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How a Race, Track, Drift and Rally Car Braking System Works? – Motorsports Tech Session

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Hello.

How are all you Motorsport Tech Session hard core fans?

Thank you for all the feed back you give us, with out you we are nothing.

If you are new to the Motorsport Tech Session then I am sure you will enjoy this article.

How a Race Car Braking System Works?

The Master Cylinder is one of the key elements of a brake system. This article will inform you how the Master Cylinder / Pump forces brake fluid through the system.

The way this happens is a basic lesson in hydraulics.

It all starts with the actuating force that is fed into the master cylinder. This force is provided by the driver’s foot on the brake pedal. The maximum force that is exerted on the brake pedal is approximately between 150 to 200 pounds of pressure, the average pressure on the brake pedal in a race condition is 100 pounds of force.

The driver is normally limited to a maximum of approx six inches of pedal travel that can be applied to the brake pedal. This is determined by the pilot leg length, closeness to the pedal and leg angle. The ability the driver has to apply the force to the pedal will be influenced on the driver body restraints like the seat belts and shoulder harness, the angle of the hip and the angle of the knee joints. Having a straighter knee joint will allow an easier operation of the pedals, and more force can be applied to the brake pedal.

The force that is exerted by the leg and foot to the brake pedal is then multiplied by the leverage that is in the pedal ratio. Most production cars are 3 to 1 or 4 to 1 this is enough of a ratio when a servo is used, however with out a servo this ratio is a little low. Most race car pedal boxes that do not use a servo and will have a ratio between 5 to 1 and 6 to 1.

To give you an example of the ratio increase here are a couple of examples:

100 pounds of pressure created by the driver to a 5 to 1 ratio pedal will deliver 500 pounds of pressure to the master cylinder push rod. (100 lbs x 5 = 500 lbs)

100 pounds of pressure created by the driver to a 6 to 1 ratio pedal will deliver 600 pounds of pressure to the master cylinder push rod. (100 lbs x 6 = 600 lbs)

However always remember if the pedal ratio is increased, the pressure will increase and also the movement of the pedal will increase.

The next consideration with a race car brake pedal system is the master cylinder bore size. The most common bore sizes used are:

.75 – Internal piston bore size O/D

.7 – Internal piston bore size O/D

.625 – Internal piston bore size O/D

The force supplied into the master cylinder is divided by the square inches of the piston, and the output of the master cylinder is pressure in pounds per square inch.

.75 Cyl Bore is .44 Sq. in. of area

.7 Cyl Bore is .38 Sq. in. of area

.625 Cyl Bore -is.30 Sq. in. of area

For example:

300 pounds of pressure created by the driver with the pedal ratio increase is applied to a .75 bore master cylinder (Force supplied into the master cylinder is divided by Square inches of the piston) 300 pounds divided by .44 = 681 pounds per square inch line pressure

300 pounds of pressure created by the driver with the pedal ratio increase is applied to a .625 bore master cylinder (Force supplied into the master cylinder is divided by Square inches of the piston) 300 pounds divided by .30 = 1000 pounds per square inch line pressure

It is easier with this knowledge to understand that a smaller bore master cylinder will deliver more pressure into the brake lines and to the brake calipers.

So why not use smaller bore master cylinders all the time? There are two reasons why this is not the perfect solution.

1) With a smaller bore master cylinder the pedal will require more travel to displace the given fluid needed.

2) Higher line pressure aggravates line and calliper expansions and thus uses up more fluid.

If a system is so stiff (meaning no or little line expansion or calliper deflection) that the driver is only using a small part of the total pedal travel, then using a smaller bore master cylinder will reduce the pedal force, or effort required by the driver to stop the car.

Once the pressure leaves the master cylinder there is not a great deal of movement in the brake lines, what does happen is a pressure build up and pressure transmittal.

To understand this theory in a practical way, please imagine you are blowing down a straw. Place a finger two inches from the base of the straw and blow you will feel the air passing over your finger.

