October 2020 Fastrack - The Brake Rules...

[ERVRCG]

I meant to put this here, but put it in the survey thread instead.

I think that restricting the rotor size with the wheels is a mistake. It's exactly the kind of rule writing we want to avoid because it invites experimentation and expenditure...not only on brakes, but now on wheels.

And since you can't bitch without offering an alternative, here's an idea that would at least keep a lid on some of that:

EP = 13 inch max or stock diameter if larger

FP/HP = 11 inch max or stock diameter if larger

It's not experimentation...I will design my brake package to the $2500 spun aluminum wheels and have to beg the wife for a couple more sets. Soon for sale several sets of panasports...

 

[Tom Feller]

I meant to put this here, but put it in the survey thread instead.

I think that restricting the rotor size with the wheels is a mistake. It's exactly the kind of rule writing we want to avoid because it invites experimentation and expenditure...not only on brakes, but now on wheels.

And since you can't bitch without offering an alternative, here's an idea that would at least keep a lid on some of that:

EP = 13 inch max or stock diameter if larger

FP/HP = 11 inch max or stock diameter if larger

It's not experimentation...I will design my brake package to the $2500 spun aluminum wheels and have to beg the wife for a couple more sets. Soon for sale several sets of panasports...

Thank you. My point exactly.

 

[Matt Blehm]

I'll put a moar gooder 4piston caliper and a smallish 2-pc rotor that I can easily get replacements for and call it a day. small, light, easy, does the job.

 

[blamkin86]

Run really large rotors? Just like running the largest wheels. Takes more power to turn them .
Run the smallest rotating parts that will do the job .
Al these guys are gunna put on big brakes and 40# and go slower. Stops gooder tho.
Gooder.

2675 * 2% = 53#

Luckily I've been running overweight all year anyway. May as well have the brakes.

Write your letters people. You know for certain now that whining here does nothing.

 

[hpmowog]

.....and when the guy who hasn’t bought the $2500 wheels so he can max out the brake package on his car writes a letter requesting a competition adjustment, what will the reply in Fasttrack look like?

“Request denied, car not fully developed.”

 

[TONY MACHI]

"Any other non-stock brake calipers and/or non-stock-size brake rotors may be used with a penalty of 2% of the base weight."
1900 the base weight+gear change=1948. + 2% of 1900 or 1948? How is it calculated?

 

[anviltester]

"Any other non-stock brake calipers and/or non-stock-size brake rotors may be used with a penalty of 2% of the base weight."
1900 the base weight+gear change=1948. + 2% of 1900 or 1948? How is it calculated?

if 1900 is the base weight then it will be 2% of that. Then you would add the other multipliers like the 48# for the gears so would total to 1986 for running weight.

 

[Aaron Johnson]

I wrote in


I don’t think there is reason to limit to 4 piston calipers. 6 in front and 4 in rear.

If we are opening thebag there is no real difference between the 4 or 6.

 

[dhrmx5]

You kids still running cars limited to 13-15 inch wheels better take a look at your hole cards with this rule proposal.

The newer cars with 18 inch wheels generally have a difficult if not impossible time of getting to weight. Adding 2% to an RX8 or S2000 that can't get to weight is a no brainer. It will allow them to put on bigger brakes and lightweight rotors and calipers. The RX8 alone will remove approx 10 to 15lbs of rotating and unsprung weight while increasing it's brake size. And I would bet real money that they can't get to their minimum weight now so they will add 0 pounds to their actual as raced weight. S2000 will be the same. My experience with the FRS points to it having difficulties getting to weight. I am not sure where the BMW slots in on weight.

We have an S2000 with 18x8s that is currently sporting a set of Ford Racing Mustang FR500S Brembos with 355mm 2 piece rotors. These brakes are MASSIVE, yet they fit just fine. For 800 bucks I matched them in the back with328mm vented 2 piece rotors and Wildwood 4 piston calipers. The car weighs just under 2800lbs. There isn't anything on the track with fenders that out brakes this car. And no, I don't bother to run cooling ducts. With this ruleset the possibilities are endless... just not for the earlier cars...

