AIS vs 6637
Senior User
Joined: Jun 2010
Posts: 483
Likes: 1
From: Washington
Senior User
Joined: Oct 2009
Posts: 453
Likes: 0
From: Dade City, FL
I got my 6637 from Clay. Why all the hatin' on the drone? I LOVE the thundering boom of several tons of American iron speeding along the asphalt ribbon. Almost drowns out the kids in the back seat. 
Postmaster
Joined: Oct 2004
Posts: 3,767
Likes: 1
I like it running empty daily driving, but 4k miles of actually working the truck (2200-2500 rpms UNDER LOAD) with the family in the cab listening to Psssssssssssssssssssssssssssssssssssssss and buuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu uuuuuuuuuuuuuuuu of the straight pipe bouncing back at you off the front of the 5er gets old.
Elder User
Joined: Sep 2003
Posts: 582
Likes: 0
From: New Baden IL
I also have the AIS with the optional sleeve on my 2002 F350. I have never had the 6637 but many PSD owners do.
I can tell you the AIS is a closed set up that draws the coldest possible air through the driver side grill area filtered by a large Donaldson air filter that can filter around 60,000 miles or so. I have the optional "Sleeve" which also draws additional cold air through the inner driver side fender. With the MBRP exhaust, my truck runs better with better turbo spool and the fuel milage has slighty improved. I am very happy I choose the AIS a few years back, wished I would have done it sooner.
I can tell you the AIS is a closed set up that draws the coldest possible air through the driver side grill area filtered by a large Donaldson air filter that can filter around 60,000 miles or so. I have the optional "Sleeve" which also draws additional cold air through the inner driver side fender. With the MBRP exhaust, my truck runs better with better turbo spool and the fuel milage has slighty improved. I am very happy I choose the AIS a few years back, wished I would have done it sooner.
Last edited by USAF CCM; Sep 22, 2010 at 10:14 AM. Reason: Spelling
Senior User
Joined: Sep 2008
Posts: 113
Likes: 1
From: East of Seattle
Excuse my low post count; I'm mostly a lurker, but this topic of air filters has been on my mind.
Cool air=dense air=more oxygen=better combustion=more power. It's part of why nitrous is so effective.
There's math behind it:
HP Output = +1% HP per 10 degree temperature decrease
-1% HP per 10 degree temperature increase
Example: 330 hp engine at 160° intake temp vs. 349.8 hp at 100° intake temp with cold air box
So I have a hard time believing that an intake that draws hot air from the engine bay is making more power than a closed system that draws in cool air. I'd be really curious to see the before and after dyno results of just an open intake mod, with the hood shut for the dyno runs.
These open intakes remind me of what the kids (including myself) did with their Honda Civics 15 years ago. Replace the well engineered but boring stock intake box with a large K&N open filter, have aggressive looks, get lots of intake noise, lots of SOTP power, but nothing (maybe even a loss) on the dyno.
Just my opinion, having BTDT.
Cool air=dense air=more oxygen=better combustion=more power. It's part of why nitrous is so effective.
There's math behind it:
HP Output = +1% HP per 10 degree temperature decrease
-1% HP per 10 degree temperature increase
Example: 330 hp engine at 160° intake temp vs. 349.8 hp at 100° intake temp with cold air box
So I have a hard time believing that an intake that draws hot air from the engine bay is making more power than a closed system that draws in cool air. I'd be really curious to see the before and after dyno results of just an open intake mod, with the hood shut for the dyno runs.
These open intakes remind me of what the kids (including myself) did with their Honda Civics 15 years ago. Replace the well engineered but boring stock intake box with a large K&N open filter, have aggressive looks, get lots of intake noise, lots of SOTP power, but nothing (maybe even a loss) on the dyno.
Just my opinion, having BTDT.
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Postmaster
Joined: Oct 2004
Posts: 3,767
Likes: 1
Excuse my low post count; I'm mostly a lurker, but this topic of air filters has been on my mind.
Cool air=dense air=more oxygen=better combustion=more power. It's part of why nitrous is so effective.
There's math behind it:
HP Output = +1% HP per 10 degree temperature decrease
-1% HP per 10 degree temperature increase
Example: 330 hp engine at 160° intake temp vs. 349.8 hp at 100° intake temp with cold air box
So I have a hard time believing that an intake that draws hot air from the engine bay is making more power than a closed system that draws in cool air. I'd be really curious to see the before and after dyno results of just an open intake mod, with the hood shut for the dyno runs.
These open intakes remind me of what the kids (including myself) did with their Honda Civics 15 years ago. Replace the well engineered but boring stock intake box with a large K&N open filter, have aggressive looks, get lots of intake noise, lots of SOTP power, but nothing (maybe even a loss) on the dyno.
