What did you do to your NBS GMT800 Tahoe/Yukon Today?

[blueinkd]

Shortblock is out and should be at machine shop Monday morning. No pics as it got late when we finished and needed to clean up.

 

[Scott in AZ]

Lil’ help? Power wire 8AWG thru Firewall Grommet.

Audio head unit + backup camera install is complete. Speaker and subwoofer is complete. Amp is mostly complete but I’ve hit a barrier.

I was not able to get 8AWG amplifier power wire through the firewall main grommet. Made a small incision in the upper engine side boot. Used Klein wire lube. Fished and poked around for about 40 mins but didn’t make any progress. This will be a really clean install when complete. OCD’s (you know who you are…) don’t hate on me! I offset the amp to pax side (right) to give more clearance for wires and avoid the groove in the console mounting plate. Form follows function. Now I just need power.

Anybody got tips on how to get thru the firewall?

Also, grounded with an 8AWG to floorboard but added a supplemental ground to the seat and console mount plate, which I believe is grounded / connected to the frame. I sanded paint down to bright metal under the supplemental ground , but can anybody confirm if this will work? @iamdub, will this work?

Thanks in advance.

 

[iamdub]

Lil’ help? Power wire 8AWG thru Firewall Grommet.

Audio head unit + backup camera install is complete. Speaker and subwoofer is complete. Amp is mostly complete but I’ve hit a barrier.

I was not able to get 8AWG amplifier power wire through the firewall main grommet. Made a small incision in the upper engine side boot. Used Klein wire lube. Fished and poked around for about 40 mins but didn’t make any progress. This will be a really clean install when complete. OCD’s (you know who you are…) don’t hate on me! I offset the amp to pax side (right) to give more clearance for wires and avoid the groove in the console mounting plate. Form follows function. Now I just need power.

Anybody got tips on how to get thru the firewall?

I think that one you were trying with is dual-layered. I don't bother messing with the factory grommets. It's just not worth the hassle or risk of nicking a wire or causing a leak. Bring a piece of your power wire to an auto parts store or hardware store (Home Depot, Lowe's, etc.) and look for a grommet like this:



You want one that fits firmly on the jacket of your power wire. Here's mine where I ran it through the floorboard, near one of the right rear seat mounts:




I drilled the hole to the OD of the recess in the grommet ("PANEL HOLE DIAMETER" in the following image), cleaned the drilling burrs from around the edge of the hole then painted the metal and let it fully dry. The wire needed a little spritz of lubricant ever so often to slide through the grommet cuz it was a firm fit. Which, is what you want for proper sealing.




"OCD" you say?

Also, grounded with an 8AWG to floorboard but added a supplemental ground to the seat and console mount plate, which I believe is grounded / connected to the frame.

Not directly. The seats are bolted to the cab floor, to sheet metal. A circuit needs to have the same ampacity throughout all of its conductors. Otherwise, the ampacity of the smallest (weakest) point will be the circuit's maximum. The battery is grounded to the frame. The body (sheet metal) is grounded to the frame with some rather electrically weak cables. You can ground that amp to sheet metal or to seat frames, etc. that are bolted to the same sheet metal, but that sheet metal needs a matching ground to the frame. So, you'd need an 8 gauge ground from the body's sheet metal to the frame or engine block. I have a 4 gauge ground from the body to the engine block, which is grounded to the frame with 1/0. It's actually the original factory main ground that went from the battery to the engine block, just relocated to the sheet metal:

I sanded paint down to bright metal under the supplemental ground , but can anybody confirm if this will work? @iamdub, will this work?

Thanks in advance.

It's a good ground, but still to the body. The body-to-battery (or frame or engine) needs to be at least 8 gauge.


Honestly, it's all probably okay. But, there's still room for doubt. For the minimal cost of ensuring your grounds are sufficient, you can ensure the amp won't be starved of power, minimizing its heat and how hard it'll have to work which maximizes its life.

 

[Scott in AZ]

This is really helpful information, @iamdub. Especially the grommet geometry cartoon. I can see now why I had so much trouble with my other grommet (different application; first and only grommet). I drilled to the ID and not to the Panel Hole Diameter.

Your power wire grommet is artwork. I’ll drill thru the floor near the rear mount of the front seat, Near my ground.Oh-See-Dee, yo! Thanks.

 

[iamdub]

Your power wire grommet is artwork.

Thank you! I detected a bit of OCD from your previous posts so I had to feed in a little.

I’ll drill thru the floor near the rear mount of the front seat, Near my ground.Oh-See-Dee, yo! Thanks.

Unless I need the power wire to end up behind the dash, I like to come through the floor since there's so much more room to work.

You gotta consider the wire routing, too. If you run it along the frame, you're gonna have to hop from the frame to whichever seat mount you choose. So, look ahead for safe routing and secure mounting points before you poke that hole. I'd pick a spot nearest the frame so you're not stretching the run laterally once you leave the frame with it. Once inside the cabin, it's all easy from there since you can run the wire under the carpet to the center console. I came up by the seat mount so the cover panel would hide and protect the wire, nobody steps there, etc.

To paint the area I drilled, I couldn't get the can in there and I didn't wanna risk painting the carpet. I sprayed the paint into a plastic cap from a brake parts cleaner can then dabbed it on with a Q-tip.

 

[blueinkd]

I think that one you were trying with is dual-layered. I don't bother messing with the factory grommets. It's just not worth the hassle or risk of nicking a wire or causing a leak. Bring a piece of your power wire to an auto parts store or hardware store (Home Depot, Lowe's, etc.) and look for a grommet like this:

View attachment 399938

You want one that fits firmly on the jacket of your power wire. Here's mine where I ran it through the floorboard, near one of the right rear seat mounts:

View attachment 399939


I drilled the hole to the OD of the recess in the grommet ("PANEL HOLE DIAMETER" in the following image), cleaned the drilling burrs from around the edge of the hole then painted the metal and let it fully dry. The wire needed a little spritz of lubricant ever so often to slide through the grommet cuz it was a firm fit. Which, is what you want for proper sealing.