 

[kruck]

Also - who is Chris Taylor and what have we ever done to him? :think:

A part of me really wanted to share publicly exactly what his letter said, but I figured that probably wouldn't be very professional...

So the car tech line will now include both the diameter and thickness of stock rotors. I suggest the stock thickness should be a maximum thickness. If not, standard wear, truing rotors, surfacing rotors to use a new type of pad material or some who may have turned their rotors to reduce unsprung weight will produce a rotor which is not stock thickness

"stock size rotor" dimensions are clearly spelled out in the factory service manual for your particular car, which a competitor is supposed to have. no point in adding that to the GCR as well.

What Matt said. The size of a stock size rotor is in your FSM, which we're all supposed to have and be able to present when requested. In my opinion, it's a pointless exercise that stock brake sizes were ever even listed on the Prod spec lines.

The allowance of any size rotor that fits in the wheel is too much. We have fitted 355/380mm rotors and 6 piston calipers inside 18" wheels with ease. There should be some sort of upper limit besides wheel size... The modern cars such as the FRS, 944, RX8 will be able to run massive brakes compared to the older cars...

The wheels do and four piston calipers limit the swept area.

Peter is exactly right. When diving through all of the different possible options here, it became pretty evident that there would be very, very few outliers here that would benefit from "anything that fits inside your wheel limitation" much more that everything else. The manufacturers make their brake & wheel packages mostly based on weight and power of a car. The wheel specs in Prod are based on stock wheel size, and so they therefore are VERY rarely much bigger than the stock size rotor. So when you look at the typical range of OE rotor diameter's on cars that are classed with 13's, versus those classed with 15's, versus those classed with 17's or 18's, the "gains" that are available are all incredibly similar, when looking at percentage increases in rotor diameter and swept area.

I think that restricting the rotor size with the wheels is a mistake. It's exactly the kind of rule writing we want to avoid because it invites experimentation and expenditure...not only on brakes, but now on wheels.

And since you can't bitch without offering an alternative, here's an idea that would at least keep a lid on some of that:

EP = 13 inch max or stock diameter if larger

FP/HP = 11 inch max or stock diameter if larger

Tom, this was one of the last settled "points" of this whole proposal. From the survey response, when combined, the votes for "unrestricted" and "limited by wheel size" was the clear winner. (It was felt that it was safe to consider these responses together, because effectively they are the same, since the wheel restrictions aren't changing. In hindsight, they should've been combined into one singular response option.) But yes I too absolutely worried about the "what if", and if we should try to take some sort of measure to save us from ourselves, and try to limit people from trying to spend ridiculous time and money to get some very minuscule amount of perceived extra gain. One possible "solution" that was discussed a lot was to mandate a max rotor size per max wheel size. Say something like 250mm max for 13" wheels, 300mm max for 15" wheels, and 350mm max for anything bigger than 15". There was two problems with this though. (1) One of the major points to all of this was to give people more options, and (2) trying to control what any singular person may want to spend on this stupid hobby is an even stupider exercise. So it was decided to just leave the rotor option open to whatever a person wants to put inside their wheel. If a person wants to spend absolutely ridiculous money to try and get 5mm more rotor diameter than their competitor, who bought all readily available, off the shelf, affordable items, so be it. You, or anyone else, is not going to keep "that guy" from spending money and trying to do dumb stuff like that. But any attempt that you make to try to do that, is just going to limit everyone else's options, make our rulebook bigger and more involved, and make tech an even bigger pain in the butt. You have to admit, the difference in performance potential between these two options is incredibly tiny.

