2nd Gen Non-Engine/Transmission BHAF Holy shwoooosh..........

[litespeed]

I just replaced my swiss cheesed factory airbox with a NAPA 2790 (Duralite).



I used a 4 1/2" long piece of exhaust pipe in the hole to smooth the airflow past the ribs in the factory elbow. I figured the smoother the flow the the better... . Right? I also left the silencer ring in there..... It looks like it actually straightens the airflow into the turbo inlet.



Wow... ... . Is this thing loud!! :--) Holy cow... ..... It sounds really cool but I cant see leaving it like this.



Does the heat shield mod help to kill the turbo whine?



When I got home today, I poped the hood and the wire on the air filter was so hot I could barely touch it. Which heat shield works best with this thing? The round furnace duct or the cut 90 degree bend? Which one would help suppress the noise better?



Thanks in advance. .



AJ

 

[SHobbs]

You think it's loud now try removing the silencer ring, lol. I have no heat shield and the wire on my filter is never hot, not sure why yours is. My filter is always cool unless it's 100* degrees outside. I have the BHAF without the silencer ring and I like the noise and there are alot of others that do too. As far the noise, well thats what the BHAF does, your engine is breathing better due to a free flowing filter. Only thing that would drop the noise a little that I have heard of is putting the Tag in the inlet of the turbo.



The Tag makes the flow into the turbo more linear I believe and makes the air flow better into the turbo, less turbulence. Have heard it drops the noise level a lttle and helps with turbo spool to some extent.

 

[RustyJC]

On my 2nd gen, the TAG cut probably 70% or more of the turbo whine and whistle under load with the BHAF.



I'm running LarryB's stainless steel heat shield and have been quite pleased with it.



Rusty

 

[litespeed]

Rusty and Hobbs,



What is the TAG?



Is the LarryB's the heat shield that covers the turbo? I think I have actually seen that one on a friends truck... ... Sounds familiar... .



Thanks,



AJ

 

[RustyJC]

TAG = Turbo Air Guide. It's a honeycomb airflow straightener.



LarryB's heat shield mounts on the turbocharger's compressor housing flange and goes around part of the hot end (turbine housing) of the turbocharger. It has plenty of room for airflow behind it, but blocks radiant heat from getting to the BHAF. Quite small, attractive and effective.



Rusty

 

[obert]

Does that filter attach directly to the elbow or does one have to fab an adapter. Ive been thinking about that mod myself.



Does the element last a long time before needing to be changed?

 

[litespeed]

Does that filter attach directly to the elbow or does one have to fab an adapter. Ive been thinking about that mod myself.



Does the element last a long time before needing to be changed?

obert,



You just remove your airbox and the BHAF will fit right onto your existing intake hose. I used a 4 1/2" long piece of 4" diameter tail pipe to slide into the mouth of the air filter. It gives you more clamping ability around the BHAF and straightens the air flow a little.



I dont know the #'s... But it looks like the BHAF has at least 2 times the surface area of the factory filter (maybe more?). Which should translate into longer filter change intervals? But there are a lot of factors involved there.



You can really hear and feel the difference..... Especially if you have 4" or larger aftermarket exhaust!



AJ

 

[RustyJC]

My BHAF (NAPA 2790) attaches directly to the elbow. It's never leaked or come loose. Others may or may not need the adapter others have mentioned.



My BHAF has been on the truck since October 2001, but I don't go off-road and the truck only has 28K miles.



Rusty

 

[WDixon27]

the bhaf clamps to the stock rubber boot that clamps to the airbox, you just swap the airbox for the bhaf, i didn't even see a need to strap it down as i don't have a off road truck, i just pushed it on one of the studs that held the box. i got mine from a link here on the board for $38 delivered but i can't remember the address

Does that filter attach directly to the elbow or does one have to fab an adapter. Ive been thinking about that mod myself.



Does the element last a long time before needing to be changed?

