Tell Me About "Roll Out"
01-13-2009, 09:47 PM
#1
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Tell Me About "Roll Out"
So I was looking at some published (CD, R&T, Edmunds, etc) 0 - 60 and 1/4 mile times and one site (Edmunds I think) was making a distinction between times with Roll Out and with out Roll Out.
From what I read, I guess the Staging Lights are about a foot behind the Timing Start sensor. They claimed that if you could just barely get into stage, that you'd have about a foot of "Roll Out" that was untimed, resulting, effectively, in a rolling start to the timed 1/4 mile.
They posted times with and without Roll Out and there was about 0.1 or 0.2 sec difference in ET at the 1/4 mile.
My question is: Is Roll Out an effective technique at the drag strip? If so, how do you take full advantage of it?
TIA
From what I read, I guess the Staging Lights are about a foot behind the Timing Start sensor. They claimed that if you could just barely get into stage, that you'd have about a foot of "Roll Out" that was untimed, resulting, effectively, in a rolling start to the timed 1/4 mile.
They posted times with and without Roll Out and there was about 0.1 or 0.2 sec difference in ET at the 1/4 mile.
My question is: Is Roll Out an effective technique at the drag strip? If so, how do you take full advantage of it?
TIA
01-13-2009, 10:40 PM
#2
Suzuka Master
iTrader: (2)
You basically just " deep stage" by creeping ahead another ten inches or so after both sets of small lights are lit. The very top set will then go out, so you know you're deep staged. It is good for a marginally better ET, but your trap speed will be ever so slightly lower as well since you only have ~1319 feet to hit terminal velocity instead of the full 1320. We're talking a small fraction of a MPH. Some tracks will require you to put "deep" on your window under your dial in.
01-13-2009, 11:18 PM
#3
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I think the article implaied that you DON'T deep stage. That you use that 12" for a running start.
Which is better to lower ET?
Which is better to lower ET?
01-13-2009, 11:38 PM
#4
Suzuka Master
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From the point where you trip the second set of staging lights, you're 1320 feet out, so I don't see how that would work. Do you have the article?
Last edited by anx1300c; 01-13-2009 at 11:41 PM.
01-14-2009, 01:08 AM
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....
A Few Words About Rollout
The term "rollout" might not be familiar, but it comes from the drag strip. The arrangement of the timing beams for drag racing can be confusing, primarily because the 7-inch separation between the "pre-stage" and "stage" beams is not the source of rollout. The pre-stage beam, which has no effect on timing, is only there to help drivers creep up to the starting position. Rollout comes from the 1-foot separation (11.5 inches, actually) between the point where the leading edge of a front tire "rolls in" to the final staging beam — triggering the countdown to the green light that starts the race — and the point where the trailing edge of that tire "rolls out" of that same beam, the triggering event that starts the clock. A driver skilled at "shallow staging" can therefore get almost a free foot of untimed acceleration before the clock officially starts, effectively achieving a rolling-start velocity of 3-5 mph and shaving the 0.3 second it typically takes to cover that distance off his elapsed time (ET) in the process.
We believe the use of rollout for quarter-mile timed runs is appropriate, as this test is designed to represent an optimum drag strip run that a car owner can replicate at a drag strip. In the spirit of consistency, we also follow NHRA practice when calculating quarter-mile trap speed at the end of the run. So we publish the average speed over the final 66 feet of the quarter-mile run, even though our VBOX can tell us the instantaneous speed at the end of the 1,320-foot course, which is usually faster.
On the other hand, the use of rollout with 0-60 times is inappropriate in our view. For one, 0-60-mph acceleration is not a drag-racing convention. More important, it's called ZERO to 60 mph, not 3 or 4 mph to 60 mph, which is what you get when you apply rollout. While it is tempting to use rollout in order to make 0-60 acceleration look more impressive by 0.3 second, thereby hyping both the car's performance and the apparent skill of the test driver, we think it's cheating.
Nevertheless, some car magazines and some automobile manufacturers use rollout anyway — and fail to tell their customers. We've decided against this practice. We publish real 0-60 times instead. But in order to illuminate this issue and ensure we do justice to every car's real performance, we've begun publishing a clearly marked "with rollout" 0-60 time alongside the primary no-rollout 0-60 time so readers can see the effects of this bogus practice.
....
A Few Words About Rollout
The term "rollout" might not be familiar, but it comes from the drag strip. The arrangement of the timing beams for drag racing can be confusing, primarily because the 7-inch separation between the "pre-stage" and "stage" beams is not the source of rollout. The pre-stage beam, which has no effect on timing, is only there to help drivers creep up to the starting position. Rollout comes from the 1-foot separation (11.5 inches, actually) between the point where the leading edge of a front tire "rolls in" to the final staging beam — triggering the countdown to the green light that starts the race — and the point where the trailing edge of that tire "rolls out" of that same beam, the triggering event that starts the clock. A driver skilled at "shallow staging" can therefore get almost a free foot of untimed acceleration before the clock officially starts, effectively achieving a rolling-start velocity of 3-5 mph and shaving the 0.3 second it typically takes to cover that distance off his elapsed time (ET) in the process.
