FV disc brakes

[Garry Sharp]

Final weight on front disc brake conversion (with bearing races).

[Hardingfv32]

And the minimum weight is set at 16.5 lb.? What might this weigh be without your machining?

Brian

[Garry Sharp]

And the minimum weight is set at 16.5 lb.? What might this weigh be without your machining?

Brian

After and before:

[Stumpthumper]

Final weight on front disc brake conversion (with bearing races).

Nice job. Gary! Thanks for making your work on this public.

[Hardingfv32]

Using your weights, would I be correct in stating that the stock kit adds 17.6 lb. just for the front conversion. This is using your hardware and Wilwood calipers. If we were to assume the same for the rear, then we are talking about 35 lb. total additional car weight using non-lightened stock castings. I would say that this would give pause for most FV competitors.

Can you speculate about how much it might cost to lighten the casting as you have down?

Brian

[Garry Sharp]

Using your weights, would I be correct in stating that the stock kit adds 17.6 lb. just for the front conversion. This is using your hardware and Wilwood calipers. If we were to assume the same for the rear, then we are talking about 35 lb. total additional car weight using non-lightened stock castings. I would say that this would give pause for most FV competitors.

Can you speculate about how much it might cost to lighten the casting as you have down?

Brian

I'll do a summary of the fronts tomorrow.

[problemchild]

Greg,

Actually I was kidding, but after looking at the responses I've changed my mind. There will always be those that will spend thousands of dollars on .95 HP or .95% reduction in drag and that's fine. Just allow the extra 1/2" for those that dont want to spend $3500 on discs and will be happy with $1000 off the shelf. Maybe they possess .95% more talent and things will be equal. Don't make it mandatory, just optional and those that want to run a 1/2" narrower track on certain tracks and wider track on others, god bless them.

You cannot base your rule package on people who don't give a damn.

As much as I hate the desecration of the class by introducing the option of disc brakes, at stupid cost, it appears to be a successful rule application with no or minimal advantage over the traditional drums. Changing track rules and allowing 4-bolt wheels will absolutely change the class, perhaps more than any other rule change since the fan shroud removal. It is ignorant to deny this certainty. I don't think the class can survive such a severe change, but those that do, have to decide if the class will be better off. Disregarding the final outcome, I believe that all the time and energy put into fighting a civil war over the issue, would be better spent on growing car counts.

[Daryl DeArman]

You cannot base your rule package on people who don't give a damn.

<snip>

I believe that all the time and energy put into fighting a civil war over the issue, would be better spent on growing car counts.

Agreed x2. I believe those that are working on these disc brake rules packages and potential solutions are attempting to do just that.

[jahillsr]

I am new to FV and am interested in what advantage is created for a driver by allowing a slightly wider track and 4 bolt wheels?

If those who did not want 4 bolt wheels used a spacer, would it not even out any advantage?

More interested in the technical reasons then the politics of it. TIA.

You cannot base your rule package on people who don't give a damn.
As much as I hate the desecration of the class by introducing the option of disc brakes, at stupid cost, it appears to be a successful rule application with no or minimal advantage over the traditional drums. Changing track rules and allowing 4-bolt wheels will absolutely change the class, perhaps more than any other rule change since the fan shroud removal. It is ignorant to deny this certainty. I don't think the class can survive such a severe change, but those that do, have to decide if the class will be better off. Disregarding the final outcome, I believe that all the time and energy put into fighting a civil war over the issue, would be better spent on growing car counts.

&lt;br&gt;<br>
&lt;br&gt;<br>

[problemchild]

Agreed x2. I believe those that are working on these disc brake rules packages and potential solutions are attempting to do just that.

It is a typical cycle of racing. A minority want to add an expensive non-performance rule change. The traditionalist majority reluctantly accept that rule change "as long as it is not a performance advantage". Then the minority, who got exactly want they asked for, want other rules changed, which will effect performance, and raise cost for everyone, but lower the cost of their non-performance rule change. All involved think their approach is good for the class and the other approach is bad.

