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I also rotate pads around to keep them as even as possible between track weekends. This also allows me to minimize the front back taper that also appears on the pads.
 

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@Alipapa - I wanted to clarify a few things with the rear brakes... As @GMS indicated, and you have learned, they are the most troublesome when it comes to track driving. They are quite sensitive to a variety of things. They tend to pick up dirt and debris easily, which impacts performance & operation. What I have learned is this...

1) Thoroughly clean the rear calipers before EVERY weekend
2) File the tabs/ears on the metal brake pad backing to allow easier operation (Thanks for this suggestion, @GMS) - It may require some touchup to get the rust off after the initial filing.
3) Lightly lube the tab/ears and SS clips to allow good motion
4) Inspect the sliding guides, and relube as necessary. - These can seize if you leave the car parked a lot.
5) Rotate pads around to keep thickness variations at a minimum (top and bottom of pad and between pads)

This will help maintain the operation in good working order. With respect to the rear calipers, the term "cleanliness is godliness" is the proper motto.
 

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@Alipapa - I wanted to clarify a few things with the rear brakes... As @GMS indicated, and you have learned, they are the most troublesome when it comes to track driving. They are quite sensitive to a variety of things. They tend to pick up dirt and debris easily, which impacts performance & operation. What I have learned is this...

1) Thoroughly clean the rear calipers before EVERY weekend
2) File the tabs/ears on the metal brake pad backing to allow easier operation (Thanks for this suggestion, @GMS) - It may require some touchup to get the rust off after the initial filing.
3) Lightly lube the tab/ears and SS clips to allow good motion
4) Inspect the sliding guides, and relube as necessary. - These can seize if you leave the car parked a lot.
5) Rotate pads around to keep thickness variations at a minimum (top and bottom of pad and between pads)

This will help maintain the operation in good working order. With respect to the rear calipers, the term "cleanliness is godliness" is the proper motto.
What is your procedure to clean the calipers?Are you using some product to help?

Also wondering how wide are your Advan wheels?

I am a track novice rapidly going down the rabbit hole so I have been reading a lot of old threads like this one. Thanks for posting all these tips for us noobs!
 

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@diegolrz - The 4C is a very rapid car, it can be a handful for a track novice, but you can do it!!!! The 4C was my first track car, and I was able to learn on it. There might be some pain and mistakes over time, but good instruction is worth EVERY penny to minimize those as much as possible. I routinely get comments on just how fast and "flowy" I can get the 4C around the corners and just how brutely fast I am coming out of corners.

Anyways, I clean the calipers with brake cleaner and the blue "shop towels". A good solid spray down, followed by a good rub all over is good enough to keep them clean. I do the "cleaning" when the rear calipers are unbolted and carefully sitting on the A-Arm. The fronts, I just remove the pads and do a good spray and rubdown inside and out. This does a very good job and makes sure you don't collect rubber or dirt that can cause binding. The rears I have had trouble with collecting race rubber and binding, and this is a quick and easy "fix".

The Advan wheels are the "standard" wide version from Matt @ Alfa9Supply. Specifically, the front being 17x8 and rears 18x9.5 et41. With this configuration, I run Falken 615K+ 215/265 wheels. I'm quite happy with this combo (sizes and tires). They are "cheap enough" and can run against the big dogs and typically last me about 6 months of track abuse. They use to last longer, but I'm sliding them around MUCH more than I use to.


Now a word of sage advice that was given to me many years ago... If you want to do upgrades on your car, then that is fine. HOWEVER, focus on safety items FIRST, reliability items SECOND, and then Instruction. Then, and ONLY then, should you upgrade HP. Your ability to drive fast is DIRECTLY related to driver skill, not HP. I have a friend that drives a Porsche GT3. I have to LIFT out of the corners so I don't run him over. Once he gets on the straight, he is gone. But my "Little Alfa" is significantly faster around the corner and I'm on stock power.... This is all due to driver skill and "desire" to push the car to the limit. I'll post a video of me following him when I get some time...
 

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Discussion Starter · #107 ·
An important fact, that I forgot to share...

