Converting an L8T hood to a functional L5P intake (functional hood scoop).

Epsilon Plus · April 14

I'm ready to dig into this a bit further and get as much info sorted out as we can. Most people end up just putting a light bar in the scoop on the gas trucks. In the spirit of OCD and hating non-functional scoops since way way back, I'd like to take a crack at solving this puzzle. So far from what I've gathered, L8T and L5P use the same physical hood PN. The air inlet area around the top of the radiator looks the same and feeds both filter boxes by the passenger side headlight area. It "looks" like the only real difference is the hood insulator, some type of plastic plenum that directs air into the top of the L5P box that sits between the hood and insulator, an open scoop PN and some bits and bobs. This looks very moddable. I'm not aware that L5P uses any type of electric actuators or mechanical modulation to shut off flow during moisture events and may just rely on mechanical drainage (holes). Part numbers found so far (for 20-23):

2020-2023:

L5P hood insulator: 84182769

L5P Silverado hood vent (custom/WT), black: 84520315

(midnight/carhardtt/Z71 plus), black: 84589745

(LT/LTZ/High Country), chrome: 84520314

L5P airbox: 85614333

In hood:

L5P front air intake duct: 84684674

L5P rear air intake duct: 85126004

L5P intake drain hole plug: 84598171

L5P air duct insulator: 84358112

L5P air intake duct cover (needed?): 84496061

Not sure how many other bits and bobs are needed. I can find a parts explosion but have to search for the parts independently on parts.gm then look at the diagram and GM parts direct and go back and forth. Non common detailed GM parts are notoriously hard to search for. Any insiders like newdude out there? Can you dissect the parts explosion and list what is needed for this swap? As far as the airbox to throttle body connection I assume the connection from the airbox to TB doesn't like up perfect since its a rigid plastic tube. However, that can be dealt with using some malleable intake tube and clamps. I may also just go to the S&B L5P intake for this and mod the tube outlet to work. Some of this stuff is reasonable as far as cost and I'm willing to throw some coins at it to get it functional. The intake air temperatures will surely be mint although I know it's not going to give it any power boosts (that is until you start adding cam/exhaust/blower/tuning so don't be so hasty to think its a wasted mod).

Any help on this topic is appreciated. Fake scoops belong on new edge Mustang GTs and Tacomas. Blasphemy on a GM product.

Edited April 16 by Epsilon Plus

newdude · April 14

2 hours ago, Epsilon Plus said:

I'm ready to dig into this a bit further and get as much info sorted out as we can. Most people end up just putting a light bar in the scoop on the gas trucks. In the spirit of OCD and hating non-functional scoops since way way back, I'd like to take a crack at solving this puzzle. So far from what I've gathered, L8T and L5P use the same physical hood PN. The air inlet area around the top of the radiator looks the same and feeds both filter boxes by the passenger side headlight area. It "looks" like the only real difference is the hood insulator, some type of plastic plenum that directs air into the top of the L5P box that sits between the hood and insulator, an open scoop PN and some bits and bobs. This looks very moddable. I'm not aware that L5P uses any type of electric actuators or mechanical modulation to shut off flow during moisture events and may just rely on mechanical drainage (holes). Part numbers found so far (for 20-23):

2020-2023:

L5P hood insulator: 84182769

L5P hood vent (custom/WT), black: 84520315

(midnight/carhardtt/Z71 plus), black: 84589745

(LT/LTZ/High Country), chrome: 84520314

L5P airbox: 85614333

L5P intermediate intake duct (to box front): 84670713

In hood:

L5P front air intake duct: 84684674

L5P rear air intake duct: 85126004

L5P intake drain hole plug: 84598171

L5P air duct insulator: 84358112

L5P air intake duct cover (needed?): 84496061

Not sure how many other bits and bobs are needed. I can find a parts explosion but have to search for the parts independently on parts.gm then look at the diagram and GM parts direct and go back and forth. Non common detailed GM parts are notoriously hard to search for. Any insiders like newdude out there? Can you dissect the parts explosion and list what is needed for this swap? As far as the airbox to throttle body connection I assume the connection from the airbox to TB doesn't like up perfect since its a rigid plastic tube. However, that can be dealt with using some malleable intake tube and clamps. I may also just go to the S&B L5P intake for this and mod the tube outlet to work. Some of this stuff is reasonable as far as cost and I'm willing to throw some coins at it to get it functional. The intake air temperatures will surely be mint although I know it's not going to give it any power boosts (that is until you start adding cam/exhaust/blower/tuning so don't be so hasty to think its a wasted mod).

Any help on this topic is appreciated. Fake scoops belong on new edge Mustang GTs and Tacomas. Blasphemy on a GM product.

