# New toy, Hot Wheels Speedometer

What mods do you have planned Smitty?

BTW If you have two cars that consistently run the same times on your big ben - you can run a comparision on the speedometer based on their lengths - the shorter one should be faster is my guess!

yeh, but big ben is sleeping in a suitcase...

I coffee table tested with a 1" strip of card stock and then a 2" strip... big change in speed...

a stroller test on his track should tell us about wheelbase...

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this could be great... a long wheelbase car has been fast in the past, but if wheelbase works against you, one must find the shortest fast car one can...

seems adding a bumper is now dumb...and no continental kits...htr's neet streeter with the bumpers removed seems a good candidate...

maybe an April 20th Altered Assault double header at the GRIDIRON...

highest speed bracket and lowest elapsed time bracket... HMMMMMM...

My local Target has these speedos *on sale* for **$12.99**...and one just happened to 'jump' into my shopping cart.

"SPEED MEASURED" ROAD RACES AT G SPEEDR'S..?...

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hmmmm ... short cars...maybe the XMAS release morris wagon from WA. !

one must find the shortest fast car one can...

Done...

(Borrowed Image)

Testing to commence tomorrow evening once batteries are installed.

Here is some information I found useful to determine a cars speed...

First lets look at measuring speed accurately. Usually we want to know the speed in scale miles per hour. But what we have at hand are the necessary tools to accurately measure speed in real feet per second. So the question becomes how to use them and how to convert the results into scale miles per hour.

To measure speed in real feet per second, lay two reference markers beside the track. The markers can be anything, but quarters are easily seen and are usually close at hand. Put the markers far enough apart to make timing easy, say 10 real feet . To simplify calculations, make the distance between markers an exact number of real feet.

A stop watch is ideal, but any watch showing seconds will do. Make sure your car is up to speed when it reaches the first marker and time how long it takes for a point on the car (say the front of the engine) to travel from marker to marker.

Finally, calculate the speed of the car. First calculate the speed in real feet per second by dividing the distance between your markers by the number of seconds it took to travel between them. Then multiply the answer by the rfps-to-smph factor for your scale from the table below. The answer is in scale miles per hour. The accuracy of this method depends mostly on the accuracy of your time measurement.

scale **43.6**

Example: Car A...took 2.5 seconds to go 10 feet. 10 divided by 2.5 seconds = 4, then multipy 4 x 43.6 to get your actual speed...which would be 174.4 mph.

Hope this helps for the penny pinchers in our group.

Preacher

only 1 pair of sensors, the clock / speedo measures how long the car blocks the 1 beam... short cars appear faster... longer cars slower...for future races cars can be classed by weight and lenth...

mattel didn't think the kids would figure it out.

I set up my new speedo for testing on a short 4.5ft tabletop track with a brief 40deg drop. The previous assesments are correct. SWB cars, like Piranah Terror or Arrow Dynamic, consistently registered the highest speeds while truely *near the end of the track* can yield useful speed data for comparison. Cars with the largest variances in speed are obviously the least consistent.

GspeedR

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model40fan4/3/14figures, I bought a speedometer off ebay $19.99 shipped... wally had 6 on the shelf today $14.95,... duh !.. bought another in case using one in each lane provides a fair comparison... if not... fast fred wins !

unit and tower ;

assembled ;

unit only has one pair of sensors... it must estimate part of the speed by the average car's lenth...

time it takes to pass the sensor...?

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.....rocket scientists to the front !...

stroller can you compare 2 consistently close finishing cars that are drastically different wheelbase lenths, on your 6 lane ?

switch lanes a few times for finding an even pair of racers... then test them for speed to see if breaking and clearing the sensor is the key...

trying to see if the car's lenth is the difference ... if so the short guys are king for a change...BRING IT ON !

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TESTED with 48" of track before the speedometer...

speed increased as i raised the incline 2" at a time...367, 384, 399, 412, 428, 444...gonna be a cool addition to our fun...

at $15 ... go get one, or two [lane 1 & lane 2]...measure speed not time ?...

like the "6 lane raceway", they will triple in price as racers find out they work...