Revised GMS SLR brake discs now utilize thick rotor core which further helps with heat management. Thin cores quickly overheat and even increased rotor diameter doesn't help much if rotor is thin, that's why you'll see race cars run very thick, but not too large brake rotors. Of course, this adds some weight penalty, but less than 1kg of weight increase for entire assembly is not all that much, compared to the the increased braking capabilities of the kit (torque to the rotor, heat management, brake fade,...).

The weights are:

OEM 305mm x 28mm - Front - 6690g
OEM 292mm x 22mm - Rear - 5660g
Total - 24700g

GMS SLT brake discs 305mm x 28mm - Front - 6890g
GMS SLT brake discs 292mm x 22mm - Rear - 4990g
Total - 23760g

GMS SLR BBK 330mm x 28mm - Front - 6990g
GMS SLR BBK 320mm x 22mm - Rear - 5290g
Total - 24560g
 

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Just a quick testimonial from a fellow Track Addict... I have been running the GMS BBK for well over a year now. Currently have about 12 track days on the rotors, and they have been fantastic. Solid, stiff, repeatable when combined with my PFC-13 pads, Torque RT700 brake fluid, AND brake cooling ducts! Most of my track session are 20 - 25 minutes long. I periodically do Chin TrackDays which does 30 minute sessions, with a 1 hour "happy hour" at the end of the day. I did one of those this past weekend. My "neighbor" at the track was one of the instructors who drive a C6 ZO6 vette. He had been looking at the 4C for quite some time, so we decided to go out together during the happy hour. I spend the first 20 or so minutes driving, and then we hot pitted and he drove for about 20 minutes. He was so impressed with the braking (and how quickly we can change directions). He was surprised that the brakes didn't change even after going back-to-back with a "advanced novice" driver such as myself. It was good to have someone else put words to what I thought I was feeling, which is that even over long sessions the braking is so repeatable you really don't notice a need to even change your brake points .

IMHO, the GMS BBK is an outstanding safety upgrade (along with brake cooling ducts) that will significantly improve your safety and stopping ability over long, hot sessions. It is expensive, but for the SERIOUS track rats it is a great upgrade. [For the more casual track person, I don't think you have to go full Monty with the BBK and other kits are just as effective when combined with brake cooling ducts]
 

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Discussion Starter · #109 ·
We've received a few questions lately regarding the difference between GMS SLT and GMS SLR brakes in terms of "floating" system.

GMS SLT left and GMS SLR right

Product Font Automotive tire Material property Art

Tire Wheel Hood Automotive tire Automotive lighting


GMS SLT discs use simplified “floating” or "semi floating" mounting system which is more common in aftermarket program. It's a decent solution to save the weight and help with heat dissipation as the center bell is made of alu. Disc is directly bolted to the center bell with bolts. This system works well with discs of rather conservative sizes (up to 320mm approx.), where thermal expansion is not as noticeable as it is with large diameter discs.

The GMS SLR discs use true floating system with bobbins (see attachments) which is commonly found in motorsport program. Instead of directly fixing the disc to the center bell, there are slots CNC machined into the alu center bell and the disc is then connected to the center bell via the bobbins which are moving freely within these slots. This renders the discs basically immune to warping as the disc's thermal expansion is not limited with the fixation of the disc to the bell.

For the SLT version, we’ve decided that given the disc size, there is no need for bobbin floating system. We’ve been running the SLT version on our car for 2nd season now, with success in any racing conditions we’ve encountered so far, but our car is also lighter with 940kg, ready to drive. For heavier USA versions, especially Spider, perhaps the SLR BBK is more “safe” option in case of serious racing use. Of course as already mentioned in previous posts, brake pads do matter. It's no sense to run huge discs with standard brake pads, unless you're doing it for the show. Unfortunately, OEM drilled discs won't last long with either OEM or high-end brake pads when driven hard, as the drilled slots will get filled with brake dust and cause uneven wear, further causing vibrations, overheating, cracking and other issues. The "warping" the clients are usually describing is actually uneven disc wear due to overheated brake pads leaving deposits on the disc. Still it's worth to try a good brake pads on OEM disc to get the idea of the importance of the brake pads. Once the OEM discs are "done", it's time to move on to more capable version, SLT or SLR.
 