Just my opinion, having BTDT.
Cool air=dense air=more oxygen=better combustion=more power. It's part of why nitrous is so effective.
There's math behind it:
HP Output = +1% HP per 10 degree temperature decrease
-1% HP per 10 degree temperature increase
Example: 330 hp engine at 160° intake temp vs. 349.8 hp at 100° intake temp with cold air box
So I have a hard time believing that an intake that draws hot air from the engine bay is making more power than a closed system that draws in cool air. I'd be really curious to see the before and after dyno results of just an open intake mod, with the hood shut for the dyno runs.
These open intakes remind me of what the kids (including myself) did with their Honda Civics 15 years ago. Replace the well engineered but boring stock intake box with a large K&N open filter, have aggressive looks, get lots of intake noise, lots of SOTP power, but nothing (maybe even a loss) on the dyno.
Just my opinion, having BTDT.
Hope this helps.
Lead Driver
Joined: Jan 2007
Posts: 6,708
Likes: 5
From: Kiowa CO
Excuse my low post count; I'm mostly a lurker, but this topic of air filters has been on my mind.
Cool air=dense air=more oxygen=better combustion=more power. It's part of why nitrous is so effective.
There's math behind it:
HP Output = +1% HP per 10 degree temperature decrease
-1% HP per 10 degree temperature increase
Example: 330 hp engine at 160° intake temp vs. 349.8 hp at 100° intake temp with cold air box
So I have a hard time believing that an intake that draws hot air from the engine bay is making more power than a closed system that draws in cool air. I'd be really curious to see the before and after dyno results of just an open intake mod, with the hood shut for the dyno runs.
These open intakes remind me of what the kids (including myself) did with their Honda Civics 15 years ago. Replace the well engineered but boring stock intake box with a large K&N open filter, have aggressive looks, get lots of intake noise, lots of SOTP power, but nothing (maybe even a loss) on the dyno.
Just my opinion, having BTDT.
Cool air=dense air=more oxygen=better combustion=more power. It's part of why nitrous is so effective.
There's math behind it:
HP Output = +1% HP per 10 degree temperature decrease
-1% HP per 10 degree temperature increase
Example: 330 hp engine at 160° intake temp vs. 349.8 hp at 100° intake temp with cold air box
So I have a hard time believing that an intake that draws hot air from the engine bay is making more power than a closed system that draws in cool air. I'd be really curious to see the before and after dyno results of just an open intake mod, with the hood shut for the dyno runs.
These open intakes remind me of what the kids (including myself) did with their Honda Civics 15 years ago. Replace the well engineered but boring stock intake box with a large K&N open filter, have aggressive looks, get lots of intake noise, lots of SOTP power, but nothing (maybe even a loss) on the dyno.
Just my opinion, having BTDT.
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
It has been done. The restrictiveness of the intake negates the effect of the temp difference (which BTW is quite negligible except at complete stops). I'm making lots of power with my 6637 under a closed hood, and don't forget that when on a dyno there is no movement allowing for cooler air to the filter. When compared to "cold air intakes" on the dyno, the 6637 came out slightly higher. There were three runs with each filter done and the engine was run at approximately the same temp to avoid heat-soak variables.
I actually have a 6.0L intake which is very similar to the AIS, maybe a little better for flow. I still need to get to installing it to see what the difference is between those two. I would hazard a guess that whatever difference there is, the AIS would be quite similar or may a little down from the 6.0L box. I've just had too much going on in my life at the moment to get it done, but I will get to it more so for my own curiosity, but also to see what the difference is to post here...
I actually have a 6.0L intake which is very similar to the AIS, maybe a little better for flow. I still need to get to installing it to see what the difference is between those two. I would hazard a guess that whatever difference there is, the AIS would be quite similar or may a little down from the 6.0L box. I've just had too much going on in my life at the moment to get it done, but I will get to it more so for my own curiosity, but also to see what the difference is to post here...
Laughing Gas
Joined: Jan 2009
Posts: 911
Likes: 74
From: Montana
I have had both and i like th AIS for the simple fact that its quite but if i had concerns with the restriction. Now i have th 6637 and i think it flows more but could do with out the noise! SOmeone please make a AIS the flows like a 6637. How hard could it be? ha ha ha
Senior User
Joined: Jan 2008
Posts: 339
Likes: 2
From: Upstate NY
I'm also very curious about this. Read all the threads using search but still leaves me wondering. There are so many opinions either way. I think this is one of those things that you won't ever find the right answer online. Unfortunately it's damn expensive to try and come out unhappy 