Saturn Sky Forum banner

1 - 17 of 17 Posts

·
Premium Member
Joined
·
176 Posts
Discussion Starter #1
The DDMWorks Big Brake kits are for the front only.

Is there also a Big Brake kit for the rear that's sold out?

Does anyone recommend 'em?
 

·
Super Moderator
Joined
·
6,459 Posts
What is your goal for the brakes, appearance or performance?
 

·
Premium Member
Joined
·
176 Posts
Discussion Starter #3
What is your goal for the brakes, appearance or performance?
Performance is the priority - appearance is second priority. I'm not driving a race car through the canyons of So Cal. I just like high power brakes.
 

·
Registered
Joined
·
2,571 Posts
No need to touch the rears aside from choice of pad material.
Actually, changing pads does a huge amount on the fronts as well, so unless, as John said, you are looking for looks, you probably don't need big brakes on the front for the street either.

I really didn't like the performance with stock pads with hard street driving and changed mine pretty soon after I bought the car. Now very happy with them.
 
  • Like
Reactions: Rob the Elder

·
Registered
Joined
·
985 Posts
Though my brakes work properly and have some decent pad remaining, I plan to do a full brake job this spring. If time becomes limited, then I will just do a brake line flush. But I hope to make things pretty like I've done on other vehicles including a Solstice GXP.

I bought Bosch pads and front rotors. They discontinued rear rotors so I settled on a pair of OEMs I got cheap off Amazon. The rears won't look as pretty as the corrosion-protected Bosch, but offer some rust protection.

My plan for the front cast iron calipers is to remove them, file and/or grind rough cast edges nicely, sand blast them, and hand paint them while off the car.

I am hoping the rear alloy calipers will clean up nicely, maybe using a gentile solution of CLR and a toothbrush if needed.

I don't care for flashy caliper colors. I really like simple gray painted ones to look OEM perfect like the example here I did on a Solstice GXP. But as you can see here, I did not remove the imperfect edging that I plan for my Sky. The paint used here was simple Rust-Oleum gray, not a high temp paint. I am trying to secure a brush-on silver used for barbeque grilles.
114715

114716

114717
 

·
Super Moderator
Joined
·
11,445 Posts
Performance is the priority - appearance is second priority. I'm not driving a race car through the canyons of So Cal. I just like high power brakes.
I was coming down S6 on Mt. Palomar with stock brakes and pads. S6 is in San Diego and drops something like 4,000' in 7 miles. It is a steep downhill with tight switchbacks. I took it "easy" (relative term and I was probably a lot more spirited than I should be) and used compression and a low gear go keep the speed down but the grade is steep enough that I was still picking up a lot of speed between corners. The brakes were fading so I was trying to use them as little as possible. Half way down I was in a corner that wound up tightening up at the end. I was carrying a lot of speed and tapped the brakes to bleed it off and tighten up the corner. Nothing. No brakes what-so-ever. I wound up on an embankment and then back on the road. The embankment wasn't much larger than the car and had I gone off 10 feet shorter I would have gone off the side of the mountain. Better pads probably would have prevented that but I wanted more than "probably".

I went with the TCE 6-piston 13" front Wilwoods and their 12.3" single piston rears.


114718


114719


The fronts are overkill but I pushed the car as hard as I wanted to coming down into Palm Springs on the twisty highway coming down from Silent Valley. These brakes got better with a good amount of heat and no matter how hard I pushed, the brakes stayed that way. These brakes make me feel much safer than the stock ones ever could.

The DDM 4 piston brakes are still Wilwoods and probably still overkill but Wilwood makes some great brakes. I love mine and a pair of front 4-piston or 6-piston Wilwoods would be a great upgrade even if you never need that level of fade resistance regardless of where you get them from.

As for rears, it's up to you. I wanted my rears to look as good as my fronts so I did the WIlwood rears (and both powder coated a custom color...only black and red are standard for TCE kits). They are still only a single piston caliper but have a larger rotor. Front to rear bias is still very balanced with this setup. The rears are MOSTLY for looks but I would go mental if they didn't match the fronts. That's just me though.
 

·
Registered
Joined
·
2,571 Posts
Brake fade can be terrifying, but I think you are right - you could have cured it with pads alone. The question is whether the pads you would have to use would be in a range where they were less than race only, i.e. they would perform well cold too. The EBC Reds I use on the coupe are great even for descending mountains and they have excellent grip cold as well, but if I were actually out on a track doing hot laps I knw that they would be insufficient.
 

·
Super Moderator
Joined
·
11,445 Posts
Brake fade can be terrifying, but I think you are right - you could have cured it with pads alone. The question is whether the pads you would have to use would be in a range where they were less than race only, i.e. they would perform well cold too. The EBC Reds I use on the coupe are great even for descending mountains and they have excellent grip cold as well, but if I were actually out on a track doing hot laps I knw that they would be insufficient.
I'd say the pads I got with the Willwood kit work very close to the OEM or the aftermarket Hawk pads I've ran on the OEM brakes but once hot, these things are far superior. Are they worth the extra cost for the extra performance? Probably not for most. For me though, that peace of mind (and hot looks) were worth every cent.
 

·
Premium Member
Joined
·
4,196 Posts
Since I tow a two car hauler periodically and live in Colorado, we have gained significant experience with brake fade with the stock brakes on the Ram and drum brakes on the trailer. The first steep hill we went down fully loaded into Bailey for club breakfast on the way to Gunnison, by the time we got to the tight right hand corner at the bottom we glided past the turnout because there was almost no brake at all.

