Speed Sport Disk Brake Package

[Speed Sport Engineering]

Attached are a few photos of the brake package we are working on putting together. Still working out some details so there will be more to follow.

[mikehinkle]

Thank you for posting these pictures.

The biggest questions I would like to see answered is:

Cost? How much will it cost to make these? I guess it will vary depending on your machine shop since I have been told that you will not be selling these yourself.

Difficulty to re-produce. I am not a machinist. Is this something that just about anyone with a lathe could make?

Which parts are off the shelf? The Wilwood calipers I assume, which pads do they use?
Are the rotors? If so what is the part number? Or are these custom.

Thanks for putting in the time and effort to develop these. I am not in favor of the rule change but obviously others are and maybe seeing a package that works and is cost effective will change my mind.

Look forward to your future posts.

[BLS]

looks good. Thanks for the update.

[pacratt]

Just to reiterate what I posted in another thread on this topic…a good portion of your conversion cost can be offset by selling your drumbrake components to the vintage FV racers.

Glenn

[Speed Sport Engineering]

Thank you for posting these pictures.

The biggest questions I would like to see answered is:

Cost? How much will it cost to make these? I guess it will vary depending on your machine shop since I have been told that you will not be selling these yourself.

Difficulty to re-produce. I am not a machinist. Is this something that just about anyone with a lathe could make?

Which parts are off the shelf? The Wilwood calipers I assume, which pads do they use?
Are the rotors? If so what is the part number? Or are these custom.

Thanks for putting in the time and effort to develop these. I am not in favor of the rule change but obviously others are and maybe seeing a package that works and is cost effective will change my mind.

Look forward to your future posts.

Cost is still being determined. We will be producing and offering the kits complete, although the calipers and rotors are off the shelf components. Everything else is custom machined. Our goal was to create a high quality package that does not alter the track width and it certainly was a very tight fit to accomplish it. This package will probably not be as cheap as the costs that have been mentioned on some other available conversions from China. But all of our machined parts will be done in the US with good material control and will fit within the standard FV wheel and track. The caliper is a standard Wilwood, which means there are a lot of pad options available. However, Carbotech has already expressed the desire to continue to support the FV community and offer pads for us as well. I'll periodically provide additional updates as we get more things finalized.

Michael

[Hardingfv32]

Calipers are about $150 and the pads about $100 per 4. There is one pad priced at $50 per 4. You can see how the costs start to add up.

This caliper was chosen because of the clearance issues at the front. Note in the front suspension photos how the disc ID (mounting holes/bolts) must clear the upright (dog bone). You are not left with much distance to develop the disc wear surface before you reach the wheel inner surface. The disc wear surface is on the order of 1.5" which is a little small for a standard front disc. The rectangle pads of this caliper are a benefit in this situation. It also has a thin bridge that allows for a little larger disc diameter.

Brian

[jphoenix13]

Does this installation require changing master cylinder bore size? Or will the existing sizes work OK?

[Hardingfv32]

Chances are that the 3/4" master cylinders will be fine. You might need to move the fulcrum point of the pedal assembly though to fine tune the pedal feel.

Brian

[tgaluardi]

I hesitate to post anything on Apexspeed because I will be put in my place. However, to quote the GCR C.1 Formula Vee Background section "...the focus remains the same: to provide a cost effective, highly competitive class that, through consistent and tightly controlled component and preparation rules, emphasizes driver ability rather than technological development of the car"
This package is a big technological development!

[Hardingfv32]

Technology development does not necessarily mean a performance development in this case.

With an estimated price of $1600-2400 this is really something that mostly Major event competitors are going to purchase. I doubt that this rule change will cause any disruption at the Regional level.

My 'opinion' is that SCCA FV's resistance to change has not served it well over time when compared to all the other FV groups around the world.

Brian

[FVRacer21]

Cost is still being determined. We will be producing and offering the kits complete, although the calipers and rotors are off the shelf components. Everything else is custom machined. Our goal was to create a high quality package that does not alter the track width and it certainly was a very tight fit to accomplish it. This package will probably not be as cheap as the costs that have been mentioned on some other available conversions from China. But all of our machined parts will be done in the US with good material control and will fit within the standard FV wheel and track. The caliper is a standard Wilwood, which means there are a lot of pad options available. However, Carbotech has already expressed the desire to continue to support the FV community and offer pads for us as well. I'll periodically provide additional updates as we get more things finalized.

