Baller on a Budget BBK (BBBBK)

bajallama

New member
from my understanding it should work on the 185 also. I don't see why it wouldn't since the brake calipers are interchangeable.
 

MWP

New member
DSC_0036.jpg


I hope those adapter bolt things have been hardened!
If its just turned mild steel, i would be very worried.
 

underscore

Well-known member
athousandleaves":1xstu077 said:
So how many mm of clearance do you have from the rotor face to the ball joint?

This is a very good question. Also what kind of performance brake pads are available for those calipers? Anything that would stand up to a track day?
 

bajallama

New member
MWP":2a846s35 said:
I hope those adapter bolt things have been hardened!
If its just turned mild steel, i would be very worried.

Is there a reason they should be hardened? It's in pure shear from my understanding.

mx6er2587":2a846s35 said:
also I would have gone with hardened 10.9 bolts instead of those 8.8s

Yes! they are only for mockup. This is what is taking the heavy shear load.

athousandleaves":2a846s35 said:
So how many mm of clearance do you have from the rotor face to the ball joint?

Looked sufficient when I mounted it, didn't check when I dropped it thought.

underscore":2a846s35 said:
athousandleaves":2a846s35 said:
So how many mm of clearance do you have from the rotor face to the ball joint?

This is a very good question. Also what kind of performance brake pads are available for those calipers? Anything that would stand up to a track day?

Read the first page, EBC and many other companies make performance brake pads.
 

athousandleaves

New member
bajallama":jh7xwcnv said:
Looked sufficient when I mounted it, didn't check when I dropped it thought.

While this might fit a 165 I really doubt that it will work on the 185. From what I can recall they have a different lower ball joint setup. The STi rotor is noticeably too close to the ball joint (~2-5mm) and will rub on the rotor when cornering.

In my opinion, the stock 185/165 brakes are PERFECTLY FINE for a road going car that sees spirited drives occasionally. If you're tracking your car then put down the money for a real brake kit that is safe enough for the road and track or just do your own DIY thing and trailer the car to the track.

Safety isn't about what's good enough.
 

bajallama

New member
athousandleaves":ly8nu03r said:
bajallama":ly8nu03r said:
Looked sufficient when I mounted it, didn't check when I dropped it thought.

While this might fit a 165 I really doubt that it will work on the 185. From what I can recall they have a different lower ball joint setup. The STi rotor is noticeably too close to the ball joint (~2-5mm) and will rub on the rotor when cornering.

In my opinion, the stock 185/165 brakes are PERFECTLY FINE for a road going car that sees spirited drives occasionally. If you're tracking your car then put down the money for a real brake kit that is safe enough for the road and track or just do your own DIY thing and trailer the car to the track.

Safety isn't about what's good enough.

?

I took my car on a "spirited drive" last night and I had complete fade within about 8 minutes in a downhill. Pumping brakes while facing a guard rail is no fun! Too me, that is far from safe! And don't say I need new pads or fluid, cause the heat is still there! It's not going anywhere, ya higher temp fluid may help but its a band aid fix IMO. I drive this car the way it was supposed to be, I don't "cruise" the canyons or tracks at all. I used to have a Starlet with stock AE86 brakes on it and I NEVER had braking problems. I drive this car the same I did that one and the brakes are terrible in comparison.


How is this not a "real brake kit"? This is the SAME monoblock caliper TRD used for it's upgrade on the Altezza and Supra variants!

http://my.is/forums/f89/trd-gurus-trd-brakes-supra-trd-monobloc-471633/index2.html

OEM quality man, far better than chinese Wilwoods or KSports.

For the 185 issue, I have read here guys have no issue running the STi rotor, but some do. Why not switch to the older ball joint maybe? I have no idea, but I have a couple friends with 185's that probably wouldn't mind me test fitting.
 

MWP

New member
bajallama":15mh7fl9 said:
MWP":15mh7fl9 said:
I hope those adapter bolt things have been hardened!
If its just turned mild steel, i would be very worried.
Is there a reason they should be hardened? It's in pure shear from my understanding.

Its not in clamped shear (how calipers are normally mounted) as your two turned steel 90deb bolt things are taking *all* the load in a small area.

The more i think about it, the more incredibly unsafe i think they are!
Even if they were hardened, they will still fail... i have little doubt about that.

