Latest brake options for 15" and 1.25" rotors?

[3literpwr]

Hey folks - I'm wondering who might have info on motorsport brake options that allow for 15" wheels and 1.25" rotors? I have been looking at a few options from Tuthill and R to RSR for bolt on calipers, but also running AP SC320 or other motorsport units. I would like to run 11.75" x 1.25" or so front rotors and possibly 930 rears. Not looking at 930 caliper replicas as an options due to the cost.

Anything else out there that offers a fair amount of pad options? This is stage rally car.

[AlistairWallace]

Not mine, but a good reference point

[wjdunham]

Very little off the shelf unless you are willing to spend $5K. I think the StopTech solution is the cleanest for 15" wheels but it's not that much less expensive than 930 caliper upgrades.

If you are willing to do some work - here is how I got 11.75" x 30mm rotors under my front wheels. Rears are stock 930 rotors with modified 964 calipers. Nothing in this solution is really difficult, but the caliper mods are very time consuming. Coleman racing can make almost any size rotor you want for the price of a new aftermarket stock rotor.

(Inexpensive) 964 front brake upgrade, would Bill V. approve?

[Locker537]

The StopTech solution feels like the best compromise of all the solutions.

[ToySnakePMC]

Beautiful cage and overall project you have there. Would love to follow a build thread on this G body.

[3literpwr]

Lot's of great info here.Would love to get some of those hats / rotors in a non-drilled version.

Originally Posted by wjdunham

Very little off the shelf unless you are willing to spend $5K. I think the StopTech solution is the cleanest for 15" wheels but it's not that much less expensive than 930 caliper upgrades.

If you are willing to do some work - here is how I got 11.75" x 30mm rotors under my front wheels. Rears are stock 930 rotors with modified 964 calipers. Nothing in this solution is really difficult, but the caliper mods are very time consuming. Coleman racing can make almost any size rotor you want for the price of a new aftermarket stock rotor.

(Inexpensive) 964 front brake upgrade, would Bill V. approve?

[stevie 77 930]

I ran across this from Elephant Racing the other day. A complete 930 style braking package

https://www.elephantracing.com/911/braking-for-911/disc-brake-calipers-for-911/930-front-caliper-pair/


https://youtu.be/px1hACKqmlk

[Bill Verburg]

Originally Posted by stevie 77 930

I ran across this from Elephant Racing the other day. A complete 930 style braking package

https://www.elephantracing.com/911/braking-for-911/disc-brake-calipers-for-911/930-front-caliper-pair/


https://youtu.be/px1hACKqmlk

The ERP kit is the best currently available for use on 911

[winders]

Originally Posted by Bill Verburg

The ERP kit is the best currently available for use on 911

ERP or Elephant Racing???

[3literpwr]

I have a set of Alcon H calipers with 32mm pistons that I was looking to adapt for rears, or sorting something with the 3.5 bolt center AP racing late model calipers below. Don't know if i'm wasting energy here. Tuthill Porsche folks seems to run stock 3.2 or their bespoke 4 piston calipers. Ironically they use the same piston size front and rear.

http://https://pitstopusa.com/i-5071397-ap-racing-sc320-brake-caliper-front-4-piston-front-lh-asa-legal-1-875-1-75-pistons-11-75-rotor-diameter-x-1-25-rotor-thickness.html

[Cory M]

Cool car. Do you even need big brakes? We have run stock Carrera brakes with the factory master cylinder and booster on the track for many years and they're surprisingly good. Upgraded race pads, fluid, and ss lines along with cooling ducts. This is in a racing application, continuous lapping, threshold braking, Hoosier tires, etc. Seems like rally on loose surfaces would put less stress (heat) on the system?

[Walt Fricke]

My thoughts same as Cory's. Super cage for the higher risks, but more brakes? Stock SC brakes can be made to last on the track, and brake these cars at over 1 G lap after lap, pretty much, on Hoosiers which are nominally DOT, but are about as sticky as a lot of full slicks - on asphalt (some concrete now and then).

[safe]

"This is stage rally car."
How long is a stage and is it gravel or asphalt or both?

If the stages aren't too long stock brakes would be plenty. If you need more brakes just go with the 930 replicas, lot of money, but tried and tested.
The Boxster front calipers on carrera rotors isn't much of an upgrade, but they are lighter than stock.

