Real cold air intake thoughts and discussion

[gmduramax]

So im going to make a new intake for my truck but I have questions hopefully someone has the answers lol.

Im running a S480 ball bearing double batmowheel with a 87 turbine. I know one air filter isnt enough so I was either going to run two filters or have a custom filter made. I have seen countless trucks pick up 50+hp from pulling the air filter on the dyno and my flexible tubing shrinks from vacuum while spooling my turbo so im sure I have a huge restriction. I currently have AFE's sealed box with their biggest air filter they claim flows 1000cfm. I seen Banks is using two air filters on his L5P video and probably for good reason. IIRC his filters flow 1000cfm also.

What im really curious of is tubing size, I believe the longer run of tube you need to increase size correct? I have a 5" 90 coming off the turbo that is somewhat kinked that goes into 5" flexible tubing. So how can I calculate the actual tubing size I would need. Would I be ok with a 4" 90 right at the turbo so it has a smoother transition then have that step up immediately to 5" going into the filter, but is that enough?

 

[moparkxracer]

Get a hold of S&B they can make you a custom filter any size you need.

 

[Bdsankey]

Honestly, the Power Driven Diesel filters will support that. I had very minimal drops across their filter (running a pressure gauge in the intake to monitor vacuum in the intake pre turbo) with my Forced Inductions S480/96/1.10 that did ~1300hp+ in Colorado. Their "Dust Bowl" filter had a slightly higher drop than their race filter (which is expected) but after blacking out the dyno room the filter had stopped all soot. If you watch the DPC 2019 economy test you'll understand what I mean. I think the highest drop in pressure I saw was ~1.6psig.

Personally I wouldn't go any smaller than 5" on the intake. You will want the interior walls of the intake pipe to be as smooth/fluid as possible to help promote laminar flow to the compressor cover. I don't know what your flexible tubing looks like but if the interior walls are not 100% smooth (I'm picturing like exhaust flex pipe) then I would ditch it and make a new one or buy one from SPD/WCFab.

 

[Chevy1925]

the smoother the transition into the turbo, the less turbulent air you will get coming to the blades, i dont see dropping to a smooth transition to the turbo inlet being an issue. The tube size wont be the restriction although the smoother the radius, the better the air flow will be to the turbo. a straight piece of 5" will flow 14000cfm based on a few calcs on the net so the air filter will be the issue either way.

put a screen style filter on the end and call it good. you dont daily that rig anyhow!

 

[gmduramax]

Honestly, the Power Driven Diesel filters will support that. I had very minimal drops across their filter (running a pressure gauge in the intake to monitor vacuum in the intake pre turbo) with my Forced Inductions S480/96/1.10 that did ~1300hp+ in Colorado. Their "Dust Bowl" filter had a slightly higher drop than their race filter (which is expected) but after blacking out the dyno room the filter had stopped all soot. If you watch the DPC 2019 economy test you'll understand what I mean. I think the highest drop in pressure I saw was ~1.6psig.

Personally I wouldn't go any smaller than 5" on the intake. You will want the interior walls of the intake pipe to be as smooth/fluid as possible to help promote laminar flow to the compressor cover. I don't know what your flexible tubing looks like but if the interior walls are not 100% smooth (I'm picturing like exhaust flex pipe) then I would ditch it and make a new one or buy one from SPD/WCFab.

I will have to give that filter a try. And I do plan on remaking off all my intake I was just using the flexible stuff for testing. Only thing is right at the turbo the 5” 90° is kinked sort of and airflow is definitely turbulent so I’m not sure if making that in 4” would be more beneficial

 

[gmduramax]

the smoother the transition into the turbo, the less turbulent air you will get coming to the blades, i dont see dropping to a smooth transition to the turbo inlet being an issue. The tube size wont be the restriction although the smoother the radius, the better the air flow will be to the turbo. a straight piece of 5" will flow 14000cfm based on a few calcs on the net so the air filter will be the issue either way.

put a screen style filter on the end and call it good. you dont daily that rig anyhow!

it is a daily

 

[Bdsankey]

I will have to give that filter a try. And I do plan on remaking off all my intake I was just using the flexible stuff for testing. Only thing is right at the turbo the 5” 90° is kinked sort of and airflow is definitely turbulent so I’m not sure if making that in 4” would be more beneficial

Could you snap a pic of what you're working with for space? I've seen guys use something like the link below on tight applications for intakes (buddy did his out of stainless for that reason, only thing he could find in tight radius to clear a y-bridge).