To your proposal, as the committee researched the idea of limiting brake diameter by class (or even weight), it was found to just not be possible. There's just too large of a range of wheel sizes and weights in any of our classes to make one fixed rule like that for everyone feasible, and would've created some serious "winners" and "losers". Unless you want to open up wheel sizes, which is a whole other can of worms. As I said above, when you look at what pretty much any car has for stock brakes, and how much larger they could possibly go within their stock wheel limitation, the percentage "gains" are all very similar.

 

[Aaron Johnson]

You kids still running cars limited to 13-15 inch wheels better take a look at your hole cards with this rule proposal.

The newer cars with 18 inch wheels generally have a difficult if not impossible time of getting to weight. Adding 2% to an RX8 or S2000 that can't get to weight is a no brainer. It will allow them to put on bigger brakes and lightweight rotors and calipers. The RX8 alone will remove approx 10 to 15lbs of rotating and unsprung weight while increasing it's brake size. And I would bet real money that they can't get to their minimum weight now so they will add 0 pounds to their actual as raced weight. S2000 will be the same. My experience with the FRS points to it having difficulties getting to weight. I am not sure where the BMW slots in on weight.

We have an S2000 with 18x8s that is currently sporting a set of Ford Racing Mustang FR500S Brembos with 355mm 2 piece rotors. These brakes are MASSIVE, yet they fit just fine. For 800 bucks I matched them in the back with328mm vented 2 piece rotors and Wildwood 4 piston calipers. The car weighs just under 2800lbs. There isn't anything on the track with fenders that out brakes this car. And no, I don't bother to run cooling ducts. With this ruleset the possibilities are endless... just not for the earlier cars...

I can tell you I will have to add weight to my s2000. I’m not a small guy and I have 150lbs of ballast in the car to make my minimum weight of 2636 with the dog box. I still carry 25lbs Of ballast to meet the stock trans minimum. Do I have braking problems. No. Will I change to a race setup. Yes. The factory rears kill the wheel bearings and pads wear shockingly quick. front rotors crack after 2 weekends and have to be replaced. I will be able to fit a nice package under the 17x8.5 wheel and it will cost some bucks, but it work well reduce the heat transfer and maybe save me money over time.

Most of all. It will look cool. When the tuner crowd walks up now the first then they notice is stock brakes.

 

[Chris Schaafsma]

I wrote in


I don’t think there is reason to limit to 4 piston calipers. 6 in front and 4 in rear.

If we are opening thebag there is no real difference between the 4 or 6.

So I know (think) this is in jest, but of course they are different (2 moar!), and the line has to be drawn somewhere. Considering that most spec line have a single piston caliper, and that 4 piston stuff is fairly affordable in the aftermarket I think it’s a reasonable rule.

 

[Aaron Johnson]

So I know (think) this is in jest, but of course they are different (2 moar!), and the line has to be drawn somewhere.

but this line is a wavy line anyways. so in this "quest for cost control" on brakes. We can save some people money by allowing 6 piston so that readily available kits can be used. Going to a 4 piston, it's now a custom kit, custom brackets etc...i understand that some cars won't have a kit available anyways, but those cars also don't have easy alternate trans, etc etc etc.

the overall performance difference of a 4 piston vs 6 piston is not really a factor, and the rotors will be similar, it just opens up options for people to find what's best for their car. it's not likley you can fit a 6 piston caliper in a 13" wheel or maybe even a 15" wheel, and it's also not likely that a 6 piston caliper would be any good to a car weighing 1600lbs, but certainly to my beast at over 2600 i could benefit from a 4 or 6 piston, but if we are going to open this slope...let's open it now, make it work and not change it. open rotors, open calipers and must fit inside your wheel size.

 

[Matt Blehm]

Wilwood Superlite 4 piston are $188 (MSRP) for the cheapest base model. radial mount 4 piston is $250. still pretty cheap. The Radial mount 6 piston will directly swap in place of the radial 4 piston and is $280- a shopping $30 more.

Hawk DTC Pads are ~$200/set and last more than a season of sprint racing (>40hrs of track time on my 160whp STU car w/ DOTs). I have some Raybestos ST43 and ST47 around here somewhere I bought from Porterfield and they were about the same price. it's been years tho.

