If you want a race-ready, fixed-caliper big brake kit for your classic Honda, you have three popular options:
- Install a Wilwood-based big brake kit from a manufacturer like FastBrakes
- Roll the dice with a fully custom kit from brands like KSport
- Custom build your own brackets around a performance-oriented racing caliper
The annoying reality is that Option 1 would give you less than ideal performance unless you sprung for the 6-piston Wilwood DynaPros (or better). The 4-piston Dynalites are notorious for flexing, and there have been reports of the newer ones leaking from the bleeders. Option 2 is known to have hit and miss quality control. And Option 3 can be expensive if you can't do your own fabrication.
As it turns out, there is an Option 4. Thanks to a small US-based shop called FatFour Customs, there is a way to get an affordable bolt-on fixed caliper big brake kit for less popular Honda cars like the Acura ILX, Honda CRV, Honda Accord, Acura TL and of course, the 4th and 5th gen Honda Prelude. Intrigued by this possibility, we took the plunge and ordered a kit for the StudioVRM Honda Prelude.
What's in the Kit?
The FatFour customs kit is, in essence, an integration of proven OEM parts. It uses a combination of the much-loved 4-piston fixed calipers from the 2005 Acura RL with the beefy 324mm diameter brake rotors from the 350Z, and a series of adapters to fit them on to the much-loved Honda of yesteryear.
Because FatFour Customs makes applications for quite a few cars, you do need to select the components to fit your car. The shopping list for our 4th gen Honda Prelude included:
- A FatFour Customs Brake Caliper Bracket
- Aluminum Hubcentric Rings
- PowerStop Evolution Rotors redrilled for 4x114.3
- New (or rebuilt) 2005 Acura RL calipers
The hubcentric rings are an important component that is unique to our application. These small aluminum rings are necessary because the center bore of the 4th gen Prelude is just a few millimeters shy of the centers on the 350Z rotors. Without them, the rotor would not center properly, and could cause balance issues at higher speeds.
The thickness of these hubcentric rings meant that we would not be able to run the 10mm spacers that we had been running on the front end of the Prelude. We compensated for this by making some alignment adjustments to help the car rotate. Alternatively, most machine shops would also be able to bore out the centers our wheel spacers for the outer diameter of the rings.
We would also need brake pads that would fit our new calipers. Our pad of choice is, as usual, the Raybestos ST-45, custom cut by Porterfield Brakes.
The total cost of the kit? Less than $950, including a set of Raybestos racing brake pads custom cut to fit our RL calipers. It's a solid deal when compared with the comparable FastBrakes kit, which comes with flexy Dynalite calipers and lack brake pads. The kit is also a total of 14lbs heavier than the stock Prelude Si VTEC brakes - A weight penalty that we are happy to pay if these brakes work as well as we hope.
Watch that Brake Balance
Upgrading to any big brake kit will inevitably affect the front-to-rear brake bias of your car. It's generally safe to assume that upgrading to a larger rotor with a larger width pad will move the brake bias further forward. The question is - by how much?
Thankfully, the formula for calculating brake bias is well-known, and there are a number of calculators that you can use to get a good estimate of your brake bias. We happen to be fans of this one hosted by Track and Build.
By taking a few measurements, we found that upgrading from the stock Honda Prelude Si VTEC's 11.1" front rotors and single piston calipers to the FatFour Customs Kit's 12.76" rotors and RL calipers moves the brake bias moving forward by 5%.
This is a welcome change, as we need as much front brake bias as we can get to ensure that the front brakes lock before the rears under hard braking. If the front bias proved to be too much, we could dial it back using the Wilwood proportioning valve that we previously installed inline with our rear brakes.
If you want to try the calculator yourself, here are the key figures for the FatFour Customs kit:
- Front Rotor diameter: 12.76 in
- Front piston 1 diameter: 1.690 in
- Front piston 2 diameter: 1.690 in
- Front pad width: 2.90 in
Pro Tip: You can get the majority of these numbers for any car from RockAuto. The pad width can be found by looking up the FSMI pad shape code (e.g. D1091 for the 2005 Acura RL front brake pads).
An Unusual Installation Process
Every kit has its quirks. With the FatFour Customs kit, those quirks were in the installation process.
The first thing we noticed is that the FatFour Customs bracket comes with US Standard ("SAE") rather than Metric hardware for attaching the RL calipers to their brackets. We suspect this is a cost-savings measure, as high-strength USS fasteners are available for much cheaper than their Metric equivalents in most of North America. While the cost savings are welcome, it is a bit annoying to see USS fasteners on a car that uses all-metric hardware.
The silver lining is that the hardware is all common automotive sizes. 9/16" is a common size for spark plug sockets, while 13/16" is a common size for lug nut sockets. Most automotive enthusiasts will have sockets for these sizes in their toolbox already.