[ajpastore]

Changing track rules and allowing 4-bolt wheels will absolutely change the class,

Greg, you got the facts wrong.
The track width rules are met in the front using the four bolt wheels and the rotors VW part#113407075

[Garry Sharp]

Here goes: In conclusion

I decided to weigh the other rotor, caliper and bracket but with the bearings to compare with Andy's 19.2 weight for his complete drum setup. Came up with this:



So 1.6 lbs. heavier.

When I started this, I wanted to see if I could come up with disc brakes for a FV that was cheaper than what was available (and you can pay for it as you go along) and close to the weight of the drums. I never though I would get this close.

The prices are all online except the scalloping which was $70.00 per rotor. Obviously, you might can get it done cheaper. I got the aluminum online from Metals Depot-about $20.00 worth for the bracket. All the aluminum is 1/2". I used Wiwood clinch nuts that they use on their brackets instead of tapping the holes. This allowed me to use AN bolts with the non-threaded portion going through all the shear planes-probably doesn't matter but that's what I did. I turned down the rotor thickness on my brake lathe.

If you can cut aluminum and drill a hole you can make the bracket.

I feel good about it but I guess I'll know for sure how I did when I arrive at turn 10A at Road Atlanta!

Thanks for listening,
Garry

[Hardingfv32]

The track width rules are met in the front using the four bolt wheels and the rotors VW part#113407075

What is that weight for this set of development parts?

Where are you with something for the rear?

Brian

[Ed Womer]

Hi Jahillsr,

In racing there are a lot of things that seem to be an advantage but in reality don't work out when applied.

In theory a wider track is considered to be an advantage but in reality it usually isn't. What has keep this discussion going is that there is a perception by some that in order to get new, read that as young people into FV racing, is to do away with the requirement of having to use the drum brakes since that is what the class started with since that is what the original car came with. The other is easy of maintenance. Well since I am 68 and have raced FV's for over 35 years and I hate messing with the brakes. It isn't that I don't know how I just don't want to.

Will a slight increase in track really make you faster? Most likely not. As the years have gone by in FV, that would be 50+, there have been changes for a lot of reasons. Most being innovation and as the old saying goes once the cat is out of the bag you can't get it back in so things change. There is a maximum track width for our class and you could spend countless ours days or your life trying to maximize the rules or just be under the rule and move on.

There is one thing you could think about with a slight increase in track is the additional stress on the spindle, but keep in mind the original Bettle weight over 1800lbs and a FV can be as light as 1025lbs.

The other thing for rules creep is that FV is based on a car built in 1964 and a lot of the parts are no longer available to buy. As Greg, Problemchild, mentioned the pursuit of disc brakes has become expensive because the rules makers decided not to allow a slight increase in track which would allow the use of off the shelf newer VW parts because of the perceived advantage, so trying to develop a part to meet the rules has evolved into a nearly 3K cost for some systems. But with innovation and creativity others have started to come up with less expensive systems. Remember that the preferred brake shoes just for the front of the car are I think over $500 for just four brake shoes. Those shoes also wear out in about a year and also eat up the drums.

There are two different rear drums allowed with the newer drum slightly wider due to it being a latter part and I guess an improvement by VW. You will see both used and I doubt there is a difference in performance.

As a note a five time national FV Champion, the late Bill Noble, who was an engine builder was a big guy and he usually weighed 60+ lbs overweight and it didn't seem to affect his performance. So will a slight increase in front track really make you faster?

As in all types of racing there are many things that you will need to learn in order to be able to go faster but once you near the front of the grid it then becomes more driver ability and just plain racing luck.

Ed

[problemchild]

Greg, you got the facts wrong.
The track width rules are met in the front using the four bolt wheels and the rotors VW part#113407075

I don't have any facts wrong.
Changing the track changes the class.
Changing to 4-bolt wheels changes the class.

