How big does the grommet opening have to be to fit the sensors through?

GoldRetriever79

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Curious, if I was to drill a hole through the firewall (and not go through an existing grommet) how big does the hole need to be and the grommet you would run the sensor cable through back to the CPU in the cabin?

Would this grommet be big enough? It is 7/8"
https://www.amazon.com/dp/B005HDIY80/?tag=rdf0cd0c-20

I think the cord looks like it would be, put I'm not sure about the end that plugs into the CPU and if it would fit through this grommet.

This grommet is for a 4 gauge wire.

Thanks for the help.

BTW, I don't have the system yet, just doing some pre-research.

1609303477598.png

Post automatically merged:

Curious, if I was to drill a hole through the firewall (and not go through an existing grommet) how big does the hole need to be and the grommet you would run the sensor cable through back to the CPU in the cabin?

Would this grommet be big enough? It is 7/8"
https://www.amazon.com/dp/B005HDIY80/?tag=rdf0cd0c-20

I think the cord looks like it would be, put I'm not sure about the end that plugs into the CPU and if it would fit through this grommet.

This grommet is for a 4 gauge wire.

Thanks for the help.

BTW, I don't have the system yet, just doing some pre-research.

1609303477598.png
Let me already make a guess.....it is going to be to small because you need to run another 2 cables through it (if I have 2 regular and a TX for example) trying to run them all through this opening?
Post automatically merged:

Curious, if I was to drill a hole through the firewall (and not go through an existing grommet) how big does the hole need to be and the grommet you would run the sensor cable through back to the CPU in the cabin?

Would this grommet be big enough? It is 7/8"
https://www.amazon.com/dp/B005HDIY80/?tag=rdf0cd0c-20

I think the cord looks like it would be, put I'm not sure about the end that plugs into the CPU and if it would fit through this grommet.

This grommet is for a 4 gauge wire.

Thanks for the help.

BTW, I don't have the system yet, just doing some pre-research.

1609303477598.png

Post automatically merged:


Let me already make a guess.....it is going to be to small because you need to run another 2 cables through it (if I have 2 regular and a TX for example) trying to run them all through this opening?
Or would this idea work well to get all cords through (did a search)

[ATTACH=full]168815[/ATTACH]

Driver66

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IF YOUR NOT USING EXISTING HOLES this is easy and super cheap. No painting involved and I've attached the links to Amazon for one stop shopping. If you have Amazon Prime everything total will be like $22. I've used this many times for access to engine and trunk areas. Not for CM stuff but just for wiring in general. Drill a 1 inch hole wherever you want, with a universal drill bit. Don't worry the final size will be adjustable to be smaller if you want. Then you get a pack of 1 inch flush mount body plugs, a pack of ten is $5.50 or just go to the hardware store and buy 1, but it will probably be a buck and change. The plugs have no hole in them so drill whatever size hole you want in the body plug. The plug is designed specifically to seal around sheet metal. Then get some RTV silicone sealer, it comes with a nozzle that's cut to size. In this case cut it small. Squeeze a little in the gap of all the way around the body plugs inner and outer sides, then just pop it into the hole you drilled. This creates a water tight seal and covers the bare metal. Because it's RTV it's completely impervious to gas, oil, heat and water, and it holds the plug fast when dry, so it won't move while your working. Nothing to worry about. Give the sealer 30 minutes to set up then just run your wires through the hole. After your all done seal the wires at the hole with plenty of RTV. So, put a hole wherever you want, no painting , completely water tight and no rust worries. Nice neat easy install. The only downside is the sealer will be a little stinky for a couple days til completely cured. Hope this helps!

https://www.amazon.com/dp/B00H3Q6KOY/?tag=rdf0cd0c-20
https://www.amazon.com/dp/B00PEZS37I/?tag=rdf0cd0c-20
https://www.amazon.com/s/ref=nb_sb_...emp+RTV+Silicone+Gasket+Maker&tag=rdf0cd0c-20
 
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scottl

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Yes, 7/8" should work depending on the grommet thickness. Not sure on the grommet in the link above. I went to Home Depot and bought something similar that worked perfect, I brought the sensor with me and tried a few different kinds, in the end it was a 3/4" ID. Wound up drilling a 1" hole to allow the the grommet to fit that was big enough for the connectors and wires to go through. If you have the GPS in the engine compartment you also have to bring that wire through. I filled the grommet and external edges with silicon caulk just to be safe.
 

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for reference the twist lock connectors are about 9/16th's of an inch in diameter. So assuming you are passing multiple wires through the same hole you need to upsize the hole enough to be able to pass the additional twistlock connectors thorough once there are already wires running through the hole. To minimize the size of the hole you need to drill you could cut a slit through the edge of the grommet to allow you to install the grommet after you have passed the connectors through the hole. Then just seal with RTV silicone.
 

Heywood

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I actually went the side of the grommet that my hood release travels through the firewall.
I just used a box cutter and made a small X

That’s on a truck, so the grommet might be a bit bigger, but that’s how I ran all of mine to the front.
 

jcp

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I recently installed my Alp system and needed a 3/4 in. grommet. This allows just enough room to pass the 3 wires (1 at a time) and have a 1/2 in. split loom sheath around the wires for protection. Fits pretty tight all in all.
 