Now block the straw with your finger. There is still the volume of air in the straw and you are still generating force by blowing down the straw. However your finger only feels the force against it.

This is a very simple example of the principle of pressure transmittal, as used in a sealed brake system.

I hope you have found this article interesting and thank you for your time.

Grant Loc has been involved with Motorsports for over 15 years and the Director of obp Ltd. obp Ltd is a major player in Manufacture and Supply of Quality Race Car Products and provides most of the leading Motorsport distributors all over the World. obp manufacture Race Car Pedal Boxes, Handbrakes,Seat Brackets, Swirl Pots etc. www.obpltd.com

Posted on August 25, 2011 by submityourarticle, 1 comment

What Is “The Blip” And “Heel And Toe”? Race Car Tips – Tech Session

Hello, ok straight to business.

What is the Blip as referred to by Race Car Drivers?

The Blip is used when you are changing down a gear without losing speed or grip. Properly done the RPM should be raised to approx 2700 to 3000 RPM just before the clutch is engaged again. You do not push the throttle and hold it, you tap it, the best term to explain it is you “Blip” the throttle, this is a quick and sharp burst.

The blip should take place just before re-engaging the clutch by doing this you will not get the shock through the drive train or slow the car down when going from a higher gear to a lower gear. In a competition environment on the race track when you are driving close to the tyres limitations of adhesion, a down shift with out a blip of the throttle could cause a loss of grip and send the car into a spin or lose grip in the straight line braking zone.

How and what is Heel and Toe?

Because you are using your left foot on the clutch and your right foot on the brake, you have to make some adjustments so you can blip the throttle. The way to do this is to adjust your foot position and use a race pedal box designed for heel and toe. You use the ball of you foot pressing on the brake pedal making sure you leave enough of the outside of the foot to roll over so you can blip the throttle. By blipping the throttle you will enable a smooth down shift with out losing any tyre grip.

The correct brake and throttle pedal relationship should locate the throttle and brake approx 30mm to 50mm apart. The throttle is set slightly below the brake pedal when the brake is hard on. The heel and toe method is a pretty hard technique to master and requires plenty of practice. The heel and toe term was phrased over 40 years ago when the brake pedal was on the right and the clutch pedal was on the left and the acc pedal was in the middle and 6 inches lower. Then you had to use your heel and toe to blip the throttle.

As I have explained with today’s pedal systems the heel and toe is not used, but the term still remains. The pedal system in most road cars are not set up for heel and toe, so drivers are forced to go through some real contortions to be able to touch the brake and the throttle pedal at the same time.

This is why I recommend you change the standard pedal set up to a race pedal system if you are using the car for track racing, rally, drifting or track days it will make life a lot easier and improve your lap times.

Thank you for your time, I trust this has been of interest to you.

Grant Loc has been involved with Motorsports for over 15 years and the Director of obp Ltd. If you like this article please go to our web site www.obpltd.com register to our email news letter and Race, New Products updates. We also have two free reports to get. obp Ltd Manufacture and Supply Quality Race Car Products to leading Motorsport distributors all over the World

Posted on August 12, 2011 by submityourarticle, Reply

Why It Is Important To Change Your Transmission Fluid

Do you want to really scare one of your friends who own a car? Tell them that it sounds like they are having problems with their transmission. Your car is probably the second biggest asset you will ever own after your mortgage and having problems with the transmission of your car is a very serious problem. Anything you can do in order to prevent damage to your transmission can help to prolong the life of your car. One option is to make it a point to have a transmission repair service center perform a transmission fluid change. It seems like most people have accepted the fact that it is important to have the oil in your car changed periodically. They may stretch out how often this is done, but they do make sure it gets done. However, most people are not aware of the fact that you also need to have the transmission fluid changed in your car. You do not have to do it as often as you need to change the oil, but it is still pretty critical that you do it.