This caused me to go study the mechanism that makes up brake fade.

Turns out there are two different major causes for brake fade. First is the build up between the pad material and the brake disk surface. As some brake pads heat up, they begin to outgas products from their manufacturing process. This gas creates an "air gap" between the pad surface and the disk surface. This type of fade can be addressed by selecting different pads that don't decompose during the higher heat of this demand loading. Slotted brakes help sweep away the built up layer of outgassing and holes in the disk increase the cooling surface area to potentially help lower the temperature of the disk.

The second type of brake fade is what I was experiencing. Brake fluid is hygroscopic. As soon as the fluid is exposed air - when you open the bottle of fluid or through the brake lines and the brake fluid reservoir- it sucks up water. The water does not mix with the brake fluid and instead being heavier than the brake fluid, migrates to the lowest points in the system. The lowest point in the system is generally at the brake pad where the actuator becomes contaminated with water. As you make high demands on the brakes, the disks and pads heat up, which in turn heats up the brake actuators at the wheel. The heat eventually causes the water in the fluid to boil and turn into a vapor. This is when the brakes "go away" because the incompressible brake fluid is pushing against a pocket of steam that is between the fluid and the actuator.

There are two key characteristics for brake fluid rating. Life span and operating temperature.

DOT 3 fluid is rated for THREE years life. After three years it MUST be changed. The reason it fails is because it absorbs enough water to become ineffective when you really need it.

DOT 4 fluid has a rating of TWO years. But it also has a higher operating temperature. The DOT2 boils at 284F while the DOT 4 boils at 311F

I have gone to DOT 4 and change it in all my vehicles every 2 years. For most of the Club cars we change it every 3 years with DOT 3 which is what the factory installs.

Their primary differences are their wet & dry boiling points and their composition.
Dry Boiling PointWet Boiling PointComposition
DOT 3205°C/401°F140°C/284°FGlycol Ether
DOT 4230°C/446°F155°C/311°FGlycol Ether/Borate Ester

The stock brakes on the Kappa are very good but the pads are not designed to perform in extreme thermal conditions. I went with pad change on our cars and the performance was noticeably better. Since we started changing the fluid regularly, that has not been a continuing issue.
 

·
Registered
Joined
·
2,571 Posts
Excellent point! Many owners of old sports car leave the fluid in there for years as they are basically show cars driven occasionally and never very hard. God help them if they ever have to stop quickly down a mountain or something. I got into the habit of bleeding the fluid out of the calipers on the race cars between races and doing a full change once a season. I changed the fluid on the Solstice last year and intend to do it again next year. I bet not many owners bother changing it until something else needs servicing.

Although experiencing serious brake fade is often a scary enough thing that it might convert many of them!
 

·
Registered
Joined
·
23 Posts
The "outgassing and air gap" is not really common any more, that was years, decades ago. New brake pads will not do that, and I've never heard advice to buy slotted or drilled rotors from race car drivers/people. My experience/knowledge is that propertly vented rotors have more surface area; slots and especially holes can cause stress fractures (when not radiused). Modern race car rotors will have holes for cooling, and pro race cars have lots of brake ducting to make sure they get the desired temperatures; conditions not applicable to street cars.

I also agree a fluid change on a regular basis is extremely important, too many people never do that.
And downright overheating and pad/rotor glazing is the other main problem, some pads will just melt at extreme temperatures, all pads have a heat range.
 

·
Registered
Joined
·
2,571 Posts
One other issue we have seen a fair bit on the track is drivers who don't follow approved pad break in. Do it wrong and sometimes the only way to rectify it is to turn the rotors and start again.
 

·
Super Moderator
Joined
·
11,445 Posts
Troy, how much fabrication was required to fit the TCE 13's?
Additionally, did you require a spacer for the wheels to clear the calipers?
Thanks
None and none. They were a direct bolt on affair. I also have aftermarket wheels but these things feel like they have substantial clearance over stock. They are designed to work with stock wheels.

I've never heard advice to buy slotted or drilled rotors from race car drivers/people. My experience/knowledge is that propertly vented rotors have more surface area; slots and especially holes can cause stress fractures (when not radiused). Modern race car rotors will have holes for cooling, and pro race cars have lots of brake ducting to make sure they get the desired temperatures; conditions not applicable to street cars.
When I bought my Wilwoods I talked to them about slotted and drilled rotors. For street driven cars they do not recommend drilled rotors. Drilled rotors are prone to cracking and unless you are inspecting them every week and are okay replacing them often then leave them for track only cars. Slotted are fine. I have never heard of slotted rotors cracking.
 

·
Registered
Joined
·
589 Posts
Slotted rotors yes....drilled rotors, unless you solely race the car, no. Drilled rotors are worse then sandpaper on a pad. I worked for Akebono for 2 years and learned more about brakes then I ever cared to learn. We were actually going to fit a pair of calipers to my car from an Audi last summer, but COVID hit and we were never back in the office after March...and most were layed off in July. We had a saying about ceramic pads, "clean wheels, no squeals"
 
  • Like
Reactions: Robotech

·
Registered
Joined
·
6 Posts
The DDMWorks Big Brake kits are for the front only.

Is there also a Big Brake kit for the rear that's sold out?

Does anyone recommend 'em?
I changed the rotors and pads on my car - a cheaper alternative to bigger. I went with R1 drilled and slotted rotors and Hawk HPS blue pads - my car stops hard now, not mushy like stock.
 
1 - 17 of 17 Posts
Top