut to be completely removed, and then the strange shaped washer behind it removed too. Now carefully tap the large bolt out. Leaving the washer on could catch it on the thread and damage both so be careful. Now simply reverse the process to fit the new arms.
A wheel alignment will be required to set everything up. Also note with these adjustable parts that you should double check that the adjustable sections are secured tightly before driving. They should only be tampered with during an alignment. Thanks to Harry for his time in fitting these parts with me.
Rear Toe Arms
Very simple, these arms allow toes adjustmewnt at the rear end of the car. Two bolts has the old ones out and new in. A wheel alignment is recommended after fitment to make sure everything is correct. Be careful with the factory adjustment bolt as described in the section immediately above. I am currently running 0.5 degrees of toe in on the rear.
Half Roll Cage
Besides the obvious benefits of safety in a roll over a full or even half cage acts like one giant strut brace, increasing rigidity of the car. This cage comes from Cusco and is made of chrome-moly. It is designed to be bolted in fairly easily, (weld in cages are AFAIK illegal on street cars in Australia) and can be removed just as easily if need be. A dummy fit first takes place, which needs removal of the seats to make room. Once the main piece is in position, drill through the floor of the car and fix the underside plates tightly. They will flex to follow the shape of the floorpan with enough force. High tensile nuts and bolts are extremely necessary. Once the four mounts are secure (each side behind the seats and each side on the rear inner guards), the bolts must be shortened to prevent fouling on the road or tyres. Lucky last is to tighten the linking joins between the pieces. Thanks to Harry once again for his time in guiding the fitment of this cage.
When changing either tyres or rim sizes it can be confusing as to which tyre specification to get to make sure the speedo is not put out. Most tyre salesmen will sell you whatever they want without a care to the accuracy of the speedo afterwards, thinking ‘close enough is good enough’. To avoid unwanted speeding fines when your speedo is telling you you are on the legal limit, you must be prepared come tyre shopping time.
Rolling Diameter
The tyres rolling diameter is the measurement of the part of the surface that touches the road. Tryin to measure this with a ruler is silly, due the the curving shoulders of a tyre, therefore we use mathematics to determine the closest number possible. Unfortunately this number can never be absolute in terms of its accuracy, as factors such as tyre pressure can alter the figure slightly, but it is still the best way to do it.
Tyre Specifications
All road tyres are specified using three numbers, which represent the width, the profile and the size of rim it is meant to fit. An example comes with the factort tyre size for the S13.
205/60 R15
(Width) / (Profile) R (Wheel Size)
The tyre is 205mm wide, has a profile of 60 and suits 15 inch rim. The width and profile is straight forward, but the profile can use some explaining. The profile represents the side wall height, and is a mathematical ratio number. This means that the profile is never a set figure, but a determining figure of the rolling diameter in relation to the width and rim size. The larger the number the fatter the sidewall, and the lower the more they look like licorice rubber bands.
Front and Rear Tyre Diameter
Ideally it is nice to match all four tyres to the factory size, but clearly the two wheels that the speedo are driven from are more important. These will always be the driving wheels, such as the rears in an S13 because it is rear wheel drive. Therefore the front wheels can be slightly out compared to the rears, but not too much as problem such as guard scrubbing can occur. For the rears, it is best to stay within only a few millimetres difference in rolling diameter to keep the speedo accurate.
Consequences of Tyre Inaccuracy
How much the speedo is altered depends on the difference in rolling diameter. Speedo inaccuracy will always be in a percentage however, rather than a fized gap. By this I mean that the speedo may under read by 10%, instead of always be under reading by a fixed amount of 10km/h for example.
When the rolling diameter is larger than factory, it makes the speedo under read. That is, you will be travelling faster than your speedo is telling you, which is very nasty for speeding tickets.
When the rolling diameter is smaller than factory, it makes the speedo over read. That is, you will be travelling slower than your speedo is telling you, a much more conservative and safe proposition.
Obviously the tyre diameter also has a direct bearing on vehicle gearing, and altering the tyre size can be like altering the final drive ratio in the differential. When the diameter is larger, the vehicle will have a slight advantage in acceleration at the expense of fuel economy and reduced top speed, and vice versa.
How to Match the Correct Tyre for a Non Factory Size
Handy programs exist to tell you the rolling diameter for a given tyre specification, by doing the maths for you. I use Gearcalc, a free application I found some time ago. It has many more functions to do with the gearing of a vehicle, but can be used simply to tell a tyre’s rolling diameter and circumference.
It is available for download here: Gearcalc
Below is table generated by using Gearcalc, to assist with selecting the correct tyre size. As an example of how to use it, highlighted and in bold is the factory tyre size for the S13: 205/60 R15. Also highlighted are the closest matches to this in diameter.
- Say you were going drag racing with stock 15×6 inch rim. You want some wider rubber under the rar to assist launching, yet you want to keep it for the street so the speedo is accurate. The wisest choice would probably be the 245/50 R15. Of course if they were only going on at the track then it might be wiser to choose a tyre with a slightly larger diameter to assist acceleration, and higher profile to ‘bag’ better on launch. Maybe then a 255/50 R15 would be good.
