Circle Track Stock Car braking

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Re: Circle Track Stock Car braking

Postby Supershafts » Mon Jan 31, 2011 4:46 pm

Depending on many things you might have a car that isn't set up for that track, and may need to brake to put weight on the nose and off the rear..

You may need to gas to put weight to the rear and off the nose...

Entirely to many things can happen to drive the car into, thru and out of the corner....

The big thing with oval racing are you competitors.... are they going to DRIVE, or use you as an added 4 wheels to get thru the corner....
Oval racing is a little more involved depending on the DRIVERS or lack of DRIVERS you are competiting with.... different areas breed different drivers, or steering wheel operators that THINK they're drivers.

I use a jeep to play on a oval here, it is really set up for drag racing, it has very tight LS's front and rear and locked t-case.... it needs braking in and coming out it needs a very particular style or she'll push right to the wall...
When i have a driver worried about me, they keep me pinched down cause they know im not going to drive thru them, and i cant get back to the gas until im nearly straight.

So there are tons of different things going on, entering the corner at your ideal spot this lap and there is a car in your way next lap...

To many differences.... You're going to have to become a driver

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Re: Braking

Postby David Redszus » Thu Feb 03, 2011 10:30 am

kngofthehill wrote:The most important thing is to be smooth. If it is asphalt you want to do your hardest braking going straight into the corner ( so you don't upset the chassis). Depending on the conditions you want to be mostly off of the throttle during hard braking then as soon as you are off of the brakes pick up the throttle as much as the corner will bear coming to full throttle as soon as the tires will allow through the apex and the exit. Again BE SMOOTH sharp throttle inputs cause wheel slip and out of controlness = bad E.T. Have Fun!!!!!!

P.S. If it is dirt ......... You are at the mercy of someone else. :D :D
This is not an attempt to pick an arguement. I have heard the term smooth used in road racing for many, many years. But I have never heard a proper definition of what the term really means.

How would you define smooth when it comes to driving?

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Re: Circle Track Stock Car braking

Postby governor » Thu Feb 03, 2011 7:23 pm

David,

I doubt you have driven a race car in any closed course competion or you would know what the term smooth refers to.

SMOOTH,

There are some guys who have no feel for the throttle or brake pedal. They mash the throttle to the floor and smoke the tires off the corner then bitch that the guy who beats him off the corner on exit of every turn must have more motor. This is the same guy who does not get his brake system balanced and locks up the rear tires or creates a push from to much front brake.. This is the same guy who will make eratic lane changes and run into others, while the other driver who is smooth on and off the throttle, smooth on and off the brake, is driving by and headed to the front.

Smooth is just as it sounds, kinda like the guy who gets better fuel mileage from his daily driver, he is smooth on the throttle, never racing to the next light and coasting to a stop while his foot is off the gas.

Oh ya and the data logger comment, come on, do you think Dale Sr, Cale Y, DW, Rust W, Bill E, Terry L, The King or any of the older Cup drivers ever used a data logger. That is what your ass is for when strapped in the seat, it is to feel what is going on underneath, not just there as a seat warmer along for the ride.

Oh and for the record I have logged over 80 feature wins in an open wheel IMCA type Mod, all w/o the use of data logger or traction control. So yes my ass kinda know's what car should feel like and how to be smooth.

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Re: Circle Track Stock Car braking

Postby David Redszus » Fri Feb 04, 2011 7:36 am

I doubt you have driven a race car in any closed course competion or you would know what the term smooth refers to.
I have taught race car driving for over 35 years, including many different types of racing. Circle track racing is the easiest of all. I have heard well over 50 different definitions of what smoothness really means. None make any sense including yours; they all seem to attempt to defy the laws of physics.

If you can't measure it, you don't understand it and you can't improve it. You can only talk about it.

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Re: Circle Track Stock Car braking

Postby ZIGGY » Fri Feb 04, 2011 11:14 am

Teaching the subject implies you have been a competition driver. Have you driven and/or taught short-track(1/4 -1/2mile) dirt? Do you consider all circle track easier than drag racing? No attempt to start a pissin' match here, just curious. Not that he needs or necessarily wants my support but I think what Governor is trying to convey is valid. Usually what we call "smooth" is backed-up by the lap times and race results.
P.S. - I have seen Google results for your name. Didn't immediately find details of your championship/s.

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Re: Circle Track Stock Car braking

Postby David Redszus » Fri Feb 04, 2011 1:49 pm

Usually what we call "smooth" is backed-up by the lap times and race results.

