NA versus T2 brake boosters

[norachelhere]

anybody know anything about the differences?
I'm upgrading the braking system on the rx7 and rumor has it the T2 booster is supposed to be better. When I started searching around on line parts stores, they don't distinguish the NA and the T2 as being different. If it is actually different, what makes it better? I'm looking for a good amount of feedback through the pedal. I hate pushing the pedal down and not getting anything back, ya know.
I've upgrading to a bigger master cylinder, so I know that will help a lot. I just don't want the booster to be so big that it makes the pedal feather light, ya know.
any input would be great
thanks

[Niburu]

I don't know if there is really that big a difference or if there even is one.
The important difference is really the 4 pot calipers from the TII & GXL over the single pot ones.

[norachelhere]

yeah, We're upgrading the calipers, but everyone over on RX7 club keeps talking about how much better the t2 booster is, for pedal feel and what not.
Correct me if I'm wrong, but the smaller the booster, the less "assistance" it gives, right?
If that is the case, why can't I just use a little honda booster or something? (assuming it bolts up somewhat easily)
or am I thinking about it wrong?
The one on there now needs replaced anyway, so I figured I might as well replace it with a better option...

[aaron1017]

http://www.v8rx7forum.com/v8-rx7-technical/47749-fc-vs-fd-brakes-brake-system-design.html

Good thread

[norachelhere]

^ thanks. I'll check it out.

[norachelhere]

Helped with the search....
don't know if it answered my question, but it helps...

[seventhgear]

i would assume...... n e rx7 that came with 4pot brakes would have the same booster as n e t2.....???
I.e. sport model, vert, etc.
maybe?

[norachelhere]

that link was talking about there being a difference... it didn't make sense because half of the info on that link, was a link to another thread, and that thread didn't make any sense...

[Rx7_guy]

The T2 master cylinder piston is larger than the N/A master cylinder so I would assume that the brake booster are design different.

[Rx7_guy]

So make sure u use a TII master cylinder....if you are converting. The only other difference I would know is vac line location since the S5 Na, S4 NA, S4/S5 NA, and Vert might be in different locations. There is a possiblity that the turbo models have a check valve for boost as well.

[norachelhere]

yeah, still no definite word on the differences.
every time I turn around, someone else is saying something else that contradicts what the other person was saying.
I'm in the process of learning what exactly a booster does. From there, I guess I'm just gonna have to cut some of these things in half to figure out what makes them different.
The end goal I'm looking for is a nice solid pedal that you can get a decent amount of feedback through. Right now, you push the pedal down and you don't get anything back through it. The only reason you know the brakes are doing anything is that the needle is dropping. I get back in my 240 and you can talk with the car though the pedals...
does that make sense, or am I just crazy

[Rx7_guy]

Bro...every car is different....and a weak engine can effect your pedal pressure cause the brake booster works on vac. Many things can effect it. In Japan many people drift rx7s so maybe your car is the problem.

If not do the 626 mod

[norachelhere]

trust me, it isn't a weak engine. We've put a lot of work into this motor just getting it up to where it needs to be.
I do understand your point though...
This also isn't the only rx7 I've driven and thus far, they are all like that, and I'm only comparing them to my stock nissan...
maybe I'm just looking for something that doesn't actually exist...

[seventhgear]

trust me, it isn't a weak engine. We've put a lot of work into this motor just getting it up to where it needs to be.
I do understand your point though...
This also isn't the only rx7 I've driven and thus far, they are all like that, and I'm only comparing them to my stock nissan...
maybe I'm just looking for something that doesn't actually exist...

IT EXISTS!!
in pricey aftermarket design!!!:lol:

u will be able to achieve harder pedal feel. type of brake fluid and SS lines will do it aswell. all about the "whole" setup.

[norachelhere]

so we're upgrading the brakes all around.
stainless steel brake lines
custom hard lines
and a bigger master...
think that will yield the desired results?

[Rx7_guy]

WTF? What is it that your doing that your going to dump 2 grand into your brake system. The stock brake system on the FC3S works very well. You can't compare the brake system of a car design in 84-85 to recent cars now. And u expected the Honda brake booster to fit in your 7? The key is really in the brake master cylinder.

