Driv200

iTrader: (1)

Trying to save weight & stay on 17's. Currently have 4 piston AP 8350 calipers & rotors. I want more stopping power w/o weight penalty of 6 piston & 18" wheel requirement. Exploring options, I found improved Pro version AP Radi cal kits. Stiffer, lighter, better cooling in 4 & 6 piston. Anyone moved to the Radi cal style & seen improvement?

I'm racing 530awhp tune at street car weight. 3200lbs.

Balrok

iTrader: (15)

Where did you find such a kit for the Evo? Last I talked to Jeff nobody had made on here yet. He did comment that any of the "standard AP Kits" from the UK take up to 3-4 months to arrive.

Driv200

iTrader: (1)

I didn't realize there weren't any kits available. Just read on website. Bummer. Guess that solves that question. I have an email chain started and hopefully will have some answers soon. Will post follow up when I hear back.

honda-guy

iTrader: (55)

are you doing competitive racing or just DE? I dont see why you're trying to save weight with 17" wheels but the car is street weight.

Dallas J

iTrader: (1)

Was thinking the same thing. Also, 18s have better tire sizes which is certainly more important than the small wheel weight difference.

Driv200

iTrader: (1)

Im racing to win. NASA & Optima series along with some local private track days I set up. Entering Optima series this year. My track car, that's street legal, is kind of the charm for me. Beating race cars in a full glass, half interior, street car is a blast. If I could afford a street and a track car, I would. To much money invested for the 5-6 events I do a year not to have the freedom to go play on the streets. Nothing from AP outside of my current 8350 set up. Looks like Stop Tech is next best thing? Any other options?

Balrok

iTrader: (15)

Might want to lay out your issues/setup/pads/fluids etc. Stoptech's (that i've ever seen) are still street calipers. So going to a big 6 piston ST won't have the effect you're expecting. Your 8350's have more stopping power in a lighter, more compact package then about anything up to the monoblock AP/Brembo race components. And even then it's more about heat dissipation and stiffness then 'power'. So even if you have 8 piston calipers you'll still get out stopped by someone on stock calipers and stick-ier tires, hence there's about a dozen factors to stopping faster.

Grimgrak

iTrader: (3)

Not happy with AP america basically dude never shipped me my brake caliper bracket which I paid for. It's been 6 months now and the caliper nipple weeps since i've gotten it. Mono 6. Havn't really driven it as car has been down for other reasons.

Driv200

iTrader: (1)

That's what I was wondering with the stiffer Radi cal design vs my already good AP 8350's. Good info. 20yr veteran on R7's, motul 600, AP Racing fluid, etc.

Driv200

iTrader: (1)

Sorry you didn't get good service.

Balrock: I am not sure I have a major issue other than my HP level and track car set up have maximized my brakes at current weight. Normal progression going faster and outpacing brakes.
* 3100lbs
* AP 8350 calipers (stock rear)
* Hawk DTC 70
* fluids mentioned above (fresh always)
* Shep everything
* carbon driveshaft
* 2.4 Stroker
My GT3 buddies wrinkle pavement when they stop so deeeeeep! Reminded me how my AP's used to stop me before current speeds.

Balrok

iTrader: (15)

Stiffness in the caliper is only beneficial in faster/longer races because of pad tapering and laying even heat wear across the rotor surface.

Firstly you won't outbreak a GT3, because weight, because weight distribution, because suspension, because setup, etc. I'm assuming since you mentioned 17" wheels you're at or around 9.5 inch so max 275's? They are on MIN 9.5" 18's (up front) which won't overheat as much because of the above and due to just having more rubber and the weight being in the back.

Moving past what you see and feel, lets get into a LOT more detail on your setup. Spring rates, shocks, what bushings, what suspension settings for shocks, suspension settings for toe/caster/camber and any weight loss mods you've done so far. Because time can be made up in many places but you can't defeat physics.

Driv200

iTrader: (1)

Alright! Love the feedback:
* Robispec KW Race set up
* Neg 3 camber upfront
* no toe
* some negative rear
* no toe rear
* Hossier R7 295/35 square 17x9.5 +38
* auto power bolt in rear 4pt w/ plates
* stripped interior behind front seats
* added ABS to RS
* Shep stage 2 trans
* Shep stage 1 rear diff (arrange plates)
* e85, built, track prepared
* no aero, no flares, stock body (EVO wing)
* no bumpers. Cusco front brace
* white line bushings
* adj sway (harder rear, softer front)
* custom rear diffuser (no parachute)
* full glass, full front interior
* CF driveshaft, upgraded pipes, coolers, etc
* STATuS race seats & 5pt harnesses
* no AC, speakers,
* lightweight battery(not relocated)

Robevo RS

iTrader: (16)

i am not sure about the abs. i would delete it and get a proper pedal box, its a tremendous difference in feel and control over the brakes. Some even taking out the booster too, like me. pedalbox gives a straight analog feel and it does help me a lot control the car.

its just a suggestion.

Driv200

iTrader: (1)

RobEvo, Definitely something I have been researching. Concerned about the increased pedal force required. It's a "all in" type of change if I do that. I left foot brake and was flat spotting tire after tire on 'fall-away-turns'. Even got some straight away lock up at threshold breaking. As you know, it's to late when you realize they lock. ABS has saved my tires....but caused other frustrations.

Balrok

iTrader: (15)

^That's kinda driver to driver. I prefer all the assistance I can get cause I don't have tree limbs for legs lol.

I'd look at adding solid bushings above the whiteline's specifically for the shimmy under hard braking. Mounting the 295's on the 9.5's is also a bit stretched so instead of the sidewall sitting straight, it's already bent over once you press the brake, likely causing you to run higher pressures then optimal. Motul can be a bit squishy after it gets hot, making the pedal travel further and further due to it loosing compress-ability. So something like Endless would do much better (Porsche motorsport oem).

However Aero and weight will help the most. The GT3's have you by ~500-600lbs with OEM aero built for the track. So I'd start to also look at furthering the $ weight savings ESP at the front, and bumper/wing swaps for "Those" events. Also HTC 70's, while good, are are pretty old compound so maybe look at how the new ones are performing.

A step further would be a bosch motorsport ABS ecu, IF you can find one.