Finish Line Beam Height
 

I think we have all probably lost a round (whether or not we knew it) to someone who took the stripe with body panels which were still in compliance with the 3" min clearance and 30" max overhang NHRA rules. Have you ever compared the height of the finish line beams to the starting line beams? The finish line is much higher, such that body panels frequently trip it. I asked the question of an NHRA guy about 20 years ago, and was told that the higher beams were to make sure the tire did not pass through within the timing system's sampling period (i.e., to make sure the timing system did not "miss" seeing the tire in the beam) when the car was running at a high speed. This was not a problem on the starting line, so they were lower there to make sure body panels did not interfere.

I'll bet that every national record in the pro classes was set by a car tripping the finish line with body panels, making it a 1317.5' pass instead of 1320'.

Why is the finish line beam still at this height? I would think that the modern timing systems are not in danger of missing a wheel, even at 350 mph. We end up with inaccurate ETs and the possibility of unintentionally giving up the stripe in bracket and .90 class racing.

I remember the first time I lost this way, giving up the stripe to a then-new Brogie roadster with its extended front "spoiler". I almost lost that way yesterday to a Suncoast roadster (gave up the stripe but ran dead on with a 0 while he broke out).

Thoughts/arguments/agreement?

Re: Finish Line Beam Height
 

Remember Steve Johnson in the final at Indy a few years back? It sure missed that one....

-Mike

Re: Finish Line Beam Height
 

You should know your opponent and be aware of the ride height of the car you are racing. That way you know if you are racing the nose or the wheel.

Re: Finish Line Beam Height
 

I thought there was an issue with his wheel not having enough area?


But if it is close to the 3" min height you won't know which one to do. Wouldn't it be better to always know you are racing the wheel?

Re: Finish Line Beam Height
 

Good topic.

I've measured my home track at 5". The body work on most tube cars will trip the beam with the nose. I saw a finish line photo of two comp cars (I believe Arnie martel was one of them) with one nose clearly in front but at full throttle it was high enough that didn't trip till the tire. The opponent's car was lower, a good foot behind, but because he tripped with the nose, got the win light. It's a quirk of the system.

Full suspension cars such as stock and superstock will trip with the wheel unless the driver drops hard, which collapses the suspension and trips the beam (often) with the front spoiler...this gets complicated because now the driver has tried to kill some et and actually picks some up. Makes for some funny numbers.

I believe it's actually pretty rare that it happens.

Bruce Deveau

Re: Finish Line Beam Height
 

Virtually all dragsters made today have either a nose or wing, extending in front of the front wheels, with a vertical surface that is several inches high with the full intent of tripping the beams.

Re: Finish Line Beam Height
 

Here is a link to the aforementioned comp photo:
http://www.flickr.com/photos/9053883@N06/1356172176/

And some discussion about it:
http://forum.competitionplus.com/showthread.php?t=1491

This link has several other links, including the infamous Steve Johnson photo. In the case of missing his low profile tire, lower beams (as I am suggesting here) would have HELPED the situation, as they would have been below the height of the opening in Johnson's wheel, and guaranteed a longer duration blocking the beams.

Does anyone have a good reason why the beams should NOT be lower?

Re: Finish Line Beam Height
 

Bumpy tracks (picture taken between the cones):

http://www.northeastdragracing.com/p...lodrssg036.jpg.

If the beam hight had been the same as the starting line and the tire hops over it, then it doesn't see anything until the back wheels... The Pro Stock Bikes were wheelstanding through the finishline at Maple Grove because of the bumps there.

Also, take a look at the image below. A 3" nose, under braking, is not 3":

http://c4.ac-images.myspacecdn.com/i...e1088f247f.jpg

So now you'd be taking a whole bunch of cars that consistently take the beam with the nose of the car, and making it so they take it with the wheel, well, except under braking. Then you have the same problem of figuring out what the car is going to take it with again anyway...

-Mike

Re: Finish Line Beam Height
 

Okay, I hadn't thought about bouncy finish lines, but holy crap - they should fix that track!!!

If finish line wheelies are still a problem, they could run a guard beam that is higher but farther downtrack. The tire would stop the clocks 99.9% of the time, and they would still have a close timing result for the rare misses.

With the lower beams, you might have the occasional braking-induced nose trip, but it seems that it would be the rare exception. I would rather see true wheel-to-wheel racing the majority of the time.

Re: Finish Line Beam Height
 

Mike Sawyer.... nice dump job by looking at your front rotors. LOL Tell your dad hi.

Re: Finish Line Beam Height
 

In this day of laser technology and high sampling rate data acquisition systems, at MOST tracks you SHOULD be able to have the beam an inch off the ground and be good. Will there be the occasional exception with somebody going through the lights on two (one) wheels? Sure, but it would be MUCH less common than what happens today, particularly with any of the classes where breakouts are a concern.