Because the brackets are made of a lightweight aluminum alloy, you also need to torque the bolts carefully so you do not strip the threads. We recommend that you follow the manufacturer's installation instructions to the letter to ensure that you do not damage the brackets while tightening everything down.
Another quirk of the installation process is that FatFour Customs recommends securing the big caliper to bracket bolts with high-temperature Loctite 243. This is a good solution for drivers with street driven cars. But racers tend to remove and replace their brake calipers quite often. We were concerned that repeatedly removing and reinstalling the Acura RL calipers would result in us accidentally stripping the threads at the track.
Fortunately, FatFour Customs also sells a stud-and-nut kit to replace the big bolts that come with the kit. This will let us install and remove the caliper without unthreading anything from the aluminum caliper bracket. Upgrading to studs is easy with the use of a stud installation/removal tool. We would highly recommend that you spring for this on any track or race cars.
We were also surprised at just how tightly the Acura RL calipers fit over the big beefy 350Z rotors. With the calipers perfectly centered, we had just over 1mm of clearance between the rotor and the caliper on either side of the rotor face. Just to make sure that things were perfect, we broke out the feeler gauges to measure the gap between the calipers and rotors on both sides. We would need to test to ensure that this wouldn't cause any clearance issues under hard cornering while on track.
We had an opportunity to test these brakes during our unexpectedly eventful USTCC East Series double header weekend at PittRace.
The bad news was that our Prelude's engine expired during the pre-race test day. The good news was that we were able to put in enough laps to put our big brake kit to the test. And boy, were we surprised by the results.
The first thing we noticed was just how much firmer the brake pedal felt under hard braking. 90's Hondas tend to have long, vague brake pedals owing to the internal construction of their Master Cylinders. We had worked hard to get a good consistent pedal feel from the Prelude's mushy stock VTEC brakes, and we thought we had a decent pedal. But FatFour Customs' kit brought the pedal feel in line with what you would expect from a modern production racecar. The tight clearances between the Acura calipers and the thick 350Z rotors was paying dividends.
Happily, the clearance concerns proved to be a non-issue. Even after a full session of hard cornering around the notoriously tight PittRace North course, there were no signs that the brake rotors had contacted the calipers. This is notable because our Prelude runs on super-sticky Hankook F200 race slicks that happen to be particularly hard on wheel bearings. If these brakes worked on our setup, they will work just fine on cars with a DOT R-compound or high performance street tyre.
Most importantly, the FatFour Customs brakes were consistent. With our stock Prelude Si VTEC brakes, we always expected a bit of front brake overheating (and fluid fade) after 10 laps of full-bore hard braking. Not so with these brakes. We were able to last the entire session without a hint of fade. We even managed to lock the front left brake going into the entry to the super-slow Turn 10, something that we hadn't experienced since we started running 245mm wide F200s on our Prelude.
While we were not able to test their thermal capacity this time around, we are pretty confident that these rotors will have no problems shedding the heat from our 2550 lb Honda. We hope to test this out as soon as our Prelude receives its new engine.
Conclusion & Recommendations
The FatFour Customs big brake kit is a real diamond in the rough. Most OEM+ big brake kits tend to focus on show rather than go. This is the first kit that we have seen in some time that has the performance to back up its show-stopping looks.
If there was anything that we could change about this kit, it would be to replace the 9/16" caliper to bracket bolts with the stud and nut setup from the upgrade kit. Yes, this does mean that you would need a specialty tool to properly torque the studs into the brackets. Even then, we think this is a worthwhile tradeoff for most performance enthusiasts.
FatFour Customs' customer service proved to be excellent as well. When we mentioned that our brake calipers didn't seem to be sitting perfectly centered on the rotors on one side of our car (which we later discovered was due to a casting issue with our OEM spindles), they offered to send thin spacers to ensure that everything lined up. When he found out that we wanted to switch to the stud upgrade, he offered to send them to us at a substantial discount. While we ended up declining these discounts and bought the parts at full price, this level of customer service is commendable.
Would we recommend this kit? Based on our experience so far, the answer is a resounding yes.
The performance and convenience of this kit is just hard to beat at this price point. The only thing we could ask for is applications for more cars.
Until that happens, we'll see you at the track.
StudioVRM and Roger Maeda are not affiliated with FatFour Customs, or any of the brands mentioned above. All parts were purchased at full price from each of our own pockets, and installation was performed at the cost of our own time.
FatFour Customs was generous enough to offer a discount on the stud conversion kit as an existing customer of their kit. However, we enthusiastically declined this per our policy and paid full price for this as well.
Any Amazon links embedded above are affiliate links, which means that we get a (very small) commission from them every time you buy a product through those links. We would appreciate it if you did exactly that. These parts are expensive, and we could really use the money.