Modified AIS filter vs Donaldson blue "6637"

ruffneck7.3 · Nov 28, 2019

Hello all, I have a stock truck as of right now, but in the next few months, I'm going to do all the performance upgrades, s366sxe, 238/80's, fuel system etc..

I have an AIS intake on my truck, came with the truck, so my question is, would I be almost as good flow wise if I modified the air box for more flow, or would I be better off going with the Donaldson blue air filter? Filtering is important to me, and the AIS is great for that, I work/live in very dusty areas during the summer..

Thanks in advance

Zeb · Nov 28, 2019

It’s hard to beat a Donaldson for flow and filtration.

JCart · Nov 28, 2019

No experience with AIS, back in the day ran 9”by 11” K&N... big mistake, on these forced induction engines, with big displacement it (K&N) wouldn’t filter out all the dust. Donaldson paper sure does though, been running them for years now. Always in the habit of wiping out the intake with a clean white cloth just to see, never even a spot of dust. Change every 2nd oil change.

Outlaw Bill · Nov 29, 2019

Yes many open up the end of the airbox into the oval inner fender hole and use some sort of sealing material.

ruffneck7.3 · Nov 29, 2019

Thanks for the replies, I haven't seen anyone use the AIS with a bunch of upgrades, I know it's a good filter, I just know I'm leaving some on the table is all

Barnbuilder · Dec 1, 2019

Outlaw Bill said:
Yes many open up the end of the airbox into the oval inner fender hole and use some sort of sealing material.

People were using a beer koozie as a way to seal the opening from the box to the fender. Hence the name Koozie mod.

I need to replace my AIS filter and trying to decide to just replace it or gut all of it and throw in the Donaldson filter also. Tired of spending money on this thing.

ruffneck7.3 · Dec 3, 2019

I hear ya there buddy, I need to replace mine also, but it's also been a few years since I've had to, which is nice.. I might go with the Donaldson, but I'm going to do a nice mount and partial enclosure for it.. I know I'll need more flow after the turbo and Injectors, so i might just keep this setup if i ever get another truck that's mostly stock or something.. that's the way I'm leaning right meow

BS Hauler · Dec 5, 2019

I am running the 6637 filter. The problem with it is your intake temperature will go thru the roof pulling hard going down the road. That kills horsepower. Never draw under hood air.

sootie · Dec 5, 2019

BS Hauler said:
I am running the 6637 filter. The problem with it is your intake temperature will go thru the roof pulling hard going down the road. That kills horsepower. Never draw under hood air.

Intake air temp means absolutely nothing on these trucks. Monitor charge air temp and it won't be a spec different.

PSD POWER007 · Dec 6, 2019

sootie said:
Intake air temp means absolutely nothing on these trucks. Monitor charge air temp and it won't be a spec different.

Heck, on my 7.3 and 6.0 running the Donaldson blue and the No Limit intakes, both open air obviously, my intake air temps are within a few degrees of ambient temps towing or not while the truck is at highway speeds. And my IAT drops fairly quick in stop and go traffic when the truck starts moving. And like you said, it’s an absolute needless worry...

mandkole · Dec 6, 2019

Anyone have a quick PN for a 5” intake, Donaldson/6637 style? I’ve always used the blue AFE and just gets ineffective after even 5k miles. May have to use their same shape paper filter.

lincolnlocker · Dec 7, 2019

Zeb said:
It’s hard to beat a Donaldson for flow and filtration.

True dat!

sootie said:
Intake air temp means absolutely nothing on these trucks. Monitor charge air temp and it won't be a spec different.

Yep. Exactly!! That was always an argument untill someone actually monitored it.

mandkole said:
Anyone have a quick PN for a 5” intake, Donaldson/6637 style? I’ve always used the blue AFE and just gets ineffective after even 5k miles. May have to use their same shape paper filter.

Nope. They don't make a 5 inch intake version. Just neck it down to 4 inch and use the Donaldson equivalent to the napa 2790.

That is what i have on my 6.7 and my last 6.7 and it is smoke free so airflow isnt hindered much. Never take it off the extreme settings. Even when towing.

live life full throttle

lincolnlocker · Dec 7, 2019

You will have to move chit or dent the 2790 size to fit though. Its bigger.

live life full throttle

SunStroke · Dec 22, 2019

It’s hard to beat the AIS for flow and filtration. Dynoed 528 with AIS and modified air box. It’s quiet and looks stock. Nothing filters better. Lasts 60k miles. The air box does need work.

fastersteve · Dec 23, 2019

What did you do to the box besides the fender sleeve mod?

SunStroke · Dec 24, 2019

The AIS filter flows really well. That filter design will handle 600+ HP with the 6.0.. The 6.0 filter housing is positioned for inline straight thru flow.. The 7.3 AIS housing is small about the size of the filter. Air enters from the side and has to turn and enter the filter from underneath. There just isn’t any room inside the box.. The only way to provide sufficient air flow is to drill out the bottom of the air box..I probably have 6 - 2” holes and some 1 1/2”.. Wide open max boost (45-48 lbs) it will draw 11 inches of H20 filter restriction. That’s nothing, commercial diesels go 25-30 inches before filter changes.. I just like the stock appearance, excellent filtration, low noise and I didn't have to buy something else