 

[RustyJC]

You can pull the mushroom-shaped inserts from the factory airbox that slip over the fenderwell studs. Turn the inserts over so that the large end is facing up and slip them over the fenderwell studs. The BHAF can then sit on the large end of the inserts.



Watch the back edge (next to the firewall) of the BHAF. Some have reported rubbing the A/C lines with the BHAF. My Jacobs e-brake solenoid keeps the BHAF away from the firewall, but if it's a problem, slip some foam pipe insulation over the A/C lines.



Rusty

 

[Gary - K7GLD]

I guess my hearing must be worse than most - I can't tell any difference in loudness from my previously drilled and K&N'd stock airbox - I'm using the NAPA BHAF...

 

[jeepit]

I like the BHAF also. It sounds so cool when shifting. I was in a parade towing my trailer with a 2005 Jeep Unlimited we are raffling off. I had to put it in low range because I kept catching up to the vehicle in front of me. Friends along the parade route commented how awesome the truck sounded just chirping down the road.

 

[JRagland]

I did what the guys above did. Just hooked the BHAF right up to the rubber intake tube and clamped it down. I had heard of using 4" exhaust pipe to reinforce the BHAF outlet, but its very strong. Mines just sitting there too. No straps or covers.

 

[WDixon27]

i have good hearing and i didn't notice a obnocious increase in sound when i went from stock to bhaf, a little more whistle but that's about it, and when first i did mine i had all of the insulation/padding off the cab floor

I guess my hearing must be worse than most - I can't tell any difference in loudness from my previously drilled and K&N'd stock airbox - I'm using the NAPA BHAF...

 

[obert]

NAPA dosent have the cover for that do they? I think it would be good to keep the big stuff out, and mabey prolong the filters life.

 

[RustyJC]

No, the covers are available at outerwears.com



Rusty

 

[litespeed]

Here are some pics of the pipe mod.....



Not sure if it does any good? I got it clamped on really tight. The long pipe gets gets the air past the ribs in the front of the elbow just before the bend. I can also keep the clamp tight. When I first put it on I noticed the clamp coming loose. It was not coming off..... Just getting loose.



Now it is super tight... .



AJ

 

[Gary - K7GLD]

that pipe looks fine - my NAPA BHAF didn't need any, since the rubber-like material in the filter inlet is extremely tough and hard - makes a good solid connecting point for the hose and clamps, with no signs of loosening.

 

[CFowler]

can anyone honestly say if the napa gold 2790 filter is going to do the job well ( filter the air) and sound good ? i would like to see but really dont want to spend 70. 00 to find out. im using a k& n now it tis a big improvement from the stock filter element , but would love to get more of that sweet whine out of it. thanks carl

 

[litespeed]

can anyone honestly say if the napa gold 2790 filter is going to do the job well ( filter the air) and sound good ? i would like to see but really dont want to spend 70. 00 to find out. im using a k& n now it tis a big improvement from the stock filter element , but would love to get more of that sweet whine out of it. thanks carl

Carl,



If you "want the whine"... ... . This is your answer.



I had the K&N for a very short period. I think it was causing more problems than what it was worth. I went back to the factory filter and drilled about 10 2" holes in my factory airbox. This helped some... . After switching to the BHAF... . I can honestly say that I "can feel the difference". The airbox was choking the engine. Or so it seems. I'm curious to see what the difference would be on a dyno.



It is just sitting in there. It fits real nice... ... . I'm actually amazed. I do plan on building a heat shield. The filter gets hot to touch! And it is not even hot down here yet... .



I took the silencer ring out for a spell... ... . Wow :--) ! Big mistake..... I put it back in. It is lould enough with the silencer ring in. More whoosh than whine with the ring.



I'm not a scientist but if I had to guess... ... I would say the Duralite is superior to K&N. Not to mention it has at least 2 times the surface area to filter with (maybe 3 or 4).



AJ