Keep water out when you run power cable through your car's firewall. The StreetWires FB4 firewall bushing protects your 4-gauge power cable from wear and chafing, and provides a watertight seal when it's tightened down. Lifetime warranty.

StreetWires FB4 Reviews

Average Customer Review:

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not needed

Written By not worth sending back, OK on Thursday, May 09, 2013

Crutchfield Customer Review (What's this?)

I'm sure in some installations it would be needed but after looking for a good location to drill, I figured out, I had a spot on the main harness grommet that worked better. And no drilling required.

It's a Bushing!

Written By Alek, Grand Rapids, MI on Friday, March 16, 2012

Crutchfield Customer Review (What's this?)

I bought this to pass a 4-Gauge power cable through the firewall of my car. I spent several hours dismantling my dashboard trying to find a place to pass this through, or a place to drill. I had no luck with that, but was lucky enough to find an unused, plugged hole in the firewall under the carpet on the passenger side of my car. The bushing didn't fit the hole, but I managed to fit it in the plug that was in the hole! Anyway, the bushing clamped down on the plug and the cable nice and tight. I've no idea how it will hold up over time, but I imagine that if a 1mm thick plastic plug lasted ~20-years that this will outlive the car!

Pros: -Solid -Fits 4-Gauge Cable

Cons: Does not include a device that magically tells me where I can put a hole in my car's firewall.

Professional Look

Written By JeffR, Taylors, SC on Saturday, December 04, 2010

Crutchfield Customer Review (What's this?)

For a clean professional installation this product is great. Requires cutting of the
firewall but if you have the right tools and the skills, it is no problem. Highly

Does what it should

Written By Tracy, Sandston, VA. on Thursday, July 08, 2010

I used one of these as I drilled a hole through my firewall to run my 4ga. power lead. I gave it 5 stars because it worked great and I don't need to worry about my power lead running through a jagged hole. Once the wire is run through it the outer cap screws in place and clamps it down so it does not move. Not that this is that big of deal but it does not come with instructions to tell you what size hole to drill. After a quick measurement though I drilled a 3/4" hole, as that was the biggest bit I had but the hole still needed a bit of filing. I'm thinking a 13/16 hole would be perfect.
As usual, Crutchfield is the best!!

Works OK.

Written By Kevin, Mesa, AZ. on Saturday, June 19, 2010

Crutchfield Customer Review (What's this?)

This product worked well. I used it to run a 4 guage Rockford wire through the firewall on my Chevy Silverado. It fit OK because the firewall was only 1 layer thick next to the power break booster where I ran the wire.

StreetWires FB4

Written By Anonymous, NC on Tuesday, June 30, 2009

I used this to run a 4 gauge cable through a Cavalier firewall. It worked exactly as I had planned out, and the cable is nice and secure, and waterproof. I used a step drill (unibit) to drill the hole, since no instructions were included I used a caliper to find the size. The Cavalier firewall was only 1 layer thick so the length was perfect.

Professional Solution

Written By Winston, Hampton, VA on Saturday, September 27, 2008

Crutchfield Customer Review (What's this?)

I found this to be the professional solution to breaching the firewall to run cable(s). Including instructions in the pack on what size hole to drill and which side or in what order should the bushing be assembled would be helpful to the novice. Otherwise this product really gives a professional look and functionally serves the purpose.

StreetWires FB4

Written By Gene, New Orleans on Monday, September 08, 2008

Is a bit too short on the firewall side, IMO.


Written By turtle, chi on Wednesday, May 07, 2008

Crutchfield Customer Review (What's this?)

no measurement specs is why its a 4.i just used a ruler and a 22mm hole
saw .it went through with no prob

Works Great!

Written By David, Hawaii on Tuesday, January 02, 2007

Crutchfield Customer Review (What's this?)

This product worked perfectly for me. It would be nice to have instructions, but the bushing is easy enough to figure out. Once I drilled through my Ford Ranger firewall, the bushing worked just like it was suppose to.

What I liked best was, once I routed my power cable in my engine bay the bushing locks the cable in place with a compression fitting. The threads were somewhat close, but I had a friend hold the engine bay side of the bushing and then I attached my side from inside. By using this bushing instead of a hardware store gromet, you are able to slip the power cable freely to get perfect adjustment and then lock it down, the hardware store gromet forces you to estimate the length, slip it on cable and then force it into your firewall for a snug fit. Pain in your side, I know this bushing saved me much headache.

A good idea...

Written By newfrontier45, Orlando, FL on Monday, October 30, 2006

...but very poorly executed. The threads are just way too short to use on anything but a single layer of thin sheetmetal. I don't know if many firewalls are that thin but the floor of my Chevy 2500HD was way too thick to use this product properly. I was able to utilize it but not in the manner in which it was intended.

A Must-Have Accessory for Amplifier Wiring Install

Written By Dan, Sioux Falls, SD on Wednesday, August 30, 2006

Crutchfield Customer Review (What's this?)

I installed this product in a 2002 Honda Accord, which has a knockout block in the firewall a little ways above the gas pedal. Upon removing the plastic knockout block I discovered a hole in the neighborhood of 3/4" diameter. I ordered the Streetwires FB4 firewall bushing and was delighted to find it fit.

The firewall bushing serves a few functions:
1) It looks great! It gives the install a professional look.
2) When the nut is tightened it cinches on the power cord, keeping the cord from sliding in and out and creating a waterproof seal.
3) The bushing, of course, keeps the sharp edge of the hole in the firewall from wearing through the power cord installation and causing a short.

My only complaints are that it is impossible to find any information regarding the dimensions of this product online. The product arrived with absolutely no instructions. And, my firewall was a bit too thick for the FB4 and I had to remove the rubber o-ring gasket in order to have sufficient thread space to secure the FB4.

The FB4, although a bit more spendy than a hardware store grommet, is money well spent. It ensures a sharp-looking, worry-free install.

Hands-on research

What's in the box?

  • Threaded bushing shaft
  • Cap
  • Nut

Product Research


General Description: The StreetWires firewall bushing is a three piece design; the threaded shaft loads through the firewall, a rounded cap screws on from one side and a nut from the other. A watertight seal is created as the ends are tightened. Your wire will be protected from metal jagged edges and moisture.

Available Sizes and Dimensions: The StreetWires firewall bushings are available in three sizes.

8-Gauge Firewall Bushing:

  • Cut-Out Diameter: 0.58"
  • Shaft Length: 1.159"
  • Inner Hole Diameter For Wire: 0.25"

4-Gauge Firewall Bushing:

  • Cut-Out Diameter: 0.88"
  • Shaft Length: 1.275"
  • Inner Hole Diameter For Wire: 0.5"

1/0 Gauge Firewall Bushing:

  • Cut Out Diameter: 1.105"
  • Shaft Length: 1.588"
  • Inner Hole Diameter for Wire: 0.75"

Our Product Research Team

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