Both require changes to the rules, which is changing the class. Those are the facts!

The significance of all these matters is debatable, but to say that changing track is an insignificant change is just dreaming. Claiming 60 lbs is insignificant is absolutely humerus. Bill was a salesman, and had the best engine. If he could win while being 60 lbs over, he would have destroyed the field if on the weight limit.

As I noted previously, when SCCA changed the max width measuring process for FF/FC, teams spent 10s of thousands of $ on wider track suspension components. This was for less than 1/4" per side.

[problemchild]

I am new to FV and am interested in what advantage is created for a driver by allowing a slightly wider track and 4 bolt wheels?
More interested in the technical reasons then the politics of it. TIA.

See post #472 for engineering values for changing track.

The wheels don't change the handling by themselves, but introduce elements of integrity and cost. Even if identical in specs, there may be aero differences and most likely, differences in the location of rotating weight. There is a lot of deflection in current FV wheels, and a lot of difference in weight. Stiffness of a wheel does affect tire performance. Adding a completely different spec wheel may or may not be significant, but to dismiss it with a shrug is irresponsible. Perhaps it is only 1/4 second per lap. That is significant when the top-3 at the Runoffs finished within .097 seconds! Perhaps if those not in the top-3, worried about the "insignificant" matters, they would not be several seconds per lap off the pace.

Rules need to be based on the potential performance that is capable, not on the performance of casual racers. I personally put very high value in the cost to the casual racers. That is why minimal changes to rules and only very strictly controlled changes is required. Opening things up just gives opportunity for people to spend money on minor but real performance gains.

[Daryl DeArman]

Rules need to be based on the potential performance that is capable, not on the performance of casual racers.

Amen.

[alangbaker]

I don't have any facts wrong.
Changing the track changes the class.
Changing to 4-bolt wheels changes the class.

Both require changes to the rules, which is changing the class. Those are the facts!

The significance of all these matters is debatable, but to say that changing track is an insignificant change is just dreaming. Claiming 60 lbs is insignificant is absolutely humerus. Bill was a salesman, and had the best engine. If he could win while being 60 lbs over, he would have destroyed the field if on the weight limit.

As I noted previously, when SCCA changed the max width measuring process for FF/FC, teams spent 10s of thousands of $ on wider track suspension components. This was for less than 1/4" per side.

1. I doubt you quite a lot on that.

2. People do stupid things all the time.

[Garry Sharp]

They work!

[BLS]

"They work!"

Nicely done, Gary.

[flattop414]

Is there anything keeping one from using the less expensive plus offset kits , and having a set of wheels offset altered to compensate? There are still lots of wheel repair outfits capable of doing the changes , and making them strong enough.

[Matt Clark]

Is there anything keeping one from using the less expensive plus offset kits , and having a set of wheels offset altered to compensate? There are still lots of wheel repair outfits capable of doing the changes , and making them strong enough.

SCCA rules won't let you run modded wheels. but F1200 & Challenge Cup is an option to fix it via the wheels.
That being said, they new 4-bolt allowance proposal completely fixes the track issue & allows inexpensive quality disc brake options.

[BLS]

"That being said, they new 4-bolt allowance proposal..."

Apparently I missed something. Is this a proposal that is under serious consideration?

[Matt Clark]

"That being said, they new 4-bolt allowance proposal..."

Apparently I missed something. Is this a proposal that is under serious consideration?

Yep. The July Fastrack has it in consideration to allow it starting next year.
If anyone wants an inexpensive solution to disc brakes finally, this is your chance to tell them you want it.

[BLS]

Thanks Matt!

[Hardingfv32]

Is this in the July labelled Fastrack? I can not seem to locate July on the Fastrack page.