Make proper dog-bone adapters.
Easy to do and they will be safe.
 

bajallama

New member
MWP":27l3w3kj said:
bajallama":27l3w3kj said:
MWP":27l3w3kj said:
I hope those adapter bolt things have been hardened!
If its just turned mild steel, i would be very worried.
Is there a reason they should be hardened? It's in pure shear from my understanding.

Its not in clamped shear (how calipers are normally mounted) as your two turned steel 90deb bolt things are taking *all* the load in a small area.

The more i think about it, the more incredibly unsafe i think they are!
Even if they were hardened, they will still fail... i have little doubt about that.

Make proper dog-bone adapters.
Easy to do and they will be safe.

Dog-bone's were my original plan but packaging will not allow them. The bolt spacing is exactly the same between the Lexus and Celica caliper.

So you're saying under a braking load the calipers will shear through two 14mm dia. areas of steel?

What is clamped shear? Do you mean the preload?

To stop an All-Trac at 1.25 G's, 1500 ft-lbs of Brake Torque is needed per front wheel.

(Cool little calculator = http://www.jakelatham.com/radical/info/ ... tors.shtml )

I had calculated the Brake Torque from the Caliper Clamp force for these calipers and rotors and it came out to only ~850 ft-lbs (all dependent on pedal pressure), but for sake of argument lets go with the larger number.

To react that moment the point of shear is of question. I haven't gone out and measured it, but say its at about 3/4 to the rotor edge from the center.

Rotor is about 1' in diamter, 6" in radi. Caliper adapters are 4" from center.

3750 lbs force reacted at brackets.

Cold Rolled has a yield strength of 36,000 psi

Shear Strength = 36k * .6 = 21,600 psi

3750/2 = 1875 lbs force per adapter bolt thing

Shear Stress = F / A = 1875/.24 = 7812 psi

Factor of Safety = 21,600/7812 = 2.76

Let me know if any of my calculations are wrong and if I made some improper assumptions.
 

athousandleaves

New member
Ok, ok, we get it.

Just relax, nobody is trying to attack what you've done. I'm sure everyone here is happy to have another educated and motivated alltrac owner in the community.

Nobody has said what you've made is categorically dangerous but we're all asking good questions that will hopefully help you strengthen your design and possibly produce something that some members will be interested in.

Speaking to your earlier reply, if the stock braking system was failing as you had described when these cars were new there likely would have been a serious recall many years ago and the cars would have earned a reputation for this. By saying that you drive the car the way its supposed to be driven do you mean the way it was engineered for commuting or how you think its a rallye car? These cars were designed for city and highway driving conditions and not much more than that, especially if the power output has been increased. Plus you're trying to compare the braking performance of a starlet that was probably well below 1000kg with some form of upgraded brakes versus a car that is into the 1400kg range? How is that comparison at all valid?

While the calipers that you've chosen ARE SAFE the way you've gone about getting them onto the car could do with some more thought. If the way you were doing it was completely sound then why wouldn't more manufacturers like AP Racing be doing it the same way?

As for the ball joint, the 165 uses a different front A arm so they're not compatible with the 185.

Also, personally I find it wise to avoid prefacing any thread with your profession if you're trying to gain trust. Using your background to leverage confidence on the internet can be difficult as usually word of mouth will carry more weight than just saying you've finished a program at school.

I'd be curious to know what the safety factor is on the stock caliper for comparison. :smokes:
 

bajallama

New member
athousandleaves":2ayaq5xx said:
Ok, ok, we get it.

Just relax, nobody is trying to attack what you've done. I'm sure everyone here is happy to have another educated and motivated alltrac owner in the community.

Nobody has said what you've made is categorically dangerous but we're all asking good questions that will hopefully help you strengthen your design and possibly produce something that some members will be interested in.

Haha, I guess you took my tone as defensive, it's not at all. (Except for the case where it was claimed as not a real brake kit, which I see that as somewhat unnecessary and far from constructive) When I mean the car will be used as it's supposed to, I don't mean commuting everyday (Although I will be doing that). Is your view of the car a simple commuter? I like the car for the nostalgia and the value. From my understanding, it's the same chassis and drive train that was used in WRC. But when a Kia Soul has better braking performance, doesn't that sound an alarm? Again I'm not trying to attack, but just state the obvious. My comparison with the Starlet is that it's not a car meant to be driven, it's an economy car. But I drove it the way it wasn't designed with a brake upgrade that was minimal in performance (went from solid to vented 25 year old rotors and still used $25 brake pads). This car is a performance car, I'm sure that's why a lot of people own them today. I am really surprised why not many other people have not had issues. I mean every time I take the car out at night, all 4 rotors are glowing red! None of my friends cars nor none of my previous cars have done that.