If I told you GM had a cold air intake that gave you an L5P style setup they never released for 2020-2023 L8T trucks that included all of the necessary parts...would you believe me? And that they still never released it or probably never plan on releasing it?

Edited April 14 by newdude

Epsilon Plus · April 14

I would believe you because you're you lol.

Are you able to hit up GM EPS and break down that parts diagram for us?

Thanks

Capt Bob · April 15

I’ve dabbled with this thought since before my truck arrived. Any help is greatly appreciated.

NaturallyAspirated · April 15

Not sure what I can do to help but I sure agree with you. And I can’t wait to get this done to my truck too.

Pryme · April 15

I’ll be watching this.

64BAwagon · April 15

The 2024 L8T air intake setup is light years ahead of anything GM has previously produced on a gas truck. Before I got my SG3 I had wondered how efficient the gas intake system was. During my 4k trip I monitored air intake temp regularly. City and highway both towing and non towing and found the IAT to be within 1 degree of ambient temp in all situations. To me that indicates air intake efficiency I have never seen before in a stock setup. After seeing this I abandoned any thoughts of working on improvements. As a comparison. My 2005 LLY Dmax when stock and no mods always showed at least 20 degrees higher than ambient at highway speeds, in traffic sometimes 30-50 degrees higher. After modifying the airbox and adding a ducting kit for more outside air I was able to improve it but never got it anywhere near the numbers on this gas intake.

I believe that trying to use the diesel setup on the hood scoop could end up disrupting the gas airflow and might actually pack air where you dont want it on the gasser. I admit I had the same thoughts on making that intake on the hood operative but after spitballing it in my head I didnt think I could get any positive results from it.

I think the only reason that trim piece exists on the gas trucks is because GM needed something to occupy that space on the non diesel applications. Rather than create two hood designs they used the same piece blocked off.

Edited April 15 by 64BAwagon

Epsilon Plus · April 15

I'm going to start ordering some parts and take a blind shot. The lower intake tube is brutal with shipping and would be nice to buy on parts.gm and shipped free to dealer but is out of stock. [EDIT]Intermediate tube from near headlight to front of box is different between gas/diesel]. Lower tube on parts.gm also shows that it may come with the drain plug already attached so I may hold off on that. Part 5 is listed as the duct insulator but parts.gm shows it coming two piece and one of them looks like part 6. Also they look on the diagram to be part 9 and 10, so order two?

I'll need help identifying parts 2 and 14. Parts 4, 8, and 13 are bolts but would be nice to get the exact PN. 3 is likely retainer 11611677, and looks like maybe need (9).

Edited June 12 by Epsilon Plus

Epsilon Plus · April 15

4 minutes ago, 64BAwagon said:

The 2024 L8T air intake setup is light years ahead of anything GM has previously produced on a gas truck.........

I believe that trying to use the diesel setup on the hood scoop could end up disrupting the gas airflow and might actually pack air where you dont want it on the gasser. I admit I had the same thoughts on making that intake on the hood operative but after spitballing it in my head I didnt think I could get any positive results from it.

I agree the stock setup is great. This mod is more about OCD about fake scoops and wanting to mod for the sake of modding. I don't have the luxury of playing with LSx cars or Chevelles anymore like yore so this truck is scratching the itch.

As far as air packing, keep in mind the engine is a large vacuum pump and will suck in what it needs regardless of low pressure zones...etc. Stock airflow and IATs are more than adequate. However, I am excessive by nature. My truck is on ZR2 suspension and 37s to haul sailboat fuel.

newdude · April 15

19 hours ago, Epsilon Plus said:

I'm ready to dig into this a bit further and get as much info sorted out as we can. Most people end up just putting a light bar in the scoop on the gas trucks. In the spirit of OCD and hating non-functional scoops since way way back, I'd like to take a crack at solving this puzzle. So far from what I've gathered, L8T and L5P use the same physical hood PN. The air inlet area around the top of the radiator looks the same and feeds both filter boxes by the passenger side headlight area. It "looks" like the only real difference is the hood insulator, some type of plastic plenum that directs air into the top of the L5P box that sits between the hood and insulator, an open scoop PN and some bits and bobs. This looks very moddable. I'm not aware that L5P uses any type of electric actuators or mechanical modulation to shut off flow during moisture events and may just rely on mechanical drainage (holes). Part numbers found so far (for 20-23):

2020-2023:

L5P hood insulator: 84182769

L5P hood vent (custom/WT), black: 84520315

(midnight/carhardtt/Z71 plus), black: 84589745

(LT/LTZ/High Country), chrome: 84520314

L5P airbox: 85614333

L5P intermediate intake duct (to box front): 84670713

In hood:

L5P front air intake duct: 84684674

L5P rear air intake duct: 85126004

L5P intake drain hole plug: 84598171

L5P air duct insulator: 84358112

L5P air intake duct cover (needed?): 84496061

10 minutes ago, Epsilon Plus said:

I'm going to start ordering some parts and take a blind shot. The lower intake tube is brutal with shipping and would be nice to buy on parts.gm and shipped free to dealer but is out of stock. Intermediate tube from near headlight to front of box shows same for L8T so removing that from list. Lower tube on parts.gm also shows that it may come with the drain plug already attached so I may hold off on that. Part 5 is listed as the duct insulator but parts.gm shows it coming two piece and one of them looks like part 6. Also they look on the diagram to be part 9 and 10, so order two?