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Discussion Starter · #111 ·
Hello everyone,

An interesting question from one of the users came up and I though it would be great to share it for those more into tracking and perhaps to help with decision between different disk surface types.

So, after some extensive track use, the groove has generated in the middle of both front discs (see attached pictures below). This is pretty much normal for the J-hook design, regardless of the pads. The reason behind this is that there is J-hook groove machined into the disc’s face and in the red circled area which is somewhat in the middle of the disc, both J-hooks are overlapping, so in this area disc’s surface is smaller than the rest of the disc, so this will wear out the pad different in this area (less wear than on the other area of the pad), so after some time, as the pad in this area is thicker, the brake pad will bite the disc here more than elsewhere. Consequentially brake pad generates more force on the disc face upon braking in this area (green marking on the attached pictures), so the disc in this area wears at higher rate than elsewhere, which will result in generated groove in the disc. Where exactly disc groove generates, depends of the rotor size, J-hook design, size and position, but always on the are where the J-hooks are overlapping. A simple plain disc is the best in terms of even wear under light use, but there are other major drawback's when it comes to track use. The main issue of plain discs is de-dusting of the rotors surface and consequentially pad deposit adhesion following by warping and uneven wear with anything more than a normal road driving.

I have also gathered some photos from other similar disc designs to show similar cases. It is nothing wrong with the discs, but the more aggressive the disc's surface, the more grooves will be generated.

991 GT3 with almost new brake discs, showing an early signs of groove being generated in the middle of the disc.
Wheel Tire Car Vehicle Automotive lighting


488 GT3, with a decently worn out discs and generated groove in the middle of the disc and decent amount of heat cracks due to heat cycles.
Glasses Vision care Automotive lighting Product Eyewear


GMS SLR BBK on a 4C with generated groove in the middle of the disc and some heat cracks due to heat cycles. 1 set of PFC-13 front pads used and now running the 2nd set on same disc. Disc wear is around 27.8mm. New disc is 28mm, while minimal thickness is 26mm. According to the trend, the discs will probably develop heat cracks before running down to minimum thickness.

Tire Wheel Automotive tire Light Tread


Here is also a decent article about different disc face’s / grooves and pros and cons of each design. Our design would be closest to Brembo type 3. How Do Disc Face Types Affect Brake Performance? | Race Technologies | Brembo Official Partner.

I hope you find this post useful and learn something new.
 

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@GMS , I’ve been meaning to ask you, and although this may not be the right place it popped up so I’ll just go ahead.
Might there be any brake cooling products in the works from you? That will probably be a winter project for my track car, and I’d prefer something well conceived and executed like your other products (rather than a DIY experiment on my own). Or is this not enough of a challenge for you compared to the other things on your plate, and I should just suck it up and make something? :D

Thanks.
 

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Discussion Starter · #113 ·
I have CAD drawings since 2019 and prototypes done for the BBK in 330mm/320mm, but more dedication is required to execute this in a proper way that we can offer this publicly. I have things in my head how to do it and what to change, but other priories were on my mind lately. If you don't care too much about the looks you can definitely try your own DIY version. Not much to mess up here. But with OEM size discs 305/292 there is a very little room to make an adapter to blow the air into the discs core. Blowing the air into the discs surface is wrong and should be skipped, but lot of such system on the market lately for other cars. Also where to draw the cold air from is a challenge without modifying the front bumper. I will look into this matter more thoroughly this winter. I'm just finishing the new workshop in the following days, so soon I'll be able to focus back to where my heart belongs to - car tuning.
 