A general guideline for how often you have to change the transmission fluid is approximately every 30,000 miles. However, this could be higher or lower depending upon how the car is used. Some manual transmissions really should have their transmission fluid changed about every 15,000 miles. However, there are actually some cars being build right now with automatic transmissions that can go up to 100,000 miles before this fluid is changed. But do not let this long life fool you. It is easy to forget that this fluid needs to be changed since it lasts so long, but it is still important to keep track of this and change the fluid.

The biggest problem with not getting the fluids changed is that there are very small metal particles that develop over time. As these particles flow through the system, they can begin to cause problems with your engine. Another thing that happens is that in time, the fluid begins to break down. This means that some parts of the engine would not be properly lubricated, which means mechanical problems can develop.

The best way to prevent problems is to regularly change the fluid. If it does not seem like it is worth the cost, find someone who had to get a new transmission and ask them how much it cost. Then compare that to the amount of money the service station would charge you to complete this process. There really is no comparison.

When you decide to have the fluid changed, you need to know that it is not as easy as changing the oil in your car. When you change the oil, gravity causes all of the old oil to flow through the engine into your drip pan. Gravity causes this to happen. The transmission fluid does not work like this; it will need to be flushed out. Only doing a partial change of the fluid and not getting all of the old fluid out can actually cause more problems than if you did not change any of it.

Stewart Wrighter searched the term transmission repair Houston when he needed help after an accident. His son searched the term transmission fluid change Houston to find a shop in the area.

Posted on August 5, 2011 by submityourarticle, Reply

The Birth Of Milwaukee Power Tools From Ashes

Remember the old legend of the Phoenix – this bird rising from the ashes of a fire – reborn and renewed. Well this is the story of Milwaukee Electric Tool Corporation which arose from the ashes to the company it is today.

We can begin our story way back in 1918, toward the end of WWI, often referred to as The Great War.

Henry Ford, the famous automobile tycoon, was on the lookout for someone to fabricate a portable, more light weight version of the one-fourth inch capacity power drill.

A.H. Petersen, a young manufacturer from Wisconsin, stepped up to the plate and took Ford’s commission. This led to the subsequent invention of what came to be known as the “Hole-Shooter.”

The revolutionary Hole-Shooter was a lightweight indeed back in those early days of power tools, weighing in at a mere five pounds. It was the first ever power tool able to be operated with only one hand while delivering enough power to take on heavy duty jobs.

In 1922, Albert Siebert joined Petersen as his business partner, and the A.H. Petersen Company was founded.

Only one short year later, their manufacturing plant was completely destroyed by fire, which necessitated closing the doors of the business.

In 1924, Siebert acquired the remaining assets of the business at public auction and it was re-opened, christened with a new name destined to become famous: The Milwaukee Electric Tool Corporation.

And so it began again, reborn after the fire that destroyed it, Siebert took the first step of a journey that would eventually take Milwaukee Tools all around the world.

During the infancy of the company, there was far more emphasis on tool repair than tool manufacturing. Seeing what were the most common failings of the tools then available allowed the fledgling research and development team at Milwaukee Tools to design new and better tools, built to last longer with higher performance than their predecessors.

The Hole-Shooter was refined and improved; and before long it was the go-to tool for workers in the metal working and automotive industries. When World War II commenced, the Hole-Shooter was indispensable to the manufacturing of military aircraft, and the U.S. Navy placed orders with Milwaukee Tools, as well.

Down through the intervening years, Milwaukee Tools has striven continually to produce products of the highest quality and workmanship. Their company motto of: “Nothing But Heavy Duty” sums up Milwaukee Power Tools nicely! Discover the quality and craftsmanship that has made them a household name for almost 100 years!

Andrew Watson of Get Tools Direct has a great selection of Milwaukee Power Tools! Enjoy the convenience of shopping and buying online 24/7 with speedy delivery directly to your door! An expert staff of experienced professionals is happy to answer any questions you might have about Milwaukee Tools or any other products and accessories

Posted on July 28, 2011 by submityourarticle, 1 comment