DIY low budget brake upgrade

[A.S. Motorsport]

Well i thought this might be interesting for the NSX community to know.
There are a lot of owners here asking for brake upgrades as the feel there current brakes aren't good enough usually sparking a discussion on whether this is true or not.

And yes a good pad, rotor and brake line setup can be adequate.
For those on a tight budget still wanting to get more stopping power:

Add Legend Type-II calipers up front they will give you more stopping power (NA1 fronts on a NA2 will also gain stopping power)
Now technically explained why:

NSX specs:
Front

NA2 40 + 32 mm pistons = 4071mm surface area
NA1 40 + 36 mm pistons = 4563mm surface area (12% more than NA2)​

Rear

NA2 48mm = 1809mm surface area (23% more than NA1)
NA1 43mm = 1452mm surface area​

Legend specs: (Type-II Acura or standard Honda)
Front

42 + 38mm pistons = 5026mm surface area
25% more than NA2 13% more than NA1.
​

Rear calipers are smaller than those of a NSX.
Best of all these callipers are very cheap.
Pads are the same.

Now it's very important to keep in mind you are playing around with the brake bais (balance) which will change the handling

In all cases it will be shifted more to the front of the car.


Example for NA1 owners:
NA2 brackets + rotors + Front Legend brakes + rear NA2 brakes.
Off course finish it off with braided brake lines, good pads and rotors.

Unfortunately late model Honda brakes don't fit (late gen MDX and TL etc)
These have even bigger floating calipers but they won't fit the bracket.

For European members:
KA9 96-98 brake calipers will also work just as all Honda KA7/8 91-95 calipers.
Getting these calipers isn't easy since Legends are rear contact me for calipers and other parts.





No this thread is just to put out information for the community, we do accept any responsibility what so ever of the effects

 

[pgilliam1]

I have 2 questions:

- Do the front Legend calipers fit the NA1 brackets (is it mechanically plug-and-play)?

- Is the approx. 10% increase in surface area in the front particularly noticeable (have you known anyone who's done this swap and tried it)?

I never really liked the braking on this car so I'm interested. Thanks for the info.

 

[A.S. Motorsport]

I have 2 questions:

- Do the front Legend calipers fit the NA1 brackets (is it mechanically plug-and-play)?

- Is the approx. 10% increase in surface area in the front particularly noticeable (have you known anyone who's done this swap and tried it)?

I never really liked the braking on this car so I'm interested. Thanks for the info.

I know for a fact that NSX brakes have been installed with out modification on a Legend an various other Honda's.

There is a lot of interchangeability in Honda brakes of the 90's.
Basic design of Legend and NSX Calipers is very similar they where the only twin piston calipers, for over 10 years with Honda.
Type-II Legend brakes are also used as upgrades on Integra's (which use the Acura Legend Type-I single piston)

I'm 90% sure this will be plug and play, I myself am also experimenting with running bigger OEM discs using different OEM brackets whilst retaining my OEM twin piston calipers.


Unfortunately the late model parts are not interchangeable
2003 MDX has 2x 44.5mm = 89mm total (6221 mm)
2007 MDX has 2x 50.8mm = 101.6mm (8925 mm)

iirc AP1 and AP2 S2000 Rear calipers are the same as on the NSX except for the lettering.

These would be very strong brakes indeed for a NSX and would upset the balance of the car although i know of may NSX's and other cars running BBK's only on the front axle.


Some of you might want to see some pictures i guess:
NA1

NA2

Legend

 

[ak]

I wouldn't do this. There's a reason why Honda changed the bias to more rearward for NA2.

 

[Mac Attack]

Thank you for the info, but I would also be leary. If I couldn't afford to replace my OEM calipers on a street-driven NSX, then I may go this route, but I wouldn't consider this from a performance-adding perspective.

Before you change calipers, I would experiment with all of our pad options and cooling (and rebuild the OEM calipers too). You'd get more bang for the $ this route than replacing our calipers with another outdated Honda caliper from the same era.

Brake bias isn't really an issue on vehicles that still have OEM ABS since the ABS will correct an improperly-balanced setup. Not saying you should slap a BBK only on the front or the rear, but ABS should adapt itself for the pre-programmed brake bias the engineers built in.

I would be worried because the NSX was meant to be driven hard. Legend, ???

- The NSX caliper fins add surface area to dissipate heat more and make the caliper more rigid.
- Perhaps the NSX calipers also have better piston seals too?
- The NSX brake inlet fitting is over the larger piston bore... The Legend is in the middle?

My $0.02.

Dave

 

[MvM]

NSX specs:
Front

NA2 40 + 32 mm pistons = 4071mm surface area
NA1 40 + 36 mm pistons = 4563mm surface area (12% more than NA2)​

Rear

NA2 48mm = 1809mm surface area (23% more than NA1)
NA1 43mm = 1452mm surface area​

Legend specs: (Type-II Acura or standard Honda)
Front

42 + 38mm pistons = 5026mm surface area
25% more than NA2 13% more than NA1.
​

Rear calipers are smaller than those of a NSX.
Best of all these callipers are very cheap.
Pads are the same.

