Foxxtron

iTrader: (1)

Simply adding a 9" or another axle per se will NOT eliminate pad knockback. Eliminating the C-Clip's with a bearing kit will help, but you need to ensure the kit you're using has high quality bearings it. C-Clip axles are notorious for their behaviour, but you will NOT completely eliminate axle movement and deflection as there will still be enough forces to induce the pad knockback (which is in cornering). Also, remember the axles themselves aren't the only thing to be concerned with but also the mass of the rotor, especially along the diameter.

Even then, BOTH solid and sliding calipers are susceptible to pad knockback, but solid calipers on a "non-steering" axle are worse because even though you've reduced deflection in the caliper itself (which is a good thing), you've now eliminated where the knockback forces can effectively go. This is one benefit a sliding caliper has over it's solid counterpart
Remember, I haven't even gone into details about caliper piston size, brake hydraulic capacity, rotor mass and diameter.

If you want to know more about the real dynamics of braking, look over at the stoptech site in their technical white paper section. They have an excellent amount of information that's extremely accurate, provided one takes the time to read them. You should also try giving their technical department a call and they can explain as well why it isn't really the best idea to install a solid caliper on the rear axle of this car.

Again, it's your perogative but you're going to end up with more than you're bargaining for. At the end of all of this, a question to ask yourself is: "am I really improving the braking or am I just being misled by appearance?"

RUNIN11Z

iTrader: (2)

Thanks for being very informative... I called Movit today, the rear kit is around four grand and they asked me for the size of the Brembo piston size to ensure that the brakes have the same bias. At least that is what he said. Also they claimed that the rear rotor is a little under 13" and is two piece with a external parking brake. Foxxtron what is a way I can ensure that I am utilizing this brake set up. Thanks for all the input. It will definately help before I drop a huge chunk of change

Foxxtron

iTrader: (1)

By not utilising it at all until you properly understand the braking parameters. Oh and 13" rotors on the rear might seem to even out the front-to-rear rotor diameter ratio as well as a possible weight savings (from the floating rotor), bear in mind that you're actually adding more MOI to the rear which isn't good for acceleration, yet will also contribute to the pad knockback even more. Again, you're also paying money to actually defeat one major benefit to having a slightly larger front rotor, which is to slightly but effectively shift brake bias to the front of the vehicle.

Also, have you actually seen the emphasis of the rear OE brakes, even in the most aggressive driving environments? Not much and there are many reasons for that.

Not trying to be arrogant or facetious, but you should give stoptech a call and get their opinion. Heck, even I could design a kit for half the Motiv price, but in the end, performance wise you're not gaining anything.

RUNIN11Z

iTrader: (2)

Well I don't see much emphasis from the oe manufactures but it seems that all the high end cars have multi-piston rears: Amg Benz, Z06, Porsche TT and numerous others. I understand what you are getting at and I'm not doubting your experience or knowledge as you been on here for quite a while and have many valid points. So to get to the point it's just plain not worth stepping up the rear brakes. So going with a better casting from PBR; C5 Z06 seems like the best option at this point. I guess I was so amazed the way the fronts perfomed that I was biased on my decision. Thanks Foxxtron for all the answers to my questions and saving me some dough.

Foxxtron

iTrader: (1)

No worries. I hope I didn't come off as a party pooper but I thought just to share some experience with you about one of the areas that I've spent lots of money on only to discover that I worsened my performance. With that stated I'm not trying to take anything away from roy as he's be one of my few inspirations behind approaching some of the mods, however it appears he works with his kits limitations and accepts it. I personally liked the appearance, but couldn't stand the performance penalties, especially the pad knockback.

It's your car, so you're certainly welcome to try as I did and see what you're satisfied with. If you'd like I can PM you with some links to some of the braking dynamics I'm talking about.