but the average speed between 1,000 and 1,320 feet. Comp-U-Link marks the time which you cross the 1,000 foot mark, and the time which you cross the finish line, and calculates the average speed between the two points.

Is this correct? Wrong? If so, what is trap speed and how is it measured? Thanks.

 

good ?
i wanna know too.

 

not from what I was told...the final speed mark is your mph when you cross the finish line.

 

Whoops double post. Sorry.

 

Yes, trap speed is an average between two points. I don't think speed can be measured instantaneously yet. I'm sure there are scientists working on it though. ;-)

 

I believed trap speed was the average over the last 100 feet, not 320 feet. Terminal speed would be the speed when you cross the line, but I dont know of any tracks that do that....

 

The next time that I go to the track, I’ll look for a sensor at 1,220 feet. If there is one, then I think that you're correct.

 

ya learn something new everyday

 

Edit-actually I think trap speed is average over last 60ft, Im sure somebody like Snoozer or Briguymax would know for sure.....

 

I found several references using google:

Trap Speed -- Trap speed is the average speed of your vehicle through the last 66 feet of track.
Reference: http://www.lakelandmotorsportspark.c...o_dragrace.htm

Speed beam - Your speed at the finish is calculated by measuring the time between when you break the speed beam and the finish line beam. The speed trap is 66' wide.
Reference: http://abilenedragstrip.com/howtorace.html

 

Correct.

 

it is the last 66 feet

some tracks do not have the sensor at the last 60 feet so it only takes the reading at the finish line. There are tracks where peopel have taken out this sensor gettin sideways and they havent replaced it.

a track here is/was like that for 10 years. it gave abnormally high traps, consistantly 2-4 mph faster

 

How does it calculate speed without having a 2nd set of lights? To get speed wouldn't it need to reference how long it takes to get between two points?

 

That's possible. All NHRA sanctioned tracks use the same guidelines, but not all tracks are able to implement new guidelines at the same time. Take for example the old Christmas tree with incandescent versus the newer LED lights. I’m willing to guess that every NHRA track does not use comp-u-link either.

 

Your are correct. Then we would be back to my original statement at the top: trap speed is the average speed between 1,000 and 1,320 feet.

 

it has a radar at the end

you dont understand this track, there are pot holes at 1000 feet and animals have/can run across it infront of a car.

its old school NHRA track and there is a reason it is shut down. for some reason the old schoolers that grew up there still loved it til the day they closed, alot because its cheaper and has bleachers like a little league baseball game

it was dangerous and having a huge IHRA track right down the road there was no real reason for it.

 

its NOT 1000 feet because our track timing system has a slot for the 1000 foot MPH and that software will or will not show it depending on if the track has the lights or not.

 

First off, regardless of what your trap sped is, sanctioned racing events only look at ET.

It's an average of the last 66'. The reason the NHRA implemented the 66' average rule is because years ago drag racers would invertently stay on the gas past the finish line just to make sure they didn't let off early. Averaging the last 66' of the race cut down on the need to stay stay on the gas past the finish plus it cut down on accidents from people running out of run-out room. Most tracks have a big painted "X" encompassing the last 66' track.

It is true that some older tracks in the US and tracks in Canada still use the old method for getting trap speed. This often means 2-4mph higher traps depending on the acceleration potential of the car and the calibration of the speed capturing device.

FYI, most magazine (MT, R&T, C&D) ET/MPHs are done with on-board accelerometers. The MPH is the ending MPH, not an average MPH therefore mag times typically have slightly higher MPHs than what you may see at the track. Same goes for the G-Techs. The ETs are close, but not the MPHs.

 

True about GTECH's, but I thought the magazines equipment gave trap speed. I have never had a problem beating a magazine time in a stock car e.t. or trap speed wise.

 

Dave B is right....the mags use on board accelerometer equipment to measure E.T. and trap though the 1/4 95% of the time. Every once in a great while mags will run cars down a drag strip, but that's not the norm.

There are several reasons why you, I and others have had no problem beating mag E.Ts and traps. First of all, they run the cars at full vehicle weight which means full tank of gas, spare, jack...everything. Second, these mag writers are mostly NOT professional drivers, just everyday car enthusiasts like us that happen to be pretty good with a pencil. They typically only get these cars for a day and learning to extract the most possible performance out of a car in one day is quite a challenge. Launching, shift points etc. all come into play. Lastly, these test mule cars are very low mileage cars that have been beat on from day one, so chances are they probably are making slightly less power than a fully, properly, broken in car.