[ Swift Sport ] Project Mu TYPE PS Brake Pads (Modifications, Part 5B)

I agonized weeks over the decision on my replacement front pads, comparing prices, reviews, and brands of several major manufacturers. Prices range from 3000￥ ($25 USD) for OEM-level equipment, to well over 20,000￥ ($190 USD) for track-use pads. Since the fronts do a lot of the braking work, especially for a front-engined, front-drive car, and the fact that I do somewhat harsh spirited street driving, selecting carefully between price and braking performance is critical. Also because this is a daily-driver, cold braking performance, brake dust, and noise are also important.

Due to a lack of real trustworthy reviews I could rely on, I recognized price is not the only determining factor. My Miata has cheap Pep Boys pads, but as I hinted before, pads do not make the only difference. For that car, I used high quality DOT4 fluid… and the car stops consistently well, even after hard autocrossing and track use. Granted, the car is rather light, but that setup is more than good enough for my use.

For my Swift Sport, though, I finally settled on a set of TM Square Street Brake Pads which are priced at 8600￥. TM Square is a small, but well-known manufacturer of primarily Suzuki Swift parts. While I’m fairly certain they don’t make the pads in-house, they claim their pad compound was engineered specifically for them. The company has a lot of race experience with Suzukis, so I expected them to work fairly well.

However, I was glad I was patient on the decision-making because during the waiting interm, I found a great deal on a brand new, unused but “second hand” set of Project Mu TYPE PS pads. They originally retail at  20,000￥, but because they were considered “open box”... they were about 5000￥ ($45 USD), shipped. Ridiculously cheap for arguably one of their best overall pads from a well-respected manufacturer, as these pads claim to have a great balance of braking performance, pedal feel, little noise, and reduced rotor wear.

I opted not to replace the rotors at this time, given that the overall condition of them are still quite good. Maybe after these stiffer pads wear down would I replace the rotors then.

Time to put it up on a lift and replace the brakes. One thing I absolutely love about modern disc brakes is the fact they are super easy to replace. Remove the one lower bolt and the whole brake assembly pivots on the upper bolt.

Perhaps the most difficult task is to push the piston in… without the right tools, it’s a minor hassle, but luckily I have access to a proper piston compression tool here at Rodeo Cars.

After a bit of cleaning and some application of high-temperature lubrication to minimize pad chatter, the whole assembly is back in place. This is also a good time to drain a bit of the brake fluid and replace it with fresh fluid. Since it is still pretty clean from my last shaken, it doesn’t need a full drain or flush.

The first thing that needs to be done once everything is cinched back up is bedding the brakes. The process to bed in a brake pad is pretty easy, but it’s quite important. The main reason to do this is to ensure some friction is done and wear surfaces are mated properly. Essentially, I need to heat the pads and rotors sufficiently by having a few relatively hard high-speed stops. Without anyone around, I found some empty stretches of road nearby where I could do this safely and not bother anyone.

After a few hundred kilometers of fairly typical street driving, my initial impressions are pretty darn good. The brake pads have never squealed (other than the first drive after a wet night due to rotor rust… but that applies with all cars). The brake pedal is firm and braking pressure is consistent.

I only had a chance to flex the pads a bit on some local winding roads before I made this post and I can say quite certainly they are as they claim. I purposely tried to quickly push hard on the brakes on every corner in order to get the brakes as hot as possible. The initial bite is strong and feels consistent through several hard braking passes. Even afterwards, I noticed minor brake dust on my wheels, but it is not that much different than the previous pads and to be fair, I tried to drive relatively hard on them.

In truth, however, I have not tested them to their maximum heat capacity, so how they fare on hard driving or circuit driving is another matter. I do have faith in their advertised performance based on the driving I did thus far and Project mu’s reputation in racing. Brake job done!

