As far as upgrades go for the BB6, big brakes are the most effective upgrade. Costly, yes... but effective as well. Some say they are overkill and that a good set of pads and rotors is all you need and for some that is the case.
I have found threads online outlining possible upgrades (without going to a big brake kit), most have said that mounting NSX calipers with Legend rotors is the way to go and if your looking for the most budget friendly and cost effective upgrade then those are great options (Plus it's keepin it in the Honda/Acura family, which is cool) Here's a link to the thread on preludeonline.com: https://www.preludeonline.com/f62/br...grades-178816/
If you ask me though, you can't beat the performance of a 12"+ diameter rotor and a 4 or 6 piston, fixed, solid aluminum caliper up front for track use or any very aggressive braking. oem brakes with iron rotors and 1 or 2 pistons just can't handle the heat and they bring on brake fade and warping of rotors. I have run a 12.5" Diameter and 1.5" Wide, Cross Drilled Rotor w/ a Wilwood Forged Superlite 4-Piston Caliper on the front of my '94 CD5 and it was wicked. You could full on stomp on those brakes @ 100mph and with no vibration, get down to 40mph in seconds and they would not overheat and be ready for more. They were purchased through a accord specialty shop online as a big brake kit (that they pieced together to sell). Included the rotors (2-Peice), calipers, cnc aluminum mounting adapters, hawk hp pads and stainless lines. For $1,200 I had to try em and despite being sort of unfriendly to everyday driving (lots of dust, creaking sounds, not alot of initial bite for that grabbing light pedal feel), they were great brakes.

Big Brake Kit Options:
From what I can find there are only 4 companies that sell a front kit for the BB6 (This doesn't include sellers that have pieced together a kit to sell utilizing off-the shelf or universal parts from makers like Brembo):

STOPTECH:
Good products from what I've heard, priced anywhere from $1,500-$2,500
Most of the kits I have found for the BB6 are kits with a 12.9" (328mm) Diameter and 1.1" (28mm) Thick Rotor and a 4-Piston Caliper. Most include pads and stainless braided lines as well.

Willwood:
Great maker, lots of braking experience, been around awhile.
Though Wilwood sells universal calipers that will technically work with the BB6 (With custom mounting) they do not sell complete big brake kits designed for our cars.
If you want to buy a complete big brake kit that uses Wilwood components, you will be looking at stores or private sellers that have pieced together kits utilizing Wilwood components. Wilwood kits like this I have found to be the cheapest @ anywhere from $850-$1,500 for a ~12" Rotor/4-Piston setup.

KSport:
Newer company, I personally like the company from the little I know about them and what I have seen but I have heard mixed things about quality.
They offer kits for the BB6 directly from their company. They offer multiple kits in both their "Procomp" and "Supercomp" product lines. 4,6, or 8 Piston and multiple rotor size options.
Kits start @ $1,750 and go upwards pf $4,800.

CEIKA:
Well known company, newer as well (2010). I personally have chosen them for my next kit. I would like to know more about people's experience with them as far as quality and performance.
They offer a wide selection of rotor sizes from 286mm to 430mm (11.25" to 16.9") and a very wide selection of calipers in multiple color options from anodized to powdercoat, even choice of a logo and it's color.
CEIKA is the only manufacturer I know of that also sells big brake kits that come in a carbon fiber rotor material (extremely expensive but very high performance). They also have cool choices that others dont seem to offer such as choices for caliper piston material, piston seal type and more. Kits start @ 1,090 and go upwards of $18,000 (no thats not a typo lol)


Anyone out there used any kits by any of these companies and have any input?
Know of any other companies that offer kits?
I know Power Stop offers upgrade kits, unsure of exactly what cars they fit but they are more of just an upgrade than a true big brake kit.

Thanks guys,
-Ian

 

From what I have found, The factory BB6 brake master cylinder has a 1" piston bore and (2) outputs or "channels" (1) front and (1) rear. The factory brake booster is a "dual" type diaphragm that has a diameter of 9.72” or 246.89mm.

When you add big brakes, there typically isn't the need for a master cylinder or booster upgrade, The makers of these kits take factory parts into consideration so that they will "work". From my experience you lose some pedal feel, the pedal doesn't feel all supercharged and "ready" with that light touchy grab that the oem brakes have. Where they really perform well is in slamming on the pedal hard and responding in a high performance driving type demand situation. With an oem master cylinder and booster and a big brake kit I found that there was less time to think about braking like you would in daily driving. They slowed you down but really wanted to know if you were gonna be throwing the car in a corner and asking for more so it was a little more dangerous when it came to where your mind was at in everyday use. I personally would like to upgrade my booster to a larger diaphragm booster so I can try and regain that touchy pedal with lots of assist for decent everyday driving and mainly for a more suitable system for high performance driving. My worry is I will have too touchy a pedal and dangerously digressive or progressive braking during performance driving.

My plan is to retrofit a booster from a 2005 Chevy Silverado 1500. I have found that the boosters from these trucks use a 11.51” (292mm) diameter diaphragm. This is a 1.79” (45.5mm) or 5.4% Increase in total diaphragm size compared to the Prelude booster (and 95% of Honda's) and so will yield 5% more assist to hopefully give me just the pedal feel and braking I am looking for. I have scoured the internet searching for specifications and looking for any oem booster retrofit options from other Hondas or Acuras and have had no luck. Honda tends to keep the diameter of their boosters the same throughout most of their cars @ right around 9.72". I even looked into the Acura Legend and RL as well as the NSX thinking the size and weight of the car or the performance minded design would use a bigger booster but that doesn't seem to be the case.

*Question:
Is the vacuum created by the engine basically sufficient for the booster? Does it reach a certain level or become a "full vacuum" to the point where there isn't really any such thing as more? I don't know enough about the physics or measurement of vacuum but I thought to increase the vacuum the booster sees to improve braking but I am thinking that the vacuum in the booster basically gets to a full vacuum and thats it, its up to how large a diaphragm surface area is that the vacuum acts upon to change braking pressure. Am I right in this or is there room to increase vacuum seen by the booster with an auxiliary pump?