DIY: Stealth EZPass Install

[jmciver]

This is a small DIY for those of you who use an EZPass, but have OCD like me and don't want it on your windshield. I searched for ways to hide it, or at least hide it from view, but nothing fit the bill for me. I know some just throw it in the door pocket, pulling it out when needed. But I didn't like that either. So then on a hunch, I figured I would take advantage of that beautiful carbon fiber roof so many of us have on our F8X's......

I decided to mount the EZPass between the rear map light fixture and the CF roof, attached to the underside of the CF roof. The premise being that the RF signals from the EZPass can be detected through the CF roof, just like through the windshield. I chose the rear light fixture, vice the front, to have more space and because there is a metal frame support rail in that runs along the front area of the roof that I thought would interfere with the EZPass RF signal. This relatively quick DIY took approx 30 min or so.

Now on to the DIY.....

First, remove the rear light fixture. I used a trim removal tool. There are two tabs that hold it in place which are located at the front two corners of the fixture. The pic below shows the trim removal tool in the approximate location where one of those tabs is located. Slowly pull down on the light fixture as you work the trim removal tool. Once one corner is pulled down a bit, work on the other corner and the light fixture will come out.




When the light fixture is removed, disconnect the harness and set the light fixture aside. What you see in the pic below is the underside of the CF roof. The grey padding is sound insulation that is attached to the CF roof panel.




I wanted to use double sided tape to attach the EZPass unit to the roof, but I knew it would not stick well to the sound insulation. So I traced the outline of the EZPass and then trimmed away as much of the insulation as I could. Not as precise as I would have wanted, but it won't be seen once the light fixture is re-installed.






It took a little while to remove enough insulation, but here is the finished product attached to the underside of the CF roof using some 3M double sided tape. I orientated the EZPass so that the "EZPass" lettering was towards the rear of the car. This is the same orientation if the EZPass were placed on the windshield.




Before I re-installed the light fixture I inserted a few layers of cardboard between the EZPass and the light fixture. The idea is to have the cardboard fill the gap to add some additional support on the EZPass to help keep it in place. So, the million dollar question... did it work? Yes it did! I tested it on an overpass toll detector in the HOV lanes on a small strip of I-395 in Virginia. I waited for the transaction to show up on my EZPass statement for final verification that my EZPass was detected. So will this work on F8X's with sunroofs (or F3X's w/o sunroofs and metal roofs)? I would suspect not, either due to interference of the sunroof cassette and/or the metal roof. But I have not verified this myself.

Hope this helps others with EZPass OCD such as mine!

[ellipsis212]

Cool idea though your OCD is different than mine since I couldn't deal with knowing my sound insulation was all chewed up. 🤣

I have a little suction cup holder for mine and it generally travels in the armrest. This only works because I use toll roads just a couple times a month.

[icegrill]

Bro, you're wild! My ocd would be like "I just cut up my roof insulation and now it's not factory"🤷🏼*♂️

[allinon72]

I like how you made a sharpie outline and the next pic looks like you went at it with a sword But I know how hard it is to cut that stuff and it's a neat idea.

[BigMo]

This is what I use. It blends right in with the dash and virtually unnoticeable. Not as discreet at OP but not bad.


https://rover.ebay.com/rover/0/0/0?m...2F254230477245

[noone]

Cool. In Florida (Sun Pass) they have little 2 x 3" stickers you can put on the bottom left of your windshield. I'm sure Maryland has the same thing!

[jmciver]

Originally Posted by icegrill

Bro, you're wild! My ocd would be like "I just cut up my roof insulation and now it's not factory"🤷🏼*♂️

Yeah, I would lying if I said my OCD was not pissed when I made my first cut into the insulation with my exacto knife and it was not "smooth". I was expecting a nice clean cut "box" for the EZPass to fit into. But there was no turning back after that. I try not to think about it.... Out of sight, out of mind.

Now if it didn't work, I may have needed to buy a whole new CF roof .....

[jmciver]

Originally Posted by noone

Cool. In Florida (Sun Pass) they have little 2 x 3" stickers you can put on the bottom left of your windshield. I'm sure Maryland has the same thing!

Nope, no stickers for the EZPass system that I know of. When I lived in WA state for a while, they used the sticker passes though...

[theoluv]

How about the license plate EZ Pass.. is that un acceptable.. mounted to the front plate

[9M71]

Originally Posted by theoluv

How about the license plate EZ Pass.. is that un acceptable.. mounted to the front plate

if OP is OCD enough to hide his drugs, I mean E-ZPass, above the dome light, I doubt he runs a front plate

[jmciver]

Originally Posted by 9M4N71U

if OP is OCD enough to hide his drugs, I mean E-ZPass, above the dome light, I doubt he runs a front plate

Ha ha, yeah right. Actually, I have never been a fan of those plate mount EZ Pass units more for theft reasons.....

