How Much Roll-Out (practice tree)?

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The Engineer
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How Much Roll-Out (practice tree)?

Postby The Engineer » Tue Apr 10, 2012 6:49 am

I'm foot-braking my tube-chassis car (2300 race weight) and typically have 1.30, 60 ft times. The front tires are 26" Goodyears and I always stop the instant I turn-on the second stage bulb.

So, what should I be using for roll-out on my practice tree?

I have a roll-out number I've been using, but wanted to get some unbiased opinions on what everyone thinks my roll-out should be.
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BCLS776
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Re: How Much Roll-Out (practice tree)?

Postby BCLS776 » Tue Apr 10, 2012 9:49 pm

It'll probably be in the 0.20 to 0.30 second range, but it's tough to compare other people's car numbers to yours. A footbrake launch is completely different than releasing a button on the practice tree box too.

Here's what I do: set your roll-out value so that your average RT on the practice tree becomes the same as your average RT with the car. Then when you are practicing you are assessing whether you are reacting the same as when you are racing. To me that's the goal -- make the practice equivalent to the real thing.
Bryan
583 in 225" hardtail dragster
Northern Lights Raceway

The Engineer
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Re: How Much Roll-Out (practice tree)?

Postby The Engineer » Wed Apr 11, 2012 6:42 am

BCLS776 wrote:It'll probably be in the 0.20 to 0.30 second range, but it's tough to compare other people's car numbers to yours. A footbrake launch is completely different than releasing a button on the practice tree box too.

Here's what I do: set your roll-out value so that your average RT on the practice tree becomes the same as your average RT with the car. Then when you are practicing you are assessing whether you are reacting the same as when you are racing. To me that's the goal -- make the practice equivalent to the real thing.


I've been using .230, so you're very close! :mrgreen:

This tube-chassis car with 4-link, anti-roll and front drag struts still reacts very quickly when foot-braked, so I would rather have the roll-out a little on the "short-side" for practice! Then I have a little more cushion at the track, from what I'm used to in practice to keep me from going red.
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d64falcon
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Re: How Much Roll-Out (practice tree)?

Postby d64falcon » Tue Oct 16, 2012 1:27 pm

What about doing a test and tune session at the track and ask for Pro light. Average your lights and then adjust your practice tree till you average the same on Pro light
Darrell
67 Mustang 3000# 310ci NA 10.17 130.5mph,1.36 60'


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