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keith kuchler

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About keith kuchler

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  1. Well, I have been racing this car in the BSL group with no issues in braking. When strapped into a race seat, the example of 70 pounds of pressure is almost like setting your foot on the brake. I am applying far more pressure. Also, you must use the correct compound of brake material. Every driver is different. By doing the math, one can customize the system to suit a drivers comfort level.
  2. Just for giggles....let's do the math for this system to find out what you can expect from it. First we will compute the area of the master cylinder used. Its bore is 23.81mm. 23.81mm divided by 25.4 gives us 0.937 diameter of the piston. 0.937 divided by 2 gives us the radius of .468 Now we square the radius..... .468 x .468 = .2196 .2196 times PI 3.14 equals .689 .689 is our area of the piston in the master cylinder. Next, we have to calculate the area of the caliper pistons. I am using the Volvo brakes that have 4 - 38mm pistons. For this calculation we are only concerned with using two of the 38mm pistons in the caliper. 38mm divided by 25.4 gives us a decimal of 1.496 diameter of the caliper piston. 1.496 divided by 2 gives us the radius of .748 Now we square the radius...... .748 x .748 = .559 .559 times PI 3.14 equals 1.75 area of one piston. 1.75 times 2 equals 3.513 total area used in the caliper. 3.513 is our net bore area of the Volvo caliper. Now we need to compute the leverage ratio between the master cylinder bore and the caliper bore. Effective Caliper Piston Area (3.513) / Master Cylinder Bore Area (23.81mm which is .689) = 3.153 / .689 = 5.1 for an 5:1 ratio Calculating pedal ratio The driver leverage is determined by multiplying the Pedal Ratio X the ( Caliper Piston Bore to Master Cylinder ratio ). I will use figure 4 for my calculation. My pedal is 9.125 long, point A. B is 1.5 long on my pedal. 9.125 divided by 1.5 is 6.08. 6 to 1 pedal ratio. The driver leverage for the front brakes is (pedal ratio) 6.08 x 5.100 = 31.00 or 31 to 1 ratio. Rear Drum Calculations The rear drums use 22mm wheel cylinders. We need to calculate the rear wheel cylinder area. 22mm / 25.4 = .866 .866 / 2 = .433 radius .433.x .433 = .1875 Radius squared .1875 x PI 3.14 = .588 area of rear wheel cylinder Leverage ratio is .588 wheel cylinder area / .689 master cylinder area = .8534 leverage ratio Driver ratio for the rear drums is 6.08 (pedal ratio) x .8534 (leverage Ratio) = 5.1 Driver ratio rear. So we now have 31 to 1 in front and 5.1 to 1 in rear driver leverage ratio By applying 70 pounds of leg force against a 6.08 to 1 pedal ratio we generate 425 pounds of force into the master cylinder. By taking the leg pressure and dividing it by the master cylinder area .689 we get brake line pressure. 425 / .689 = 617 PSI We now take the 617 PSI and multiply it by the area of the caliper pistons. 617 x 3.513 = 2170 pounds of clamping force on the caliper. Rear pressure is 617 PSI x .588 wheel cylinder area = 362 pounds of force to the drums. Because of the servo action of the rear drums, less force is required by the wheel cylinder, so smaller pistons can be used. Finally, the contact area between the shoes and the drum surface is large, much more than that of the disc brakes. This requires less pressure against the shoes since the force is acting against a large area.
  3. I was recently asked how I created my booster-less brake system on the race car and what parts I had used. The first part that you will need to procure is the master cylinder. I used ATE 34311120832 from a BMW 528I. This part will need new reservoir grommets and adapters. https://www.autohausaz.com/pn/BM-34321102282 https://www.autohausaz.com/pn/0004310935 You will need to obtain your pedal housing and remove all frame work and unnecessary hardware from it. (See picture ) Measure the bolt spacing and diameter of the new master cylinder to help create the doubler that will get welded on to the back of the pedal housing. Once the doubler is welded, attach the brake cylinder to the pedal housing and clock it correctly. It must be turned so that the cylinder will clear suspension components. I used a spherical hiem joint along with an adjustable push rod to actuate the brake master cylinder. ( See push rod ) You will need to relocate the hiem joint in a new location on the brake pedal arm. I simply drew a straight line from the master cylinder plunger thru to the brake pedal arm and marked the location. Once the hole is drilled attach the hiem joint, adjust the plunger push rod and test the actuation. It should move smoothly with no binding. The next part of engineering the brake system will consist of several parts. I used the Volvo calipers for front braking and the 320I drum brakes for the rear. The rear brakes used the 22mm actuators to apply pressure. Because the master cylinder sits below the other brake components in the chassis, it is critical to not have bleed back. To prevent brake fluid bleed back, residual valves need to be incorporated. I used wildwood valves. 260-13784 260-13783 I installed mine per the picture below. Attach the brake reservoir to the master. Attach the brake lines and bleed appropriate. A nice firm brake pedal is the result.
  4. I will take it. How do you want paid?
  5. For Sale: 19MM BMW 2002 ST Suspensions Rear Sway Bar Installed for one track day. Practically brand new. Comes with bushings. Price does not include shipping. 19MM round bar.
  6. For Sale: Used 168mm Limited Slip differential from a E36 318i/ti. Price does not include shipping. The E36 318ti lsd's were the last of the smalll case lsd's, and as such were the most capable in handling higher amounts of torque than earlier diffs. Unit pulls a break-a-way torque of 30 to 34 foot pounds.
  7. Please give shipping quote to 85086. Thanks.
  8. Thank you all for the compliments. I was able to take it out on track for the first time yesterday morning during a 6:00AM to 9:00AM track practice. It definitely drives different than a 911. Thank you Mark....you are very kind. Pahrump and Willow are in my plans. Currently I have signed up to run at Coronado in September. It will be a break from the heat here in Phoenix.
  9. Thanks Ken. You probably do not realize this, but the talks I had with you at the track were a huge influence on implementing this build. I want to thank you again for taking the time to speak to me about the BMW 2002.
  10. Hmmm......true...but it is my first BMW 2002 M10. Unfortunately, the world of 911's has reached into the stratosphere. I had to find a more reasonable platform. Without the use of these forums and people like Jim Froula of Racecraft sharing their projects, one would have a very difficult time creating a competitive car from scratch, first time out.
  11. I used VAC springs and their titanium retainers. Thanks. I have been cleaning out barrels of media dust every time I take it out. The dust is finally settling down.


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