GI: Big brake kits, floating rotors!

[green-lantern]

no, nobody got the rear kit in my GB. In fact I'll probably even limit the next GB even more by saying the only option you'll have is choice of 3 caliper colors. It's enough of a pain to do a GB, then having to keep track of people is worth more than the nothing I get paid to do this.

no, i did not calculate the bias for their rear kits, or the 330 front kit for that matter. It's very possible they sized the pistons in the 355 rear kit to match, but I don't know and I will not go through the trouble of finding out.

I swore I posted a link to the diagram, if I didn't pm me with email and i can send it

The brake bias with stock rears was barely off anyway right? I didn't notice any big difference in stopping power with these, just these will put up with a ton more abuse. I haven’t had brake fade since I got them.

[fastfalcon94]

Stealth316 (Stealth 316 - Brake Upgrade Options) mentions how to calculate the brake torque. But there are a few variables we need that we don't have. Now stoptech sells a 330, 355, and 380 mm front setup all with the same 328mm rear setup. They also have this article which makes it sound like it doesn't matter what size the rear is, as long as the front is bigger.

Rear Brake Upgrades

On the xyz-racing FAQ page (XYZ Auto Parts) it states that the rear needs to match the front. Meaning if you order a 355mm front, you need to order a 355mm rear. It would be nice if that was confirmed with numbers for us though.

"In case your rim is for 18 inch, it’s a wrong decision if the rotor size you choose for front brake kit is 355mm, and rear brake kit for 330mm. In our brake design, you are supposed to choose the same rotor size for front and rear brake kit, it’s because we have settle on the ratio for front and rear brake pads.

If you choose bigger rotor size in front brake kit but with smaller rotor size for rear, such as Front: 355mm/Rear: 330mm, consequently, the brake will be out of balance easily, and it will be dangerous if you brake suddenly.

If short, if the rim you have is 18 inch, then you must choose Front and Rear 355mm brake kit, and please don’t really think that smaller rotor size isn’t likely to touch the rim. It’s certainly a wrong decision as it’s easier to interfere with the wheel and more dangerous
"

[green-lantern]

Now, down to technical business before I get to pricing:

XYZ kit piston area: 2415 for 355mm rotor

Stock piston area: 2721 for 314mm rotor

Stoptech piston area: 2274 for 355mm rotor

AP Racing "formula" kit piston area: 2511 for 343mm and 355mm rotor

K-sport 8 piston kit piston area: 3059 for 356mm rotor

I'll save you the calculation for brake torque split, (difference from stock, + is more front torque than stock) corrected for rotor size, and just post them:

Stock: 100%

XYZ 355 on 2G: +1.81%

Stoptech 355 on 2G: -3.37%

Stoptech 355 on 1G: -0.41%

AP racing 343 on 2G: +0.73%

K-sport 356 on 2G: +25.48% (ummmm)

So, what does this all mean? XYZ 355 kit will be slightly more front biased than stock, as I spec'ed to correct for typical track car's new weight distribution and increase in weight transfer on sticky tires. That and K-sports are wayyyyy out there in balance.

If short, if the rim you have is 18 inch, then you must choose Front and Rear 355mm brake kit, and please don’t really think that smaller rotor size isn’t likely to touch the rim. It’s certainly a wrong decision as it’s easier to interfere with the wheel and more dangerous
"

I must of read this part 3 times scratching my head thinking wtf are they talking about. After clicking the link I see what they are talking about.



It would be nice getting the rears also but I'm not sure it's worth the extra cash. Combined we have put quite a bit of abuse on these without any complaints (as far as I know anyway). R/T93 reported some pretty hot temps on the rears during track days but I don't think they faded on him. Some of us were kicking around the idea of using ducting for the stock rears. Honestly I think you will be pretty damn happy with just the front XYZ's though. I overheated my stock brakes two years in a row on the Dragon but after I got these I never had problems since, NG road course or the dragon. If Chris's math is right and I trust it is (never checked it) the bias is only off +1.81%, I can live with that.

[R/T93]

I have stock rears and they are adequate, just need some cooling is all.

[J. Fast]

Is it possible to get a set of bells and rotors in a larger diameter... say 362 to 380mm somewhere in there? No calipers, just the floating rotors, hats, and hardware?

[Unlogic]

The price in this group buy was really good.

Being located on the other side of the pond I just opted to buy a set of these from a local reseller over here. I should be getting them in 2-3 weeks hopefully.

[anyonebutme]

Is it possible to get a set of bells and rotors in a larger diameter... say 362 to 380mm somewhere in there? No calipers, just the floating rotors, hats, and hardware?

I'll check on price after NG.

[fastfalcon94]

Am I doing this right? I think I am. It looks like the 355mm kit would rub on my moda r6's (18x9 w/ 38mm offset). I need to track down the 330mm front template now. I'm just not sure how much of an upgrade it will be considering it's only 15mm bigger than the stock 2g fronts.

[Unlogic]

May I ask where you found the 355mm template?

Should probably check my own Rota P45 rims before my kit arrives.

[fastfalcon94]

I pm'd a few people on here and someone sent it to me. What is your email? I can shoot it over. Now if anyone has a 330mm front template my email is fastfalcon94@gmail.com