Upgrading 1.6 Brakes

[john!]

I have to say looking back at this thread...

Did the upgrade with NB8A calipers courtesy of irwin83r, plus DBA slotted all round and greenstuff pads with castrol response fluid.

I was concerned about bias, more because I had this image of any form of brisk stop becoming a drama of locked up fronts and no control. In reality what I have found is that there is no such drama, under threshold braking conditions, I have had a few small easily dealy with lock-ups at the front. In fact the brakes as they are at the moment are certainly by my standards and experience incredibly progressive and fade free, with enough feel so that is hard to lock them up without a very deliberate and violent prod on the pedal.

I think maybe suspension helps here, as it minimises the tendency for nose dive, even with so-so tyres (gt radials ).

Definitely one of the more worthwhile upgrades for an NA6.


john!

[Fatty]

righto john. so if you still have more front bias well that begs the question then...

why not just leave the fronts standard na6 and only upgrade the rears to na8 / nb variants??

wouldn't this give you improved braking performance with more rear bias??

seems a lot of people upgrade all 4 corners, then fit a later model bias valve , effectively removing some of the stopping power of their new bigger front brakes... just wondering if i can save myself some cash here?

[zoomzoom]

upgrading only the rears would defeat the purpose of upgrading, as the only benifit of upgrading is they dont heat up as bad, and as it is only the fronts that heat up then it would be pointless.

Bigger brakes cannot make you stop any quicker they will only take longer to heat up therefore your brakes continue to work for longer before getting overheating and being ineffective.

[john!]

Bigger brakes cannot make you stop any quicker they will only take longer to heat up therefore your brakes continue to work for longer before getting overheating and being ineffective.

Exactly, the best brakes in the world are only as good as your tires, but it is a great feeling to know that you can slow down as quick as your tires will allow, not just once, but repeatedly without worrying about brake fade, which is one of those things I learned about very early in my driving adventures, thrashing a datsun 120why without power assisted brakes down a hill. Needless to say the brake pedal chose that moment to go to the floor, leaving me going about 90 towards a fence in front of a creek with a 90 degree corner to negotiate. How I didn't kill myself or the car I will never know (can't believe that was the first car I ever took up to 100mph, ah happy days).

john

[zoomzoom]

oh so familiar. That is my first experience with brake fade, dd'ing for my mate in his 120why, braking fron 100kph and finding that by the time you get down to about 60kph the coin sized rotors have heated up so much that you have your foot on the brake but they just arent slowing you down anymore.

[Boags]

Bigger brakes cannot make you stop any quicker

From a physics point of view (and this is only in my head) - that is incorrect. The larger the diameter of the disc, the better the braking. The larger the surface area of pad, the better the braking.

I'm happy for you to tell me i'm a knob an explain why i'm wrong though!

Boags

[yarnmx5]

I have done the NA 1.6 brake upgrade, using NB8B rotors front and rear...I think they are NB8 (2001 model?) supplied by mania. I changed the brakes because of fade on the track once hot. Before anyone questions this I had hawk Hp+ pads at the front, DBA slotted front rotors and good motul brake fluid.

When I changed to the larger rotors & calipers, also using HP+ pads, motul and front DBA slotteds...I haven't come close to fade since. Although I have stuffed up a front left D01 tyre (flat spotted) from locking up the front..which IMHO is quite easy to do with the NA6 proportioning valve. I have been told turning the valve back to front may help the situation, however I am not sure if it is a wise thing to do....anyone done this??

[zoomzoom]

Boags, what we are saying is even with the small na6 brakes, you still have enough leverage and friction over the wheel to make it lock, which means you have surpassed the stopping power of your tyres, and therefore by going to bigger brakes you will not gain anything in that respect.

The gain of the larger brakes is both in the larger pad surface, so the friction is spread out over a greater area and is not as dense and therefore not as hot, and also the size of the disc, in that it takes longer to heat up being larger, and also can diccipate the heat better due to more surface area.

Your car will still wiegh about the same, and your tyres are still the same size so there is the same amount of energy being tranfered from kenetic to thermal energy. The larger brake can just cope with this heat better.

[Boags]

Thanks for not calling me a knob!

I see what you mean now. Once they are locked up there is no point improving the braking capabilities...

I'm still right though, with bigger better brakes you will be able to lock em up quicker!

Boags

[john!]

This site has probably been linked to before, but nevertheless remains completely relevant:

http://www.turnfast.com/tech_brakes/brakes.shtml

john

[Fatty]

thanks guys, i really appreciate all of your input.

however i can only interpret what you are saying, based on my own personal experience.

i have not yet had my car on the track, not to say that i won't, but at present brake fade has not been an issue.
but i have found that i just can't seem to lock up these little brakes, except for when it is wet. therefore i think that my braking capabilties are not limited by my tyres, rather they are limited by the brakes themselves.
therefore i think my initial question remains pertinent. is it possible to just upgrade the rears , and gain some additional stopping power?
at present it just feels like i can lean on the brake pedal as much as i want in dry conditions, and the car continues to a slow stop with a bit of a lurch to the front. (ie- no lock up)
as boags said in his first post, (and as much as my understanding of physics is fairly limited), it just still makes sense to me that by increasing the stopping power at the rear brakes, my car will stop better and bias will be more even.

[zoomzoom]

Maybe you just need some heavier boots Fatty
The ol' na6 brakes could certainly do with an upgrade though, it's on the list, sadly the list isn't being completed very quickly, it seems along with the list and some spare time you also need money...go figure?

[mitch_f1]

This is a superb thread, so i thought id bring it back up with this question.

From what I have read, the NB8B calipers are bigger than the NB8A calipers, but are the NB8A calipers bigger than NA8 calipers?

I guess with the bigger calipers, you can run bigger discs, but then they wont fit within stock 14" wheels. But is there that much of an improvement in braking performance going for NB brakes over NA8 brakes on an NA6???

Also, will brake pads from my NA6 rotors fit into rotors from the NA8...I guess they would from what has been said above, with them being interchangeable (just needing to change the bracket)

[mitch_f1]

no one???

[Jeo]

As far as I know, and this only taken from what I've read online and very small amount of practical experience upgrading my NA6 brakes to NA8 ones.

NA8 and NB8A brakes are the same
NB8B are bigger again

Most 14" wheels won't fit with the NB8B, but most are fine with NA8/NB8A.

NA6 pads will not fit in NA8 calipers. I bought new pads when I got my NA8 setup.