BMC Volume Size

[Donovan]

Ok, on the continuation of stupid questions on my part as I continue with my quest to track down required parts to get everything together, and maybe at last I might be able to start putting it all in the car, just have the last few bits and I should be good to go.

My search is for brake calipers. I am getting a set of 310mm x 20mm Wilwood rotors and calipers for up front, and thought I had everything sorted until the question of piston size was asked, and I sat there with a blank look on my face going "I don't know". So the next question was, it will depend on the size of your Master Brake Cylinder, and again, queue blank look followed by the answer "I don't know"

Now I have googled to my fingers are bleeding, but I can't seem to find anywhere where it says what the volume size is on a NA6C, and I don't have the manual for it. Short of bleeding the system and then filling it back up again to see how much it uses, I can't think of anything else.

Because I am lazy, I thought I would throw the question out there and see if anyone knows before heading down that path.

[Keith Jones]

If you are going with 4 pots you need 1 and 3/8 inch pistons.

I have this setup on my race car and they are fantastic. The car stops from 230km/h into the hairpin at Pukekohe from 80m.

However, unless you are going to use the car for serious racing with big power I wouldn't bother with the big rotors and 4 pots. The 1.8 brake set up is fine with the right pads for a track day car. I ran a 165bhp engine with the 1.8 brakes for several full race seasons without any problems.

[Donovan]

Thanks for that, I assume you are just running the standard BMC and pedal box.

Getting it made up to be a track day car, Targa, and considering the GTRNZ if I ever get the car sorted out right.

As for power, does a 260KW LS1 V8 sound like enough, all though, you can never have enough HP.

Just had a look at the photos of your car, where did you get the hats made up for your rotors and about how much did they cost?

[sprsta]

this might help

http://forum.miata.net/vb/showthread.php?t=363284

[Keith Jones]

Yes, the BMC and pedal box are standard.
The rotors and hats came as part of the kit from Goodwin Racing - 11" front rotors, 10.75" rear rotors and Wilwood 4 pots for the front. Am still using the standard 1.6 rear calipers and the brake balance is perfect, no need for a bias valve. The whole front wheel setup is much lighter than standard, even with the big rotors. Good for reducing unsprung weight.

I believe Wilwood are now making a kit for the MX5 (Maiata)
http://www.miataturbo.net/showthread.php?t=51715

A V8 MX5 on the track would be great, though I don't think the NZGT rules allow an MX5. I'm pretty sure the cars have to be fixed roof.

[Donovan]

I believe Wilwood are now making a kit for the MX5 (Maiata)
http://www.miataturbo.net/showthread.php?t=51715

A V8 MX5 on the track would be great, though I don't think the NZGT rules allow an MX5. I'm pretty sure the cars have to be fixed roof.

From what I could see on that link, it was for only the 95 onwards, mine is just a plain jane 90. I had a look on the Wilwood site, and they don't have a kit for anything older than the 95, I assume they are a different brake setup from the NA6C and the NZ8

I know that the OSCRA used to allow open tops, as they had a TVR350 and Rotary Turbo MX5 racing, but maybe now that they have merged with the Super GT, they might have changed the rules, guess I am going to have to have a read at some stage.

[Gravelben]

...I assume they are a different brake setup from the NA6C and the NZ8...

Not a lot different - bigger disks and pads with the same caliper on a different bracket IIRC. 1.8 brakes are a pretty common swap for FI 1.6 cars and/or heavy track use, though the original brakes are fine at standard power levels. So a big brake conversion would presumably fit either.

[Euen]

949 Racing have also come out with a Wilwood based front kit which is good for 90 - 02. Uses different discs to Wilwood's own kit.

http://949racing.com/949-miata-big-brake-kit.aspx

[Donovan]

949 Racing have also come out with a Wilwood based front kit which is good for 90 - 02. Uses different discs to Wilwood's own kit.

http://949racing.com/949-miata-big-brake-kit.aspx

Well, I thought I had decided on the path I was going to take my brake setup, until the link above (sigh). I did a bit more poking around in regards to kits, and then stumble across this kit

http://www.good-win-racing.com/Mazda-Pe ... d=Amb497MI

Which is the same price that I have been getting for rotors, 4 pot calipers and getting brackets and hats made up in NZ (excluding the freight cost).

Smaller rotors on the front, 280mm compaired to the 310mm I was originally looking at, but no hassle with trying to muck around getting hats and brackets made up, and comes with the braided lines, rear rotors and fluid for the same price as the NZ solution!!!

So now I have to figure out whether I am better off with the 4pots and 310mm rotors, or the 6pots with the 280mm rotors (plus a lot less stuffing around as everything is all there)

I used to be indecisive, but now I'm just not sure.

[Keith Jones]

Be carefull of the extra costs to land this kit in NZ.
My Goodwin kit, same as this but 4 pot, cost around USD1500, but landed here with freight and GST was about NZD3,300. It's a heavy box so freight is expensive.
However it was still cheaper that I had been quoted locally and better rotor material than anything local.

[Donovan]

Have talked to the supplier and he said that he ships stuff to NZ all the time, and the freight cost are USD$180, so the only other thing is the GST, which I would have got stung getting the gear here in NZ as well.

Because of the high NZ dollar at the moment, converted to NZD the kit is about $2,700 (+GST), which is the same price that I have been quoted just for the front rotors, 4 pot calipers, pads and custom made hats and brackets. So get more stuff for the same price, don't have to worry about getting someone to measure things up and stuffing around.

I think I have just talked myself into them haven't I