I'll need help identifying parts 2 and 14. Parts 4, 8, and 13 are bolts but would be nice to get the exact PN. 3 is likely retainer 11611677, and looks like maybe need (9).

Looks like your list is correct for the L5P bits. You can get rid of 84598171 the drain as it comes part of 85126004 main duct.

11570173 bolt x8, 11570015 retainer x8, 11611677 push retainer (shows x11 but not sure if you need all 11?). As for the hood vent, there is a chrome L8T one that is for the cleaner kit that never got released yet, 84528765. Should be orderable.

Looking at the two main tubes, they are the same #s that were part of the kit. The kit does have its own cold air box but can't get it.

For documenting purposes, my source has 87826828 as the factory cleaner kit. It had its own cold air box and high flow filter. GMC kit was 87826829. Neither of these exists at the moment asides from on paper/online. The numbers show up on all sorts of GM dealer parts websites but you CANNOT order them for those who are attempting to try it who come across this.

Edited April 15 by newdude

Pryme · April 15

14 minutes ago, 64BAwagon said:

The 2024 L8T air intake setup is light years ahead of anything GM has previously produced on a gas truck. Before I got my SG3 I had wondered how efficient the gas intake system was. During my 4k trip I monitored air intake temp regularly. City and highway both towing and non towing and found the IAT to be within 1 degree of ambient temp in all situations. To me that indicates air intake efficiency I have never seen before in a stock setup. After seeing this I abandoned any thoughts of working on improvements. As a comparison. My 2005 LLY Dmax when stock and no mods always showed at least 20 degrees higher than ambient at highway speeds, in traffic sometimes 30-50 degrees higher. After modifying the airbox and adding a ducting kit for more outside air I was able to improve it but never got it anywhere near the numbers on this gas intake.

I believe that trying to use the diesel setup on the hood scoop could end up disrupting the gas airflow and might actually pack air where you dont want it on the gasser. I admit I had the same thoughts on making that intake on the hood operative but after spitballing it in my head I didnt think I could get any positive results from it.

I think the only reason that trim piece exists on the gas trucks is because GM needed something to occupy that space on the non diesel applications. Rather than create two hood designs they used the same piece blocked off.

The 20-23 trucks show the same temp as ambient also. I was displaying IAT for awhile but it was always the same as ambient so I ditched that gauge.

64BAwagon · April 15

My concern for the air was that it may disrupt the flow of the hot air and put it in places you dont want.

OCD should actually be called CDO, that would make it more alphabetically correct.

Epsilon Plus · April 15

39 minutes ago, newdude said:

Looks like your list is correct for the L5P bits. You can get rid of 84598171 the drain as it comes part of 85126004 main duct.

11570173 bolt x8, 11570015 retainer x8, 11611677 push retainer (shows x11 but not sure if you need all 11?). As for the hood vent, there is a chrome L8T one that is for the cleaner kit that never got released yet, 84528765. Should be orderable.

Looking at the two main tubes, they are the same #s that were part of the kit. The kit does have its own cold air box but can't get it.

For documenting purposes, my source has 87826828 as the factory cleaner kit. It had its own cold air box and high flow filter. GMC kit was 87826829. Neither of these exists at the moment asides from on paper/online. The numbers show up on all sorts of GM dealer parts websites but you CANNOT order them for those who are attempting to try it who come across this.

This is gold. Thanks. Can you confirm how many insulators (look to be spacers for duct to hood) are used or if they come with the lower duct?

newdude · April 15

1 hour ago, Epsilon Plus said:

This is gold. Thanks. Can you confirm how many insulators (look to be spacers for duct to hood) are used or if they come with the lower duct?

Insulators come on both ducts. Looks like 8 total. 84358112.

Epsilon Plus · April 15

9 hours ago, newdude said:

As for the hood vent, there is a chrome L8T one that is for the cleaner kit that never got released yet, 84528765. Should be orderable.

I wonder what's different between the one quoted and the chrome diesel one? The diesel one (84520314) is almost $47 cheaper.

I remember waiting in limbo for the ZR2 knuckles to come back in stock. Looks like the same thing will be happening with the upper and lower duct.

Edited April 15 by Epsilon Plus