Technical Advisory Committee Chris Huggins Posted November 19, 2020 Technical Advisory Committee Report Share Posted November 19, 2020 (edited) Hey everyone, With the advent of the 2021 "2x" brake rule going away, there is finally an opportunity for the E30 to upgrade to a low-consumable-cost brake option for the front. With my experience operating e30's in this series for many years, I have had great success on the OE brakes. My current setup is Stock Girling calipers with Zimmerman rotors. Condor supplies my brake lines, and I use PF08 or ST43 pads. This setup has weaknesses: 1. Rotors - The rotors last about 14 hours at most tracks, even with massive 3" custom cooling ducts. We have cracked rotors on many occasions, leading to some pretty hairy moments having to finish a race with a terrible braking vibration. Luck kept us from "exploding" a rotor and having a big issue 2. Consumables Costs - The rotors get changed after ever weekend on the track, including doing "testing" or "DE" days. Pads are good for 1 Race weekend, and the left overs get used for testing and DE. The rotors are $30 each (FCP helps with this), and the front pads are $200/set. 3. Component Sourcing - The Caliper brackets are NLA new. The guide pins are currently NLA and have been for a year or so, and I just used up my last NOS set of those plus swapped my last set of good brackets from left to right (One pin wears faster than the other). The calipers require frequent rebuilds to replace the seals, which have been intermittently available. At least this stuff is cheap when it is available. Looking to improve upon this, and minimize risk of rotor failure in longer races, I have designed a custom kit to fit the E30 front and work with the stock E30 rear. The kit is designed, as much as possible, around off-the-shelf Wilwood (a champcar supporter!) components. It's primary concern was minimizing ongoing consumables costs and maximizing ease of service. Components: Wilwood Caliper 120-13232. Forged Superlite 4 Radial, 4 Piston, 1.25" Pistons Wilwood Rotors 160-2898 (RH) and 160-2899 (LH). 11.75x1.25 with a 8x7 mounting pattern. Many other rotors will also work (for example HAWK HR8002R and HR8002L) Wilwood Bobbins and Bolts 230-14845 (qty 2 required). 5/16 x .750. Locktite and Safety Wire recommended. Pads - Any '7420' pad shape, which is an extremely common shape. Almost any compound can be had for <$200 in this shape. Lines - The Wilwood caliper is supplied with 1/8-27 NPT female threads. The kit will come with an adapter to allow use of the stock E30 brake lines (M10x1.0 DIN) Custom Components: Hats, Machined from 7075-T6 Aluminum, with black anodize Type 3 Adapter Brackets, Machined from 1018 Steel, with black powder coat Costs: I would like to offset some of the manufacturing setup costs by selling hats and brackets to other E30 teams. Getting one part made and getting 10 parts made is pretty much the same costs when you request custom CNC work. Therefore, I don't know the exact cost of hats and brackets at this point. I would like to sell them in pairs, and I would suggest a team buy one pair of brackets, and 2 pairs of hats to have a spare set. My best estimate for costs if I can sell QTY 10 of each is $300 for the pair of brackets $200 for a pair of hats Brake Line Adapters are ~$15 ea, but I am still looking for a source of these in stainless instead of brass Caliper Mount Hardware - 3/8-16 for the bracket, 3/8-24 for the nut, plus some 12-point nuts. Titanium stuff would be $80, steel would be much less but I have not found a source of appropriately graded hardware at this time. I am not looking to profit from this - Just offset some of the costs for my own kits. Fixed Costs are for the Wilwood components, which you would buy direct from your preferred source: Calipers - $500 Rotors - $100 Bobbins - $100 Pads - $200 Lines - You have these already Brake Bias: With stock brakes, the torque bias (assuming equivalent pad compounds) is 67.6% front. With this kit in the front, and stock rear, the torque bias is 66.8% front. The pedal feel will be marginally softer due to the smaller front piston area. Weight: The rotor is 9.6 lbs per Wilwood The caliper is 5.4 lbs per wilwood The adapter bracket is 1.2 lbs The hat is 1.2 lbs Total = 17.4 lbs per corner Stock Rotor = 10.5 Stock Caliper and Carrier = 8.8 lbs Total = 19.3 Don't worry, it has been thoroughly scienced, and I am more than happy to explain the process if there is concern. These von-mises stress images have the deformation scale multiplied ~75x for visibility Timing = The prototypes are on the 3d printer now, so within a few days I should be able to test-fit to a car. I still need to order a rotor and caliper for this purpose. Once that confirms fitment, I will need to source the components. I have a local source for USA made stuff, but the price is about 2x the overseas costs. Lead time is probably 6 weeks from order, so getting this done for Road Atlanta next year is possible but unlikely. More likely March 2020 delivery to anyone who is intersted. If you are interested, shoot me a pm. If you have concerns or questions, post them here and I will do my best to address them. Edited November 18, 2021 by Chris Huggins 1 Quote Link to comment Share on other sites More sharing options...
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