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Project DBA R35 GT-R: Upping Stopping Power with Brembo and Race Technologies

by Mike Kojima

 

As you can see so far in this series, we are doing a lot of things to fight the weight of the GT-R. At 3800 pounds, the GT-R wheels throw around a lot of mass with a great deal of speed and grace, but it can only do it for short periods of time before the weight takes its toll, mostly on the brakes and tires.

Well, we are working on the tires part with bigger tires, less rotating and unsprung weight and tuneable suspension to get the rubber on the road better. Now its time to work on on the brakes.

One thing about the brakes is that the GT-R already comes with huge brakes, almost the biggest you can stuff in the 20" wheels. The front brakes are huge 6-piston Brembo units, and the rear are 4-piston. The stock front rotors are large 390mm x 32.8mm and the rear are 380mm x 30mm.  Those are some serious brakes.

However, the GT-R is a seriously heavy, powerful and fast car, and to cope with this, Nissan uses a very aggressive brake pad that quickly wears the rotors and makes horrible dust. We would drive for a couple of miles to dry the brakes after washing the wheels and in that space, the wheels would get dusty again!

Big brakes, aggressive pads or not, you can't fight physics, and when a GT-R is equipped with sticky tires, the brake will cry uncle after a few laps around the track. So, we will plan some mods that will let us have decent stopping on the street without killing rotors and making tons of corrosive dust, and it will be the biggest thing you can use that will fit in the stock diameter wheels to be the ultimate in stopping on the track with race pads.

Read more about Project GT-R!

 

Since the GT-R is heavily controlled by electronics, probably being one of the most heavily electronically controlled cars produced, we didn't want to mess with the hydraulic proportioning of the brake system at all, hence our use of the stock calipers. 

The system is engineered by Brembo and distributed/supported by Race Technologies LLC, which is Brembo’s performance partner in the USA and other select overseas markets. The Brembo R35 GT-R upgrade consists of 2 piece disc assemblies, caliper spacers, and brake pads. 

 


The front Race Technologies rotor is 405mm in diameter and 34mm wide. This is an increase from the stock rotor, which is 390mm in diameter and 32mm wide. The new rotor weighs 29 lbs compared to the stock 26.4 lbs- an increase of 2.6 lbs. 

The Race Technologies disc assembly is Brembo’s high thermal rotor, which means that the faces of the rotor are proportionally thicker and the vent air gap narrower to give the rotor a higher thermal mass and more heat capacity. This is one of the reasons why the rotor is heavier than stock. 

The rotor is a full floating type with the rotors floating on large steel spacers. This gives a larger surface area for the braking forces to bear on to reduce wear on the aluminum hat. Floating rotors allow the friction ring of the rotor to move freely against the hat. This prevents the rotor from distorting into a cone shape with heat, this giving a harder pedal and better braking. 

The rotor bolts have stainless leaf springs that put tension on the rotor to disc interface so the rotor won't rattle against the hat. This is a good feature on a street car. Race cars don't use these because who cares about noise!

 

The hat mounts the rotor on pillar vents machined into the hat which allows air circulation between the hat and the rotor. This helps keep heat out of the knuckle and hub bearings. 

You can see how narrow the air vents are on the high thermal capacity spec rotor compared to others you might have seen. You can also see how thick the friction faces of the rotor are.

 

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Comments
8695Beaters
8695Beaterslink
Monday, January 15, 2018 6:20 AM
Interesting how the pads sit below the caliper. Does this cause any ill effects long term? Like uneven wear on the pad or rotor? I could potentially see the pads wearing with a taper, becoming thinner on top than on bottom due to the resultant pressure point not being centered on the pad.
spdracerut
spdracerutlink
Monday, January 15, 2018 8:37 AM
It doesn't look to sit too far below. Assuming the brake pad backing plate is stiff enough, shouldn't be an issue. But you know how it goes, always a compromise somewhere and this is a compromise in using the stock calipers. Good trade off IMO as it's a major cost savings along with potentially not messing up the stock ABS system.
Mike Kojima
Mike Kojimalink
Monday, January 15, 2018 10:49 AM
I assume that it isn't ideal but I will take the gain in swept area.


warmmilk
warmmilklink
Monday, January 15, 2018 12:26 PM
So what does Project "DBA" stand for? I thought it was DBA rotors and stuff, but you guys are using Brembo stuff, so that's not it. Where does DBA come in?
warmmilk
warmmilklink
Monday, January 15, 2018 12:35 PM
Do you guys have pics of how the adapter bracket attaches to the car? I'm just curious cause it looks kinda weird... only 3 holes? I'd think it'd need 4...

Also, doesn't the brake proportioning with the bigger front rotor and the caliper sittig further out from center? Doesn't that effectively give it a bigger torque arm when the same amount of braking pressure is applied?
Mike Kojima
Mike Kojimalink
Monday, January 15, 2018 1:08 PM
DBA is the chassis code for the second gen GT-R starting in 2012.
Mike Kojima
Mike Kojimalink
Monday, January 15, 2018 1:12 PM
Our FNG messed up and didn't get a picture of the spacer on the knuckle. It is not an adaptor bracket so it only needs 2 holes. As far as the proportioning, the rear brakes have more swept area as well and the front has more leverage and more swept area but more braking is done by the front. So far it seems to work ok. If it doesn't when we drive the car harder we will note that in future articles. Brembo does OEM level development and is the OEM supplier of brakes for this car so I assume that this is all well thought out. While bedding in the brake, they felt really good.
warmmilk
warmmilklink
Monday, January 15, 2018 2:30 PM
haha, had no idea DBA was the chassis code...

I'm not trying to imply it doesn't work, just that the whole "brake proportioning isn't affected" was repeated multiple times and that didn't make sense to me with the bigger rotor and adjusted caliper location.

Now that I'm thinking of it as a spacer rather than adapter, I think I figured out how it sits.

how thick are the brake pads on a GT-R? does going to this thicker rotor require getting a thinner pad?
Mike Kojima
Mike Kojimalink
Monday, January 15, 2018 2:42 PM
You know I didn't measure how thick the pad is but it's not a problem because the caliper is designed to take this thickness of rotor. In fact, the CBA GT-R had a 380mm x34mm rotor with the same caliper. The DBA went to 390mmx32mm.
Colorado S14
Colorado S14link
Tuesday, January 16, 2018 2:14 PM
Warmmilk, these are radial mount calipers and as such to move them out you space them up. With a lug mount caliper (what I bet you are picturing) you are right you would need the 4 hole spacers.
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