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

Epsilon Plus · June 12

Horsepower is always there if you can free up air in/out. Will this add anything to a stock truck? Maybe ~5rwhp under the right conditions. When it would absolutely become a great supporting mod is after adding full exhaust and a tune, or especially with a cam/heads....etc. The stock L8T setup already gets great ambient intake air temperatures (which is crucial for max timing/power in modern ECU controlled engines). This mod will just insure that it continues to under more conditions and again, become a supporting mod for other added power items. An LT2 cam, ported intake/TB, 2" headers with true duals, or just a good ol fashioned blower.... all that stuff isn't off the table and might some day be in the cards. This intake will compliment stuff like that nicely.

I set out to buy and build the best possible truck I could to be my last truck I'll need. Getting rid of the fake vent for a true factory cold air intake system for under $700 fits that mold nicely.

The last piece (front intake tube) finally got through processing and is being shipped out. Full parts list and all that jazz soon to come.

Edited June 13 by Epsilon Plus

Epsilon Plus · June 26

Air box lid is going to need some wizardry. The plastic tray thingy on the battery needs to be shaved or the battery moved back towards the firewall 1/4" (might be able to loosen mounts and shift it). Diesel must have either a narrower battery or different top tray. Larger issue is the front of the lid interference with the front transmission cooling line. Diesel likely has a different entry point or something. A Dremel to the outter casting webs of the lid may take care of it or else something more drastic is needed. Unfortunately, I'm very limited on time to play with it right now and it's also the middle of Arizona summer so I'm going to shelve this for awhile. Maybe an S&B box might fit better there but at those prices I'm not going to be the guinea pig just yet. Everything else dropped right in. Only the lid and it's aggressive casting material webbing is the road block now.

trackboss · June 27

If anyone is interested I replaced the chrome one on my 2022 duramax with a black one for personal preference. It is in like new condition. Maybe 500 miles on it before I swapped it out.

What you see is what you get.

$65 shipped

Epsilon Plus · June 27

Top down shot of the straw that broke the camels back on this mod.

From pics online, diesel doesn't have a cooling pipe in that spot. Unless the S&B or Banks is somehow smaller or misses that area (doesn't look like it from pictures), this mod is officially dead. Can't move the box back because of the battery and needing to line up with the hood. Unfortunately, even with all that massive room under the hood, this particular space is tighter than a frog's ass.

Sometimes you win, sometimes you lose. RIP L8T hood mod.

gemarsh · June 28

2 hours ago, Epsilon Plus said:

Top down shot of the straw that broke the camels back on this mod.

From pics online, diesel doesn't have a cooling pipe in that spot. Unless the S&B or Banks is somehow smaller or misses that area (doesn't look like it from pictures), this mod is officially dead. Can't move the box back because of the battery and needing to line up with the hood. Unfortunately, even with all that massive room under the hood, this particular space is tighter than a frog's ass.

Sometimes you win, sometimes you lose. RIP L8T hood mod.

Don't buy the S&B for testing, it won't fit. I can go out and take a picture if'n you like.

Epsilon Plus · June 28

The S&B and Banks both look bigger than stock so not surprised. Thanks though.

I'll probably try modding the top of the lid and playing with some plastic moulding/welding since I'm stubborn and like to tinker. Unfortunately, even if I get it to work it won't be a plug and play drop in mod for everyone else like I was hoping it was. My buddy has a 3D printer......hmmmm lol

kevin74 · June 28

4 minutes ago, Epsilon Plus said:

The S&B and Banks both look bigger than stock so not surprised. Thanks though.

I'll probably try modding the top of the lid and playing with some plastic moulding/welding since I'm stubborn and like to tinker. Unfortunately, even if I get it to work it won't be a plug and play drop in mod for everyone else like I was hoping it was. My buddy has a 3D printer......hmmmm lol

Just throwing this out there - we have local O'Reiiley's auto parts that can build/make steel hydraulic lines. I wonder if it would be easier/cheaper to see if you can have a different shaped coolant line made? Just spitballing ideas, not sure if this would work or not

Epsilon Plus · June 28

3 hours ago, kevin74 said:

Just throwing this out there - we have local O'Reiiley's auto parts that can build/make steel hydraulic lines. I wonder if it would be easier/cheaper to see if you can have a different shaped coolant line made? Just spitballing ideas, not sure if this would work or not

I thought about doing a 90° AN fitting and a braided line.

Turns out, I think that's an engine oil cooler line.

Edited June 28 by Epsilon Plus

SKEETER1978 · July 11

On 6/27/2024 at 8:14 PM, gemarsh said:

Don't buy the S&B for testing, it won't fit. I can go out and take a picture if'n you like.

I had that thought...to take the box from the diesel sb intake...i have the gas one and is very close to oil and trans lines

Edited July 11 by SKEETER1978

SKEETER1978 · July 11

What might work is making/3d printing a custom lid for the sb filter gas intake to attach to scoop intake

Epsilon Plus · July 17

On 7/11/2024 at 1:48 PM, SKEETER1978 said:

What might work is making/3d printing a custom lid for the sb filter gas intake to attach to scoop intake

I have also thought about cutting the hood inlet pieces off the diesel box and bonding them to the gas box.

Even if the S&B diesel box fit, it has a hard duct to the throttle body that is in a different position than the L8T. The stock setup uses a flexible bellows that attaches right at the lid and makes the swap easy. However, if the box did fit making a custom TB connection and eliminating the Hemholtz resonator would probably be easier than dealing with the oil line.

My buddy has a 3D printer but I dunno the first thing about them or how technical it would be to recreate the lid with a lower frontal area.

Edited July 17 by Epsilon Plus

Epsilon Plus · September 29

There's a small chance the Banks would work. It looks like it dives down right where the oil line would be. I'd need a closer picture, especially from a horizontal angle if anyone has one. If the point of that box sits lower than where the line would be, we could have an option. Additionally, the Banks would be easer to adapt to the L8T throttle body since it has a short fixed pipe and goes right to flexible bellows. Would be a decent mod to have that box and get rid of the stock Helmholtz resonator in the process.

Epsilon Plus · September 29

Looks promising......

revrnd · October 2

A commentt after someone mentioned the duct work being more of a ram air set up than a cold air intake. With the diesel having a turbo, wouldn't that negate any ram air effect? Ram air might be more effective on a naturally aspirated gasser.

On the GMT400, I remember the air cleaner being connected via duct work to the RH side inner fender panel to draw air from outside.

Also about separate diesel and gasser hoods, the two models of K2XX trucks had specific hoods...

Epsilon Plus · October 6

True "ram air" would require jet engine velocities. Automobile engines are large vacuum pumps. They will draw in what they need from wherever you put the inlet. The only purpose for external (outside the engine bay) feeding is for lowering air intake temperatures which for this platform is negligible since stock is so good. The functional hood on the Duramax is mostly a marketing gimmick mixed with another way to increase air volume without redesigning the cowl and tight front air box area. L8T gas won't benefit from this mod unless it's got a blower on it or pushing over 600HP IMO.