As you work your way up the HPDE ladder with NASA, your lap times aren’t really that important. What is important is learning new tracks, recognizing flagger stands, and knowing what to do with your hands. However, as you progress through HPDE4 into Time Trial, then lap times actually do matter. And to get a lap time with NASA, you need to have a transponder and that transponder has to be mounted somewhere on your car.

An AMB “My Laps” transponder has a rechargeable battery that last about five days. As you drive across the start/finish line it picks up the number you see printed on the outside of the plastic case. You register this number with NASA prior to the event. While you are on track NASA knows when your car crossed the line and you get a time. But, how do you mount this to your car?

For Time Trial, where you mount a transponder on your car doesn’t matter much, as long as the signal can get from the device down to the track surface where the sensors are at the start/finish line. In road racing, you want to mount the transponder as far forward on the front of the car as safely possible. I once lost a podium position, which my eyes told me I won, by.001 seconds. This occurred because my transponder was mounted rear of my radiator when my competitor had his mounted just behind his front bumper. As we both crossed the line “bumper to bumper” with me thinking I was ahead his transponder signaled first and I lost. “Excuses, excuses,” I know.

AMB makes an easy-to-use mount that securely holds its transponder — sold separately, of course. I/O Port Racing Supplies has these in stock for a reasonable price and mailed one directly to my house.

For Time Trial, it could be argued that the rear of the car is the most advantageous place to mount a transponder because you are trying to capture your fastest single lap on track during a session. That generally is later in the session where tires are nice and warm, you have dialed in the course and you aren’t accelerating for the first time down the straight from a lower speed. Based on that you want to be moving as fast as possible before the transponder registers at the start/finish line which means the rear of the car is the better location. Sure, I may be splitting hairs here but remember, Time Trial is a game of milliseconds and every millisecond counts.

For the ease of affixing a transponder mount to a daily driver street car/weekend Time Trial car, I picked up a license plate frame from the local auto parts store for less than $18.

Once you have decided where you want to mount your transponder, front or rear, next you have to find a way to do it. The most common thing I see at a lot of NASA events is a simple zip tie on a tow hook. I don’t recommend this because when the tow truck comes, they are going to connect to your tow hook, which could damage a costly transponder. Instead, I recommend using the transponder mount AMB designed to hold the device in place. And, for simplicity’s sake, I came up with a super easy and inexpensive way to mount it to your Time Trial car.

This is all you need to mount your transponder to your car, and every street car has this simple position to mount it: a license plate holder. I used a generic license plate holder, the AMB transponder mount and a couple of short nuts and bolts.

Since every street car already has two holes drilled into the rear of the car for a license plate, why not use those available holes to mount a transponder? This is a very easy solution to the, “How and where do I mount this thing?” question. I grabbed a four-hole license plate frame from a local auto parts store, an AMB transponder mount from I/O Port Racing Supplies and some small nuts and bolts from my local hardware store. That was everything I needed to build my own portable and removable transponder mount.

Before you go crazy and start drilling holes in the license plate frame, take a second to trial fit and make sure everything will line up nice with the design of the rear of your car. Had we mounted high on this frame, we would have run into clearance issues with the rear bumper cover.

After I had all my parts, not including the transponder, this entire project was going to set me back less than $40. I took the time to mark on the license plate frame where I wanted to bolt on the transponder mount after mocking things up on the back of the car. I made sure there wouldn’t be any issues with my rear tow hook location or the exhaust and that the transponder signal would have a clear shot to the track surface to ensure all of my laps counted. Once I had all of that dialed in it was time to start drilling.

Like any metal-drilling project, the keys to success are two things: 1. Mark where you want the hole to end up. 2. Use a punch to indent the metal so the drill bit does not walk around. And if you want to protect your drill bits — obviously, I don’t seem to care — a piece of wood below the license plate frame for the drill bit to not intersect with the concrete garage floor is a good idea.

I initially was a bit impatient with my handy cordless drill and thought I could quickly blast two small holes into the license plate frame. But when the drill bit kept walking all over the license plate frame, scratching the finish and not penetrating the metal, I remembered it pays to use a punch to indent the metal before drilling. I chose to drill one hole first, bolt on the AMB transponder mount and then drill the second hole to ensure everything lined up like it should. This is just DIY projects 101.

I chose extremely short, small bolts to affix the AMB transponder mount to the license plate frame. I did this so the bolts wouldn’t touch or harm the paint of my car when the license plate frame was mounted on the vehicle. I used nylon lock nuts to ensure the bolts wouldn’t come loose while on track.

Once the first hole was successfully drilled, I used a short bolt and a nylon lock nut to affix the AMB transponder mount to the license plate frame. Then I drilled the second hole and used the other bolt and nut to permanently attach the mount to the frame. Once the transponder is charged for the weekend, I just pop it into the mount. When I arrive at the track, I use a screwdriver to replace my license plate with my homemade transponder mount. It takes me about 40 seconds to do it.

Simple, easy and cheap, which is exactly how I like things. This is all of the parts assembled and ready to register laps during the next NASA weekend. All that is left to do is mount it on the car when I arrive.

With this easy-to-use transponder mount I can spend less time worrying about where my transponder should be mounted and more of my time focusing on faster laps around my favorite track. The transponder signal allows me to compete against my friends among the different NASA Time Trial classes to see who is the quickest regionally and, if I’m feeling speedy, eventually nationally.

Arrive at the track, unscrew your license plate and replace it with your new handy and easy to use transponder mount. Next, go lay down that super-fast lap and win the day!

Rob Krider is a four-time NASA Honda Challenge 4 National Champion, the author of the novel, “Cadet Blues,” and is the host of the “Stories and Cocktails” podcast.

Image courtesy of Rob Krider

Join the Discussion