Mein Kampf mit großen Bremsen

[curtis]

Yet another attempt for technical discussions toybreaker will be proud. /ubbthreads/images/graemlins/grin.gif

Started my quest for big brakes a year ago. Found a stealth RT and pulled the stuff. Then realized the calipers would clear my wheels because of the backspacing/offset of the rotors. Well solution new bigger rotors. Found the new durangos have 13.25 rotors oh yea. So I cut some centering rings to discover the depth was to deep and hit the control arm beyond what was fixable so then ended up with wilwood aluminum hats and vented rotors super light. Milled out the new 4 holes for the studs but not enough for the calipers to clear the wheels... DAMN IT

So done some trading and ended up with a set of slotted cobra rotors and camaro calipers with ron's cnc cut brackets. DONE but a new problem arrives after I got them. Did some searching to find that the bias is now over 40% more to the front. This along with the Q45 master I have on the car which has a much larger piston and more bias on the front is going to turn the pedal into an impending lock up controller.


So the solution I'm going to do is one of two things with the deletion of the abs

1 just get an adjustable proportioning valve from a local circle track place or ebay and or
2 source out a rear calipers with a larger bore.

Which leaves me wondering is there a Mitsubishi that comes with an e brake control feature with a larger bore to offset the bias back to normal? /ubbthreads/images/graemlins/dunno.gif Or just get a set of camaro rears and make brackets but don't know how they're set up.

If so I may leave the abs. I had a problem with the abs light staying on about the time I tore the car down so not sure what the problem really is. I hot wired the abs pump and he relays kicked and it fired up and I also ohm'd out the wheel sensors so it maybe just a bad wire from the fuse block or something.

Post away.... Oh and yes this title was inspired by Aaron and his VR4 video. If your wondering and was under a rock that week. click me

 

[cheekychimp]

Quote:
Which leaves me wondering is there a Mitsubishi that comes with an e brake control feature with a larger bore to offset the bias back to normal? Or just get a set of camaro rears and make brackets but don't know how they're set up.



Do you know what the bore on the rear GTO (sorry GT3000) brakes is? Those have an ebrake, bolt up nicely if you use the GT3000 rear control arms and I would imagine have a larger bore given that the GT3000 master brake cylinder is a popular upgrade over here.

 

[DarkDevilMMM]

I think it's time for someone who chalk up something for using Evo brembo front and rear brakes, I know it's been done before, someone just need to mass produce it, pleeeease curtis.

I think most parts like brake master and stuff should fit easily or with minimal mod, maybe /ubbthreads/images/graemlins/dunno.gif

 

Curtis, I have a rear mustang caliper with a toyota Rav4 12.45 front rotor in the rear. I am coupling this with a set of 3k vr4 calipers with a set of MK4 supra 13.1 rotor. I bought the kit from Blackhole, I do however need brackets re made as his were basically hand made and I don't think I trust them enough to put on the car.

 

[curtis]

^pictures please. I'll have to look at some mustangs next junkyard visit.

 

[RedTwo]

GTOs don't have handbrakes integrated into the caliper though. Pistons are 38.1mm for both single and dual piston models FWIW.

It's a hard task finding handbrake fitted rear callipers!
CD, CE and CN9A Evo I-IV essentially have identical brakes to the VR4.
FC3S RX-7 series 4/5. single piston rears, probably around 36mm.
S13, S14 and S15 Silvia's have single piston, that I think is 38mm.

 

[467]

Have you looked at the different Mit split points available 3500, 3700, 4200?

Split Points:
Year FWD AWD
90-91 All 4200 3700
90-91 All w/ABS 4200 3700
92-93 All, 94 NT 2500 3500
92 All, 93-94 NT w/ABS 2500 3500
94 T ??? ???
93-94 T w/ABS 2500 3500
91-92 GVR4 N/A 5200
95-99 ??? ???

 

[Dialcaliper]

Except under extreme heavy braking, the stock valve is the most rear biased of all of the mitubishi valves, so no help there.

Also, a prop valve won't really help to move bias forward under light braking, only heavy effort.

Curtis, knowing your resources, the easiest thing to do would be to machine +size brackets for the rear and use bigger rotors. For a variety of reasons, you don't need 40% larger rear rotors - a 20% or so increase will probably suffice (12-13" rotor).

If you're curious, here are a few of said reasons:
1) The braking you expect to be doing is more severe than the original brake design.
2) With stiffer suspension (and increased pitch stiffness), more weight is transferred to the front under braking, so you want more front bias than is present on the stock setup.
3) Even though you have 40% more bias in the front, the system is operating at lower pressures - the split point is effectively raised relative to car deceleration, so the prop valve cuts in later.

There's no point in perfectly matching the original brake bias again unless you plan to also use a prop valve to lower the split point (since the whole system is running lower pressures with bigger brake pistons), or more likely, go to a dual master/bias bar (which is the only real effective way of controlling brake bias under all conditions instead of only having a couple properly biased braking pressures as with a prop valve)

I'd suggest simply increasing the rear rotor diameter to 12-13" with the stock caliper on brackets - just design it to keep the caliper spacing the same (or adjust it if you feel like it). If it still doesn't feel right, use slighly sticker pads on the rear.

No matter what you do, you'll never have both perfect heavy braking, light braking and even pad wear unless you completely redesign the whole system. The best course is to shoot for proper heavy braking and deal with the pad wear - that's why you went with bigger brakes in the first place

 

[curtis]

That's probably the easiest thing to do but probably will just leave it as is until the car is running and I've tested everything. I just don't want it locking up instantly with 1/16 of an inch travel on the pedal. With the Q-45 master and its increased bore diameter I was use to it in just a few days and actually like it much better because it reacts faster. It maybe just fine as is but until I drive it I'll never know.


I wish Adolf would do a new video or just let us back in the conference room. Fricking Jackstand ballin is getting old. /ubbthreads/images/graemlins/grin.gif

 

[jepherz]

I have camaro calipers up front and custom brackets/rotors in the back which restores the bias to nearly stock. E brake works too since it's the stock caliper.

 

[curtis]

Which rotors did you use out back?

 

[cheekychimp]

Quoting RedTwo:
GTOs don't have handbrakes integrated into the caliper though. Pistons are 38.1mm for both single and dual piston models FWIW.



You just use the GTO control arms with their drum handbrake setup and use the calipers independently. That's what I did.

 

[RedTwo]

But the work involved in swapping to GTO control arms is a little more than that of swapping calipers and making brackets. It does make it easier though, that's why there's a GTO rear end in the drive way /ubbthreads/images/graemlins/laugh.gif

Did you have to make custom handbrake cables or swap the toe adjustment thingy on the control arm?

 

[Rausch]

Quote:
I wish Adolf would do a new video or just let us back in the conference room. Fricking Jackstand ballin is getting old.



You finish those brakes, and I'll put a word in. He don't wanna see you crying again /ubbthreads/images/graemlins/smile.gif

 

[curtis]

/ubbthreads/images/graemlins/rofl.gif