GoldRetriever79

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Thanks everyone for the responses so far. Next couple of questions, I have an 09 Camry. I'm not a car expert by no means....so I have been trying to do a lot of reading about how to tackle this. I don't know much about going through grommets, etc. I did see this youtube video about a 2011 Camry and drilling left of the brake (an area where the clutch punchout would be from what I have been reading).




I looked under my car (09 Camry) and I'm finding the exact same layout.....same circle you could drill through.



1609443714195.jpeg



Considering the video above (and reading through youtube commits....seems like earlier versions of the camry have the same layout and were successful for drilling) would you all say this would be a safe spot to use the stepbit on to drill?

Again, I don't have any experience putting something through a grommet....and not 100% sure if it is safe to go through things or not. I have read about being careful not to hit wires through existing grommets. I'm sure there is one under the driver dash....but it is really crammed under there and I'm not sure really what to look for.

However, I was wondering if this is a grommet that you can go through? It is on the passenger's side, in the engine bay, looks like down behind the glove compartment ( if I were to trace a line through the engine bay into the cabin).

Also, the long stems sticking out of this.....are those the "nipples" of the grommet? I have read you can cut the tips of these off to run wires through them. Just wondering if this would be another option besides drilling? If this is an option....it would be real easy to go to from the engine bay. I wonder if the glove box would have to be taken off to get to it though from the inside.

1609443301130.png



This is a zoomed out pic of the location with the flashlight pointing at it.

1609443694292.png



Again thanks for everyone's help and advice.
 

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jcp

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Thanks everyone for the responses so far. Next couple of questions, I have an 09 Camry. I'm not a car expert by no means....so I have been trying to do a lot of reading about how to tackle this. I don't know much about going through grommets, etc. I did see this youtube video about a 2011 Camry and drilling left of the brake (an area where the clutch punchout would be from what I have been reading).




I looked under my car (09 Camry) and I'm finding the exact same layout.....same circle you could drill through.



View attachment 169005


Considering the video above (and reading through youtube commits....seems like earlier versions of the camry have the same layout and were successful for drilling) would you all say this would be a safe spot to use the stepbit on to drill?

Again, I don't have any experience putting something through a grommet....and not 100% sure if it is safe to go through things or not. I have read about being careful not to hit wires through existing grommets. I'm sure there is one under the driver dash....but it is really crammed under there and I'm not sure really what to look for.

However, I was wondering if this is a grommet that you can go through? It is on the passenger's side, in the engine bay, looks like down behind the glove compartment ( if I were to trace a line through the engine bay into the cabin).

Also, the long stems sticking out of this.....are those the "nipples" of the grommet? I have read you can cut the tips of these off to run wires through them. Just wondering if this would be another option besides drilling? If this is an option....it would be real easy to go to from the engine bay. I wonder if the glove box would have to be taken off to get to it though from the inside.

View attachment 169004


This is a zoomed out pic of the location with the flashlight pointing at it.

View attachment 169007


Again thanks for everyone's help and advice.
On my 2001 Maxima SE, The main wiring harness comes down from engine bay and runs behind the driver side wheel well cover into the car just above the dead pedal (Automatic) I used a step drill and drilled a 3/4 hole a few inches over from the main harness (closer to the steering wheel) It was nerve racking, but after I did it thought that really was easy :) If the hole cutout shown comes out behind your wheel cover, you should be golden. If the cutout looks to come out closer to the brake boost cylinder. See if you can run it behind the wheel well cover instead. On my 2001 Maxima, it was the safer location (after all that is where the main harness comes in. Use a 1/2 wire split loom and some silicone. The wheel cover prevents 99.5 % of water that might come in. I estimate.
 

Maz3

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I used this one (3/4" diameter) which is double walled and heat shrinks to make an excellent firewall seal:


I fit two ALP Rx and one Tx connectors through it - one at a time, with some water based lube. It was a tight fit, but once in I was extremely happy with it.

You can see the install here if you're interested in what it looks like:


Good luck @GoldRetriever79
 
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hellcatguy

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Something to consider before you drill any holes. I have a 2017 Challenger and used an existing harness grommet. The hole I made was the size of a phillips screw driver. I used an old pen body which fit over the connectors to pass through the grommet. I used silicone spray on the pen body and cable to pass through the hole. I got the three sensor wires as well as a net radar wire through the small hole. A dab of rtv around the wires ensures no water intrusion.
 

OBeerWANKenobi

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If you can't find a nice preexisting grommet --I personally wouldn't mess with the one behind the glove box as usually it's a PITA to take apart and there's HVAC junk back there-- I think I'd go for this option:

1609776736284.png


Just make sure there's nothing on the other side before you drill through. Once you're fairly certain it's fine. Start with a nice small drill like a 1/16" or 1/8" and after you're through, stick something in there so you can see it from the other side. If it still looks ok then go to your bigger bit or the tree bit. If it doesn't look great, abort. You can easily fill the small hole and move along like nothing happened.
 

