Low Dollar Brake Upgrade unsprung weight reduction

[Racecomp Engineering]

PFC has a part number for 2 piece stock sized rotors. I've been meaning to look into that.

We've been working with them a lot lately...their 2 piece rotors are extremely good.

- Andrew

[RuyGuy2]

Originally Posted by Racecomp Engineering

PFC has a part number for 2 piece stock sized rotors. I've been meaning to look into that.

We've been working with them a lot lately...their 2 piece rotors are extremely good.

- Andrew

There web page is a bit confusing doesn't list anything for the BRZ but it does for the WRX you wouldn't happen to have part numbers?

[SuperTom]

Like the creativity and saving weight is extremely important on an underpowered vehicle.

Did you know this kit is available. Ive had it for a few years and its great, Although it was like ~$900 bucks back then. But you get 30 lbs total off the front and most comes from the 2pc rotors.

https://www.ft86speedfactory.com/wil...l#.Xp0Ir25Fw2w

[86TOYO2k17]

Originally Posted by SuperTom

Like the creativity and saving weight is extremely important on an underpowered vehicle.

Did you know this kit is available. Ive had it for a few years and its great, Although it was like ~$900 bucks back then. But you get 30 lbs total off the front and most comes from the 2pc rotors.

https://www.ft86speedfactory.com/wil...l#.Xp0Ir25Fw2w

+1 on this, I’ve only ever seen it at 1,100$ but they frequently have a 12% sale going on. So you can easily pick it up for 970$.

[NoHaveMSG]

Originally Posted by churchx

I know not even that difference, but also that two piece rotors i mentioned (pitty that only ones i know of for stock brakes are very expensive DBA ones) are unsprung rotational weight, reduction of which should be most effective out there :P
Then again often impact/gains from that weight reduction by lighter wheels/brake assembly or even lugnuts are overstated, and it certainly is wrong if one hurts other more important areas for sake of enhancing less important ones, eg. if one puts too overlightened wheels too much at expense of their rigidity/strength, or if one chooses less grippier tires only because they are lighter, and same with brake caliper retrofits from other cars with different suspension, different weight, different weight distribution.
You have done all homework properly before doing swap? Is pad area same? Is pad area geometric center at same distance from center? Similar piston area is just one of many variables affecting resulting brake torque. I'm guessing that you have no access to brake dyno, bet have you done skidpad tests on both stock & retrofit calipers? Have you enough track experience and consistent enough driver to trust your "feel"/"butt dyno" to properly gauge "feel and function identical"? Do you want based on your current experience put enough trust trailbraking from 200kmh into corner with small runoff zone till wall?
In my eyes from retrofit from other cars at most i'd consider willwood 4pot for wrx (of course, full kit, including rotors of specific diameter), with stock rears for lighter weight, as twins stock fronts are same as wrx's (rears from legacy gt), so i'd expect similar bias. As to why it's important to retain brake bias, simply with it too far off one way car stability/handling safety under heavy braking will be affected, and to other end of spectrum - fronts (which do most of braking) will be underbraked, thus braking distances will grow. Also if one still uses some nannies, they are designed with specific bias in mind i guess.

The WRX 4 pot is also 1.62 and should only effect bias marginally.

[86TOYO2k17]

Originally Posted by NoHaveMSG

The WRX 4 pot is also 1.62 and should only effect bias marginally.

His DIY kit and the WRX kit are basically the same thing minus him missing the rotors.

[churchx]

for if same, i guess also worth checking compatible pad shapes & area, fact that those are for 350z while wrx 4pot is, well, for wrx, would make me double check things, if they really are same.
He should have stated earlier that he plans to install also biasing valve, that should allow to make any needed adjustments. Though that rises total cost and installation simplicity imho way past "low dollar", especially if further rising budget via pairing with two piece rotors. So it all turns back that it makes more sense to get BBK right away, possibly subbie 4pot one. No custom mounting bracket required, already two-piece rotors, lot of weight saved (which was stated among prioritized goals).

[NoHaveMSG]

Originally Posted by churchx

for if same, i guess also worth checking compatible pad shapes & area, fact that those are for 350z while wrx 4pot is, well, for wrx, would make me double check things, if they really are same.
He should have stated earlier that he plans to install also biasing valve, that should allow to make any needed adjustments. Though that rises total cost and installation simplicity imho way past "low dollar", especially if further rising budget via pairing with two piece rotors. So it all turns back that it makes more sense to get BBK right away, possibly subbie 4pot one. No custom mounting bracket required, already two-piece rotors, lot of weight saved (which was stated among prioritized goals).

If you buy a willwood BBK and it is 4 pot 1.62, it is going to be the same caliper car to car. The only difference will be the bracket, or if it is a narrow vs. wide. Even with different piston sizes the main casting for the caliper will be the same, just machined differently.

The bias change is minimal. We are talking .697 vs .698

[RuyGuy2]

Originally Posted by SuperTom

Like the creativity and saving weight is extremely important on an underpowered vehicle.

Did you know this kit is available. Ive had it for a few years and its great, Although it was like ~$900 bucks back then. But you get 30 lbs total off the front and most comes from the 2pc rotors.

https://www.ft86speedfactory.com/wil...l#.Xp0Ir25Fw2w

The Price point is nice, I have had .8" rotors crack and/or warp very quickly in the past i like the 1" (25mm) Size. Or even the 1.2" rotors.

Here is what I was looking at doing.

These Hats,
https://www.wilwood.com/Hats/HatProd?itemno=170-9206

These Rotors,
https://www.wilwood.com/Rotors/Rotor...%20%20&appid=0

I will have to space out my calipers to go from 11.44" rotor to the 11.75"

The inside offset is the same with these rotors and hats as it is with the wilwood kit that has the .8" rotors. With that being constant these hats with these rotors will work.

Probably have about $265 into each Rotor.

[churchx]

NoHaveMSG: but are stock rotors & willwood 4pot ones of same diameter? Is caliper at same distance from rotational axle? After all, by simple principle of lever, depending on distance even with same torque/friction at caliper/pad, brake torque at wheel may differ. That, and pad shape/area. Several things making up actual torque. Of course, again, with adjuster valve in picture it doesn't matter much.

RuyGuy2: btw, what is part number of those 350z calipers? I'm curious to compare with subbie 4pots.

[NoHaveMSG]

Originally Posted by churchx

NoHaveMSG: but are stock rotors & willwood 4pot ones of same diameter? Is caliper at same distance from rotational axle? After all, by simple principle of lever, depending on distance even with same torque/friction at caliper/pad, brake torque at wheel may differ. That, and pad shape/area. Several things making up actual torque. Of course, again, with adjuster valve in picture it doesn't matter much.

RuyGuy2: btw, what is part number of those 350z calipers? I'm curious to compare with subbie 4pots.

Don't know, and that is a fair point.

[RuyGuy2]

Originally Posted by churchx

RuyGuy2: btw, what is part number of those 350z calipers? I'm curious to compare with subbie 4pots.

What 350z caliper? I have no idea what you're talking about.

[churchx]

Ouch. Indeed, somehow meshed up, in OP brake lines were ones from 350z. On calipers, only that it's 1.62" willwood 4pot from speedwaymotors.

[Ernest72]

Doesn’t rrracing have a good deal using Wilwoods. My only reason for not going wilwoods is they do not have dust boots. I get plenty of bad weather and snow in NY and not sure if I would have to rebuild sooner.