Ace

Every once in awhile I do something with the truck for no particular reason, just for the heck of it. Bored, I guess. So I get a wild hair up my butt and install one of those filter minder things, because I'm thinking I might need to clean that K&N air filter a little more often after seeing the massive amount of dirt that came out of it when I finally did get around to cleaning it a coulpe weeks ago.

So, with a clean, freshly oiled K&N and my intake mod, which some of you may remember from last year:

http://stuff.is-a-geek.net/PhotoAlbu...ics/CTD_54.jpg

...after some testing and checking, I am horrified to see that around 10lbs. boost starts pulling down the filter minder! And 15lbs. pulls it ALL THE WAY DOWN! Dang, that sucks. Somethin's not right here. So I start a little experimenting.

I put in a stock replacement filter - no change.

I unscrew the airbox cover and leave it just hanging open a couple inches. Problem solved.

Well, sorta. The intake is obviously still restricted, even after being opened up by approximately 50%. Out comes the airbox, and off comes the grill and valence, once again. I ditch the intake tube entirely and fab up a new one that is more than double the size of the stocker, and open up the core support hole another 50% as well. Fortunately the earlier mods including the scoop and valence connector are already "right-sized."

Put everything back together, and now the problem really is solved. Even with a stock Wix replacement filter. I'm gonna leave that in there for better filtration, since airflow does not seem to be an issue with it.

What did I learn?

1) A 1st gen with a stageIII, stock IC injectors and a turned up pump does not need a BHAF to flow plenty of air.

2) K&N is a waste of time and money, considering the filtration quality tradeoff. It will make absolutely no difference in the airflow unless you have the intake opened WAY up like I do now.

3) At some point involving bigger injectors and turbo upgrades a BHAF will become necessary to keep up with the airflow demand.

Interestingly enough, I could actually "hear" a distinct change in the tone of the turbo whine at higher boost levels. It was straining against the intake restiction before.

apwatson50

What do you think about this air filter: EaAU4510

From:

https://www.amsoil.com/storefront/eaau.aspx

I like the fact that its cleanable with compressed air.

Ace

Pretty expensive. It will be interesting for me to see how long the stock replacement filter lasts around here. I think I can buy three stock replacements for that price. It will probably be time for me to do an ol' Smokey mount and BHAF by then.

apwatson50

Yes but its about the same price as a BHAF, and you only have to buy it once. Plus you can get it cheaper than the price listed there.

Ace

But the question for me is: "Will it flow enough air to support big HP?" I have serious doubts about the capacity of the stock airbox, under any circumstances. I think if you are going to cut a big enough hole in it to support the airflow, you are probably just better off ditching it altogether. Kinda like I found out with the tube. There's only about an inch of clearance around the filter in there.

56speedy

could you put up some pic please of what you did/ made. that would be nice for the rest of us, please
smitty

apwatson50

I was actually thinking of using it as a replacement for the BHAF, using my current ol'smokey mount.

Ace

Oh, I see. Well, that's a different story then. Sure why not. You're obviously making way more than stock power, with the 190s, etc. Maybe worth it to do a filter minder check just like I did, to make sure the flow is still there.

As I recall, there used to be a thing in the sticky about making a larger intake tube for the stock airbox, but I can't find it. Mine's all put back together, so pics aren't really practical at this point, since you can't see it very well. Basically you just replace the tube that runs from the core support with a much larger one made out of sheetmetal (or your choice of materials). Cut larger holes in the airbox and core suport to mate it up and you have double or more airflow capacity with the stock airbox.

lowwag64

Ace,when you said
"double the size of the stocker, and open up the core support hole another 50% as well."
do you have any pics? what dia. did you end up with?
I have a filter minder too,but i thought it was reading wrong?

Ace

Here's some pics from when this started. Just imagine the hole in that first picture another inch taller:

http://stuff.is-a-geek.net/PhotoAlbu...ics/CTD_45.jpg
http://stuff.is-a-geek.net/PhotoAlbu...ics/CTD_53.jpg
http://stuff.is-a-geek.net/PhotoAlbu...ics/CTD_49.jpg

Actually, it was a half inch off the top and a half inch off the bottom.

flashgordon

Hmm, now im going to have to put one of those filter minders in my truck, just to see if there is a air flow, problem. With the stock air box and mild pump tweek.


Flash

BC847

Kinda like this?

Ace

Yep that's it! Where the heck did you dig that up? You're memory's way better than mine. That one's a "tad" larger than what I have now, but very similar...

BC847

It's what I ran prior to the Stock-Pot cold air box. I made the bigger duct from the same metal that seamless gutters are made from as it's thin enough to work with easily.

flashgordon

I thing, you should thro up your pic of you air box