We believe the use of rollout for quarter-mile timed runs is appropriate, as this test is designed to represent an optimum drag strip run that a car owner can replicate at a drag strip. In the spirit of consistency, we also follow NHRA practice when calculating quarter-mile trap speed at the end of the run. So we publish the average speed over the final 66 feet of the quarter-mile run, even though our VBOX can tell us the instantaneous speed at the end of the 1,320-foot course, which is usually faster.
On the other hand, the use of rollout with 0-60 times is inappropriate in our view. For one, 0-60-mph acceleration is not a drag-racing convention. More important, it's called ZERO to 60 mph, not 3 or 4 mph to 60 mph, which is what you get when you apply rollout. While it is tempting to use rollout in order to make 0-60 acceleration look more impressive by 0.3 second, thereby hyping both the car's performance and the apparent skill of the test driver, we think it's cheating.
Nevertheless, some car magazines and some automobile manufacturers use rollout anyway — and fail to tell their customers. We've decided against this practice. We publish real 0-60 times instead. But in order to illuminate this issue and ensure we do justice to every car's real performance, we've begun publishing a clearly marked "with rollout" 0-60 time alongside the primary no-rollout 0-60 time so readers can see the effects of this bogus practice.
....
My original quesiton: Does it really work at the strip? How do you do it effectively?
01-14-2009, 12:33 PM
#6
Team Owner
I shallow stage but for different reasons. Since I no longer have a transbrake (break) and have to rely on the regular brakes to hold the car back while building boost, I have more margin for error if the car creeps forward accidentally.
Shallow staging is somewhat effective when the timing starts once you cross the last beam which is the way it is for most of us.
Deep staging is more beneficial for the guys where the reaction time is factored into the ET.
Shallow staging is somewhat effective when the timing starts once you cross the last beam which is the way it is for most of us.
Deep staging is more beneficial for the guys where the reaction time is factored into the ET.
01-14-2009, 04:55 PM
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When I was at The Rock I am almost certain that Reaction Time was NOT included in the ET; I had a few atrocious RT's, but ran consistent ET's.
If that is the case, you're saying Shallow Stage/Roll Out could improve the ET. Is that correct?
If I can actually pick up 0.1 or so on ET from Roll Out, with my current mods, I think I might be able run 14.0xx.
What is the best technique to Shallow Stage? I'm sure some practice is helpful, but other than very carefully creeping in, any suggestions?
If that is the case, you're saying Shallow Stage/Roll Out could improve the ET. Is that correct?
If I can actually pick up 0.1 or so on ET from Roll Out, with my current mods, I think I might be able run 14.0xx.
What is the best technique to Shallow Stage? I'm sure some practice is helpful, but other than very carefully creeping in, any suggestions?
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01-16-2009, 11:12 AM
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How much distance is there between the Pre-Stage beam and the Stage Beam?
01-16-2009, 01:03 PM
#9
Team Owner
I believe 12" but not completely sure.
You're right, reaction time is not included on a test and tune night.
I've sat at the tree for 3 seconds before trying to get my boost just right, crossed the finish last, but still ran a lower ET than the guy next to me.
Bracket racing I believe it is, and most pro classes it's included.
You're right, reaction time is not included on a test and tune night.
I've sat at the tree for 3 seconds before trying to get my boost just right, crossed the finish last, but still ran a lower ET than the guy next to me.
Bracket racing I believe it is, and most pro classes it's included.
01-16-2009, 02:08 PM
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That's what I would have guessed. I can estimate 12" pretty well (well enough).
Hope to get to the strip early spring. If so, I am going to work to get a very shallow stage and see if I push my ET down.
Late Feb/Early March last year ran 14.379 nearly stock. Pully, CAI, J-Pipe, Better Tread, with a shallow stage, I am hoping for some decent improvement in ET.
Hope to get to the strip early spring. If so, I am going to work to get a very shallow stage and see if I push my ET down.
Late Feb/Early March last year ran 14.379 nearly stock. Pully, CAI, J-Pipe, Better Tread, with a shallow stage, I am hoping for some decent improvement in ET.
01-24-2009, 09:38 PM
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So I was looking at some published (CD, R&T, Edmunds, etc) 0 - 60 and 1/4 mile times and one site (Edmunds I think) was making a distinction between times with Roll Out and with out Roll Out.