Sorry to have to intrude on this, but your numbers are NOT correct!

Front-calipers:
NA1: 40+36mm: Total Surface is 2275 mm2
NA2: 40+32mm: Total Surface is 2061 mm2 (= 9.4% LESS than NA1)
Legend: 42+38mm: Total Surface is 2520 mm2 (= 10.8% MORE than NA1)

Rear-Calipers
NA1: 43mm: Total Surface is 1452 mm2
NA2: 48mm: Total Surface is 1810 mm2 (= 24.6 % than NA1)

So, in effect, the Legend would give you only a 10.8% gain over the NA1 calipers (or 22.3% over the NA2 calipers).

Just my 0.02

 

[pgilliam1]

I know for a fact that NSX brakes have been installed with out modification on a Legend an various other Honda's.

There is a lot of interchangeability in Honda brakes of the 90's.
Basic design of Legend and NSX Calipers is very similar they where the only twin piston calipers, for over 10 years with Honda.
Type-II Legend brakes are also used as upgrades on Integra's (which use the Acura Legend Type-I single piston)

I'm 90% sure this will be plug and play, I myself am also experimenting with running bigger OEM discs using different OEM brackets whilst retaining my OEM twin piston calipers

Thanks, there's a lot of good info to consider here.

 

[NSX-Files]

According to the captions with the pics, the Legend caliper is a trailing unit so if mounted on an NSX the bleed screw would be in the wrong position. NA2 front brakes use a larger rotor so the effective radius is greater, hence probably higher brake force than the NA1 caliper even with smaller pistons.

 

[A.S. Motorsport]

According to the captions with the pics, the Legend caliper is a trailing unit so if mounted on an NSX the bleed screw would be in the wrong position. NA2 front brakes use a larger rotor so the effective radius is greater, hence probably higher brake force than the NA1 caliper even with smaller pistons.

Correct.


MvM,
according to my calculations...
40+36 = 76

76mm is your total diameter equalling a surface area of 4536.46mm

 

[M-P]

Correct.


MvM,
according to my calculations...
40+36 = 76

76mm is your total diameter equalling a surface area of 4536.46mm

No...MvM is correct. You cannot add diameters to get total area. You have to calculate the area of each piston individually, then add the results together.

I checked them and MvM's numbers are correct.

 

[A.S. Motorsport]

No...MvM is correct. You cannot add diameters to get total area. You have to calculate the area of each piston individually, then add the results together.

I checked them and MvM's numbers are correct.

Here is the sample calculation of a single NA1 caliper...

indeed, nice catch.

 

[robbiedawg]

all i can say is that there are some people on here who are a hell of a lot better at math than i am

 

[nsxtasy]

First of all, there is no such thing as "NA1 brakes" or "NA2 brakes", and I would be leery of any vendor using those terms. NA1 and NA2 refer to the 3.0-liter and 3.2-liter engine and have nothing to do with the brakes. The NSX was sold in North America with two brake setups. The '91-96 NSX (which were all NA1 models) had one setup. The '97-05 NSX (including NA2 with manuals and NA1 with automatics) had a different setup.

No...MvM is correct. You cannot add diameters to get total area. You have to calculate the area of each piston individually, then add the results together.

Actually, what matters is not the area under the pistons, but the area in which the pads come into contact with the rotors. The area of the pads is quoted in the specs section of the service manual. For the '91-96 NSX (which are all NA1 models), it's 58.0 sq cm (5800 sq mm) front, and 38.8 sq cm rear. I don't know what it is for the '97-05 NSX, but IIRC the front brake pads are interchangeable between the two. Some of the Legends have the exact same size and shape front brake pads as the NSX and I suspect that is true of the ones under discussion here.

 

[M-P]

Actually, what matters is not the area under the pistons, but the area in which the pads come into contact with the rotors. The area of the pads is quoted in the specs section of the service manual. For the '91-96 NSX (which are all NA1 models), it's 58.0 sq cm (5800 sq mm) front, and 38.8 sq cm rear. I don't know what it is for the '97-05 NSX.

Correct, but for arguments sake, I was just confirming MvM's comment.

Larger diameter pistons equals more force on the brake pads though, given the same brake line pressure that is.

 

[A.S. Motorsport]

Correct, but for arguments sake, I was just confirming MvM's comment.

Larger diameter pistons equals more force on the brake pads though, given the same brake line pressure that is.

indeed, and yes pad's are interchangeable.

I use NA1 and NA2 since most of the non technical or non-NSX technical find that easy to use, although you can get confusion with AT and MT cars.
As far as cooling is concerned iirc there where aluminium universal cooling fin kits from Spoon or J's racing i'll have to look that up.

master brake cylinder specs are the same for Legend (91-04) and NSX although as far i can see not interchangeable.