I had some aluminum hats made at a local machine shop for $100/ea.
11.75" Rotors are $87/ea from Coleman Racing. you can get cheaper ones in the 12.2" and 13" varieties since they're a standard size for the circle track folks.
The mounting bracket I made in the garage from some scrap 3/8" alu. $0

(280+100+87)*2 + 200 = $1134. So toss in some -3AN lines and I'm at roughly $1200 (per axle) for a 6 piston radial mount setup. This is not going to break the bank, and will save money in time vs. the constant pad changes and caliper rebuilds I did on the RX7.

Yes there are many ways to add cost to that- floating rotors, higher end calipers, and pricier pads will marginally improve performance over that setup, but they will drastically increase price.

 

[GT6]

"The size of a stock size rotor is in your FSM, which we're all supposed to have and be able to present when requested. In my opinion, it's a pointless exercise that stock brake sizes were ever even listed on the Prod spec lines."

If this is the intention of the proposed rule, I think referencing the spec line is incorrect. By making a specific reference to a source (that is incomplete) you negate the reference to other sources.
Include reference to the FSM in the wording and include the phrase, "stock rotor dimensions".

OR, remove all of the references and say, "stock rotor dimensions". Maybe include the words, "or smaller". (Then, when someone asks what are the stock dimensions, they can hunt around until they find the FSM and see if something like the width is even listed.)

 

[Al Seim]

Not a big deal but rulebook only mandates FSM possession for L2 cars. Stock is still stock of course, but harder to document.

 

[Dick Barlow]

Back in the day there once was a guy in the Northeast who won like 34 of 35 races (keep record on side of car) in DSR with a Fiat Abarth. When people told him something was illegal he would always point to the FSM. Of course it was in Italian and nobody could read it!

 

[Matt Blehm]

"The size of a stock size rotor is in your FSM, which we're all supposed to have and be able to present when requested. In my opinion, it's a pointless exercise that stock brake sizes were ever even listed on the Prod spec lines."

If this is the intention of the proposed rule, I think referencing the spec line is incorrect. By making a specific reference to a source (that is incomplete) you negate the reference to other sources.
Include reference to the FSM in the wording and include the phrase, "stock rotor dimensions".

OR, remove all of the references and say, "stock rotor dimensions". Maybe include the words, "or smaller". (Then, when someone asks what are the stock dimensions, they can hunt around until they find the FSM and see if something like the width is even listed.)

I haven't seen a service manual yet that doesn't list minimum rotor thickness as a maintenance inspection item. they may or may not have diameter, hat offset, etc listed though.
I was able to find that info pretty easily online tho for many cars. Rockauto.com often has pictures and drawings/dimensions when you go searching for parts on their website.

 

[Matt Blehm]

Back in the day there once was a guy in the Northeast who won like 34 of 35 races (keep record on side of car) in DSR with a Fiat Abarth. When people told him something was illegal he would always point to the FSM. Of course it was in Italian and nobody could read it!

That was also back when a number of people couldn't convert from inches to mm!

 

[dhrmx5]

I can tell you I will have to add weight to my s2000. I’m not a small guy and I have 150lbs of ballast in the car to make my minimum weight of 2636 with the dog box. I still carry 25lbs Of ballast to meet the stock trans minimum. Do I have braking problems. No. Will I change to a race setup. Yes. The factory rears kill the wheel bearings and pads wear shockingly quick. front rotors crack after 2 weekends and have to be replaced. I will be able to fit a nice package under the 17x8.5 wheel and it will cost some bucks, but it work well reduce the heat transfer and maybe save me money over time.

Most of all. It will look cool. When the tuner crowd walks up now the first then they notice is stock brakes.[/quote]

So your car is approx 2300lbs with out driver? That's impressively light. While on the ST committee the S2000 guys were complaining they couldn't get the cars to 2500 lbs.