That said, getting all tracks across the country to adopt this new timing system is not likely to happen over a short period of time, and we'd be running one configuration at NHRA national events, another at IHRA national events, yet another at division events, and yet another at our local tracks. So, it probably won't change until somebody has a near zero dollar solution.

So though I agree with you Mike, though I'd rather spend my time in front of NHRA bitching about something I care about more, like payouts...

PS - I agree with CBS Jr. on the dump job...

Re: Finish Line Beam Height
 

Remind me again, what's the problem here? These heights have been that way for years...

Re: Finish Line Beam Height
 

Yes, but 20 years ago there weren't many S/G cars which would trip with bodywork. I think the Brogie Series V was the first one to consistently do it. We've already seen our share of controversies over finish line lights (the Indy incidents mentioned above), and it seems to me that everyone would benefit if you knew for sure that the wheel was taking the stripe. I suppose I could go with the flow and build an air dam on my car which either trips the stripe, or looks like it could but doesn't. Maybe it's just me, but I think the most fair racing (especially in breakout classes) would be where we all know it is the wheel taking the stripe.

Re: Finish Line Beam Height
 

But why? It's the body that hits the beams in T/F, F/C, P/S, TAD, TAFC, S/C, T/D, etc., etc.

Haven't looked at track specs in a while, but as I recall, the starting line beams are spec'd at 1" off the ground, the rest of the beams on the track are spec'd at 5". The starting line is different because, remember, it's the BACK of the front wheel leaving the line that starts the clock. If it were at 5" like the others, it'd be the back of the car...

The rulebook has very explicit ground clearance requirements. If you want to have a body that is in front of your front wheels and is over 2" off the ground, you can do that, but the length is limited to 30" in front of your front wheel centerline (see the rulebook). Again, this is "fair" because it's been that way for years. As I noted previously, every dragster made for years very carefully follows, and exploits, these rules. Just because some S/G full body car makers are slow to pick it up, there's no reason to punish every one else.

Re: Finish Line Beam Height
 

It doesn't just effect super gas . What about stock and superstock where your not allowed to extend the bodywork? There is no reason for complaints in the classes where you are allowed to put an extension on. The pro-mods with short overhangs have been doing this for years ,and as far as the pro's go they all have to be the same overhang .So you can't really use them as an example. Lowering the beams may be the only way to be fair to everyone.

Re: Finish Line Beam Height
 

The problem is that in brackets, S/G and S/ST you can never be sure which part of the car will trip the beams. You will find many cars that will trip them for sure with the body, some (like mine) that definitely won't trip, and a lot of cars that are questionable (and probably trip with the wheel when on the throttle and body when off the throttle). I personally think that it would be most fair when judging the stripe if all cars tripped with the wheel.

Re: Finish Line Beam Height
 

I see a front spoiler in your future :)

Re: Finish Line Beam Height
 

The starting line beam height is 2" to the top of the beam, and the beam is 1/4" diameter.

In my experience, these are rare events. The number of races that are that close and the number of times in which it's questioned what part of the nose or tire tripped the beam is quite rare. In a stocker you really have to nail the brakes at the right moment to get the nose to dive that far. Changing the finish line beams would create many more problems than it solves.

As Mike said (with is rotor on fire) under braking even a supergas car drops considerably. You probably couldn't go low enough to solve the problem.

Bruce Deveau

Re: Finish Line Beam Height
 

Yeah, but it's a '73 Vega, and they just don't look right with a spoiler. That, and I want to be able to get up the trailer ramps without scraping.

Then again, my car is ugly anyway, and I'll be doing some bodywork this winter... I could make one that easily removes... Maybe I'll make it adjustable so that every other race I set it up to trip on the tire or the spoiler...

Re: Finish Line Beam Height
 

If not a spoiler, a simple vertical fin on the front below the front bumper would suffice I would make it out of 1/8" aluminum paint it flat black, make sure it has 3" of ground clearance and that the front edge is no more than 30" in front of the spindle. I had a similar fin on my dragster nose and I have seen a couple of Willeys pro-mod cars with beam breakers like I just described.:cool:

Re: Finish Line Beam Height
 

wheels may bounce a little , but body panels change / distort as to downforce........look at a lot of door cars....they have that flat black tab hanging down there some where to trip the lights............whats the maxium forward distance from the spindle.....? 30 or 33 inches ..or something like that

Re: Finish Line Beam Height
 

30 inches.

Re: Finish Line Beam Height
 

i wish stock and super stock could hang a tab to take the beam consistantly but its not allowed. senseless rule,every other class can. i hate hitting the brakes and going faster! did it at indy.

Re: Finish Line Beam Height
 

Billy put in a BIGGER brake pedal EDDY

Re: Finish Line Beam Height
 

if i would not have hit the brakes id have been ok!