*also posted on cumminsforum.comHow is the BHAF affected by driving in heavy rain? Is there a possibility that it would get wet from the water going up through the wheel well past the shock tower? If it gets wet will it ruin the paper element? I don't run a heat shield, but do they help keep the water out of the filter? Thanks!

Typically they don't get wet under the hood... But if it does you'll know because the filter minder will be drawn down to the RED zone limit... As for my filter its 6 years old (120K miles) and I gotten it wet several different times without a problem. The secret is if you do get it really wet (during washing the engine bay) to allow it time to dry before starting the truck. But as for typical daily driving in heavy rains... Naw... It just fine...

For the most part, any water that may be splashed under the hood just rolls off of the Outerware prefilter cover. If you encounter enough water to soak the Outerware prefilter, you already have MUCH bigger problems than a wet air filter.........like water injection to the engine which NO filter of any kind will protect you from unless you install a snorkle kit or some sort.

My filter ends up soaked all the time, but mainly because I have a bad habit of hitting every pool of water I see. The ditch floods and goes across the road when it rains a lot and theres usually 40ft of at least 6" deep water that I always fly through and give my truck a power washing. I never thought about it much, didn't see why a wet filter would be a problem, engine will dry it out eventually. As I think about it however, a wet filter would expand in my mind, making the filtration pores bigger, therefore allowing in bigger particles. Not sure on that though, might expand but maybe it squeezes all the media together, making the pores smaller. In any case, keeping it dry would definitely be the best route. I do think it is hard to get wet if you drive it right (not flying through floods). I think the "cold air" kits do put a plate between the battery/filter and the engine/filter, which would seem to keep most of the water out, if not all, but like I said, it is hard to get it wet if your not trying to.

Thanks guys, I'll probably make the heat shield just for a little added splash protection.Out of curiosity, does anyone have a picture of a BHAF that's worn out or too dirty?

Mike once said to me after showing him my black (stock media is white) filter: Color doesn't count... What counts is how much vacuum (water column) its creating... Mine is road dirt grey and still not creating any vacuum yet... I just check the old filter minder... Said that here, also has pics so you can see everything. http://forum.mopar1973man.com/showthread.php/1682-BHAF-32-Prefilter-is-45-Where-can-I-get-prefilter-cheap-please?highlight=BHAF

huh. never thought to put the filter minder on. do you just drill a hole for it?

Pull the filter minder and grommet out of the stock box... Measure the hole for the stock box and re-drill a hole in the end on fthe BHAF. Install the grommet and the filter minder... Current condition after 6 years and 120K miles... http://forum.mopar1973man.com/attachment.php?attachmentid=923

I been building heat sheilds for all the trucks around here. 01-02's I will try to post pics tomorrow.

I been building heat sheilds for all the trucks around here. 01-02's I will try to post pics tomorrow.

Please do... I might be interested in one... Might kind of looks beat up...

I'm still not sold on the BHAF idea, how is hot air good? I realize you can get more air, but less cold air is better than more hot air. If your stock, or CAI setup doesn't pull down a filter minder than your not going to see a gain from a BHAF, you will actually probably see a loss of hp, or a rise in EGT's. Every 1* rise in IAT means a 1.5* rise in EGT's. :shrug:

I'm still not sold on the BHAF idea, how is hot air good? I realize you can get more air, but less cold air is better than more hot air. If your stock, or CAI setup doesn't pull down a filter minder than your not going to see a gain from a BHAF, you will actually probably see a loss of hp, or a rise in EGT's. Every 1* rise in IAT means a 1.5* rise in EGT's. :shrug:

my box could not keep a filter seated. after it was snaped the filter would not seal and would always colapse the filter. there has only been once that the BHAF wasn't seated, when i took it off(for work) and had a friend put it back on. plus most people realize i'm not playing when they see a CAT filter under the hood. if mileage is effected by the IAT sensor like some people believe, then you would see would see increases with warmer air and low boost.

I think Cummins rates their enignes at 85*F, and you lose 1% power for every 10* rise.. (going to have to find that reference).. So colder is better.It still takes x amount of fuel to make 100hp to do 65. If you have warmer air it will take more boost to get the same air to cleanly burn x amount of fuel... Luckily air:fuel ratio's aren't fixed in diesel so a fudge factor can be in play to still get clean burning.. so a mileage increase might occur.As far as my opinion of warmer air for better mileage is the same theory as why winter mileage sucks. Warm air makes everything better, less air resistance on the truck, warmer tires roll easier, warmer drivetrains have less resistance, I think all of that is the bulk of the reason warmer air nets better mileage, same thing in winter I think the cold effects on those items far outweighs a minor change in BTU's of #1 or treated #2.

From cummins:Maximum allowable air temperature rise over ambient at intake manifold 16.7 C [30 ºF]Intake Manifold Air Temperature Warning Limit 74ºC [165ºF]Intake Manifold Air Temperature Shutdown limit 76.7ºC [170ºF]Diesel engines are best suited for air temperatures between 60 and 90°F [15 and 32°C]. Engines can withstand temperatures below or above this range, but their efficiency drops.Intake Air That Is Too HotEngine horsepower fails about 1% for each 10 degrees of intake air temperature rise above 90°F [32°C].An engine rated at 250 horsepower will develop only 240 horsepower when the intake air temperature is 130°F [54°C] with the same fuel delivery.Air That Is Too ColdCummins Diesels are rated on the basis of intake air at 85°F [29°C] temperature, but in most localities engines operate part of the time at temperatures of freezing or below. A drop of 60 degrees in intake air temperature results in a 160-degree drop in compression temperature.