Brian

[Matt Clark]

since I can't link directly, look at the "Recommended Rule Changes for 2021" dated 07/20/20

https://www.scca.com/pages/cars-and-rules


copy & pasted, changes in bold italic:

FV
1. #28955 (Formula/Sports Racing Committee) Allow 4-bolt pattern wheels from 1967-1973 Type 1
In GCR section 9.1.1.C.3.C, make changes as follows:
"Wheels shall be standard fifteen (15) inch X 4J as used on the 1200cc and 1300cc VW sedan as defined herein or 1967-1973 Type 1, or any steel fifteen (15) inch X 4.5J VW wheel with the same 5-bolt pattern as the standard fifteen (15) inch X 4J wheel or 4-bolt pattern of the 1967-1973 Type 1, all within the track dimensions of C.2. Wheels may be balanced only by the use of standard automotive balance weights (adhesive or clip on). Hub cap clips shall be removed."

[Dietmar]

Not that it matters, but 67 Type 1 had 5 bolt wheels.
4 bolt started in 68

Dietmar
Quixoteracing.com

[mikehinkle]

Has anyone considered that the currently available disc brakes that are being produced by the few vendors may not fit the current rule? Only the EMPI/Mass produced kits would fit the current rule.

From the GCR Formula Vee Preparation Rules:

No component of the engine, power train, front suspension, brakes shall be altered, modified, or substituted unless specifically authorized. Mass-produced, direct replacement components may be substituted for the following as long as they are of the same material and dimensionally identical to the original VW components they replace:

• VW transmission components
• Rear axle components
• Front suspension
• Brake components

These replacement parts must be generally available to all competitors and must offer no competitive advantage over the original VW parts.

In my opinion the intention of this rule is to ensure that 1) major suspension components and brake components are mass produced by a manufacturer who can ensure that the components are safe as well as meet some type of quality control and testing requirements.
2) Ensure that all competitors have access to parts that make up the major systems of the car. This would curb making specialty machined parts for parts of the car that would affect performance. In turn it would control costs of the class.

Webster dictionary definition:
mass-produce
: to produce very large amounts of (something) usually by using machinery

Does the specialty runs of the currently available packages meet this definition?

If you believe that the rules do allow the current expensive and specialty disc brake options available then there is something else that needs to be considered. The entire section of the Formula Vee Specifications that calls out the requirements for the disc brakes makes no mention of thickness or strength of any metal except for the rotor. I could create a disc brake kit with a box of tin foil as long as the rotor was no more than 11.75 inches and a minimum thickness of 0.20. The hub that holds my wheel onto the car and the caliper that stops the car could, in theory, be made completely out of tin foil.

[B Farnham]

Has anyone considered that the currently available disc brakes that are being produced by the few vendors may not fit the current rule? Only the EMPI/Mass produced kits would fit the current rule.

From the GCR Formula Vee Preparation Rules:


In my opinion the intention of this rule is to ensure that 1) major suspension components and brake components are mass produced by a manufacturer who can ensure that the components are safe as well as meet some type of quality control and testing requirements.
2) Ensure that all competitors have access to parts that make up the major systems of the car. This would curb making specialty machined parts for parts of the car that would affect performance. In turn it would control costs of the class.

Webster dictionary definition:
mass-produce
: to produce very large amounts of (something) usually by using machinery

Does the specialty runs of the currently available packages meet this definition?

If you believe that the rules do allow the current expensive and specialty disc brake options available then there is something else that needs to be considered. The entire section of the Formula Vee Specifications that calls out the requirements for the disc brakes makes no mention of thickness or strength of any metal except for the rotor. I could create a disc brake kit with a box of tin foil as long as the rotor was no more than 11.75 inches and a minimum thickness of 0.20. The hub that holds my wheel onto the car and the caliper that stops the car could, in theory, be made completely out of tin foil.

"No component of the engine, power train, front suspension, brakes shall be altered, modified, or substituted unless specifically authorized."

^^^ The first part of that section of the GCR is the answer to your question. There is a specific section that spells out what the rules are for disc brakes if you so choose to run them. The rest of the argument is irrelevant due to that sentence.