[Locker537]

Originally Posted by Cory M

Cool car. Do you even need big brakes? We have run stock Carrera brakes with the factory master cylinder and booster on the track for many years and they're surprisingly good. Upgraded race pads, fluid, and ss lines along with cooling ducts. This is in a racing application, continuous lapping, threshold braking, Hoosier tires, etc. Seems like rally on loose surfaces would put less stress (heat) on the system?

I'm a novice on the track, but this was my thought as well. I run "Wide A" calipers from the Carrera 3.2 with ducts for cooling on the front and they are very reliable. The car has been setup this way for over a decade. Probably closer to two.

[3literpwr]

Good questions above, but i'll give a few data points as to why i'm going this route.
First off, stage rally is a wildly challenging environment for cars. Having road raced first, it's very difficult to understand the environment unless you've done it. I have rallied since the early 2000's and built a number of cars, all with stock-ish caliper setups. While not 911's, these cars have torched calipers boots, faded and induced fear on many stages. I have also had a 944S2 NASA / PCA car that I ran before too.

A couple factors to keep in mind.

1. Rally stages can be long! In many cases, rallies are normally 100-140 miles total. These races are run in blocks of stages and one might go out for 20-50 miles of racing in one stint. I have in many occasions, finished a 10-20 mile stage and pulled right up to the next competition stage start with my car and brakes overheating. It's like running a enduro stint at the track, pulling into the pits and heading right back out.

2. Rally tires have WAY more grip than people think! And, speeds on stage vary wildly from 20mph corners to 120mph straights in the woods. It's also important to remember that while a race track might have 10-20 turns total, rally stages will have turn after turn of roads you've likely not seen before.

3. One of and most important skills in rally driving, is left foot braking! While useful on track car, it really becomes a key to speed and control in rallying. Once mastered, you'll use your left foot to balance the car, induce pitch to get grip and most importantly aid in turn in. This is the step that road racers often seem to learn last, but never go back once they become accustom to it. This does however, induce way more heat into the brake system. https://www.youtube.com/watch?v=sP7opLTgeLw

4. Forest rally and rally in general leaves little margin for error. Doing nearly 100mph on a forest road requires lots of confidence and having brakes fade is not rad. With little no room to run off course, leaving the stage surface is not an option.

5. Few run rallies here in the states in 911's, but europe still has a fair share. Most everyone running there is in a FIA historic class that requires stock or 930 parts. It's well documented that stock parts are only good for so many stage miles and pad wear is a major issue.

[safe]

Number 3 is probably the biggest issue, you need to ride the brake a lot so they don't get to cool down between applications.
I think the Elephant Racing replicas is a no-brainer.
I use 930 brakes on my Targa and rear 930 + 928S4 fronts (caliper and rotors) on my coupe. The later fits barely under the right 15" (split rims with thin barrels), but I'm not sure I would recommend that, specially on a rally car.

[VFR750]

Stop Tech level 2 track version will fit inside 15” front wheels. The version that uses the 20mm pad

I run Pagid RSL-29 pads, I think they are pad shape 2555. This is not listed as compatible, but side by side shape comparison reveals a difference of 1-2 mm. Interchangeable with DR-21 shape.

Stock rear with RSL-29 pads. The rear rotor and pads are just fine as is. Mainly because they don’t have to accommodate faded fronts.

Best part is the master cylinder and booster do not need to be changed. Very powerful. Seem to be fade proof on a 2600 lb car. I found it was easy to overbrake. The brakes feel the same after lap 2 through lap 25.

Downside is they squeal loudly under trailing brakes or light application.

Stop tech upgrade was substantially less expensive than 930 parts. Because nothing else needs to change.

I paid $1749.00 for the front kit.

[VFR750]

Originally Posted by AlistairWallace

Not mine, but a good reference point

I made the table. Went with st43 fronts. Stock rear

You do not need the 930 master cylinder.

The piston sizes in the st43 caliper are sized specifically to match the ATE 48mm piston area. I confirmed this both by asking and measuring the two pistons (each side).

This is an older table.

[glerbone]

I just picked up a set of the tuthill calipers. You run them with the stock 19 mm master cylinder and the rear rotors for a standard Carrera 3.2 rotor for the rear and there are two piece rotor and hat set up for the front. They are light and appear to be high-quality. They’re designed to go on a rally car so you know they are going to hold up. They have been using them on cars for years now. I weighed the same options as you and they appear to be as good as running 930 breaks and maybe with better heat dissipation. They were less than half of buying a set of 930 calipers and rotors

[3literpwr]

These!