[Lifetime Goat]

I was going to upgrade my stock front rotors and pads and read that a lot of people only upgrade the pads. If my goal is to get better stopping power from 90 back to 30 do I have to replace the rotors and pads or is there a good pad that will work with my existing stock rotors?

[64speed]

I used power stop rotors, affordable drilled and slotted and they are zinc coated so they don’t rust.

[Formula8]

I am no expert but I can tell you pad compound plays a pretty big role in this. Especially for a single stop like you are describing. I had a NOS GMPP pad on my brake conversation that had outstanding initial bite and overall stopping power. Unfortunately, it made a ton of noise under braking and produced even more brake dust than noise. I ended up changing to Powerstop Z26's which cured the dust and noise, but the strong initial bite went away as well. Overall stopping power might be the same but I have nowhere near the confidence in them as I had in the GMPP brakes. Bottom line is I think this is like picking a cam. There is always going to be some compromise involved.

[64speed]

Oh forgot to mention. Yellow compound hawk pads

[Steve C.]

"Save the drilled rotors for cars-n-coffee crowd"

https://nomoneymotorsports.com/2019/...smooth-rotors/


.

[Schurkey]

LOOK at the pads you're buying. There's a two-letter code on them somewhere; the further down the alphabet the better the stopping power.

First letter is "cold" braking, second letter is "hot" braking.

https://www.motortrend.com/how-to/di...des-explained/


But the sad truth is that the tires, wheels, and brakes were so undersized for so many decades that there's not a lot of hope for "stock" parts in a genuine high-performance application. 11 inch front rotors aren't big enough for REAL stopping power. That said, with decent pads and rear brakes, and if the whole system is in good condition including the fluid, the stock stuff works "OK" for most street use; or one-and-done stops from higher speed. Keep in mind that the most-contaminated fluid in a brake system tends to be at the low points of the system--the wheel cylinders. Which also means that's the hottest fluid in the brake system. Boiling water in the brake system is not a good thing.

If this is about a GTO, (GM intermediate) they tended to have 9.5" rear drums. Upgrading the rear to the 11" drums makes a lot of sense, costs very little, and doesn't screw-up the park brake if you have a well-stocked Treasure Yard.

[78w72]

agree pads make the most improvement, but new rotors are pretty cheap if the originals have been turned before & getting thin. i use powerstop slotted rotors with hawk HPS pads on a 72 firebird, it stops noticeably better than my 81 4 wheel disc car with stock pads/rotors.

im not sure hawk sells colored pads, thats EBC last i checked. the hawk HPS pads are excellent, have very low dust & dont require any preheating like some performance pads do, they arent too hard on rotors either. the advice i was given for rotors is to not sue fully drilled on the street, they are prone to cracking, slotted are a step above stock & all thats needed for a street car.

[ZeGermanHam]

To get one thing out of the way right off the bat, drilled and/or slotted rotors are just for looks, and don't make the car stop any quicker. Back a looong time ago, drilling & slotting rotors was workaround for preventing brake fade due to gas buildup between the pad & rotor surface during extreme heat scenarios. Modern pad compounds do not experience gas buildup at high temps like the old pads did, so the slots & drilled holes are no longer needed to prevent fade. On a street car, there is ZERO benefit to having slotted or drilled rotors - none - because your brakes will never get hot enough to begin with. It's pretty much the same story in high heat track settings with modern pads. As a track (road course) instructor, I have spent countless days lapping cars and hauling them down from 130, 140, 150mph+ lap after lap right on the threshold of ABS engagement (i.e., maximum braking) using non-slotted, non-drilled rotors. I avoid drilled rotors for track use due to their susceptibility to cracking, but that's not a major concern on the street due to lower demands. Regardless, I think drilled rotors just look cheesy, so I stick with blank rotors, but will use slotted (only) if that's all that is available. It's also important that the slots do not extend to the outer edge of the rotor (makes them crack more easily), and the slots on cheapo rotors often do, so be on the lookout for that.

Pad selection will make the biggest difference in braking performance if you aren't changing the size of the rotor or the type of caliper. The pads that come with most disc brake conversion kits are total junk and should be thrown in the trash. Personally, I prefer semi-metallic pads made by Performance Friction (PFC). I do not like carbon ceramic pads due to their low initial bite characteristics, although they are very low dust, but I don't really care about that. Never been a big fan of Hawk products, and have witnessed numerous negative experiences with them at the race track over the years. On a road car they will be fine, but I just prefer PFC.

