DSM's can make pretty incredible horsepower numbers. Fortunately, most of them - 93-99 - have pretty good brakes. Alas, us poor 90-92 guys really got the shaft. We got tiny ~10" rotors and a crappy single-piston caliper on the front, and an even dinkier setup in the rear. Not exactly confidence inspiring when you've got a car that can get over 100mph without much effort.
So, on my car, I decided very early on to upgrade the brakes to some really beefy units, since I knew eventually I'd do some road racing, where even the (quite good) large 2-piston calipers don't quite cut the mustard.
One big consideration if you're going to upgrade the brakes on your DSM is that brakes are lifed parts, i.e. they wear out. The kits are not cheap, and unfortunately, they are not a one-time cost.
Larger rotors and more sophisticated pad compounds are much more expensive to replace, and many are not commodity items you can go get at your local NAPA or Autozone. If you are considering larger brakes for your DSM, make sure you've got the budget for replacing the brakes (and tires etc etc) if you're going to be racing.
One last note about brakes: cooling. You can increase the longevity of all of your braking parts - both during a race and over the course of a season, by doing proper ducting, and getting cool air to your brakes. It can be the difference between replacing pads and rotors every 3 outings, or once a season.
One of the most cost-effective, and effective setups available is the kit that TCE Performance Products makes available for DSM's. It is centered around Wilwood calipers, and uses parts built by TCE to fit our cars.
There are other, more expensive kits out there, but they just didn't seem to have the quality or bang-for-buck I was looking for in my car. The general consensus I seem to have gotten is that the AEM kits are overpriced and not very capable. I can't speak much about the Brembo or Baer setups that are available, only that they are about double the price of these setups, and being a, ah, value-minded fellow, I didn't see the percentage in the price/benefit, and I doubt most drivers will.
For the absolute maximum in braking and brake cooling, RRE seems to really like the Stoptech caliper and Aerorotor. I tend to believe them, since they've been through a lot of setups on their road racing car.
For me, being able to get into this setup for relatively cheaply, was key, and they proved more than adequate at my local racetrack, Second Creek. SCR is known for being particularly hard on brakes.
Installation is very straightforward, for the most part. This won't be a direct step-by-step like some of my other writeups, since TCE's instructions are actually quite good. I'll just highlight some things I noticed along the way that may help you out.
First, you must remove the old caliper and rotor. Removing the caliper is generally easy - remember to have a bucket to catch the draining brake fluid in.
The rotor can be more problematic, as it has likely rusted to the hub over time. Visit VFAQ.com, and you can see how to thread in a bolt to pop the rotor loose.
Also note that Todd (the "T" in TCE) has two different sized brackets he sends with the brakes - 1/4" and 3/8". Either is adequate. There is also a "wide rotor" upgrade available to allow the Wilwood caliper to use wider rotors, since some of us are seeing rather short rotor life of the thin rotors with heavy use. Talk to TCE For details (fig. 1)
Now that the calipers and rotors are in place, remove the old rubber lines and run the new stainless lines in their place. I recommend you've got a set of flare wrenches for these, to prevent stripping the small 10mm fittings. Remember, these are compression fittings, so there is no need to put a million foot-pounds on these. Gutentight will work just fine.
Now that everything is installed and in place, it's time to bleed the brakes. You'll want to completely flush the system, especially if you haven't bled the brakes in a while (a year or more). Follow the factory order listed in the manual. (fig 2) I suggest doing a complete fluid bleed and changing to a high temperature fluid such as ATE Blue, or Motul 600.
One problem particular to the 1990 cars is the 15/16" master cylinder. The volume of fluid contained in the Wilwood calipers is a bit better matched to the larger 1" caliper, so I figured I would go ahead and do that upgrade since mine was probably ancient, and this would reduce my (huge) pedal travel.
Here are some brake master cylinder numbers I was able to gather while doing this project:
you'll want to verify these numbers when you go to order the part. I just asked for a 1" master cylinder for a '91 GSX without ABS. Worked quite well.
- #MR129443 = 1" MC for a 95 w/ ABS
- #MB895873 = 1" MC for a 95 w/o ABS
- #MB587022 = 1" MC for a 91-94 w/o ABS
- #MB500405 = 15/16" MC for a 90 GSX
If you are upgrading from the 4-piston Wilwoods, as I was, you are in luck, and can reuse your old pads. While the 4-piston caliper has two braces running near the center of the caliper, the 6-piston BSL-6 has just one, which unfortunately is right where the "tab" on the 4-piston pads runs. However, you can cut this piece off with a dremel, fit it ot the 6-piston brakes, and all will be well. See the location of the cuts in the center of the pad in figs 3-4.
For a size-comparison of the 4 vs 6-pistons, see figs 5 and 6. Note the blueing on my 4-pistons from the heat of the track! Given enough time, they will take on an almost tan color!
One final note: Wheels! Not all wheels will fit these kits. Stockers certainly won't, and many 16" wheels don't either. Kosei K1's, and Volk TE-37's do, I know that for sure. The problem comes with spoke clearance on the caliper itself, not any rotor interference. See the mounted pictures (figs. 7-9)
Testing & Results & Impressions
The difference in braking power is immense. I first moved from the '90 single piston caliper to the 4-piston Wilwood setup. It was unbelievable. I had almost no (albeit some) fade problems at Second Creek, but great stopping capabilities. My reason for upgrading was that the 4-piston caliper is a bit weak, and flexed under high piston pressures, resulting in a squishy and inconsistent pedal feel. Not the most confidence-inspiring thing coming down off of 120mph, when you're a newish driver like me.
The 6-piston caliper stopped all of that. Pedal was hard as a rock, and consistent every single time. I was able to move my braking points about 10 feet later. Be that from driver confidence or actual increase in braking power, I'm not sure. Regardless, my times improved by over a second with the addition of the brakes.
My one reservation with the Wilwood setup is in the rotor thickness. It is quite small, and mine wore down relatively quickly. Due to the heat-stresses, I also had a number of cracks in the rotor I had to have "turned" out. If I were to do it over again, I'd get the larger rotor for its strength and heat-sink ability.
As far as weight, even with the larger 12.2" rotor I was running under my 16" K1 wheels, the total package saved about 5lbs, overall, due to the extremely light caliper, and aluminum center-hat of the rotor.