From cummins: Maximum allowable air temperature rise over ambient at intake manifold 16.7 C [30 ºF] Intake Manifold Air Temperature Warning Limit 74ºC [165ºF] Intake Manifold Air Temperature Shutdown limit 76.7ºC [170ºF] Diesel engines are best suited for air temperatures between 60 and 90°F [15 and 32°C]. Engines can withstand temperatures below or above this range, but their efficiency drops. Intake Air That Is Too Hot Engine horsepower fails about 1% for each 10 degrees of intake air temperature rise above 90°F [32°C]. An engine rated at 250 horsepower will develop only 240 horsepower when the intake air temperature is 130°F [54°C] with the same fuel delivery. Air That Is Too Cold Cummins Diesels are rated on the basis of intake air at 85°F [29°C] temperature, but in most localities engines operate part of the time at temperatures of freezing or below. A drop of 60 degrees in intake air temperature results in a 160-degree drop in compression temperature.

I would guess that most of that pertains to any Cummins engine. I do think that the 30* rise over ambient applies to any Dodge engines. Look at the IAT numbers the Mike posts, and look at what I see, and I run cooler than stock on IAT's. I also don't think there is a shutdown limit on our engines, but ??

But now looking at ISX post...

Diesel engines are best suited for air temperatures between 60 and 90°F [15 and 32°C]. Engines can withstand temperatures below or above this range, but their efficiency drops.

So I would have to drive around in 25-50*F weather for optmial temp of IAT... I hate to sat it but that is the worse temp I take a nasty hit to MPG's and drops down to about 16-17 MPG...

Intake Manifold Air Temperature Warning Limit 74ºC [165ºF] Intake Manifold Air Temperature Shutdown limit 76.7ºC [170ºF]

Well you better not look at my IAT reading on a hot summer day when I fire up... I've seen 170-190*F in the manifold from heat soak easy... Never shuts down...

An engine rated at 250 horsepower will develop only 240 horsepower when the intake air temperature is 130°F [54°C] with the same fuel delivery.

Very true because the air is less dense and requires less fuel so in turn creates less HP... But now from a cruising stand point it does much better on MPG's...

I believe the 60-90F part was for ambient air temp.. If the IAT is 30F higher then it would be 30F, and the grids are running just to keep the engine happy at that temp, so I am almost certain that, that part meant ambient air. They skipped around a lot on quickserve :ahhh:Not sure on the IAT shutdown temps being for our CTD. All that info was just in a huge service bulletin on cummins quickserve that was pretty general. I figure most of it pertains to all diesels. I did see some other things about 200F IAT limit or something if I looked hard enough.

If so.. 60*F (100*F IAT) to 90*F (130*F IAT) outside temp would be right on the mark for me then... Now 200*F I heard of a few big boys with twins seeing close to 200*F worth of IAT at like 60-70 PSI of boost... Yikes!

If so.. 60*F (100*F IAT) to 90*F (130*F IAT) outside temp would be right on the mark for me then... Now 200*F I heard of a few big boys with twins seeing close to 200*F worth of IAT at like 60-70 PSI of boost... Yikes!

Based on the verbage I took that as the temp at the intake manifold. It's still amazing to me how much hotter your IAT's are than mine. On a 90* day driving 65 with the ac on my IAT's are about 100-102*. I wonder why yours are so hot, did you have the SG before your BHAF?

Based on the verbage I took that as the temp at the intake manifold. It's still amazing to me how much hotter your IAT's are than mine. On a 90* day driving 65 with the ac on my IAT's are about 100-102*. I wonder why yours are so hot, did you have the SG before your BHAF?

Simple answer... When you got 190-200*F coolant passage within 6" of the IAT sensor that why... This coolant passage runs the entire length of the manifold on the head. Trust me me IAT and ECT sensor match exactly after sitting cold but after the coolant rises to 120-140*F the offset starts to grow... This why I shake my head to someone that thinks they can make a better cold air intake for a 24V 2nd gen... Hard to do when Cummins is heating the entire manifold with coolant... As for the Stock air box and the BHAF the IAT temp are exactly the same it doesn't change it one bit... Always a +40*F over outside temp difference...

Simple answer... [ATTACH=CONFIG]1270[/ATTACH] When you got 190-200*F coolant passage within 6" of the IAT sensor that why... This coolant passage runs the entire length of the manifold on the head. Trust me me IAT and ECT sensor match exactly after sitting cold but after the coolant rises to 120-104*F the offset starts to grow...

But thats not really any different than the 3rd gen, other than the MAP sensor gives the IAT temp, and the IAT sensor is in the pre-turbo pipe (but not used for IAT :banghead:) It still seems that all of the airflow thru the intake manifold (don't really think there is much difference in the intake manifolds from 1st thru 3rd gens) would be fast enough that the head won't heat soak it. Even when I idle the IAT's are only 15-20* above ambient. Now with a good heat soak on a hot day they get to 150-160*, but quickly drop to +30, then slowly to +8-15* depending on a/c, load, speed, etc.. The MAP sensor isn't the intent of this photo, but you can see the MAP sensor in the bottom.. http://www.dieselmanor.com/diy/CMS3-gauge/G3image5.htm