[prostreet64]

I recently installed new stock style rotors and am considering new calipers and pads. In the Dec issue of HMM they have an article on the Wilwood D52 replacement 2-piston calipers which come with their own BP10 pads. Does anybody have any experience with the pads? The calipers sound like a pretty good upgrade over factory, but I want to make sure I get the right pads for my street/strip TransAm.

[geeteeohguy]

Originally Posted by 64speed

I used power stop rotors, affordable drilled and slotted and they are zinc coated so they don’t rust.

How many miles do you have on them and under what conditions?

[firechicken]

I've had the drilled, slotted and zinc plated power stop rotors on my car for like 10 yrs or so. Summer street driving and 1/8 mile racing. They've been fine and still haven't rusted. Not that many actual miles I guess since I'm still on the same pads that came with them.

[JLMounce]

Originally Posted by prostreet64

I recently installed new stock style rotors and am considering new calipers and pads. In the Dec issue of HMM they have an article on the Wilwood D52 replacement 2-piston calipers which come with their own BP10 pads. Does anybody have any experience with the pads? The calipers sound like a pretty good upgrade over factory, but I want to make sure I get the right pads for my street/strip TransAm.

I have the Wilwood D52 front and D154 rear calipers with the BP10 pads. Are they better than the pads that came with my standard disc kits? Yes. Would I necessarily recommend them if you were simply buying them to go in your factory calipers? Probably not.

The initial bite is a bit weird with them. They don't grab instantly, but tend to ramp into a pretty heavy bite at minimal pedal effort. It makes being smooth around town interesting.

I haven't had them in any performance or panic stop situations, so I can't comment on that.

I will say that my favorite street pad that I've used over the years is the old Bobcat compound pads from Carbotech. I believe that compound is now called the 1521. It's a great street performance pad that has good initial bite, modulates well, is very low noise and dust.

It's not meant for real performance applications like auto x or open track though, it doesn't deal well with temps over about 800 degrees.

[78w72]

ive read the d52 calipers dont have as much piston area as a stock single caliper so not as much or even clamping force? have considered them for weight savings but never tried them.

for the pads, i am very happy with the hawk HPS pads i use, they dont require any heat up on the street, bite feels the same on first couple uses as they do after 20 uses. excellent pedal feel & very low, light colored dust after months of use that wipes off with a dry rag, & no signs of aggressive rotor wear.

im not a auto-x or road racer but my comparison besides the street use are with 2 other 2nd gen cars i have with good working newer brakes, i drag race them all at different times/speeds. the 78 T/A has semi metallic fronts & stock drum shoes rear, runs mid 13s at 103+mph, the track has 3 exits at the end, it requires very hard force on the pedal to make the 2nd exit & still very firm using the last one.
the 81 301t car has stock 4 wheel disc with older performance friction brand carbon front pads & stock organic rear pads, it runs mid 14's (2 seconds faster than stock & is 99% stock) with hard pedal it will make the 1st exit but 2nd is what i use so im not stomping on the brakes.
72 firebird with a 500+hp 467 stroker runs low 11's but does 121-123mph (has traction/launch issues) its stock disc/drum with slotted rotors & the hawk HPS pads, stock rear drums/shoes, at 121+mph it will make the 1st turn off pretty easy with just medium pedal force but i usually go to the 2nd exit.

crazy how just some good front pads can make a huge difference over even a 4 wheel disc car going 20+mph slower.

[prostreet64]

JLM, thanks for your input. I may give them a try and then adjust accordingly.

[JLMounce]

Originally Posted by 78w72

ive read the d52 calipers dont have as much piston area as a stock single caliper so not as much or even clamping force? have considered them for weight savings but never tried them.

The difference is pretty negligible. The factory single piston design has a piston area of 6.77" while the Wilwood D52 replacement has 6.28" of piston area.

Because the Wilwood caliper is much stiffer than the iron GM caliper, you do end up transmitting more pressure to the pads and rotor.

Where the area sizing can start to get a little weird is when you're looking at the rear calipers which will typically be a D154. That caliper has several different piston size designs available. Depending on what the car needs and how it's used, one size may be better. There are 1.19" dual piston and 1.62" dual piston versions. Typically you're going to want the smaller of the two for natural brake balance, which is the direction I went.