Maybe you simply need to adjust the pedal height?
Do u have new brake rotors?
Shitty pads? (I use EBCs)
Do u have the "soft" suspension. You do know that all N/A rx7s except the GTUs has a soft suspension. The other FCs come with Hard suspension...4 pot calipers, bigger brake master. Tighter suspension. Two different animals.

Also take in consideration that shitty shocks and tires can make the car seem like braking is no good.Ever took in consideration that the suspension on a rx7 is completely different then the Nissan and Honda? The FC and FD are harder to control in corners than nissans and also has a smaller steering radius, butI think the t2 rotors are larger than the nissan and the nissan only hasa single pot caliper system..

You simply need to do your research.

[norachelhere]

sure....

[Rx7_guy]

nevermind...not worth it

[norachelhere]

WTF? What is it that your doing that your going to dump 2 grand into your brake system. The stock brake system on the FC3S works very well. You can't compare the brake system of a car design in 84-85 to recent cars now. And u expected the Honda brake booster to fit in your 7? The key is really in the brake master cylinder.

I wasn't sure. In my head, the booster was what controlled the firmness of the pedal. I also had it in my head that the bigger the booster, the more assistance it gave. The thought was, if I took a little booster off of a honda, to replace the big ass booster that is on the car now, it would give me the pedal feedback I'm looking for. I don't want to deal with manual brakes, however, I still want to feel whats going on? does that make sense?

Maybe you simply need to adjust the pedal height?
Do u have new brake rotors?
they were machined not long before we got the car. Only machined once. They are visually in good shape. I know, only a micrometer can really show if it is good or not, but I've seen worse rotors that gave better stopping.
Shitty pads? (I use EBCs)
they aren't fantastic pads, but they are decent ones. You know the Bendrix ones they sell at advance? they are those. And they have a large amount of life still to them. Clean them up and they would still look new.
Do u have the "soft" suspension. You do know that all N/A rx7s except the GTUs has a soft suspension. The other FCs come with Hard suspension...4 pot calipers, bigger brake master. Tighter suspension. Two different animals.
I know the difference between the soft suspension models and the GTUs. That is basically rules out here though because the car has eibach springs ang tokico struts (not my choice, the previous owner did it) This car also has the 4 pot calipers. It isn't so much that the braking itself is bad. My major concern is the control of the brakes. The pedal is so soft and easy to push that you don't really have any control. Let alone any feedback. The pedal feels no different between 60% braking and locking the tires up. I guess I'm spoiled and I'm used to being able to tell what is going on with my brakes by what I am getting through the brake pedal.

Also take in consideration that shitty shocks and tires can make the car seem like braking is no good.Ever took in consideration that the suspension on a rx7 is completely different then the Nissan and Honda? The FC and FD are harder to control in corners than nissans and also has a smaller steering radius, butI think the t2 rotors are larger than the nissan and the nissan only hasa single pot caliper system..

The rotors are pretty close to the same. And the nissan does only have single pot calipers. I know that suspension and the different set ups place a big difference in cornering and braking and what not. I also know that you can change the set up to get the results that you want.
I don't care for the honda brakes, even though you get better feedback from that set up. I also know that I'm very in tune to my 240 seeing as I drive it everyday, and I just fit that car so well. I'm taking that into consideration too.

You simply need to do your research.

Again, I'm not really compplaining about the actual amount of stopping power produced. I'm complaining about the ability to control it. Look at it like this. When you play gran turismo, the buttons are pressure sensitive. The idea is, it will give you better control over the car. Have you ever actually tried to feather the brakes, or the gas through a corner? It is a major pain in the ass because anything over 20% pressure is just flooring it. Thats basically what I'm talking about with these brakes. You just push the pedal down and you are either not stopping enough, or you're at full stop. There isn't any difference in the pedal between half braking and locking the tires up. I know it isn't a problem with just this car because I've driven other rx7s and I thought the same about them.
So, with that, am I making a little more sense with what I'm trying to accomplish?

[norachelhere]

also, just a little side note. The stock hardlines where damaged recently, so they needed tp be replaced anyway. So all of that is more of a "need" than a want, ya know.
The "want" is the bigger rotors/calipers, bigger master, and better pedal feedback...