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I have CAD drawings since 2019 and prototypes done for the BBK in 330mm/320mm, but more dedication is required to execute this in a proper way that we can offer this publicly. I have things in my head how to do it and what to change, but other priories were on my mind lately. If you don't care too much about the looks you can definitely try your own DIY version. Not much to mess up here. But with OEM size discs 305/292 there is a very little room to make an adapter to blow the air into the discs core. Blowing the air into the discs surface is wrong and should be skipped, but lot of such system on the market lately for other cars. Also where to draw the cold air from is a challenge without modifying the front bumper. I will look into this matter more thoroughly this winter. I'm just finishing the new workshop in the following days, so soon I'll be able to focus back to where my heart belongs to - car tuning.
Thanks Rudi.
Yes, I think drawing air from new holes in the front bumper would be the best solution - in the portion of the side lobes where there is no mesh. But that’s where we need something attractive like a GMS carbon fibre intake, not a 4Canada hatchet job! ;)
I didn’t know about blowing it into the middle of the disk - every kit that I have seen directs the hose to a flange on the back-plate and I always wondered why that would not lead to warping since it would disproportionately cool only one side. Good to know.
I’m afraid that I’d want this to work on stock rotors - your BBK might dissipate enough heat on its own, but it isn’t a mod that I am ready for (yet). But even if a system designed for your BBK could be modified for installation to the OEM setup, it would help. The front 3/4 is the same, just the bracket at the hub would need attention.

Left in your capable hands.

Best of luck with the shop move! Is this now your built to suit property?
Pictures when you are in, please!
 

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Discussion Starter · #115 ·
Blowing air into the one side of a disc's surface like you mentioned is not OK per exact same reason you have stated.

Yeah on a paper it's my land. I'm in debt for the next 20 years, my hands are rough as sandpaper, my forearms are like a monkey's from all the physical work and I visually and mentally grew older in past two years since biting into this chapter of my life. 125sqm workshop, 125sqm living space. Woods behind the house, one of Europe's best roads 400m away from the house, 100km away from the proper circuit and all the business partners like CNC, water jet, CNC bending, welders, paintshops, tuners, suspension and steering parts partners etc., all within a radius of 25km. Nothing spectacular probably for most of you magnates out there, yet all I ever wanted and dreamed of. Right now it's 23:39 here and I'm listening to guitar shredding in the workshop on some fine sounding Marshalls, preparing orders for dispatch and sorting out my GMS warehouse inventory. I'm sleeping on a couch in my new office since I moved my inventory in, earlier this week. I haven't ate a warm meal since, I take shower every second day outdoors as I haven't finished the bathroom yet, and no one is breaking my balls how to live my life. Life is just beautiful. I almost dropped a tear of joy writing this... 🖤

Here is where the customers and those of you coming for a visit will be met. And yes, this is the couch I sleep on. Small but it serves me well for now. 🥰 The rest of the premises I probably won't share due to privacy concerns, but you can expect regular posts about the work in the workshop.
Comfort Automotive design Couch Grey Luggage and bags
Property Table Personal computer Computer desk Desk
Tire Wheel Automotive design Motor vehicle Toy
Automotive design Shelving Toy Shelf Gas


P.S.: Thanks to each and everyone for supporting us, we couldn't have done it without you. I appreciate every order, inquiry, email, visit, chat or whatever that keeps me fueled and motivated. Thank you so much.
 

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Congrats.
Very happy for you. Yup, nothing great in life ever comes easy. If it did, we could probably have done better.
Sounds perfect. Well, once you get that bathroom working. Doubt your wife will be all too pleased until then! :D But from what you have told us and shown us, it’s a dream come true!
Well done, well deserved.
Best of luck with it!!!
 

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I have CAD drawings since 2019 and prototypes done for the BBK in 330mm/320mm, but more dedication is required to execute this in a proper way that we can offer this publicly. I have things in my head how to do it and what to change, but other priories were on my mind lately. If you don't care too much about the looks you can definitely try your own DIY version. Not much to mess up here. But with OEM size discs 305/292 there is a very little room to make an adapter to blow the air into the discs core. Blowing the air into the discs surface is wrong and should be skipped, but lot of such system on the market lately for other cars. Also where to draw the cold air from is a challenge without modifying the front bumper. I will look into this matter more thoroughly this winter. I'm just finishing the new workshop in the following days, so soon I'll be able to focus back to where my heart belongs to - car tuning.
+1 for a GMS brake duct solution. Let me know when to send the money!


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