That said, the system doesn't like the larger bore master than I have along with the GM disc/disc combination valve. The combination valve is mostly the problem as it will decrease pressure to the rear brakes in hard braking applications and with the larger bore master cylinder, there's not enough pressure out back. This winter I'll be going to a 1" bore master and ditching the combination valve for a proper proportioning valve.

[78w72]

Originally Posted by JLMounce

The difference is pretty negligible. The factory single piston design has a piston area of 6.77" while the Wilwood D52 replacement has 6.28" of piston area.

Because the Wilwood caliper is much stiffer than the iron GM caliper, you do end up transmitting more pressure to the pads and rotor.

Where the area sizing can start to get a little weird is when you're looking at the rear calipers which will typically be a D154. That caliper has several different piston size designs available. Depending on what the car needs and how it's used, one size may be better. There are 1.19" dual piston and 1.62" dual piston versions. Typically you're going to want the smaller of the two for natural brake balance, which is the direction I went.

That said, the system doesn't like the larger bore master than I have along with the GM disc/disc combination valve. The combination valve is mostly the problem as it will decrease pressure to the rear brakes in hard braking applications and with the larger bore master cylinder, there's not enough pressure out back. This winter I'll be going to a 1" bore master and ditching the combination valve for a proper proportioning valve.

thanks for the info on the d52's, if they dont have less clamping force i will consider using them.

[prostreet64]

78w72, I appreciate the input. I have only made a few 1/8 mile passes on the new 463 in the Trans Am. I hope to make it into the 10s for the 1/4 mile after I have worked out the final settings for the engine and suspension. Fortunately we have a long track at Gainesville Raceway. The first turnout is maybe 1/4 mile or more past the finish line and then there is one at the very end of the track. My son's car, the 69 Bird, has run 118 and with factory front disc and rear drum and box store pads it does not take any great amount of pedal effort to make the first turn off. That is with power brakes though. I think if my car ends up running near 125 I will be in good shape with the Wilwood calipers and the 'right' pads. Hope to find out early next year when the test and tunes resume.

[Verdoro 68]

I've had the D52s with stock rotors on my car for a few years now. I was never happy with the way the stock single piston setup stopped the car and saw a noticeable improvement with that D52s in regular street driving. Most of that improvement was probably because of the pads, but I'm happy with them. The pads do put out what I'd consider a decent amount of dust though.

[78w72]

Originally Posted by prostreet64

78w72, I appreciate the input. I have only made a few 1/8 mile passes on the new 463 in the Trans Am. I hope to make it into the 10s for the 1/4 mile after I have worked out the final settings for the engine and suspension. Fortunately we have a long track at Gainesville Raceway. The first turnout is maybe 1/4 mile or more past the finish line and then there is one at the very end of the track. My son's car, the 69 Bird, has run 118 and with factory front disc and rear drum and box store pads it does not take any great amount of pedal effort to make the first turn off. That is with power brakes though. I think if my car ends up running near 125 I will be in good shape with the Wilwood calipers and the 'right' pads. Hope to find out early next year when the test and tunes resume.

the turn offs at my local track are much shorter than that, ive never measured them but maybe the 3rd is close to 1/4 mile, the second seems to be 1/8 mile or less. im sure your car will be fine at 1/4 mile turn off with mostly stock brakes, try some hawk HPS or other entry level performance pad & im sure you will notice an improvement.

im shooting for high 10s myself if i can dial in the suspension that is not set up for drag racing at all. plus i have a occasional fuel starvation issue i have to deal with if i want to go any faster, but this is mostly a street car & im more than happy with ow 11s on box stock 722 E-heads & a ported HO intake with cliff built q-jet!

[prostreet64]

I know the feeling. On my son's car we had to go to 1/2 " fuel lines and sump the tank to get past a fuel starvation issue early on. He is still running the q-jet on an rpm intake and iron heads. I had already updated my car even with the 403 because I knew I would need better fuel delivery at some point. What is your 1/8 mile time and mph with your current setup? I went 7.01 at 99 on one of my 4 passes which is all I have to go by for now. I was carrying 150 lbs extra in the trunk and still have a # of tuning variables to work out. Regular race weight is 3650 with me and 1/2 tank of fuel.