300mm Big Brake kit vs 276mm Micro Big Brake kit with 15x6.5inch Watanabe's?

[B^2]

I'm in the process of doing a couple upgrades on the suspension of the 510 and I'm looking for some guidance regarding brakes. So far I've ordered the rear coilovers and the front weld on kit for the 280zx struts. Right now for an engine I'm running an L20b with dual Mikuni 40's but at some point in the future I may upgrade to a Ka. I've heard some people say the 300mm rotors that could with the big brake kit won't fit the watanbe's I have which are 15x6.5 while some people say it's very tight. You can see my wheels here: watanbe wheels

My questions are:

1) Will I notice a big difference in performance between the two rotor sizes if I'm just casually driving the car with some canyon cruising? Eventually, I'd like to try autox and swap in a more powerful engine but not if 300 vs 276mm for rotor size is splitting hairs for my application.

2) Should I be looking somewhere else besides t3 for a front brake kit on 280zx struts?

3) Should I just get new 280zx pads, rotors, and calipers and call it a day? I figured the cost for all that stuff isn't too far off from buying new/more modern stuff.


Please let me know if there is something else I should be thinking about.

[rosso]

1. You will probably not see or feel any difference in the two rotor sizes on the street or even during autox.

2. T3 makes nice stuff and their micro kit for 280zx struts is stated to fit under the watanabe wheels. Other kits may not.

3. T3 price is reasonable at $900 but the stock 280ZX stuff is much much cheaper. Rotors $12 ea, calipers (with core charge) $60 ea and pads $20. Total ~$150

 

The stock 280ZX stuff is more than adequate for the street, if you want to change out the pads for a track oriented pad that would probably be more than sufficient.

280ZX is almost 3000 lbs, the 510 about 800 lbs less.

[datzenmike]

At the end of the day, stopping is defined by these limits.... vehicle weight, speed, traction

 

The 510  weighs about 2,200. My info shows from  1,940 to 2,061 for the sedan and 2,039-2,138 for the goon. I'm not sure if that's a 'dry weight' or fully loaded with all fluids and a full tank (about 70 pounds) so I went with the highest guess, then add a 200 pound driver (with work boots) about 2,400 pounds to stop. This is extremely light for any car.  Passengers will make a big difference in the stopping distance

 

Speed... what can I say, the faster you go the harder/longer to stop.

 

Traction.... depends on tires. Some are softer compound and grippy while others are harder rubber... a compromise for longevity. Lower vehicles have less weight transfer off the rears and brake better.

 

 

Generally the stock brakes will lock up the stock tires. If you have lowered the vehicle height, tweaked the suspension, added better traction tires and rims you may not be getting all the stopping the car is capable of on the stock brakes. I think that 280zx (2,740lbs.) or even Maxima* (3,000 lbs) struts with their massive (in comparison to stock) calipers and vented rotors are good enough. As mentioned they stop an 800 pound heavier car with driver and are a fine upgrade and include larger front wheel bearings too. You can also change to a more aggressive pad at the added expense of increased rotor wear.

 

Certainly the 280zx struts and brakes are cheaper than $900 ones, and pads, calipers and rotors universal and also cheaper. Remember that they are equal once the tires lock up and stopping comes down to weight, speed and traction and not so much the brakes. I would assume that for $900 these brakes would be more fade resistant that the 280zx which are passenger car brakes and not really intended for continuous racing applications. Multiple panic stops are well within their range and more so on a light 510.

 

  * I have these struts on my 710 (2,860 lbs with me in it)  and they are just a mm or two smaller diameter rotor than the 280zx and calipers similar but not exactly the same as the zx. I think this is because the 280zx is Nissan's flagship car and it wouldn't look right to have a Maxima car with better/larger brakes. I also have a set of '81 280zx struts and will see next summer if the zx calipers and rotors will swap onto the Maxima struts. Just curious if they will, and if so, do they brake any better.

 

'84 Maxima struts

 

 

'81 280zx struts