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Does anyone know what Cummins reccomends for a 4BT as far as CFM for an air filter , I have an air filter connected to a snorkel that is rated for 600 cfm,
Wondering if this is restricting air flow causing high EGTs ?
I viewed the link, and see no flow rating for that filter.
Post the HP/TQ tag info.

Cummins, RPM, HP, CFM, EXH TEMP, EXH FLOW CFM.

4BT................2500 ...... 105......289……. 890 ............. 750
4BT................2500 ...... 120......336……. 970 ............. 922
4BT3.9...........2500 ...... 100......253……. 1000 ........... 684
4BT3.9-G1.....1800 ........ 86......147……. 850 ............. 357
4BT3.9-G2.....1800 ...... 102......157……. 850 ............. 381
4BTA3.9 ........2500 ...... 120......298……. 900 ............. 751
 

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I called the manufacturer, and saw the other websites that posted CFM, so I’m in the clear @ 600 CFM intake since none are even past 400.. thank you .
Remember, those numbers are for stock configuration, any performance modifications will change them...
 
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Remember, those numbers are for stock configuration, any performance modifications will change them...
Dougal has included air filter flow requirements for the various power levels here.
Power Recipes
Beyond that you will need to take into account the total intake systems restrictions as well to keep turbo inlet vacuum within spec, Holset calls for IIRC less then 15"H2o. for me at the 200HP level a snorkel and the ~4' of 4" tubing was possible, at 300HP 12" of 4" right out of the filter box with a filter 2X the size that opened to a scoop in the hood was required to keep it within spec. All the time spent fiddling with this has been worth it, IMO power=efficiency and efficiency=power with the turbo diesel engine and every little thing you can do to increase efficiency has a 2 way pay off.
 

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Discussion Starter · #6 ·
Awesome thanks, I’m mostly stock with 40hp injectors , new injection pump with 3200 gov spring , fuel pin and fuel turned up half a turn , going to be running super HX30W soon, Aftercooled engine , also the inline filter is attached to a snorkel which in my opinion is a true cold air intake , advertises here 600CFM.
I’m maybe pushing 150 hp if that, just trying to rule out simple issues first , might take off the filter and go for a short run and see if that is any effect .
 

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Awesome thanks, I’m mostly stock with 40hp injectors , new injection pump with 3200 gov spring , fuel pin and fuel turned up half a turn , going to be running super HX30W soon, Aftercooled engine , also the inline filter is attached to a snorkel which in my opinion is a true cold air intake , advertises here 600CFM.
I’m maybe pushing 150 hp if that, just trying to rule out simple issues first , might take off the filter and go for a short run and see if that is any effect .
Look at the power recipes thread I think what you described will be 200HP build as long as your charge air cooling is up to the task.
 

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Discussion Starter · #8 ·
Look at the power recipes thread I think what you described will be 200HP build as long as your charge air cooling is up to the task.
Well that’s the issue , I’m running an aftercooler , I don’t have much room to stuff an air to air intercooler so I’m trying to make do with those aftercooler right now .. since I’ve seen other engines non intercooled running more modifications..
 

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Well that’s the issue , I’m running an aftercooler , I don’t have much room to stuff an air to air intercooler so I’m trying to make do with those aftercooler right now .. since I’ve seen other engines non intercooled running more modifications..
The cold air intake will be well worth the time and space it requires in the big picture for sure helping the aftercooler to keep up a dedicated radiator for it would be helpful if space permits, a little gain here and a little gain there will add up.
 
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Dougal recommended that I install a couple Donaldson Informers when I asked about my snorkel/filter setup vs air requirements. May be worth a try if you’d like solid numbers.

On right is after a Donaldson Top Spin and snorkel, on left after a Ford OEM cone filter (brand new).

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Discussion Starter · #11 ·
Dougal recommended that I install a couple Donaldson Informers when I asked about my snorkel/filter setup vs air requirements. May be worth a try if you’d like solid numbers.

On right is after a Donaldson Top Spin and snorkel, on left after a Ford OEM cone filter (brand new).

View attachment 134880
Anymore pics of that setup ? What vehicle is this in ?
 

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Anymore pics of that setup ? What vehicle is this in ?
Yep, project is a 4bd1t in a K30. Link to thread here linked where the discussion of air intakes starts. Dougal and others have helped me immensely. Wouldn’t be where I am without them.

Topspin to imitation ARB snorkel meant for an 80s series land cruiser to Ford filter (I’ve since added a second informer).

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Turbo to IC in front of the radiator.

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What vehicle are you working with?
 

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Awesome thanks, I’m mostly stock with 40hp injectors , new injection pump with 3200 gov spring , fuel pin and fuel turned up half a turn , going to be running super HX30W soon, Aftercooled engine , also the inline filter is attached to a snorkel which in my opinion is a true cold air intake , advertises here 600CFM.
I’m maybe pushing 150 hp if that, just trying to rule out simple issues first , might take off the filter and go for a short run and see if that is any effect .
Good idea, with the filter removal, however, consider sand ect. may enter on your short run...I keep an old pair of pantyhose, to cut sections from, too tape to the open intake, for such runs...
 
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The only way to check the restiction is with the informers or restriction indicators. just pulling the air filter will not really tell you much. Cummins list 25 inches of water as maximum with a dirty air filter. The spec sheet for my 6BT list their dyno as using 10 inches as their reference point. Mine runs between 7 and 10 depending on the right foot.
 

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With a Super 30 turbo you can get close to 250 HP but don't know if the aftercooler is up to the task there. If you run a separate radiator and circulating pump for it there may be possibilities. 40 HP on the injectors tells you nothing. Need to know the size of the holes in the tip to judge their power increase. OEM 4bt engines with the VE injection pump came with 4x.012 tips. Those will run out of steam around 225 HP. The most common change is to 5x.012 which is what the 250 HP 4bt marine engine used. Those can go well over 300 HP. The main issue becomes air and although you might get to that level with a single turbo, the power curve will be mostly on the top end. Twins cure that issue.
 

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Discussion Starter · #18 ·
So where would I find an Inline air filter that will work with my snorkel setup?
also I was about to order the super 30 turbo, but now I’m worried if the aftercooler could handle it, I would rather keep it because I’m not sure where I could fit an intercooler , honestly all I want is to be able to climb grades / cruise @75 without having to back off the throttle for high EGTs, I don’t need not want a ton of power ,simply reliability and a cool running motor . my Land Cruiser is tall and weighs 7k lbs . But I know bread vans handled the giant bricks well.
 

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I have a ford cone filter housing that has been modified to 4" inlet/outlet from my old snorkel I'll part with PM me if interested.

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