Michael

Michael,

I would focus on the fronts first:
1. That is where most of the braking is done and where we have the most problems.
2. We have a good aftermarket drum for the rear. (thanks Richard)
3. Rears do not need 1/2 the adjusting of the front (in my experience)
4. Rear discs might drag more than the fronts - so would hurt more than help (just a hypothesis)

I think the front disc/rear drum gives the most bang for the buck.

Chris

[Hardingfv32]

I wonder if there are not some fundemental complications using disc/drum in a performance application. Cannot recall seeing such a combination on any foreign street sports car or race car for that matter.

As an example: In a racing application both ends of the car's brake system have to develop temps at a similar rate to control the balance at different stages of the brake application. This could be difficult using a disc/drum system. I am assuming brake balance is important.

Brian

[Matt Clark]

I hesitate to post anything on Apexspeed because I will be put in my place. However, to quote the GCR C.1 Formula Vee Background section "...the focus remains the same: to provide a cost effective, highly competitive class that, through consistent and tightly controlled component and preparation rules, emphasizes driver ability rather than technological development of the car"
This package is a big technological development!

I really do not consider this a technical development... it's just a basic disc brake setup. Nothing trick or fancy, just updating something that was replaced on the street cars 40 years ago. We have to try make the class appealing to anyone under 40 years old.

I think the front disc/rear drum gives the most bang for the buck.

I wonder if there are not some fundemental complications using disc/drum in a performance application. Cannot recall seeing such a combination on any foreign street sports car or race car for that matter.

I remember going to Nelson Ledges a long time ago to look at the FST cars, and talking with Greg Rice for a while, where I seem to remember him saying that he preferred the Disc front / Drum rear when he built his FST car, and that he only changed when the rules mandated he do so. I could be wrong, though.

With an estimated price of $1600-2400 this is really something that mostly Major event competitors are going to purchase. I doubt that this rule change will cause any disruption at the Regional level.

While the price obviously has yet to be determined & finalized, this is something that so many people continue to ignore. Those running at the National level will most likely all change over, but I would say most Regional drivers would never see any improvement in lap time with them. If you watch times & how people brake now (myself included), I would say 85-90% of us do not even get 100% effectiveness out of drums anyway. The fast guys will continue to be faster, the slow guys will continue to be slower... but it does tighten up the equality of everyone in between.

[David Ferguson]

I wonder if there are not some fundemental complications using disc/drum in a performance application. Cannot recall seeing such a combination on any foreign street sports car or race car for that matter.

As an example: In a racing application both ends of the car's brake system have to develop temps at a similar rate to control the balance at different stages of the brake application. This could be difficult using a disc/drum system. I am assuming brake balance is important.

Brian

Look in the E Production section of the GCR. Many of the cars (like a Datsun 240z) have disc front and drum rears specified -- and they have to race that way.

[Bill Bonow]

I remember going to Nelson Ledges a long time ago to look at the FST cars, and talking with Greg Rice for a while, where I seem to remember him saying that he preferred the Disc front / Drum rear when he built his FST car, and that he only changed when the rules mandated he do so. I could be wrong, though.

Matt, you're correct. Greg read the rules, picked the best package at that time and built a damn fast car.
Front disc rear drum likely be the "hot lick" (my .02).
Not going to go into detail, but there are some "gotchas" in rear discs on VW swing axles.

[Doug FST 5]

The front disc, rear drum setup has its advantages but the failure prone rear drum remained a concern. Once the lateral play in the axle is controlled the FST rear disc setup is trouble free.

Doug FST 5

[problemchild]

The front disc, rear drum setup has its advantages but the failure prone rear drum remained a concern. Once the lateral play in the axle is controlled the FST rear disc setup is trouble free.

Doug FST 5

I was not going to go there, but since you chose to, I was avoiding the heavy Chinese discs required by the FST rules. Once I was forced to run the mandated discs, I had several failures. One minor advantage of the disc setup, is the caliper tends to retain damaged/stripped discs ..... so you just slow down with excessive drag ..... rather than crash. I would rather have parts that don't fail in the first place however.

I still have the 2 sets of those drums that I built for FST, and are scheduled for the next scrap run. Lots of German 4-bolt drums still kicking around. They are much beefier and have enough beef to machine down to 5-bolt specification. That was why I held on to them for all this time, but, I am now selling off all racing inventory, and scrapping what won't sell.

