Alright, I'm looking for advice on this on...

Dad is currently running a K&N filter in the factory box.

After learning a great deal about lubes, filters, (etc, etc...) in the past year, I've became a not-so-great fan of K&N air filters. If you have a high-power application that needs all the flow it can get, then fine, but for street applications, I'll stick with a dry paper filter.

Question is this. Truck is stock ('98 1/2 ISB/Automatic Trans) and spends most of it's time either running around doing errands or hauling a trailer.

Two options:

1. Replace K&N with a Fleetguard AF25541 drop-in panel filter.

2. Go to a BHAF, actually a Fleetguard AH19037.

In regards to this though, how much of a gain is to be realized on a stock truck? Maybe I should be asking how restrictive is the factory box???

Is it absolutely neccessary to install a heat-shield? If so, the BHAF is a no-go for us (NOT MY TRUCK and he doesn't want to go installing shields on it as of now)

Any downsides to a BHAF?

Thanks,

Jelly.

 

I think K&N is getting a bad rap these days. They make a very good air filter and the only reason I dont have one anymore is because I got ride of the stock air box for the aFe Megacannon. The stock air box is restrictive and putting holes in it is (I think) the only way to open it up. But the biggest draw back of the air box is possible leaks letting in debris (with any filter in it). I ran the K&N for 30,000 miles and I never had any oil, dirt, dust, or anything else for that matter in or on my turbo blades.

 

There was a testing company that did tersts on K & N and found the yes it was less restrictive but it was allowing more dirt though on the fine scale (microns...).

K & N also were plugging faster because of the oil that is put on them. At this point they were losing performance!

K & N had less filter media that stock paper filter (measured area) This also leads to plugging faster and loss of performance!

All you got to do is a search on "K & N" filters and do some reading. Don't just read K & N site... Read the others too...!!!!

If you going to race your truck go for it!
But if your going to run the hills in the dirt & mud forget it!

 

I find it kinda funny that after all these years K&N now sucks where as before they were the BEST hands down...and where did all these other aftermarket filter companies get their ingenuity from? Hey, I guess it all boils down to personal preference. Some guys wont run anything other than paper. Do what makes you happy.

 

Few are saying that the K&N sucks.....the reality is that there are much better choices for a diesel.....AFE Proguard 7 is a great choice, IMO.

K&N is somewhat like BANKS....they rave and rave about how good they are.......while there are others that dont have to brag - and are simply superior.

 

jelly: The heat shield is very easily removable- it just replaces the stock airbox and makes room for the BHAF. No holes or any other mods to the actual truck. If you don't like it, remove 3 nuts, pull it out , put stocker back in. Not as like with the scotty where you drill a 4.5" hole. (I love my scotty air2 but a 4.5" hole in a truck is not for the faint of heart )
I think that the BHAF is a very nice filter for the standard application. The oiled filters are getting a bad rap mainly due to the fact that people don't know how to oil them right. Either they leave holes in the oil layer -leads to very bad filtering or they do overil them so the oil gets sucked in- bad for whaterver is directly behind the filter like MAF sensors turbos etc)
My stock airbox was a piece of junk. It had no straight edges in the sealing area, so I had crud on the turbo in stock form. No more since the BHAF, none with the scotty. I won't comment on the K&N in the stock airbox except that the ones I saw had the same sealing problems like my stock air filter due to the warped box. (And that some people aren't able to read the instructions on how to clean and re-oil the filters... but that's the same for all brands of oiled filters)

AlpineRAM

 

First off guys, the K&N filter is NOT BAD...it's a very high quality piece.

BUT, for going down the road in your daily-driver street driven vehicle, it's just not the best choice for filtering.

If you take care of them (no over oiling, etc..) they will function properly and last a long time...but I'll take a paper filter for maximum filtration levels and lower silicon/insoluble levels.

I haven't given the air box on dad's truck a look over yet...are they really that bad at sealing properly?

So, AlpineRAM...is there already a heat shield on the truck? Is the one we're suppose to make up just bigger or something?

Does the Fleetguard AH19037 actually fit right into the factory intake tubing with no sealing issues?

Thanks.

 

If your not modifing the truck for more Hp or running at the rev limiter all day then there is no use in going to a larger air filter. The truck will not gain any Hp by changing to a larger air filter.

JMO.

 

jelly- there's no heat shield in the stock truck. The heat shield is a sheet of aluminium or stainless cut and bent in a way that it replaces the stock airbox.It will be held by the bolts that hold the original airbox. You'll connect the BHAF to the turbo intake. In the FAQ section there is a template for the heat shield.
I think that for a non- bombed truck the stock air system is sufficient under normal use. I replaced mine since it wasn't stock any more. Since these vehicles are rare over here I can't say that the stock airbox is generally crappy. The ones I saw that were warped may have been caused by handling wrongly. Nevertheless it's no bad idea to check the airbox for defects, if there's a crack on the "clean" side the best filter won't help.

AlpineRAM

 

It fits well but sometimes the flange has a tendancy to collapse slightly. The BHAF was designed to mount over a pipe, not inside a hose. This can be solved with a short piece of PVC pipe inside the flange of the BHAF to stiffen the flange so it doesn't collapse when the clamp is tightened. I'm very happy with my BHAF and 100% confident that my engine is getting the cleanest air possible.

 

I bought a piece of aluminmum at the junk yard for two bucks, got the pattern off the tech tips, removed my old air box, mounted my heat shield using the air box bolts, used the old air box hose and clamp, and in less than two hours I was on the road. It would take about 15 minutes to put the old one back on and you would never know it.