My inquiry was not intended to impugn anyones ability or track success. Simply to determine how various drivers explain their success or failures. Nothing more, nothing less.

Each type of racing, from boats, to snowmobiles, to drag bikes, to circle track, to off-road, to road racing in the rain, has its own set of requirements. The common denominator is not driver ability (which can vary greatly) but the laws of physics that determine the actual performance limits.

Over the years we have been involved in more championships and track records than I can count. But that has absolutely no value whasoever. What matters is an understanding of vehicle dynamics and how the driver influences it and how it controls the limits of the driver.

When we compare logged data from a track record lap to a so-so lap, we try to see where the differences are to be found. We then attempt to compare what the driver senses to the events shown in the data. Sometimes drivers "feel" things that are not there. Sometimes driver don't "feel" things that really are there. The very best drivers use data logger information to gain a significant competitive advantage.

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Re: Circle Track Stock Car braking

Postby ZIGGY » Fri Feb 04, 2011 3:11 pm

Ah, I accept and believe your point that human perception may differ from reality (as determined by data - which themselves may be inaccurately interpreted). I know that there is an on-going effort to identify & quantify the elements that make great drivers great. I also think there well may come a time when a computer controlled race vehicle can outperform the best humans. Directly to the discussion of "smooth", I expect you may agree some elements of it can be measured;e.g.throttle movement to tire slip maybe... But that's an area of expertise of yours, not mine. Regardless, I'll continue to believe in "smooth". Like the Supreme Court justice and obscenity, I know it when I see it.

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Re: Circle Track Stock Car braking

Postby David Redszus » Sat Feb 05, 2011 1:40 pm

Returning to the issue of braking.
If the objective is to maximize braking performance in a straight line, as found at the end of a long straight, then we need to make all four wheels do their job. The amount of brake force on the front wheels can be greater than that on the rear wheels due to forward weight transfer under hard braking. To test the longitudinal brake balance, simply drive the vehicle at slow to moderate speed and stomp on the brakes to lock up all four wheels. If all four will not lock up, you need to find and fix that problem.

Assuming a vehicle with a wheelbase length of 100 inches, the beginning of the rubber skid marks should be 100 inches apart. If they are less than 100 inches, it means the fronts locked up before the rears; if greater than 100 inches, it means the rears locked up before the fronts. The front to rear balance can be adjusted using master cylinder sizes, a balance beam with twin master cylinders, wheel cylinder or caliper piston sizes, or friction compounds. This technique works well on tracks with long straights.

But short tracks are another matter; they often do not have real straights. Even what we call a straight is actually a large radius. Now we have the problem of braking in a turn which produces a diagonal weight transfer. Ideally, the braking force would be different at each wheel based on the vertical loading of that tire. For a given track, this can be adjusted using friction compounds, and/or brake force regulation. But it would change for each track based on the combination of G forces; lateral and longitudinal.

Some vehicles do not like to turn into tight corners. In such cases, an excess rear brake bias can assist the turn-in of the vehicle, while front brake bias will make matters worse.

The best way to measure braking force is by use of a two axis accelerometer recorded with a data logger. Brakes can generate more horsepower than engines but are very often neglected; under optimized and under utilized.

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Re: Circle Track Stock Car braking

Postby 4banger » Sun Mar 23, 2014 6:09 am

As I race on a 3/8 mildly banked dirt track, I would like to start by saying " the first thing to do is get seat time and learn what to expect on the track. That is learn what the car does going into the turns and how it comes out of the turns. Get a feel for the car and then the track. The biggest difference in the track champion and a new driver is knowledge! The champ knows what to expect and where to expect it and how the car will react to going into the turns and how to brake, then how to get back on the gas without spinning and losing traction.
A new driver doesn't need a million dollar engine, just a good engine and seat time so he or she can learn what to expect and how to react.
The best thing to tell a new driver is have FUN !! :lol: When it's no longer fun then it's time to let someone else drive. Kurt Busch is a good example of this. [-X
After getting some seat time and experience with the car, the best thing to do then is get behind the track champion and go where he goes and do what he does. That's how I learnt . AND find someone you can trust to tell you the truth about suspension set up as most other drivers will tell you something wrong :^o or have a hard time remembering just how much something is suppose to be set to! #-o Best of luck
I thought I was wrong once but I was mistaken...

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Re: Circle Track Stock Car braking

Postby David Redszus » Sat Mar 29, 2014 11:58 am

I doubt you have driven a race car in any closed course competion or you would know what the term smooth refers to.
As I said earlier, various drivers have various definitions of the term smooth. This includes professional and amteurs alike.

