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9th Gen Suspension Springs, Shocks and Brakes.

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post #16 of (permalink) Old 11-29-2017
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Originally Posted by Maven76 View Post
never said they couldnt, but why would you want the ATS/CT6/CTS brakes? its just a fixed caliper compared to our sliding. No real upgrade in performance. No appreciable difference in pad size, reduced wheel fitment when using. Just a change for the sake of change

Id be going with something like a Wilwood FNSL6R in 4.04" area piston(for a higher effort pedal feel) clamping a 365mm BMW E92 rotor, or better yet a full on Alcon MONO6 setup for the 3series. (same bolt pattern for rotor, just need a centering ring, and same exact piston area as our stock caliper)

Or you could go cheap and just put some Camaro SS 345mm rotors and calipers and and even get Chevrolet branded calipers. Even cheaper still just rock some Caprice 345mm rotors and calipers, they fit inside stock 18" alloys based on my testing

The ATS with the heavy duty brakes and the Older CTS-V uses a 4 piston Brembo caliper. Adding a larger rotor adds more unsprung weight, and I think it will be more effective if we were able to add to the piston area. Are you saying the stock 10th gen Impala's single piston front caliper is equal in performance if not better? Not being sarcastic, I am looking for a real answer.

My car has 22" wheels so my only concern is the stock wheels for the winter, but considering the ATS and CTS-v both came on 18 wheels with this brake setup I think I will be fine.

I could go with the larger rotor combo to go along with the upgraded rotors.....but I was just pointing to something that could possibly work with the stock rotors keeping the cost down. You can get the calipers pins, and pads for about $250-300 from ebay or Amazon.
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post #17 of (permalink) Old 11-29-2017
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Yes, adding a larger rotor adds unsprung weight, and the difference between a 321mm stock rotor and a 345mm Caprice rotor is about 3-1/2lbs.

On a race car that could be significant, it might also even be an issue if it was that much of a variance from one side of car to the other. But only if you had an incredibly well calibrated butt chassis dyno and drove the hell out your car, Most people have such numb hands and ass that they can't even tell an underinflated tire, never mind 3.5 pounds of additional unsprung weight.

And of course since virtually no one shops for tires by weight, the fact that your unsprung corner weights could vary by well over 3lbs just by a tire change negates this issue as a reason to justify going with a smaller rotor.

That benefit of the extra weight of the 345mm rotor gives a larger "lever" for the brakes to act on, larger swept area, a larger pad, and additional mass to dissipate heat.

Adding caliper piston area will increase pedal travel and reduce pedal feel. In other words you will get the same brake pad force with less pedal force, but with longer pedal travel. I don't consider increased piston area an upgrade. You may if you like long, soft pedals.

Of note, switching to a 4 piston caliper does not necessarily increase caliper piston area... The ATS 42mm pistons arranged in opposed pairs actually equates to slight LESS piston area than the stock 60mm single floating piston in the Impala. (4.31"≤ vs 4.37"≤, less than 2% variance). 4 piston calipers don't apply more force just because they have more pistons. Compared to a sliding caliper of the same area, any difference in performance comes from increased rigidity of the caliper. We've got serious cast iron caliper, they don't suffer the same flex as a floating alum caliper does. I have no reason to believe there would be a performance advantage resulting from a fixed caliper.

345mm rotors fit in stock 18's. This car should have had the 345s stock, not the medium car 321s.

Dropping $300 on an ATS caliper setup is a waste of money and time for any potential fabrication, from a performance upgrade point in my opinion. A simple pad change with a well researched performance pad upgrade will change the way your brakes perform and feel.

