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Steve Quien
Junior Member
USA
151 Posts |
 Posted - 05/17/2010 : 11:50:28
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Probably the most unknown drag racing value is rollout. Some think it is the amount of inches that their car rolls out of the stage beam (they are partially correct).
When racers inquire about their rollout, we can't provide one simple answer. Rollout is the time from when the driver initiates the leave until the car physically leaves the starting line that starts the Elapsed Time (E.T.) clock. The start of the race can be initiated by rolling out of the stage beam (stage beam makes -- light on tree goes out), guard beam breaking (some tracks don't have a guard beam, but its purpose is to limit rollout length), or either one happening first. It is important to know this because if your track is using a different method than another track, your Reaction Time (RT) will change !!
Rollout consists of 7 variables of which the driver has control of 5 and track personnel control the other 2. The Track sets up the height of the beams on the race track and if they are set too high, the rollout is increased (harder to red light). If they are set low, the rollout is decreased (easier to red light). The track also has control of traction. If the track is slippery (tires spin) then you will have a longer rollout.
The 5 variables that you can control are:
1.Weight of Vehicle
2.How you stage the car -- shallow or deep
3.Clutch / Converter Slippage
4.RPM of the leave
5.Front Tire Diameter / Air Pressure in the front tire
When you are practicing with a practice tree whether it is a table top or the full sized tree, it is important to use a rollout number that your vehicle can attain. After you practice and get consistent at that rollout number, you should make the vehicle work with you -- don't try and compensate to work with the vehicle.
If you have a delay box then you use the delay box to vary the rollout number so working with the vehicle just got a whole lot easier, but remember, the rollout is still a variable. Even with a delay box, you can still red light if you stage too deep or get too much traction.
Good luck racing and practice daily !!!
NOTE : L.E.D. Bulbs effect rollout .03 to .04 secs -- deduct from your Rollout Time when practicing. .32 on incandescent is .28-.29 on L.E.D.’s !
TYPICAL ROLLOUTS
Jr. Dragster - Gas Motor .40 - .44 Seconds
Jr. Dragster - Alcohol Motor (sm. front tires) .36 - .38 seconds
Jr. Dragster - Alcohol Motor (lge front tires) .31 - .34 seconds
Motorcycle .18 - .22 Seconds
Pro Stock Bike .24 - .28 Seconds
Pro Stock Car .24 - .28 Seconds
Super Comp Dragster .18 - .22 Seconds
Super Stocker (3200 lbs) .30 - .34 Seconds
Top Fuel -- Dragster / Funny Car .28 - .32 Seconds
Calculation (Estimate Only): Weight of Vehicle / 10,000
3200 lbs / 10,000 = .32 Seconds
This estimate does not work for vehicles that slip clutches excessively.
When L.E.D. Bulbs were first introduced, they caused a firestorm of controversy both in the Sportsman and Pro Categories. The biggest change was the instant on characteristic of the L.E.D bulb which was causing the drivers to leave the starting line anywhere from .03 to .04 quicker. In the Pro Categories, drivers that were average on the tree were becoming Great Drivers ( low Reaction Times) and drivers that were already quick on the tree were RED Lighting. The sportsman racers who raced on the Full Tree in the no delay box categories were all dealing with RED Lights and trying to adjust their cars and even themselves to slow down .03 to .04 seconds !
L.E.D. stands for Light Emitting Diode and they are instantly illuminated when current is applied. L.E.D. bulbs use a cluster of L.E.D.’s to form a lamp that can be seen by the driver. The typical L.E.D. bulb used in the drag race application has 39 L.E.D’s and uses either a magnified or straight-faced lens. In one design the bulb is driven directly from 110 A.C. where the other design uses a 12-volt D.C. transformer. The 110 A.C. version is much lighter (weight) of the two. The L.E.D bulb replaced the incandescent flood lamps that heat a filament that in turn glows to produce light. The time it takes for the filament to heat enough for the driver to see is dependent on voltage input and the ambient light of day or night. This time can vary substantially.
Driver’s RT’s used to vary from day racing to night racing with Incandescent bulbs because the filament could be seen heating up sooner when it was dark which made driver’s leave earlier. The L.E.D. bulb is instant on which makes the driver very consistent from day to night. The L.E.D. bulb is also more consistent in appearance as the incandescent bulb’s coating used to vary from a light shade to a dark shade depending on the manufacturer.
The L.E.D bulbs cost about $60 each and the incandescent bulbs cost about $12. To outfit an entire tree would cost over $600 if done in L.E.D.’s, but most tracks and drivers use only the Amber L.E.D’s as if they wait to see green they are way too late and of course, no one wants to see RED !! Cost is the main reason that only the larger tracks are using L.E.D. bulbs and most tracks only use them on the driver side of the tree. Some of the larger tracks even use green and red L.E.D.’s.
The future will bring L.E.D. bulbs to the stage bulb of the Christmas tree. This will allow the driver to know if he has a solid stage or a high-speed flicker that is sometimes undetectable with an incandescent light bulb. The cost for these will be even higher than the L.E.D. flood lamp, but it is still better for the racers to know that they are properly staged than to RED Light !
Steve Quien
Race Operations
stevequien@gmail.com
901-483-8942 Cell
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stronglikebull
Junior Member
USA
403 Posts |
Posted - 05/17/2010 : 19:18:08
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| That is probably the most interesting post I have ever read about the tree,Steve when it comes to electronics you sound as intelligant as Dan Carlson or maybe even more than Joe Schmall from Fastronics.com,Thanks for the Info! SHAKE'N'BAKE |
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FastnFurious
Junior Member
130 Posts |
Posted - 05/17/2010 : 21:28:06
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Hey Joe, thanks for the plug - I think, but It's fastronixsolutions.com. Look at your package of Fastronix "Goin Banana's" color cable ties in your trailer. Also Scott Dugdale must be way ahead of the game because I noticed at the MDRA spring meeting he already had the LED Stage bulbs on his practice tree.
Joe Schmall |
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Start Line Roll Out Information - FYI