[ Swift Sport ] Project Mu TYPE PS Brake Pads (Modifications, Part 5A)

After all my recent Hokkaido and Eastern Honshu road trip around Japan, my brakes have been run down to about a quarter remaining, so I figured one of the most important “modifications” I can do is maintenance in the form of a good brake job on my Suzuki Swift Sport.

Brakes are one of the most important safety aspects of a car. In conjunction with good tires, good brakes can literally be the difference between life and death... or a wrecked car. Almost all modern cars use disc brakes, but some economy cars, such as kei cars, use drum brakes for the rear. Their stopping methods are different and there are some minor positive reasons to use drums over discs for the rear, but suffice to say most sport-oriented cars utilize discs all around.

Disc brakes, as the name implies, use large, typically steel, disc rotors attached to the wheel and hub. One or more brake pistons push against brake pads which apply pressure to the spinning disc, slowing the car down by changing the kinetic energy state to sound, heat, and wear. Most discs also incorporate vents and spacing in the center of the disc to better dissipate heat. More advanced rotors are made of materials that better reject or give off heat like carbon-ceramic or use of mixed metals like steel in the disc and aluminum in the hub hat.

The stopping action of disc brakes is very similar to the way a typical brake system on a bicycle works, with two little pads applying pressure against a spinning disc. Well, in the case of a bike, the wheel itself.

Drum brakes are a completely different design, because they utilize brake pads that push outwards against a spinning brake drum to reduce speed. The main problem with this setup is the inability to reject or reduce heat quickly, critical for sporty applications. 

The benefits of a disc brake are numerous which is why almost all manufacturers currently employ at least disc front brakes. They reject heat quickly, are durable and easily maintained, and may have better stopping power than most drums. Some economy cars utilize drum brakes for the rears simply because of manufacturing costs. However, on off-road truck applications, drum brakes can have some advantages. Drums are essentially sealed items, so in muddy, dusty, or wet applications, drums can still stop despite environmental effects. One additional benefit of drum brakes is the ease and reliability of the mechanical parking brake which does not require the hydraulic booster system to function at all, since the lever actually moves the brake pad directly.

Brakes are an oft overlooked modification for ricers (Iike me). Some car guys dump money into exterior mods or some into improving power or handling… but overlook or cut corners on the brakes. For me, many of the cars I’ve had stop well enough with their stock setup… that’s my excuse at least.

Basic upgrades to brakes mean replacing pads to a more aggressive compound. This usually means more dust and noise, since a more heat-resistant, “stronger” material means more sacrificial wear to the rotors and eventually, the pad itself, resulting in more frequent replacements.

The next level of upgrade is usually to also replace the stock rotors with slotted or cross-drilled disc rotors. Such opening slots allow worn dust and material to be “swept away,” and there are some additional cooling benefits to the increased surface area, but there are some drawbacks like the additional risk of warping or cracking under extreme duress.

The biggest upgrade is to replace the brake system with larger calipers, allowing the use of bigger pads and discs. Some larger calipers also mean there are more pistons which can put more consistent and firmer pressure on the pads, resulting in amazing stopping distances, repeatable over prolonged use. (Assuming the tires are not the weakest link.) Of course, model-specific brake upgrades can be wildly expensive.

Is it all really even necessary? It’s true stock brakes can more than handle slowing a car down quickly for normal day-to-day traffic. But repeated, quick, and harsh stoppages in extreme conditions as found on a racetrack or even on a long touge mountain run, the brakes “fade” and squeak in agony due to warping from heat and pressure, potentially leading to spongy, inconsistent braking feel, weaker pressures, or failure to stop.

It sounds strange to say brakes “fade” because they are still there. It actually just means brake pressures fade or weaken to the point of failing to stop as expected. Assuming the pads and discs are otherwise properly maintained, the most common fault of brake fade during spirited driving is fluid fade, the boiling of the brake fluid itself due to heat transfer. This increased heat in the fluid leads to air separation and loss of pressure. Typically, one can feel the fading gradually from a “spongy” brake pedal that requires more pressure than usual to slow the car.