GoldRetriever79

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Updates. First, a big thank you to everyone who has chimed in thus far. Talking over with wifey (the boss) she wants me to hold back on drilling, going through stuff, etc for now. However, I do think the hole spot that I pictured would be the best drilling location. Looking around, I am a bit hesitant as it is very close to the brake boost cylinder (as mentioned by jcp) at least I think that is what it is best off of looking at car anatomy parts of the internet. But, I do reasonably think that spot is probably is a safe spot to drill all things considered. I think Obeer makes a great a point about not drilling deep and seeing what you can see before going any deeper. So, this is option is put on hold for now....may come back to it.

I have ordered the ALP system today (to start with duals, with bluetooth with wifi and wired controlled speaker for the front). Down the road, I will get the 3rd head. I will likely post a picture of the front of my car asking all of you opinions on best placement of heads when I get to that step.

But, I'm going to take the unorthodox step first of doing a complete engine bay install for now and run things through bluetooth/phone. I have read using the search future on this the pros and cons. I do think I should be pretty prepared here. I have ordered 2 IP65 waterproof boxes to put the CPU in....one of the boxes already has grommets on it that you can go through for wiring, dry desicannt beads you can put in the box to absorb any potential moisture, I will add a humidity gauge to put in the box to monitor moisture level, RTV slicone sealent, a mulitmeter, a wire crimper, a low profile mini ad-a-fuse, and extra low profile mini fuses to power the correct amp level for CPU.

To double check here....I will be going through the radio fuse (that is 15amps) will put that 15 amp fuse in the bottom slot on the add a fuse and the top slot I will put a 5 amp fuse. Is that ok? From what I have read, that would appear to be fine.

I will tap into the fuse box. I have measured out a spot in the engine bay that is well away from the engine and is located by the fuse box (which is located more up front of the engine bay). I will zip tie down the box (still need to get those) and buy cord protectors for the sensor cords.

Lucky....my grill will require no cutting....I can put my hands through the grill slots and the sensors/cords will easily go through the engine bay area to the grill.

But, this is an exciting project. I have an R1 (been holding off on upgrading and waiting to see what Theia looks like...I could get an R7 at anytime), but I wanted to get the very best Laser Jammers on the market first.
Post automatically merged:

To be clear, I ordered to 2 different IP65 waterproof boxes to be on the safe side. Both of theses boxes have features I like about them. But, I like the one that already has grommets on the sides of it so I don't have to drill into the box. But, I also like the other one where I can see through it.

https://www.amazon.com/gp/product/B082LQDW9V/?tag=rdf0cd0c-20

 
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grayman

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Good luck on your install approach it certainly seems to be adding extra work, expense, complexity, and cost. I am so thankful to have a spouse who may occasionally have a passing interest in what I'm doing, but not dictate how or if I do it. Heck I even messed up a car alarm install when we were newly married and she only lightly ribbed me about over the years, certainly doesn't dictate what I'm doing.

A thoroughly investigated location for a grommet which you seem to have done is simple. Drill the hole, put a grommet in there, route your wires, create a drip loop and seal it up.
 

MASI

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If you are concerned about the size of the hole (can't tell from your OP) you can always cut the wires, pass them, then solder and heat shrink them. If you are only passing 3 wires, you can get by with a fairly small hole. This also makes it easier to get the wires through an existing (OEM) passway instead of drilling a new hole through the firewall.
 
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GoldRetriever79

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I have remoted installed everything. I have been done for a couple weeks now. Thanks for everyone's input. Next step would be to get a TX head.
 

MASI

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I seem to recall that his has been strongly recommended against doing by the manufacturer, but maybe I’m misremembering.

I'm pretty sure that pings can fly, but maybe I'm mis-remembering.

It has been well established that electrons pass soldered splices very well. And so long as you insulate and seal the wires, you will be fine.
 

Deacon

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I'm pretty sure that pings can fly, but maybe I'm mis-remembering.
Probably so. That seems to be a theme with you.

It has been well established that electrons pass soldered splices very well. And so long as you insulate and seal the wires, you will be fine.
I’d be interested to know how you think you’re going to keep the shielding intact. I’d check with Dunning first. He may have some input. Or maybe Kruger. I’m no expert myself, so I’ll have to see what Tom has to say about it.

If you cut the end of the cable that is attached to a sensor the warranty is voided. Any good installer will install without cutting cables. If they want to cut the extension cable we have no problem with that but the cable attached to sensor will instantly void the warranty.
1611702745104.gif
 
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MASI

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I’d be interested to know how you think you’re going to keep the shielding intact.

Ever heard of foil?
Every major manufacturer of shielded cable uses foil in shielded cable. And it works very, very well - even up to the GHz range.

Perhaps you (or your memory) know more than big cable manufacturers like Belden and Times Microwave?
 
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Deacon

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Perhaps you (or your memory) know more than big cable manufacturers like Belden and Times Microwave?
Like I said, I’m no expert. I’m just speculating that keeping unbroken shielding is part of the reason. I’ll should leave the speculation and tinfoil to you. I’ll defer to the manufacturer the more specific matter of flying pigs, who had this to say:

If you cut the end of the cable that is attached to a sensor the warranty is voided.
 

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