If the intention is to make all of the cars running discs around the country illegal then you're not going to make a lot of friends. If the intention is to make a lower cost kit then contact a manufacturer and get the ball rolling.

Also by the definition of mass produced there are many things on everyone's car that wouldn't meet that definition such as offset shock mounts, sway bar, aftermarket brakes shoes, etc.

[Matt Clark]

Does the specialty runs of the currently available packages meet this definition?

That is a valid point that I have heard before, and the answer is just a "no".... but it was basically written off as a necessary thing. If disc brake kits for 5x205 broke the track width rule, then custom parts were needed. To avoid that, all the rule makers had to do was allow a tiny bit extra width.

The entire section of the Formula Vee Specifications that calls out the requirements for the disc brakes makes no mention of thickness or strength of any metal except for the rotor. I could create a disc brake kit with a box of tin foil as long as the rotor was no more than 11.75 inches and a minimum thickness of 0.20. The hub that holds my wheel onto the car and the caliper that stops the car could, in theory, be made completely out of tin foil.

This is something I have been repeating to many people, although I was looking at it more from a "must have" competitive advantage aspect. If someone was to make a super small & lightweight hub/rotor, and then take up the required additional weight with a 10lb bracket, that kit would absolutely be a jump in performance. That kit would also be very expensive... so it would be a double-whammy against the idea & spirit of things.


I have a couple posts on the Formula Vee USA Facebook page that kinda get into more detail, but to be truly accurate & fair, we need to at least try to account for rotating mass parts vs. static parts (which isn't really that hard), and to also factor in the weight delta of the 5x205 vs. 4x130 wheels. I think this is a real opportunity to "fix" a rule that got out of hand fast, but we need more back & forth with the CRB to know what is going on.

[FVRacer21]

Mike,

The words “Mass produced” are followed by the words “direct replacement”. The disc brake rules were written to curve out a exception to allow development of something that did not come with the original car.

The first sentence says “unless specifically authorized”. They are.

While I can sympathize with the sentiment, legally I think it is a non starter.

I am still waiting to see what the 4 bolt wheel rule will do and does the new Wilwood caliper fit the existing EMPI kit?

Respectfullly

Chris Zarzycki

[Matt Clark]

does the new Wilwood caliper fit the existing EMPI kit?

Yes, that new EMPI/Wilwood caliper is a direct bolt-in replacement for stock cast calipers. The Wilwood calipers are pretty nice, so this should be a sweet little kit, if/when they make an all-in-one kit we can buy.

[mikehinkle]

"No component of the engine, power train, front suspension, brakes shall be altered, modified, or substituted unless specifically authorized."

^^^ The first part of that section of the GCR is the answer to your question. There is a specific section that spells out what the rules are for disc brakes if you so choose to run them. The rest of the argument is irrelevant due to that sentence.

If the intention is to make all of the cars running discs around the country illegal then you're not going to make a lot of friends. If the intention is to make a lower cost kit then contact a manufacturer and get the ball rolling.

Also by the definition of mass produced there are many things on everyone's car that wouldn't meet that definition such as offset shock mounts, sway bar, aftermarket brakes shoes, etc.

There are many components of the car that are obviously custom. No one would argue that a exhuast is not mass produced/widely available etc. The rule only indicates that " • VW transmission components • Rear axle components • Front suspension • Brake components " must be mass produced/widely available.

I understand the argument of " unless specifically authorized. "

My point is that the rules, as currently stated, suggest that these components should be mass produced/widely available and I believe that the intent of that is to ensure safety while controlling costs and ensuring that no one can make specialty components for major systems of the car that could be a advantage.

If the majority of the class believes that disc brakes can be created in your basement like other components of the car then the wording " Brake components " should be removed from the rule. If that's the case I am ok with it I am just stating that currently it does not seem to fit. To be clear I am not a fan of expensive disc brakes but if that is what is decided to be ok by the majority then it is what it is.