View attachment 399947


"OCD" you say?

View attachment 399940

View attachment 399941




Not directly. The seats are bolted to the cab floor, to sheet metal. A circuit needs to have the same ampacity throughout all of its conductors. Otherwise, the ampacity of the smallest (weakest) point will be the circuit's maximum. The battery is grounded to the frame. The body (sheet metal) is grounded to the frame with some rather electrically weak cables. You can ground that amp to sheet metal or to seat frames, etc. that are bolted to the same sheet metal, but that sheet metal needs a matching ground to the frame. So, you'd need an 8 gauge ground from the body's sheet metal to the frame or engine block. I have a 4 gauge ground from the body to the engine block, which is grounded to the frame with 1/0. It's actually the original factory main ground that went from the battery to the engine block, just relocated to the sheet metal:

View attachment 399942




It's a good ground, but still to the body. The body-to-battery (or frame or engine) needs to be at least 8 gauge.


Honestly, it's all probably okay. But, there's still room for doubt. For the minimal cost of ensuring your grounds are sufficient, you can ensure the amp won't be starved of power, minimizing its heat and how hard it'll have to work which maximizes its life.

You make me want to Build my own ground straps!!! Im assuming you are making those in house??
What kind of ring terminals are u using?? Care to point me in the direction of your supplies??? That wire loom is sexy too!

 

[iamdub]

You make me want to Build my own ground straps!!! Im assuming you are making those in house??
What kind of ring terminals are u using?? Care to point me in the direction of your supplies??? That wire loom is sexy too!

I JUST replied to your other thread about the "while I'm rebuilding the engine..." stuff.

Yeah, I made 'em up at home. It's 1/0 welding lead, so it's OFC and not the cheaper, lower-quality CCA. Lugs are from Amazon. I soldered and crimped them on. Heat shrink tubing (also from Amazon) has adhesive sealant that activated when you heat the tubing to shrink it. The mesh sleeve is leftover extra I salvaged from a past project at work. It's cheap on Amazon. Here's an example: https://a.co/d/3ZrSOyQ. Note they have different sizes and colored options as well. I have a handheld hydraulic crimper- yup- from Amazon. The most expensive part is the wire. Just aim for OFC instead of CCA. Determine the highest amperage you'd ever need to support (have or are planning a big sound system or other high-amperage equipment?) and get the appropriate size of wire. For a given ampacity, you'll need a larger gauge of CCA than OFC. For a somewhat rough example, 4 gauge OFC is good for 100 amps (as with a ~1,000 watt amp). To support that same amperage, you'd need a step or two larger CCA.

Know anyone that works at a plant or is a welder? Safety guys often fail welding leads that have too many cuts. For a Big 3 upgrade, you'll need about 12' but that's cutting it close. If you can find a welding lead that was taken out of service, get as much as you can and cut out the good sections to make up your cables. I made a "Big 5" since I upgraded the starter wire and body-to-frame cables.

 

[915_Tahoe]

Hoe has been sitting for almost a year, and finally got her moving again.

Fixed-
replaced inner/outer tie rides
Installed longer torsion key bolts
Wheel alignment
State inspection and renewal
Replaced RH frnt leather seat covers

 

[RAMurphy]

I think that one you were trying with is dual-layered. I don't bother messing with the factory grommets. It's just not worth the hassle or risk of nicking a wire or causing a leak. Bring a piece of your power wire to an auto parts store or hardware store (Home Depot, Lowe's, etc.) and look for a grommet like this:

View attachment 399938

You want one that fits firmly on the jacket of your power wire. Here's mine where I ran it through the floorboard, near one of the right rear seat mounts:

View attachment 399939


I drilled the hole to the OD of the recess in the grommet ("PANEL HOLE DIAMETER" in the following image), cleaned the drilling burrs from around the edge of the hole then painted the metal and let it fully dry. The wire needed a little spritz of lubricant ever so often to slide through the grommet cuz it was a firm fit. Which, is what you want for proper sealing.

View attachment 399947


"OCD" you say?

View attachment 399940

View attachment 399941




Not directly. The seats are bolted to the cab floor, to sheet metal. A circuit needs to have the same ampacity throughout all of its conductors. Otherwise, the ampacity of the smallest (weakest) point will be the circuit's maximum. The battery is grounded to the frame. The body (sheet metal) is grounded to the frame with some rather electrically weak cables. You can ground that amp to sheet metal or to seat frames, etc. that are bolted to the same sheet metal, but that sheet metal needs a matching ground to the frame. So, you'd need an 8 gauge ground from the body's sheet metal to the frame or engine block. I have a 4 gauge ground from the body to the engine block, which is grounded to the frame with 1/0. It's actually the original factory main ground that went from the battery to the engine block, just relocated to the sheet metal:

View attachment 399942




It's a good ground, but still to the body. The body-to-battery (or frame or engine) needs to be at least 8 gauge.


Honestly, it's all probably okay. But, there's still room for doubt. For the minimal cost of ensuring your grounds are sufficient, you can ensure the amp won't be starved of power, minimizing its heat and how hard it'll have to work which maximizes its life.

Looks like the amp I have installed in my baby. Nice job, looks great.

 

[iamdub]

Looks like the amp I have installed in my baby. Nice job, looks great.

Thank ya. Oldie, but goodie! That and the subwoofer are period correct for an '08 Tahoe.