Brakes

[BigMike]

Bill made some good comments:

Regarding vented rear brakes (upgraded rear brakes), not so necessary with the FX16 since it's not a mid-engine like the MR2. The front brakes will be doing more of the work.

We need to figure out if we can find some larger front rotors for the FX16. Maybe Supra rotors or something from a heavier Toyota with the same 4-bolt wheel pattern?

[Sirdeuce]

Pick n pull field trip anyone?

[Sirdeuce]

Okay, now we have an MR2. Reduce braking efficiency in the front, increase the rear. '85-'86 front brakes. This allows the vented discs to be retained while reducing the front braking. They were slightly smaller. Then do Mikes trick, put front brakes on the rear. only problem is the loss of the E-brake.  Another way to tune the brakes is by using different pad materials. Organics have less friction than metallic or ceramic. Just need the right combination.

[BryanH]

Changing the brake balance with pads gets real tricky on the track.  It's not so hard at an autox where temps only need to come up a little bit to be effective.  The problem we may run into is the pads heating up at different rates and different pads having different efficacy over a given temperature range.  It could be real tough to get the desired results. 

What we need is a proportioning valve. :) 

Given that this is an enduro, I wonder if sticking with the 87+ front brakes might be a better idea since they will dissipate heat better.  I cooked some Carbotech SSF pads with my SC at Buttonwillow after 7-8 laps.

[Sirdeuce]

Ok, same brakes front and rear? Prop valve, definately. Another thing we can do is move weight to the front.

[BigMike]

Bryan,

Have you ever heard of MK1 guys fitting Supra front disk brakes to the front of the MR2? Assuming the bolt pattern is the same and the diameter is larger, we could try this maybe!

[BryanH]

I haven't heard of it.  What Supra has a 4x100 bolt pattern?  The MK3?  MKII is 4x114.3, MKIV should be 5x114.3.

[Sirdeuce]

Early Supra was 4x114, later was 5x100, Might be able to fit Supra brakes on genII 2's.

[BryanH]

You know what would be awesome (but overbudget)?  Adapting the Spyder ABS system to the MK1.  That thing has incredible brakes.  And is already 4x100...

Now the Spyder, that car is an Elise waiting to happen.  They're only 2195lbs stock. :)

[BigMike]

This is what I am getting at. Let's find some rotors that have a larger diameter and with the proper bolt pattern, and we'll make it happen. We only need this for the front. We'll use the stock MR2 front brakes in the rear and some larger diameter brakes in the front.

Just for shits & giggles, I'll check prices on Spyder rotors and calipers on Monday.

[BigMike]

I cooked some Carbotech SSF pads with my SC at Buttonwillow after 7-8 laps.

This is the only reason I am worried about this. But, your car is 500 or 600 pounds heavier than our LeMon car and also had more power. So, maybe we won't be toasting our brakes like you did, but they gotta last 8 hours straight two days in a row.

Another way to look at this, if I am being this paranoid, what are other people doing? I'm sure the majority of the cars will be using stock brakes with just upgraded pads only. I would think the stock brakes would be sufficient but from what you said, that's the only reason why I am looking into larger brakes....

[Sirdeuce]

Ok, I found a little piece of info we all might take into consideration when we build our cars. The front calipers on a 1990 (maybe others too)  Celica GT has a caliper piston diameter of 57mm. The diameter of the front caliper piston on an AW11 is 46mm. That's like 53% more area! The only thing noted is the bolts to the adapter plate are a size larger. The same pads and other hardware are said to be the same. Simple upgrade with a low cost.

[BigMike]

More notes on the rear vented rotor upgrade...

Now that my car is reliable and I'm driving it for what it is instead of taking everything to the extreme, I have gotten to really know the car like I had back when it was N/A (back in 1999). I've already put 6,500 miles on it in just under 4 months.

One thing I've noticed now, and I don't know why I didn't notice this before, the rear brake bias with the rear vented rotors is WAY too much. I really need a proportioning valve installed. I have had the rear end come out a couple of times if I brake hard while entering a corner.

We can't have that with the LeMons car. So if we go larger calipers & vented rotors in the rear, we will need a proportioning valve.

So to hide the cost, all we have to do is just tuck it away up with the gas tank somewhere. Shouldn't be a problem at all really

[Sirdeuce]

Put the larger calipers on both the front and back?? Use a prop valve to balance from there. The larger pistons will decrease the leg force required to slow the car! Another fatigue reducing adjustment for the LeMons car.