[HB280ZT]

Yes, that new EMPI/Wilwood caliper is a direct bolt-in replacement for stock cast calipers. The Wilwood calipers are pretty nice, so this should be a sweet little kit, if/when they make an all-in-one kit we can buy.

Matt,

Can you provide use with some more information on this new EMPI/Wilwood caliper so that the people who do not know about it can look into it? Thanks part number would be great.

R/--
Harry
FV#77 CRF

[Matt Clark]

Matt,

Can you provide use with some more information on this new EMPI/Wilwood caliper so that the people who do not know about it can look into it? Thanks part number would be great.

R/--
Harry
FV#77 CRF

Sure... but I will say there is not really a ton out there, although they did a nice video on their Facebook page. Several vendors are listing & selling them now, but I can't remember who was cheapest.
Bare single caliper part number is 16-2526-7, kit is 16-2526-0.

https://www.facebook.com/EMPIinc/vid...2194120971975/

[Hardingfv32]

To be clear I am not a fan of expensive disc brakes but if that is what is decided to be ok by the majority then it is what it is.

'Unless specifically authorized' is part of the sentence and not free standing. The meaning of the sentence is very clear.

Again, these disk conversions are expensive because the 'top priority' was that drum brakes rules were not to be modified. The fact is that at this point there is no know performance advantage using disc brakes as demonstrated by the Runoff's front runners. The fact is that you do not have to have disk brakes. In this case we have to ignore the bias that expensive parts always mean more performance.

Authorizing inexpensive disk brake systems is politically much more complex. I doubt there are enough FV competitors interested to get the idea off the ground. Most competitors simply cannot be bothered with the work required to make the conversion much less the expense of $600-800 for parts.

Brian

[Matt Clark]

The fact is that at this point there is no know performance advantage using disc brakes as demonstrated by the Runoff's front runners. The fact is that you do not have to have disk brakes. In this case we have to ignore the bias that expensive parts always mean more performance.

This I will 100% agree with.

I doubt there are enough FV competitors interested to get the idea off the ground. Most competitors simply cannot be bothered with the work required to make the conversion much less the expense of $600-800 for parts.

But I have to very much disagree with this. There has been a *lot* of interest & support from what I have seen, both on the internet (outside of ApexSpeed), and at the track from many people. Sure, a lot of folks may not bother to switch, but if I am running at the front & looking to spend $500 on CarboTech shoes... it seems to make a lot of sense to switch to a decent 4-bolt brake setup.



As far as the politics go, if there is no advantage (as has been repeatedly proven now), and many younger and/or newer people want them... why not let us do our thing? It doesn't hurt whatsoever, and can only keep/gain newer FV racers.

[S Lathrop]

I have been following this discussion for some time and I think I have a decent feeling for the issue.

Based on my experience with FF and F2000 cars and brakes, there is a big issue that I don't think is being considered or maybe no one has experienced it yet. That issue is the different way and time of the phases of a braking cycle that disk brakes have and drum brakes have. This is especially true when the driver releases the brake pedal. I do not know how the 2 types of braking systems differ in the timing of the release.

As we were working with different brake pad compounds, we found the the release of the brake pressure and the time it took for the rotor to run free, significant things happened. What the driver will feel is that one end or the other will have a tendency to lock up just before the brakes release. This does happen and it can be a frustrating issue to fix. My guess is that the disk front and drum rear setup may show up as high tire ware at the front even before it shows as a brake locking issue. I ran into this problem in the 1990's and did not get a solution or explanation until the late 2010"s.

[Matt Clark]

That issue is the different way and time of the phases of a braking cycle that disk brakes have and drum brakes have. This is especially true when the driver releases the brake pedal. I do not know how the 2 types of braking systems differ in the timing of the release.

My guess is that the disk front and drum rear setup may show up as high tire ware at the front even before it shows as a brake locking issue.

Steve,
Just so I understand what you are saying...
Do you mean that is only a potential issue when you mix disc front & drum rears?