Amazon.com: 5" OD 90 Degree Tight Radius 304SS Mandrel Bend Pipe Tubing Tube Stainless Elbow : Industrial & Scientific

Buy 5" OD 90 Degree Tight Radius 304SS Mandrel Bend Pipe Tubing Tube Stainless Elbow: Pipe Fittings - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[gmduramax]

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[Chevy1925]

it is a daily

Where did black beauty go?

go what ever the same size the compressor cover inlet is. if its 5", you may need to do a pie cut/weld style intake 90* but i think you are splitting hairs in comparison to what a true cold air intake that flows enough cfm through the filters can give you.

I would get your filter and setup figured out first, then come back to the 90* if you really want to see if it give any changes.

 

[gmduramax]

Where did black beauty go?

go what ever the same size the compressor cover inlet is. if its 5", you may need to do a pie cut/weld style intake 90* but i think you are splitting hairs in comparison to what a true cold air intake that flows enough cfm through the filters can give you.

I would get your filter and setup figured out first, then come back to the 90* if you really want to see if it give any changes.

black beauty is the daily when the daily is busted
And splitting hairs is what I do lol if I make it I want it to be one and done but I agree the filter is the problem

 

[gmduramax]

Fresh air

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[Chevy1925]

Mmmm. Hmm. Dead sexy

 

[MAXX IT OUT]

Could you snap a pic of what you're working with for space? I've seen guys use something like the link below on tight applications for intakes (buddy did his out of stainless for that reason, only thing he could find in tight radius to clear a y-bridge).

Amazon.com: 5" OD 90 Degree Tight Radius 304SS Mandrel Bend Pipe Tubing Tube Stainless Elbow : Industrial & Scientific

Buy 5" OD 90 Degree Tight Radius 304SS Mandrel Bend Pipe Tubing Tube Stainless Elbow: Pipe Fittings - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

I was thinking about getting this to make a new intake setup, Anyone know where I can get a stainless MAF flange ?

 

[Bdsankey]

I was thinking about getting this to make a new intake setup, Anyone know where I can get a stainless MAF flange ?

PPE 116454021 is mild steel. I haven't seen a billet one but I also haven't looked the hardest.

 

[NC-smokinlmm]

There are kits you can buy to build your own intake, they come with prebent mandrel tubing you cut and weld as you build it. They also come with maf mounting locations etc. Best bet is to search under LS stuff though.

 

[Bdsankey]

There are kits you can buy to build your own intake, they come with prebent mandrel tubing you cut and weld as you build it. They also come with maf mounting locations etc. Best bet is to search under LS stuff though.

Is an LS MAF mounting the same as 01-07 Duramax mounting?

 

[MAXX IT OUT]

I think DHD has mild steel flange, but I everthing else I can find is Aluminum. I might just make mine own flange and save 35 bucks.

 

[MAXX IT OUT]

Doing some rough CAD before I build one out of aluminum. On the drive home, it definitely had cooler intake temp(down a easy 20 degrees) would start to go up when stopped, but went back down when driving vs only get hotter like it used to. Definitely worth the effort, but having to sort out where I will be pulling cold air from since I don't want to suck too much water while driving in a rain storms.

 

[Chevy1925]

cardboard aided design, nice! i plan to make something up for my tracker. the intake gets fed alot of radiator heat from the fan.

 

[gmduramax]

cardboard aided design, nice! i plan to make something up for my tracker. the intake gets fed alot of radiator heat from the fan.

I gotta doThe Limo but I’m lazy