[Doug FST 5]

Yep Greg - I recall when you ran FST years ago that you had trouble with the rears. That experience hasn't been common in the FST community at large. I'm not sure why that is and we probably never will. We've got over a decade of running this configuration and the reliability has been quite good for us.

Doug FST 5

[Speed Sport Engineering]

Quick update on the disc brake package. Things are progressing and we are anticipating on track testing next week.

[crypt0zink]

Small aero details, gives me ideas for Vintage FV...

[pacratt]

Small aero details, gives me ideas for Vintage FV...

You just try it, John...LOL
Glenn

[tgaluardi]

WOW!! I am impressed! After many months of work we have a solution to a problem that did not exist!!!

[Hardingfv32]

You will always have vintage racing if that is what you desire from your car's design.

SCCA FV as a class has been damaged by decades of stagnant rules. FV through out the world is my proof.

Brian

[Speed Sport Engineering]

After a lot of hard work, I'm happy to say we are ready to give the disc brakes a full on track test. We really believe this will be a positive step forward for FVs. None of this was done in an attempt to improve performance, but simply as a means to reduce the maintenance requirements and the need for expensive brake shoes. With the advent of the latest brake shoe materials, brake maintenance had become the single largest time consuming aspect of preparing for a race. Those who were using the drum brakes to their full potential understand the issues and effort they took. Updating to a disc package will be fully optional and by no means a requirement. That is why we made such a hard effort to design a system that didn't alter any geometry on the car and closely matched the weight of a drum system so people can make their own decisions whether to convert or not. Switching components on my car mid-season and putting effort into this to test these was not exactly something I wanted to do, but I really believe it's in the best interest of the class. I expect to be on track with these this week, and if all goes well, they will be available for those wishing to convert.

[FVRacer21]

Mike - nice job - just like I would have done - even down to the wheel studs instead of bolts.

When and which track are you hitting?

ChrisZ

[nhJohn]

To minimize total design width, maximize rotor width, was there consideration given to a single piston floating caliper design?
Yes, I know that has pad wear issue an reduced piston pressure...…
John

[Hardingfv32]

To minimize total design width, maximize rotor width, was there consideration given to a single piston floating caliper design?John

I research the use of floating calipers but did not fined any research comparing their use with non-floating calipers. I assume there is a performance advantage that is so obvious that it does not warrant discussion. I have never seen a modern race car (unrestricted design) using floating calipers.

Floating calipers would have made the front system design much easier. .250 /.375" thick disc are all we need. You can actual have discs with too much mass for your application. There are formulas available for determining the proper disc mass.

Brian

[Speed Sport Engineering]

Last Friday we tested the disc brakes at Blackhawk. Things went very well with no issues. I was very happy with the overall feeling of the brakes, and it even took very little bias adjustment from where it was set with the drums. It takes too long to switch from the drums to the discs to do a true back to back comparison for an objective lap time comparison, but lap times were where I would have expected them to be. With Blackhawk being our closest track, over the years I've done thousands of laps there. I would say brake points were basically the same with the discs as they were for the drums. The biggest difference is in the amount of pedal force it takes to stop the car at the limit of the tires.

We've been running brake pressure sensors for several years now, and after utilizing the data it became apparent the amount of pedal effort it takes to get the most out of the drum brakes is staggering. It's at the point I wonder if most people are even using the drums to their full potential. We've actually cracked numerous backing plates from the force of the wheel cylinder on the shoes.

With Carbotech shoes prior to 2014, I was recording line pressures that were being clipped by the sensor limits of 1100psi on the front. When the newer compounds came out in 2014, the front line pressure had dropped to 800psi. I was seeing about 300psi with the discs. Surprisingly, sitting in the car in the shop or paddock it is difficult to even press on the brake pedal hard enough to generate much more then 800psi in the front lines, which is an indicator on just how much effort it takes on the pedal on the track. (Some of this depends on the pivot ratio of the pedal)

What does this all mean? I think it depends on how well individuals were maximizing the drums. For those who could generate enough pedal pressure to use the drums effectively, the discs now require a much more delicate touch and I would argue a bit more skill to effectively brake. For those who weren't getting the most of the drums, the discs will probably help.