Yes I agree, I don't want to take shortcuts but I am always open to suggestions! I have no other options for a design to retrofit, though. But if you have ideas, throw them my way. I already had to lose the rear UCF calipers because packaging would not allow. Dog-bone style adapters are typical because that's what applies to their package, but the bolt spacing is the same between the ST and the UCF. Therefore I make a simple adapter as shown, or I make a very odd aluminum dog bone that moves the caliper in a different clocked position. I plan on seeing what the FOS is on the stock caliper, and being cast iron, I don't see it being much better.

I don't care about anyone's trust to be honest. I'm here to offer my knowledge and skill to the community, trust me or not, the results will show (If you know what FSAE is then you know what I have seen and done in order to offer everyone). I'm not hiding in my garage doing mystery things to my car, I'm sharing my design with you guys so you to can have a car that will give Porsche's and Lambo's a run for their money. Since I live in LA, I have the chance to make guys cry when they see an 80's Toyota keep up with their R8's and brand new M3's. It's the best feeling in the world to be truthful.
 

bajallama

New member
Oh and I thank MWP for questioning my bracket and in no way was my response an attack on him. I honestly believe it was far from strong and thought I would retain a higher FOS. But it does bother me even at worst case having FOS of 2.7. I did the same calcs for the 10.9 bolt and it came to around 8 and I want to match that at least, so I am looking into alternatives (maybe 4140 or a complicated dog-bone).
 

MWP

New member
I got not sign of a defensive tone when reading that reply :)
Its good to see you calculating it out.

I need to draw an image....
A normal dog-bone wouldn't have the same swivel problem as its fixed in two places to the strut, eliminating the side load on the studs.
You would also bolt up the dog bone with 8.8 or 10.8 bolts which are far stronger than those studs.
Untitled_1.jpg
 

bajallama

New member
Brake Force direction is other way! :p

Yes I understand what you mean, I had a talk with a stress engineer today at work about the design. I saw it as a non-issue as is because the brackets are so close to the calipers that the rigidity of the caliper and the hollow indexing dowels would make up for any need of a bridge or tie as the dog-bone incorporates. But again as stated, packaging of a dog bone is very tough since the bolts will intersect each other. He seemed to understand that the hollow dowels in the caliper take all the shear load and index the caliper. This makes sense as the bolt is just slopping inside the holes and really just take up what little outward component force there is (the bolts are not perfectly tangent to the center) and keep the caliper tight against the upright. So I measured the minimum thread engagement and it barely squeeks by, by like .025. So I guess an aluminum dog bone it is with steel threaded inserts probably. I may possibly put the adapter to upright bolt in double shear since I have the room, but will cost me machine time. I'm getting my 3D printer Wednesday so I hopefully can have something mocked up by the end of the week. Thanks for the advice!
 

underscore

Well-known member
If you had the same bolt/stud setup you have now but had a connection between the cubes, wouldn't that be enough to keep them from rotating and causing a weak point? Or since the bolt spacing is the same, you might have to just offset the caliper from the normal position a bit. The adapter would look funky but it should be able to work, no?

bajallama":180zj1vv said:
Brake Force direction is other way! :p

He's Australian, you should know that those guys do everything upside down and backwards.
 

bajallama

New member
Haha, probably. Yes, I can't believe I never mentioned it but there is another piece to the bracket. It indexes on those steps that are on the shafts and holds the two bolt adapters together. Yes it helps with the shear force but since there is always slop in loosely mounted components, I never saw it as nothing but a locator.
 

underscore

Well-known member
Could you not either incorporate it into the design to turn the three pieces into one, or just get it welded together to be one piece?
 

bajallama

New member
Ya that's the plan with the dog bone design. The problem with welding is the strain it puts on the metal. It would need to be treated after to be normalized, etc. As MWP said a dog-bone is the easiest way and can be made from Aluminum. I just had my doubts on the ability to package it since these calipers are so large, but I think I can do it now. It's going to be a somewhat exotic design however.
 
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