Baller on a Budget BBK (BBBBK)

bajallama

New member
underscore":25cgt3ub said:
I haven't done them recently but I've been meaning to check all that stuff out, what static gap are you referring to?

It would be the brake rotor gap when your suspension or car is not moving, just sitting there
 

Spectra1

Member
If I end up going further with this brake kit for the 185's, I can get you some spacers to get your kit to work better.


I would be interested in some of those spacers as well. I have the same Porsche brake kit as Underscore.
 

bajallama

New member
Finallllyyy got around to working on the rears and I think I found a solution. If you saw from my previous posts I am using the Legacy GT rear rotor and after turning the hub down and trimming the dust plate, the rotor fits perfect with the parking brake. My original plan was to use the LS430 twin pots, but packaging was vary very hard to do and would not have been strong enough. So after running through different options I settled on using the single pot SC300 rear calipers, and guess what, they are almost perfect! The bolts are bigger so the upright will need to be drilled out and possibly some massaging with a file as the the hole centers are off a few thousands. Also the mounting faces may need to be machined down a tiny bit but it's amazing how the offset is almost perfect!

Also I'm an idiot and bought calipers off of a SC400 at the junkyard and that is what is pictured below. They fit a 307 mm rear rotor instead of a 290 like the 300 and Legacy. but they bolt up the same so one more trip to the junkyard and I think the BBBBK will be complete!

Stock
caliper1.jpeg


SC
caliper3.jpg


Caliper Bolts

caliper2.jpeg
 

MWP

New member
Nice work :)
So, you end up with a rotor that's about 1mm bigger in diam, but is thicker & vented, and a twin pot caliper.
 

bajallama

New member
MWP":3lr1iu0i said:
Nice work :)
So, you end up with a rotor that's about 1mm bigger in diam, but is thicker & vented, and a twin pot caliper.

Well the SC is not a twin pot, it's a single 42mm piston. What size is the 185 rear rotor? The 165 has only a 269mm rear rotor.

Here is the calcs I came up with for the upgrade:

Stock Line Pressure (350 lb Gain): 445 psi
Rear Caliper Clamping Force: 445 psi * 1.48 in^2 * 2 (Floating Caliper) =1323 lbs
Friction Force: 1323 *.33 = 436 lbs
Rear rotor effective radius: 4.61"
Brake Torque: 436 * 4.61=2012 in-lbs = 167 ft-lbs

LGT rotor and SC300 Caliper:

Stock Line Pressure (350 lb Gain): 445 psi
Rear Caliper Clamping Force: 445 psi * 2.14 in^2 * 2 (Floating Caliper) =1905
Friction Force: 1905 *.33 = 628 lbs
Rear rotor effective radius: 4.88"
Brake Torque: 628 * 4.88=3071 in-lbs = 256 ft-lbs

I read through my excel sheet and made some small changes. I had realized that you multiply the floating caliper by 2 and the fixed has no multiplier (duh). So with those changes I came up with these bias:

Stock:
73% Front
27% Rear


LS430 Front & SC300 Rear:

70% Front
30% Rear

And the kit comes out to a 39% improvement over stock with an increase in thermal mass and better heat disipation.
 

MWP

New member
All Australian ST185's got a rear rotor of (DBA744):
Vent: Solid
Diameter: 288
Height: 60
Thickness: 10

JDM ST185's had a much smaller rear rotor.
 

bajallama

New member
MWP":wz5n731x said:
All Australian ST185's got a rear rotor of (DBA744):
Vent: Solid
Diameter: 288
Height: 60
Thickness: 10

JDM ST185's had a much smaller rear rotor.

hmmm, then it may not be much of an improvement for the 185 guys except that you get a slightly bigger piston and vented rotor. 205 is probably the better option for those whose residing country sold them. For the US, rear still exceed $300 with used rotors :(
 

MWP

New member
Next time im on a track ill try to remember to measure rear rotor temperatures.
Our local track (Mallala) is the hardest circuit on brakes in Australia.

I overheat my front pads/rotors (std 185, using DS2500 pads) in 1-2 fast laps :(
 

bajallama

New member
ATTENTION

Alright so I sold the last kit and I'm currently getting quotes for making kits for the 185 guys. I however do not have a 185 and my access to one is somewhat "challenging"? Anyways, I went to the junkyard on Friday in search for a 184 LCA and upright and forgot the necessary tools to pull an axle because I'm an idiot. I have machine shops hounding me for models so this is where I need your guys help.

What clearance are you looking for? If any of you have a STi rotor laying around and some washers, can you test fit and see how much space is required to space the rotor out? I would like some pictures also. I had currently estimated that it needed around .125" of offset. I will be waterjetting a steel plate that sit behind the rotor and have the steel concentric ring tacked on the inside. So this will slip on over your hub/wheel studs before installation of the rotor. The bracket will then be redesigned for the larger .125" step.
 

bajallama

New member
MWP":px792ip1 said:
Argh, i wish i could help.
Im not in a position to buy calipers or rotors as yet :(

Ahh, no worries. Did your buddy get his kit yet? I haven't heard back from him since I shipped it.
 

bajallama

New member
underscore":3tn7ctz9 said:
I'd push it out a bit more than an 1/8" to have adequate clearance on an STi rotor.

What are you thinking? How much material did you shave off your ball joint?
 

underscore

Well-known member
I've taken a fair bit off already and it still rubs, I'll try to measure once I can get it to stop rubbing.
 

MWP

New member
bajallama":2ud24uvy said:
MWP":2ud24uvy said:
Argh, i wish i could help.
Im not in a position to buy calipers or rotors as yet :(

Ahh, no worries. Did your buddy get his kit yet? I haven't heard back from him since I shipped it.
Yup, it arrived yesterday. Thanks.
 

MWP

New member
So im finally starting to look at doing this upgrade :twisted:

328mm WRX STI rotors on the ST185... maybe i have smaller ball joints or something??
I have plenty of room.

PHOTO_20161001_164531.jpg
 

deecee

New member
MWP":3ixhvekr said:
So im finally starting to look at doing this upgrade :twisted:

328mm WRX STI rotors on the ST185... maybe i have smaller ball joints or something??
I have plenty of room.
And how much room is there under compression? With my rotors, there is around ~1.5mm space between ball joint and rotor.
 

MWP

New member
Lol, I didn't think about that, thanks :twisted:
I have some other parts I need to have water cut, so was going to have some behind rotor spacers made up anyway.
 
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