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CCG8 / FLG8
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Discussion Starter · #1 · (Edited)
I replaced the 4-pot GXP calipers and rotors with '09-'11 CTS-V 6-pot calipers and Centric rotors. They really feel good even after going from GXP EBC Yellowstuff pads to ceramic pads for the 6-pot. Installation required drilling the hubs for the larger bolts but that was all the modifications required. My GXP SS lines worked fine and these fit inside the 19" VMR 701s with a bit of room to spare. The rear uses Camaro SS Brembos and blank HSV rotors, (no brackets and e-brake is retained). Sorry for the crappy cell-phone photos.
 

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Droooooool.
 

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GM Enthusiast
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So how do the 6pistons compare to the GXP brakes? Any notable difference?
 

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CCG8 / FLG8
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Discussion Starter · #4 · (Edited)
With the 4-pot I had ceramic pads and didn't like the initial bite so I changed to EBC Yellow pads. With the 6-pot calipers I'm trying ceramics again and they feel better than the Yellow did in the 4-pots.
 

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Looks great! Someday I wish I can do this! I love the fact that the front rotors actually fill in the wheels. I always felt like the G8 had tiny rotors, especially us GT folks.
 

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How did the Centric Rotors turn out, are they pretty close to oem quality?

I bought a full set oem SS rotors two years ago, but going with 6pot instead so I really don't want to pay $200+ (they don't even make the aluminum/cast rotors anymore for the cts but have ZL1 two piece rotors) for each side. I can find them centric rotors for CTSV on tirerack for $103+shipping instead.
 

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CCG8 / FLG8
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Discussion Starter · #8 ·
The Centric rotors seem to be quality pieces. Contrary to what they say on Centric's website, they are not co-cast. They are 1-piece steel. This means they are heavier than the OEM co-cast CTS-V rotors by about 3 pounds. The weight on Centric's site is wrong. These are about 1 pound heavier than the 2-piece CTS-V or ZL1 rotors but at $100 each, are well worth the money.
 

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09 LR G8 GXP 6M (#1420)
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So how do the 6pistons compare to the GXP brakes? Any notable difference?
You won't notice a difference unless you're on a road course, where fade becomes an issue. No real difference on the street because the (reverse) traction of the tires is the limiting factor there.
 

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how hard was it to drill the hub im doing the conversion soon
 

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You won't notice a difference unless you're on a road course, where fade becomes an issue. No real difference on the street because the (reverse) traction of the tires is the limiting factor there.
I agree with all you are saying but would like to add that there is a difference in pedal feel and the initial braking force available at first application when slowing down from speed.
 

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I love how mine feel. Very stock like.

I do agree maybe overkill for the street. I got full take off of a wrecked ctsv so the deal was about the same as the 4 pots would have been.

At 120+ and 275 tires up front the calipers will lock the fronts up and abs will cut in, maybe a little more delayed tho.

Somewhat interesting feeling slowing down that fast from such high speed. But for normal driving i feel the bite is great it feels like i hardly am using the brakes but they feel so effective.

Sent from AutoGuide.com Free App
 

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Moddin' and Roddin'
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how hard was it to drill the hub im doing the conversion soon
For my part I took it to a local performance shop so they could use their machine shop to drill it out properly on-center and straight with lubricating/machining oil. But that's because I knew I'd be using the calipers for track days.
 

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09 LR G8 GXP 6M (#1420)
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I agree with all you are saying but would like to add that there is a difference in pedal feel and the initial braking force available at first application when slowing down from speed.
True dat. :)

For my part I took it to a local performance shop so they could use their machine shop to drill it out properly on-center and straight with lubricating/machining oil. But that's because I knew I'd be using the calipers for track days.
I did a couple of track days soon after upgrading to the six pots and my instructors kept telling me to brake way too early. By the end of each session though, they were convinced. ;)
 

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CCG8 / FLG8
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Discussion Starter · #16 ·
Here is a photo of 4-pot and 6-pot pads. This set-up feels stock-like in normal driving as to pedal feel. I feel the intial bite is better but the real fun is attacking the pedal quickly. It really throws out the anchor!
 

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For my part I took it to a local performance shop so they could use their machine shop to drill it out properly on-center and straight with lubricating/machining oil. But that's because I knew I'd be using the calipers for track days.
Yea I want to do that but I don't want to take the hubs off and go get another alignment too much of a hassle for me lol
Alright I'll get a 14mm drill bit
 

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Front Caliper Bolt Help ASAP

The Centric rotors seem to be quality pieces. Contrary to what they say on Centric's website, they are not co-cast. They are 1-piece steel. This means they are heavier than the OEM co-cast CTS-V rotors by about 3 pounds. The weight on Centric's site is wrong. These are about 1 pound heavier than the 2-piece CTS-V or ZL1 rotors but at $100 each, are well worth the money.
So I got the hubs drilled out, mounted the centric rotor and noticed that the GM 1157088 Bolts hit the back hat of the rotor. DAMN, what to do next.

Did you run into this problem???

I'm away from my work so no cut-off tools here. And I need a 14mm nut to tread onto the bolt before I cut it. I measured it and they are 50mm and not the 40mm that should work.

Wood it work to get a spacer on the back side of the bolt, or should I try to cut it off?
 

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Went to Orschelns and picked up so grade 8 45mm and washers should that work? I guess I got cts bolts instead.
 

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Moddin' and Roddin'
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I did a couple of track days soon after upgrading to the six pots and my instructors kept telling me to brake way too early. By the end of each session though, they were convinced. ;)
Yup! In fact, with the Carbotech pads I run, I actually had trouble modulating the brakes. They were touchy and I'd brake too much, so I'm still working on that. My instructor commented, "The car definitely has brakes."

So I got the hubs drilled out, mounted the centric rotor and noticed that the GM 1157088 Bolts hit the back hat of the rotor. DAMN, what to do next.

Did you run into this problem???

I'm away from my work so no cut-off tools here. And I need a 14mm nut to tread onto the bolt before I cut it. I measured it and they are 50mm and not the 40mm that should work.

Wood it work to get a spacer on the back side of the bolt, or should I try to cut it off?
I had this problem, but that's because the GM bolts I'd received from Greg were M14x2x50. It's all he had at the time. So when I received the 50mm bolts from Greg, I sawed or ground them down to roughly 45mm and then they would align perfectly with the end of the holes on the caliper.

What you actually need is an M14x2x45. Greg does have those now. So if you want to save yourself the pain, order them from him. They're off the ATS.

Don't use an M14x2x40. It won't be long enough.

Went to Orschelns and picked up so grade 8 45mm and washers should that work? I guess I got cts bolts instead.
3mm lock washers will work with 50mm bolts (and is what I'll be using, in combination with plain zinc-coated steel bolts from Fastenal, since I've had my caliper bolt holes Timeserted). If you're going to use the GM bolts, you could likely do the same thing; though if you intend to use the GM torque specs, I'd stick with grinding the bolt down.
 
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