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post #18 of (permalink) Old 11-30-2017
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Ok. Thanks for the input. How about using the larger rotors and stock calipers? That should just take a very simple bracket tp space the caliper away the needed distance.

can you elaborate on this:

http://www.whyhighend.com/floating-v...-calipers.html

Last edited by Marcellus; 11-30-2017 at 11:04 AM.
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post #19 of (permalink) Old 11-30-2017
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Originally Posted by Marcellus View Post
Ok. Thanks for the input. How about using the larger rotors and stock calipers? That should just take a very simple bracket tp space the caliper away the needed distance.
thats a viable and worthwhile upgrade assuming the stock caliper and bracket will properly engage a 345mm diamter rotor. The Caprice uses a different caliper than the Impala even though the caliper design, material, and piston size is the same. This leads me to believe the Impala/Malibu/Equinox/LaCrosse/Etc... caliper will not mate with the 345mm rotor due to the caliper's internal radius, or the pad shape the caliper uses. (The caliper bracket IS definitely different) Which is a real shame because theres a larger selection of performance/upgraded brake pads for that pad shape.

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post #20 of (permalink) Old 11-30-2017
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post #21 of (permalink) Old 11-30-2017
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link doesnt work. maybe type it without the http and www and the site wont shorten it and itll function

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post #22 of (permalink) Old 11-30-2017
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post #23 of (permalink) Old 11-30-2017
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also, since the piston are is similar, wouldn't the 4 piston rotors have about the same pedal travel?
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post #24 of (permalink) Old 11-30-2017
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Originally Posted by Marcellus View Post
also, since the piston are is similar, wouldn't the 4 piston rotors have about the same pedal travel?
I didnt get a chance to read through the link you provided yet to elaborate on what they say,
but to answer this question, yes your pedal travel would be basically unchanged with the ATS 42mm calipers on as compared to stock, because they have such a close functional piston area to the stock floating caliper.

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post #25 of (permalink) Old 12-01-2017
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Okay...
So basically most what that article says is true, but there are some serious caveats, and of course there is one glaring error.

Quote:
Originally Posted by whyhighend.com
The fixed caliper can apply more squeezing power and apply that power more evenly during braking as force is directly applied to both sides even if its a two piston brake
They do have the word "can" in this sentence, so I guess technically it could be construed as correct if you use the meaning of can as a qualifier, as opposed to an absolute.

Anyway...this is where they get it all wrong. Based on the rules hydraulics, and physics of brake caliper function(not material choice or manufacturing) this is WRONG . Given 2 calipers with same piston area the multiple piston fixed caliper DOES NOT apply more squeezing power than a floating caliper. It cant, Newtons 3rd law and the basics of hydraulics and pressure tells us so. However material and overall design will allow 2 calipers with same piston area to provide differing clamp loads at same brake pressure due to caliper structure, NOT piston arrangement. A monoblock billet caliper can apply more force than a lightweight aluminum floating caliper because the monoblock wont flex. Just like a massive cast iron floating caliper will apply more force than a superlight multipiece fixed caliper. Look at N-body or C5 alloy floating calipers to to see why people are opposed to them. But also look how many guys ditched the stock C6 Z06 8 piston calipers. Caliper material selection and structure/build quality have far more to do with brake feel or clamping load than piston arrangement.

In virtually all examples a fixed caliper is more expensive, they are correct, but often times packaging and mass restrictions based on other vehicle design elements determine caliper choice, this is one likely reason why youll find fixed calipers on 4cylinder Colorado trucks that clearly dont need them when we all know there are floating calipers on much heavier vehicles that would stop the truck perfectly well.

Another way we can tell a common OE 4piston caliper isnt providing significantly more brake clamping force is that GM almost always keeps the floating and fixed caliper piston areas VERY close to each other, and uses the same master cylinder for both applications, if the fixed calipers were far superior in delivering increased clamp load GM would spec a a different master cylinder in order to maintain pedal feel and pedal travel equality between the vehicles. The 2015 Camaro has no less than 4 diffeent front brake setups and engines, they all use the same master cylinder

Some add'l points of my own:
Floating calipers have less failure points, and fewer parts.
Fixed calipers often require more maintenance to achieve consistent pad wear and quiet operation.
Floating calipers typically offer increased wheel clearance.
OE floating caliper/pads typically are not significantly lighter than the floating caliper they replace.

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