Brakes. Someone once told me "You have to stop before you can go." The One Lap makes for many different needs in a car, and brakes are no different. They need to function reliably on big, high-speed road courses like Daytona and VIR, but still be able to stop the car on the highway while stone cold.
Over the years I've had reasonably good luck with the basic performance of the braking system. At times the pedal was too touchy or too hard, but the stopping capability had been well suited for most events and street driving. One Lap is a different deal, so a phone call to Tobin at Kore3 was in order. Tobin had given good advice in the past as to proper parts selection and setup, and he has real-world experience with using the parts he sells.
Like much of the Camaro build many of the parts are budget friendly. The front calipers are C5 that were purchased new from a member advertising in the For Sale section, supported by Kore3 mounting brackets and hardware. The rears are all early 4th-gen Z28. Though not what I would really like to have, they have served well, but my reliability-centric brain has been going over everything in the car, so the front hubs, bearings, spindles, calipers, and pads are all up for inspection, rebuilding, and upgrading.
The first was to inspect the spindles for damage and wear, and fortunately they were in good condition. The hubs however were OE GM hubs purchased years ago used. Though they appeared to be in good condition there was no way to tell without additional inspection methods to determine if there were any other concerns. It was time to upgrade to a set of aluminum hubs with new bearings and hardware. The Kore3 hubs come black anodized to resist corrosion, tapped for ARP studs, have the bearing races installed, and include a sealed dust cap. All that made installation prep very easy.
Another item discussed with Tobin was the use of a solid spacer to set the bearing preload. By using the spacer spacer kit, which includes a variety of shims, the preload of the hub can be set to a target endplay.
In this case Tobin suggested 0.0015" based on real-world experience. This is very important since the thermal expansion rate of the aluminum hub and the steel spindle shaft are different. Plus, the hub is outer ring rotation, so the bearing cups and hub will be hotter than the spindle shaft as well. Setting the preload takes a bit more work than just turning the nut and setting a cotter pin, but the result is a much more controlled. There is very little wheel movement when completed. Below is how the endplay was measured using a dial indicator set on the caliper bracket.
With that done attention was then set on the calipers. Brake fluid heating occurs from the transfer of heat from the brake pad backing into the caliper piston. There are various ways to help reduce the heat transfer, and one of them is to change the caliper piston material that does not transfer heat as quickly as the OE aluminum piston. Doug Rippie Motorsports sells stainless pistons that fit the bill and requires no other changes. Add in a new set of $8 caliper piston and dust seals and the calipers are good to go.
The pads proved to be more difficult to deal with. During October testing at Buttonwillow we used on the advice of Tobin a Hawk DTC30 pad. Tobin warned that the DTC30 needs heat to work well, so when cold they take additional pedal effort. On the track and warmed up they were great, but when cold they did not work well. We're going to go back to the Hawk HP+, which have worked well on the street and track. We won't be doing 20-minute sessions on any of the tracks were going to so there's no big concern, but there will be more testing before we hit the road for South Bend. Though some might consider the DTC30 testing a failure, I consider it a success. Tobin's words rung true, the cold stopping capability is not acceptable for me, so we move back to what we know.
The front rotors are C5, but they are a super-beefy DBA part that Tobin recommended. They are serious pieces. If I hurt these things the rest of the car will likely be on fire.
The master cylinder now on the car is a manual 7/8" standard from a 1995 Dodge Spirit (Thanks JR.) Though the pedal travel is a bit longer than what I would like the effort and feedback are good.
The brake fluid will be the NAPA heavy-duty fluid that I've always used. The fluid has only boiled at one event that was really hard on the brakes. Since that time the front caliper and caliper piston material have changed. Add in some brake ducting and fluid boiling should not be a factor.
During testing in October Jon and I did six 20-minute sessions on the big course at Buttonwillow. The only thing we did to the car was put in fuel. The brakes worked well without ducting, so that should help to offset the change to the HP+ pad.
Up next, safety harnesses, hardware, and HANS
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