Overall, I think this will significantly reduce the amount of maintenance and prep work that goes into racing a FV. As an example, we changed all 4 corners of brake pads in less then 20 minutes. Most of the time was removing the wheels. I also think it brings a bit of driver skill back into the game and reduces the advantage of those who spend a large amount of time tweaking the drums.

[aerobullet]

Did you have to machine the rear hubs to install the disc carriers?

[problemchild]

If FV guys must insist on using disc brakes, you should take the opportunity to exclude the use of any aerodynamic devices, backing plates, or fairings from the rule package. Write the rule now, before someone starts doing it.

[Hardingfv32]

Did you have to machine the rear hubs to install the disc carriers?

The rear axle tube (bearing housing) casting should be machined where the caliper mount is bolted on.

Brian

[Hardingfv32]

... Write the rule now, before someone starts doing it.

Why? Nothing to prevent banning after someone comes up with something. You are going to have to be very creative to develop anything under the current rule set. I doubt any of the rule developers have that kind of creativity necessary to write a useful rule.

Brian

[smsazzy]

If FV guys must insist on using disc brakes, you should take the opportunity to exclude the use of any aerodynamic devices, backing plates, or fairings from the rule package. Write the rule now, before someone starts doing it.

There is already such a rule. It was developed in response to the brake backing fairings at Road America. AKA, the pizza pans.

[smsazzy]

I doubt any of the rule developers have that kind of creativity necessary to write a useful rule.

Brian

Maybe not. But at least we actually race a car and promote the class instead of banging away on a keyboard in our basement.

[Ed Womer]

I think it is great that Mike and I guess his dad as well have spent the time to come up with a nice looking disc package. If I was still racing I would switch in a heartbeat. After 30 plus years of wasting my time to deal with drum brakes and what has become a huge expenses as well this is a welcome change. Hopefully the cost to switch will be similar to what the Challenge Cup have found was available.

If the cost to purchase the disc set up is the same as one set of brake shoes then what is the problem? Mike's observation from the test is clear that there is no performance advantage and it might be easier to brake but there is no advantage.

Ed

[Hardingfv32]

Maybe not. But at least we actually race a car and promote the class instead of banging away on a keyboard in our basement.

Did I highlight one of your weak points as a rule developer?

I can safely say that I have put in more track time testing my new car than you have racing in the last two years. There is absolutely no value racing with a car that is not right. Major events are simply not the place to do development these days.. too little track time. Test days are half the expense with 3X the track time. My driver is just as happy testing. I can safely say that the development of this new car has been more problematic than any I have built in the past.

Now there is disc brake design and development to be concerned with. Even though it is not a wise use of my time, I could not resist getting involved with such an exciting car design change. The car's design is my main hobby, not the actual racing. I can work on the car seven days a week but you can only race 10-12 days a year at my income level.

Brian

[Hardingfv32]

...Hopefully the cost to switch will be similar to what the Challenge Cup have found was available...If the cost to purchase the disc set up is the same as one set of brake shoes then what is the problem?
Ed

1) Has anyone started using disc brakes in CC yet? CC is changing or has a rule set that makes the track increase acceptable. All the heavy lifting is being done with the rule set.

2) Even the CC disc package costs more than a single Carbotech shoe set. The SCCA FV disc package has a track rule to comply with. This requires a very unique design that is going to have a 'very' limited sales demand. Low volume means high cost. The Varacins brake system will be much more expensive than the CC proposed offering. I know the design/fabrication costs for a high performance system like this and there is not many cost reduction options. Lets see if anyone else can do better.

Brian

[pacratt]

Once again, if initial $$ output is your main concern, please refer to post #4 in this thread.
It's not a joke or backless comment...there IS a big market in the vintage groups.

Glenn

[GrahamLoughead35]

Formula Vee racing is already the cheapest source of Formula car racing out there. If this is a problem for you running in an SCCA major then vintage or Challenge Cup would be a better option. Or should I even say karting. A lot of people including myself, who want to run out front at the runoffs, will spend top dollar to maximize the car. We are always looking for the best ways to get the most out our of cars and will usually spend whatever it takes to get that perforce advantage. I do not know what Mike has decided on the price of these brake packages will be but I'm sure they will be a plotless expensive than any other formula class. Vee racing is the most affordable competitive racing out there and I do not think there should be an arguments that it is too expensive because it is not.

[Jnovak]

If the pedal pressures are too high then change the master cylinder size or change the brake pedal ratio. Master cyl change is easier imo