- Next we might want to upgrade to a larger rim for the street that mizes a good balance of size and performance. For a 16 inch wheel 225/50 R16 on the front and 245/45 R16 would be near perfect. For a 17 inch rim a 215/45 R17 for the front and 245/40 R17 for the rear is quite good.
- Now perhaps you wanted some pimp style 19 inch chromies. 205/25 R19 would be a good bet all round.
Clearly the table can be used for other cars, just look up your factory size and then search for those closest. Notice the difference in diameter one size up in profile can make, so take care to get the exact tyre you want. Anything not listed here canbe found by using gearcalc. Enjoy!
|
R 15
|
195
|
205
|
215
|
225
|
235
|
245
|
255
|
265
|
275
|
|
40
|
537.00
|
545.00
|
553.00
|
561.00
|
569.00
|
577.00
|
585.00
|
593.00
|
601.00
|
|
45
|
556.50
|
565.50 |
574.50
|
583.50
|
592.50
|
601.50
|
610.50
|
619.50
|
628.50
|
|
50
|
576.00
|
586.00
|
596.00
|
606.00
|
616.00
|
626.00
|
636.00
|
646.00
|
656.00
|
|
55
|
595.50
|
606.50
|
617.50
|
628.50
|
639.50
|
650.50
|
661.50
|
672.50
|
683.50
|
|
60
|
615.00 |
627.00
|
639.00
|
651.00
|
663.00
|
675.00
|
687.00
|
699.00
|
711.00
|
|
65
|
634.50
|
647.50
|
660.50
|
673.50
|
686.50
|
699.50
|
712.50
|
725.50
|
738.50
|
|
R 16
|
195
|
205
|
215
|
225
|
235
|
245
|
255
|
265
|
275
|
|
35
|
542.90
|
549.90
|
556.90
|
563.90
|
570.90
|
577.90
|
584.90
|
591.90
|
598.90
|
|
40
|
562.40 |
570.40
|
578.40
|
585.40
|
593.40
|
601.40
|
609.40
|
617.40
|
624.40
|
|
45
|
581.90
|
590.90
|
599.90
|
608.90
|
617.90
|
626.90
|
635.90
|
644.90
|
653.90
|
|
50
|
601.40
|
611.40
|
621.40
|
631.40
|
641.40
|
651.40
|
661.40
|
671.40
|
681.40
|
|
55
|
620.90
|
631.90
|
642.90
|
653.90
|
664.90
|
675.90
|
686.90
|
697.90
|
708.90
|
|
60
|
640.40
|
652.40
|
664.40
|
676.40
|
688.40
|
700.40
|
712.40
|
724.40
|
736.40
|
|
R 17
|
195
|
205
|
215
|
225
|
235
|
245
|
255
|
265
|
275
|
|
35
|
568.30
|
575.30
|
582.30
|
589.30
|
596.30
|
603.30
|
610.30
|
617.30
|
624.30
|
|
40
|
587.80
|
595.80
|
603.80
|
611.80
|
619.80
|
627.80
|
635.80
|
643.80
|
651.80
|
|
45
|
607.30
|
616.30
|
625.30
|
634.30
|
643.30
|
652.30
|
661.30
|
670.30
|
679.30
|
|
50
|
626.80
|
636.80
|
646.80
|
656.80
|
666.80
|
676.80
|
686.80
|
696.80
|
706.80
|
|
55
|
646.30
|
657.30
|
668.30
|
679.30
|
690.30
|
701.30
|
712.30
|
723.30
|
734.30
|
|
R 18
|
195
|
205
|
215
|
225
|
235
|
245
|
255
|
265
|
275
|
|
30
|
574.20
|
580.20
|
586.20
|
592.20
|
598.20
|
604.20
|
610.20
|
616.20
|
622.20
|
|
35
|
600.70
|
607.70
|
614.70
|
621.70
|
628.70
|
635.70
|
642.70
|
649.70
|
656.70
|
|
40
|
613.20
|
621.20
|
629.20
|
637.20
|
645.20
|
653.20
|
661.20
|
669.20
|
677.20
|
|
45
|
632.70
|
641.70
|
650.70
|
659.70
|
668.70
|
677.70
|
686.70
|
695.70
|
704.70
|
|
R 19
|
195
|
205
|
215
|
225
|
235
|
245
|
255
|
265
|
275
|
|
30
|
599.60
|
605.60
|
611.60
|
617.60
|
623.60
|
629.60
|
635.60
|
641.60
|
647.60
|
|
35
|
619.10
|
626.10
|
633.10
|
640.10
|
647.10
|
654.10
|
661.10
|
668.10
|
675.10
|
|
40
|
638.60
|
646.60
|
654.60
|
658.60 |
670.60
|
678.60
|
686.60
|
694.60
|
702.60
|
