chronohunter

iTrader: (1)

no unfortunately, a proportioning valve only lets you reduce rear brake not increase it and what we are talking about here is a matched, relative to front, increase in rear brake to keep the bias front to rear in the proper proportions.

There is no way to do it without compromising the front (and therefore negating the front upgrade) without a matched increase in the rear system...

EVOBrakes

iTrader: (67)

This is off the top of my head - and I haven't looked at it again jut recalling what it took to get the first set.

My last customer w/ this kit got PFC-1's.

About $850 for front rear if I recall correctly.

It has to be cut from a larger pad.

There are 2 basic shapes that fit that new design Brembo caliper - a narrow and wide annulus.

I believe Pagid makes it as well - add a few hundred dollars for those in a race compound.

If I can confirm wtf si going on between these kits and the new GTR brakes I may be able to do something w/ Hawk or otherwise.

EVOBrakes

iTrader: (67)

I assume you mean me

As far as I can tell - what Stoptech does is size the piston/effective radius ratio to match the stock setup.

Remember - the driving variables for brake torque are the piston area and effective radius of the pad swept area.

Stoptech seems to think most cars are front biased by about 10 percent too much - so they size the pistons accordingly to move bias rearward a bit.

EVOBrakes

iTrader: (67)

Why no adjustable prop valve?

Don't the rally cars have those? They use it to rotate the car at will by increasing rear brake torque?

EVOBrakes

iTrader: (67)

http://www.stoptech.com/tech_info/wp...g_valves.shtml

chronohunter

iTrader: (1)

Your link explains it nicely

You can only reduce rear pressure with a valve (if you think about it it makes sense). The rally cars mentioned have in some way added rear bias (see ways to do it below) so they have technically "too much" rear brake therefore they have a workable range to use the valve to get the proper bias for the variety of conditions they face.

You can put a less aggressive front pad relative to rear pad but as stated in my previous post you have now compromised the front brakes to gain the correct bias and now have negated a great deal of the benefits of the big front brake kit.

Ironically if you disconnect the ABS on and EVO (and many other cars) you will find too much rear brake! But unfortunately you can't put a proportioning valve on an ABS car, you have to re-plumb the system which is a lot of work and your better off putting a balance bar (race set-up) in at that point. You will not have ABS though.

Also without ABS you can keep it all plumbed stock (leave the ABS fuse out) and swap rear pads around (keeping aggressive fronts) and finding the proper bias through trial and error. Remember though no ABS so your tire bills will probably go up and if it rains you'll have too much front bias unless you swap pads again and you lose the great safety net that ABS is and it is quite a good system on an EVO. This would only be recommended for a very savvy racer on a budget.

or.... you can just but the rear big brake kit with the front instead, doesn't it sound easier and worth the money now!

ragdoll

Consider air ducting from the front of the car to the brake rotors. It will make a very large difference and cost like 30 bucks and a few hours time. My S4 has this from the factory and I've never seen brake fade with my stock brakes(13" rotor, 2 piston[same as Z06's])

theshadow

Wouldn't mind disconnecting the ABS system...but I've heard that simply ripping out the fuse for it would send the ACD nuts (I have a 9 RS). Wondering if anyone can confirm that (and tell me where the fuse is so I can yank it)

As far as trailbraking goes I've never had a problem doing it with a front BBK and stock rear brakes with the same compund of pads all around. If shutting down the ABS would make the brakes more rear biased I'm all for trying it out to see what happens.

It's not like you need to trailbrake into every corner anyways (although it can be fun to do nice little four wheel drifts out all the time).

Smogrunner

iTrader: (5)

My setup exactly! I took Pauls advice AFTER he drove beyond my brakes limits. He got the win anyway, but just barely. (Performance Friction 2 piece rotors in my case.)

I remember Paul explaining his braking philosophy in this way:

"Don't brake 'til you see God, then count to 3, THEN brake."

Hey, anyone up another trailbraking argument. Like the one from three years ago? That was awesome.

Galant VR-4 #34

iTrader: (4)

I use the same brake technique Paul spoke of and I do think it helps my brakes last for the 40 minute National races I run in. The only thing I would add is that I have to run DTC 70s up front with SRF fluid to keep them on the car the whole race. My car comes off the track at 3500 pounds so Im over 3550 for a good portion of the race with a full tank of fuel. Im in the 340whp range and of course have to run stock brakes per scca rules. I run PF-01s or carbotech xp 12s on the back. If you lose your abs you will quickly find that (as Paul stated) that the evo bias is towards the back, I was locking up my rear tires every time I broke when I lost my abs sensor.

Stock calipers and rotors are what I run with no issues (long as I have the DTCs SRF and AMS brake kit.

Marty