Smooth is just as it sounds, kinda like the guy who gets better fuel mileage from his daily driver, he is smooth on the throttle, never racing to the next light and coasting to a stop while his foot is off the gas.

This comment does not shed any useful light as to what you mean by "smooth".

Oh ya and the data logger comment, come on, do you think Dale Sr, Cale Y, DW, Rust W, Bill E, Terry L, The King or any of the older Cup drivers ever used a data logger. That is what your ass is for when strapped in the seat, it is to feel what is going on underneath, not just there as a seat warmer along for the ride.

Oh ya, the data logger comment. We have massive amounts of data (as much as 121 data channels per car) from professionals and beginners on all kinds of tracks from short track bull rings to Daytona. Todays top drivers ALL use data collection and they could not imagine how one could be without such a useful tool. And for your information, today's drivers could run rings around the old timers based on ability if not on guts and courage. It took guts to drive those old jalopies they called race cars. Your ass is not a very accurate sensor. It is inaccurate, dampened by the suspension, seat and ass padding and a weary brain with poor memory cells. You don't have a clue as to what is going on underneath.

Without data, all you have is talk. Most of it pure BS.

Oh and for the record I have logged over 80 feature wins in an open wheel IMCA type Mod, all w/o the use of data logger or traction control. So yes my ass kinda know's what car should feel like and how to be smooth.

Oh and for the record you may have won amateur races but you clearly do not know why. When a vehicle is driven to the grip limit in any direction (which is all any driver can do), it becomes apparent that the limit is a very raggd edge and never smooth. It does not matter if on clay, loose dirt, asphalt, dry track or wet, the limit is always ragged.

What some drivers mean by smoothness, is to avoid over-reacting with car controls (steer, throttle, brake), so as to avoid inducing additional dynamic instability. This often results in slow response to grip changes; now smoothness is slow.

The real secret to driving is to keep the car smooth nor matter how hard or fast the driver may have to respond in order to do so. This means keeping the car balanced under all conditions; corner entry, mid-corner, corner exit. Data can show where a car is out of dynamic balance much more clearly and accurately than can ANY driver, no mater how talented he may be.

Driver response overshoots or undershoots will cause a change in grip limits, which are already changing with each foot of track.

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Re: Circle Track Stock Car braking

Postby 340king » Wed Apr 02, 2014 11:57 pm

This is an interesting post that was started almost 10 years ago.

I think you have hit on part of the smoothness answer Dave. One of the better compliments I was given came from an experienced driver who watched a race I was in. My car was horrible; wrecking loose on entry (full lock), then dead push on transition (full lock) and when I finally got the car to turn, I was so unloaded that it was loose off. He noticed all that and said he was amazed at how straight I kept the car. So the smoothness truly is in how the car appears on the track (I was flailing around in the cockpit trying to keep up with the car).

I have brake bias gauges in the car and really like them. It allows me to go back to a sweet spot for a certain track condition. It also allows me to get close, even if it isn't optimum. Having the car be spot on in the opening laps is crucial to moving up quickly. Many drivers struggle to get a rhythm established in the opening laps. Out braking them or rather better braking them going into the corners is a great way to gain positions.

The car talks to you in the driver's seat. You have to know what it needs. The brakes are a great way to adjust the car, especially on entry. If the car is tight, some additional rear brake with a slight drag on entry can free up the car. Of course there are times when you need a lot of rear brake and being smooth means killing the engine on corner entry. It is anything but smooth in the cockpit, but it looks smooth from the stands.

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Re: Circle Track Stock Car braking

Postby David Redszus » Thu Apr 03, 2014 10:35 am

I have brake bias gauges in the car and really like them. It allows me to go back to a sweet spot for a certain track condition. It also allows me to get close, even if it isn't optimum.
If you can measure brake line pressure, front and rear, you are on your way to developing a really superb braking system for your race car. The brakes are typically the most underdeveloped (and least understood) system on the car and yet one that can provide a great advantage.

By knowing the line pressures, and the rotor (or drum) dia, caliper piston (or wheel cylinder) diam, the wheelbase length, track width, tire size, corner weights, and friction co-efficient of the pad or shoe lining, we can calculate the amount of brake force being applied to each wheel during straight line braking or braking during corner entry. The hydraulics can now be modified to apply the correct amount of brake force to each corner, even as conditions change.

Brakes can then be used to help the driver attack the course rather than just hanging on.


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