From what I read, I guess the Staging Lights are about a foot behind the Timing Start sensor. They claimed that if you could just barely get into stage, that you'd have about a foot of "Roll Out" that was untimed, resulting, effectively, in a rolling start to the timed 1/4 mile.
They posted times with and without Roll Out and there was about 0.1 or 0.2 sec difference in ET at the 1/4 mile.
My question is: Is Roll Out an effective technique at the drag strip? If so, how do you take full advantage of it?
From what I read, I guess the Staging Lights are about a foot behind the Timing Start sensor. They claimed that if you could just barely get into stage, that you'd have about a foot of "Roll Out" that was untimed, resulting, effectively, in a rolling start to the timed 1/4 mile.
They posted times with and without Roll Out and there was about 0.1 or 0.2 sec difference in ET at the 1/4 mile.
My question is: Is Roll Out an effective technique at the drag strip? If so, how do you take full advantage of it?
Rollout distance is about half the diameter of your tire, so if you've just barely broken the beam, your car can roll about a foot before the beam is again unblocked and the ET clocks start.
There are two effects that come from this. The first is that, as you've surmised, you get a rolling start before the ET clock kicks in, and for a more or less typical street car on street tires, your ET will improve by something close to half a second. The second is that you can launch pretty much right as the filament in the third yellow bulb just begins to warm, instead of on the green. This will give you a half second (five car length) advantage at the finish line if you're running that street rat in the other lane.
Note that Edmunds' estimate of three tenths is incorrect. I assume they're measuring from the time the vehicle first begins to roll, but what happens when you launch is that the first tenth or two is eaten up by driveline, chassis and axle windup. Then it takes around three tenths to cover that first foot.
You get full rollout by moving forward very slowly after the pre-stage light comes on, and stopping a microsecond after the stage light illuminates. Pretty simple, really.
The distance between the two beams is about eight inches, so be careful and deliberate as you inch forward.
Bruce
01-31-2009, 01:47 PM
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First of all, the stage light is activated by having your front tire(s) block an infrared beam positioned about three inches above ground level. Regardless of what is happening (or has happened) with the starting lights, the ET clocks don't start until your tire has rolled completely though (and out of) that beam, so your ET is not affected by when you start.
Rollout distance is about half the diameter of your tire, so if you've just barely broken the beam, your car can roll about a foot before the beam is again unblocked and the ET clocks start.
There are two effects that come from this. The first is that, as you've surmised, you get a rolling start before the ET clock kicks in, and for a more or less typical street car on street tires, your ET will improve by something close to half a second. The second is that you can launch pretty much right as the filament in the third yellow bulb just begins to warm, instead of on the green. This will give you a half second (five car length) advantage at the finish line if you're running that street rat in the other lane.
Note that Edmunds' estimate of three tenths is incorrect. I assume they're measuring from the time the vehicle first begins to roll, but what happens when you launch is that the first tenth or two is eaten up by driveline, chassis and axle windup. Then it takes around three tenths to cover that first foot.
You get full rollout by moving forward very slowly after the pre-stage light comes on, and stopping a microsecond after the stage light illuminates. Pretty simple, really.
The distance between the two beams is about eight inches, so be careful and deliberate as you inch forward.
Bruce
Rollout distance is about half the diameter of your tire, so if you've just barely broken the beam, your car can roll about a foot before the beam is again unblocked and the ET clocks start.
There are two effects that come from this. The first is that, as you've surmised, you get a rolling start before the ET clock kicks in, and for a more or less typical street car on street tires, your ET will improve by something close to half a second. The second is that you can launch pretty much right as the filament in the third yellow bulb just begins to warm, instead of on the green. This will give you a half second (five car length) advantage at the finish line if you're running that street rat in the other lane.
Note that Edmunds' estimate of three tenths is incorrect. I assume they're measuring from the time the vehicle first begins to roll, but what happens when you launch is that the first tenth or two is eaten up by driveline, chassis and axle windup. Then it takes around three tenths to cover that first foot.
You get full rollout by moving forward very slowly after the pre-stage light comes on, and stopping a microsecond after the stage light illuminates. Pretty simple, really.
The distance between the two beams is about eight inches, so be careful and deliberate as you inch forward.
Bruce
I am not clear on whether you are saying a very shallow stage will result in 0.5 Sec or 0.3 sec improvement - the drivetrain spool-up, ect occurs whether you shallow stage or not right?
The other thing I don't know is with my previous time how shallow I was staged. Did I use up all or only part of foot or so. Assuming I used up some, but not all, I should not the full benefit of a very shallow stage. So instead of 0.3 - 0.5 sec improvement, I'd only assume 0.1 to 0.2 - give or take. Does that sound like a reasonable expectation?
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