 

[MvM]

First of all, there is no such thing as "NA1 brakes" or "NA2 brakes", and I would be leery of any vendor using those terms. NA1 and NA2 refer to the 3.0-liter and 3.2-liter engine and have nothing to do with the brakes. The NSX was sold in North America with two brake setups. The '91-96 NSX (which were all NA1 models) had one setup. The '97-05 NSX (including NA2 with manuals and NA1 with automatics) had a different setup.

You are correct of course.

What should have been said:
The 1991-1996 brakes with front rotors of 282x28 mm and 282x21mm rotors in the rear

versus

The 1997-2005 brakes with front rotors of 298x28mm and 303x23mm rotors in the rear.

I stand corrected :smile:

 

[dablackgoku1234]

I recall reading something somewhere a long time ago that the NSXR is a NA1 front with a NA2 rear. Does this sound right?

 

[A.S. Motorsport]

I recall reading something somewhere a long time ago that the NSXR is a NA1 front with a NA2 rear. Does this sound right?

sounds unlikely iirc they are standard NA2 brakes.
Does make sense but i'm nearly sure it they are NA2's

 

[NSX-Files]

Actually, what matters is not the area under the pistons, but the area in which the pads come into contact with the rotors. The area of the pads is quoted in the specs section of the service manual. For the '91-96 NSX (which are all NA1 models), it's 58.0 sq cm (5800 sq mm) front, and 38.8 sq cm rear. I don't know what it is for the '97-05 NSX, but IIRC the front brake pads are interchangeable between the two. Some of the Legends have the exact same size and shape front brake pads as the NSX and I suspect that is true of the ones under discussion here.

Actually, I believe pad area does not affect braking force, rather it can affect the longevity of the pads and the ability to dissipate heat. Effective radius (basically the distance from hub center to where the pistons press against the rotor), total caliper piston area, brake line pressure and coefficient of friction of the pads are the factors used in calculating braking force.

If you can find it online, there was a great article about the science and math of braking systems in Grassroots Motorsports a while back. It was very educational.

 

[M-P]

Actually, I believe pad area does not affect braking force, rather it can affect the longevity of the pads and the ability to dissipate heat. Effective radius (basically the distance from hub center to where the pistons press against the rotor), total caliper piston area, brake line pressure and coefficient of friction of the pads are the factors used in calculating braking force.

If you can find it online, there was a great article about the science and math of braking systems in Grassroots Motorsports a while back. It was very educational.

This is correct. Surface area has nothing to do with braking force at the same pedal force (except maybe on the microscopic scale, but that is generally neglected). Larger surface area means less pressure on the rotor which equates to less heat at a given point (will be same amount of total heat, just more spread out).

General rules of thumb:
-Larger rotor = Less braking force required for necessary braking torque (less force equals less heat as well)
-Larger piston area = Less pedal force (line pressure) required for same braking force
-Larger pad area = Less pressure applied to rotor and less heat at each point on rotor surface

 

[CL65 Captain]

sounds unlikely iirc they are standard NA2 brakes.
Does make sense but i'm nearly sure it they are NA2's

No, that is correct. The Type R uses a NA1 caliper front and NA2 caliper rear.

Down at the bottom of the table.

http://daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=967#BrakeBiasTable

 

[A.S. Motorsport]

No, that is correct. The Type R uses a NA1 caliper front and NA2 caliper rear.

Down at the bottom of the table.

http://daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=967#BrakeBiasTable

Does have a logic to it.

 

[nsxnut]

I fail to see how legend calipers are helpful.

Increasing the stopping power will only help if the current setup is not able to lock up the wheels. I do not believe this is true.

More force with the same pad will only reduce the amount of effort needed to push the brake petal. Doesn't do squat for stopping the car faster.

The stock setup is subject to fade this is not addressed.

 

[nsxtasy]

No, that is correct. The Type R uses a NA1 caliper front and NA2 caliper rear.

You mean, it uses a '91-96 caliper front and a '97-05 caliper rear. :biggrin:

I assume you're referring to only the NA2 Type R version, since the Type R produced in '93-95 was before there was a '97-05 brake setup to use.

 

[M-P]

I fail to see how legend calipers are helpful.

Increasing the stopping power will only help if the current setup is not able to lock up the wheels. I do not believe this is true.

More force with the same pad will only reduce the amount of effort needed to push the brake petal. Doesn't do squat for stopping the car faster.

The stock setup is subject to fade this is not addressed.

I agree with nsxnut on this. The only reason to really want bigger pistons with a given rotor and pad is if it requires too much pedal force to stop the car. Too much pedal force can cause fatique if you do long track sessions.

Larger piston diameters might also lower brake fluid temps slightly (at least localized heat at the piston surface). Call it distributing the energy lost as heat to more fluid through the larger surface area.