[espressoo]

Are you sure the Ezpass transponder was detected or did they run your tags and match it your transponder? I installed my transponder really high on my windshield and if I’m driving over 35 thru most gates on the toll roads it doesn’t read. I chalked it up to the CF roof. Each toll booth takes a photo and matches my tags to my transponder so it shows up on my statement.

[jmciver]

Originally Posted by espressoo

Are you sure the Ezpass transponder was detected or did they run your tags and match it your transponder? I installed my transponder really high on my windshield and if I’m driving over 35 thru most gates on the toll roads it doesn’t read. I chalked it up to the CF roof. Each toll booth takes a photo and matches my tags to my transponder so it shows up on my statement.

My EZPass statement differentiates between a plate read vs a transponder read - I have seen both. On the date in question, my statement indicated it was the transponder that was read. I also have multiple transponders on my account with multiple cars/plates assigned to my account as well.

[SD ///M4]

So back when the M Performance Carbon Fiber Diffuser was released, people bought that, installed it, and discovered that the "kick to open" trunk feature didn't work. The common explanation given was that the CF acts as a Faraday cage, effectively blocking the signals necessary for this to work. There are several threads and hundreds of posts on this. I have one installed and my "kick to open" feature no longer works. So how does this work, especially since the CF roof if probably thicker than the CF in the rear diffuser?

Is your EZ-Pass only used on toll roads? Here in San Diego, our FastPass allows us to drive in certain carpool (HOV) lane without passengers (for a fee) and can also be used for the Toll Roads located in Orange and LA counties. If you have passengers in a carpool lane, no FastPass is required. With your relatively permanent installation, you'd get charged a toll in the HOV lane even with passengers.

I have a gel mat cut to fit in the flat space on the dash to the left of the Nav screen. When I need to use my FastPass in a carpool lane with no passengers I pull it out of the door bin and put it on the gel mat before I get in the carpool lane and it holds it securely, even on the entry/exit ramps. If I have a passenger, I don't need to use the FastPass. If I'm using one of the Toll Roads, I put the FastPass on the gel mat when I first get on and then take it off because it's not needed to determine the distance you travel as the fee is fixed for the limited access Toll Roads.

This is the easiest solution for me given the variable nature of how I have to use my FastPass.

[jmciver]

The carpool EZ Pass transponder used here is different than the standard EZ Pass transponder that I use. I have no need for the carpool variant based on how often I use the HOV lanes so my install supports how I use the EZ Pass.

Regarding the faraday cage comment, I am not a composite materials engineer, but what you said does not make sense to me. CF is a composite material with no metallic ingredients - similar to plastic. Therefore, the CF should not interfere with the RF signal from the transponder. The only reason I figured this might not work would be due to the thickness of the CF roof compared to the signal strength of the RF signal coming from the transponder. But as I mentioned above, the proof that it worked was based off what I saw on my billing statement.

As for why the "kick" feature didn't work with the CF diffuser, that puzzled me a bit too since the CF should not interfere with the signal. Unless the signal from the kick sensor is so week, the thicker CF was able to interfere with it. FWIW, I have heard that some people were able to get the kick feature working with the CF diffuser installed - albeit intermittently.

[Tangent]

Originally Posted by jmciver

CF is a composite material with no metallic ingredients - similar to plastic. Therefore, the CF should not interfere with the RF signal from the transponder

CF is electrically conductive though and that does make it interfere with RF signals. There are plenty of reports of CF shark fins killing people's Sirius/XM reception, and if you search around you'll find loads of similar reports for other rf signals. HERE'S one that shows an RC antenna signal going from 1.6 mW down to 0.02 mW from a CF RC boat hull.

[jmciver]

Originally Posted by Tangent

CF is electrically conductive though and that does make it interfere with RF signals. There are plenty of reports of CF shark fins killing people's Sirius/XM reception, and if you search around you'll find loads of similar reports for other rf signals. HERE'S one that shows an RC antenna signal going from 1.6 mW down to 0.02 mW from a CF RC boat hull.

So as I mentioned above, I am not a materials engineer/expert..... But fortunately I work with people who are so I decided to get smarter on CF. And you are correct, CF does have some metallic properties (which I did not realize). Additionally, I learned that while CF would not make an ideal Faraday cage, the texture and weave of the CF changes the metallic properties of the CF as well.

All that to say that CF does attenuate RF signals under certain conditions, but is still significantly less than metal. So in my application, with the EZ Pass mounted just under the CF roof, the signal from the EZ Pass transponder is still strong enough to be detected.