The commonality of all modern brakes is this brake fluid. The standard OEM-supplied brake fluid is acceptable, but DOT4 or synthetic fluids allow much more heat transfer before the liquid reaches the boiling point, allowing consistent brake feel during aggressive use.

But I digress… it’s time to change the brakes on my Swift Sport!

[ Alto Works ] HKS Super Power Flow

Turbo cars can benefit greatly with a well-designed aftermarket air intake, as the stock intake can be, on some cars, a bit restrictive and can limit the additional amount of air necessary for high boost pressures. A higher flow filter, directed to draw air from cooler areas of the engine bay or directly from the front, can help improve power at higher RPMs.

However, there can be several drawbacks with aftermarket intakes, even the best designed ones. Noise is increased, unshielded filters can draw in hot air near the exhaust manifold, and exposed filters can draw in more debris or potentially water. Also importantly, engine tuning can be negatively affected, as the proper balance of air, fuel, and timing is absolutely critical.

Simply dropping in a cone filter does not necessarily improve performance. Many unknowing car owners pull out the stock intake piping, drop in a cone filter, and call it “good.” Stock intakes are designed a certain way for a reason; sometimes extra piping and large, empty Helmholtz chambers are needed and the location of air snorkels are well engineered. Moreover, the Mass Air Flow sensor is placed a certain distance away from the intake throttle body to properly measure air, but sadly, I’ve seen under enough hoods to realize not everyone knows this.

In California and some states in America, the replacement intake must also be certified CARB legal, so options are limited. In Japan, virtually any reasonable intake can be installed and still pass Japanese inspection. Knowing the potential drawbacks of installing an aftermarket intake, I figure the potential benefits still outweigh them and so all my cars have aftermarket intakes installed at the moment, all from highly reputable manufacturers.

Upon inspecting the original intake and filter, I found that it seems actually quite well designed as it is. The intake is piped in from just behind the right headlight, potentially drawing in plenty of fresh air, though sadly the intake piping is slightly small in diameter and has too many sharp bends, potentially decreasing airflow speed and pressure.

The filter design itself seems actually quite good, as the pleated filter offers plenty of surface area to draw air in. I contemplated keeping the original air box and simply altering the intake snorkel to improve airflow. Thankfully the previous owner of this Alto was gracious enough to include an uninstalled HKS Super Power Flow as part of the package, so I neither needed to buy an aftermarket part, nor modify my existing intake.

HKS filters have been criticized in some circles for being ineffectual or even poorly designed, as they say it can allow too much air particulates to enter the intake. Some famous Japanese tuners swear by them, though, and I’ve talked to a few owners who have put many miles (or should I say, kilometers) with the intakes and claim they work well.

Well, why not drop it in and see how it goes?

The mounts it came with were OEM and did not appear to be the mounts HKS originally included, according to their manual, so I had to use some aluminum brackets for a proper fit to avoid hitting the hood or other components in the engine bay.

While there is likely not a huge benefit for a stock-tuned engine, it might open up an ounce of HP if the engine can breathe more. The replacement HKS Super Power Flow intake sound is lovely, the sound of rushing air clearly audible in the cabin, even with windows up. These sounds, combined with the woosh of the recirculating valve, make the car sound lively around 3000 - 6000 RPM.

Along with this installation, I used a super thin .3mm aluminum sheet bent and shaped to block off extra radiant heat from the engine, hopefully encouraging cooler air to be drawn in from around the right headlight. (Although it looks like cardboard from some angles, the brown is actually just an adhesive backing sheet I opted not to remove at this time.)

This heat shield modification is only temporary until I redesign it with a thicker and larger aluminum sheet, which is already in progress. I would also like to use the dummy right inlet to the side of the headlight to potentially force more air directly into the air filter. Let’s see how that goes in the future...