OK my last post until it’s available to everyone and we really have something to discus.

The new rotor is a custom designed vented rotor, that was penned in house, very close to the mass of the solid Renault rotor that we currently use. (based on CAD models)
The final design and production is done by Willwood with their proprietary racing cast iron recipe. The width is not set in stone yet, but it is in the 15.75 to 16.5 mm range. That stretches the fit limits of brake hardware.

The challenge of this project was, casting, purchasing volume, price
and consistency / future availability . We needed a company that wanted to or could be our partner in this project.

It was very difficult to find a company that could cast the rotor with the
4 mm narrow venting width. Lots of companies said they could do it but most led to a
dead end.
Next if they could cast it with the narrow vent window, it needed to be at a
volume we could afford or they would share the cost with us. That narrowed it
down even further.
Finally we needed to meet a price point so we could sell them at a reasonable cost, we are right on the edge of that and the last company standing was Wilwood.
This has taken over 2 years…with lots of e mails, phone calls,face to face meetings, shipping sample parts across the US, handshakes and finally closed doors on all but one manufacture.
I could have finished this project in 3 or 4 months with more than one company at $100 / $110 a rotor or $200 / $220 for a 2 piece aluminum hat / vented rotor design.

2 years ago we were still looking for the original tooling or a company to partner with us to produce a batch of 1.9 cylinder heads. Again it was possible to have it done, but the cost was not even close to what we could afford. The avg cost of the bids was about 90 K for the first batch of 20 heads. So if and when you needed a head we would have had to add $4500 to the cost of the rebuild…10 K rebuild for our class is never going to work. That’s when we started looking for an engine to update the car with. I won’t go into all the challenges of that project, but we are close to running a SRF with one of the candidates.

A little history about our brakes, originally the “Sport Renault” used the bakes just as they came from the street car, stock pads and all. They didn’t work very well cold, but did the job…the Min weight at the time was 1525 LB.
Over the years the min weight crept up, plus the first drive train update we gainned 12 to 15 foot lbs of torque. Ours tires have changed quite a bit as well, if you can remember a lap time from 1985 /86 compare it to the a current time…at some tracks the difference is shocking, as much as15 seconds. I don’t remember the year the Min weight was raised to where it is now 1670, but it was around 1994 or 95 I think.
AS the weight has gone up, so has the overheating problem. Since then we have made a couple of brand and compound changes to try and help the problem. The pad compound we currently use is Hawk Blue. The temp range is something like 450 to1000 Deg F. I do have “real time Rotor Temp data “ from my car and Tray’s. Peak temps are down 200 / 250 deg F
Fast guys can run the solid rotors from 800 to 1200 F on and avg braking track and on a heavy braking track 1300 F plus on the fronts is not uncommon. The digressive feel is the avg temp being higher than what the compound was designed to operate at,which also increases the wear rate. All of that heat has to dissipate somewhere; The solid rotor isn’t very good at transferring heat to the air. Much of it goes in the hubs and wheels. On the flip side it’s also why you feel like you have pretty good bakes cold or just off the grid.
Consistent manufacturing / future availably was another key of the project. When is the last time you guys have seen a Renault driving down the street ? For that matter when was the last time you saw a solid rotor on a new street car? SRF’s do use a fair number of rotors a year, but not enough for the “Top Shelf” Brake companies (ie Brembo) to continue producing our rotors. I talked with another U.S. company that was about to stop importing our rotor. (an Asian aftermarket part)
What we have left is a couple of Asian manufactures casting our rotor out of whatever Cast Iron Recipe they have. The Cast Iron recipe is largely what the feel, stopping power of the brakes comes from. (without pad compound changes)
So in effort to make sure someone would build the same “Spec Rotor” for years to come. We went through the trouble of producing the rotor, so some improvement was designed in and has been needed for a long time. The vented rotor is the right choice for our brakes.

The release of the new rotor has nothing to do with the pending drivetrain update. It just took that long to bring it to production. However I’m sure the small increase in performance will be greatly appreciated.

Don’t think for minute we didn’t or do not consider the interest of all of our
owners…we do!

I want to thank the guys that have an idea of the effort it takes to make this happen at a reasonable cost…the key is reasonable cost. This could have been a slam dunk at about 40% more and released well over a year ago. For all of the guys that are not so sure, please hold the negativity until you have first hand knowledge of the new rotor.

This has turned out to be a huge task, but all the effort is worth it. When the guys that tested the rotor say “wow” when can I use these..!

Mike D

Well said, Mike. Thank you for the historical background as well.

Mike,

Thanks for you clear, detailed and rational explanation of the problems and the process involved in both the brake and motor issues. I certainly feel much better about the transition, and I would bet so do many other SRF guys, now that we understand the issues more fully and the efforts you have made to minimize the costs to the SRF community. Please continue the transparency and the communication as we move toward the new motor.

Dave Coppock

I am impressed that you could get a reasonably priced custom design that requires so few other changes. Great job. My only question now is do I try to squeeze a few more races out of the new set of Asian rotors I have or put them in the "emergency spares" catagory.

So now that we have new rotors, can we detune the new engine less? Given a choice between $10,000 for the same performance and & $10,300 for significantatly more performance I will choose the latter every time. I would even go higher for more performance. The Ford motor lasted the SRF roughly 20 years, if we are lucky the X motor will last the SRX just as long, so what will the SRX's competition be like in the future? I suspect it will be faster, and that the SRX will lose popularity if it becomes the slowest class in the SCCA.