Just gutted my airbox....
 

Wow. Why did I wait so long? What a nice difference. Butt dyno says it feels better. Probably a nice combo with the Magnaflow cat that went in recently. I just ran up it past 150 km/h and it was just pulling smooth and strong. Brand new Purolator Pure One air filter in there, which is supposed to flow a bit better than a standard paper. Wonder what a K&N would do? Probably makes more sense to just do the K&N with a CAI tho.
As far as sound, no complaints. Haven't tried it on a cold morning start yet, but after sitting in the driveway for 2 hours with the hood up, it didn't sound bad at all on start up. Even at wide open throttle it did not sound too loud. If anything, it could have been a bit louder. Wonder if the 98 just has more sound insulation?
Two thumbs up for this mod! :)

Oh, and one thing I discovered tonight was that the intake from my 93 L67 would NOT work. The compressor for the ELC on the 93 is behind the airbox, while it is beside the airbox on the 95. So no can do to that mod! bummer

Was thinking about putting in a K&N filter, but I really don't think that would make sense. The biggest flow related issue now, I would think, is not the filtering media, but rather the rubber accordian pipe after the airbox. That cannot be doing anything good for the flow. Until that is dealt with, I just can't see that what I use to filter can in anyway compensate for the horrible things being done to the airflow by the accordian pipe.
Or am I missed something?

I run a K&N filter - and I will tell you I can't notice any sort of difference at all.
Even though K&N is a good product - a simple replacement K&N filter won't provide the 10hp claims they make all the time - you need a new intake for number like that.
As for a gutted box - I still don't think you will really see much gains - and gains that will likely not justify the cost of the K&N

If you have more mods done and you had a K&N in, you would see more noticable changes in performance.

One thing to realize is that if you get a K&N you'll pretty much never have to replace it, lol.

Well, again, what is the greatest restriction in your intake system? I think mine right now is the accordian pipe, more than the filtering medium. But I do have a ported and polished LIM that is about to be installed, and I am gonna do something with the exhaust manifolds at some point too, so I am probably flowing more air than you are anyway.
Real helpful if you add any mods to your signature.

what I was saying is as a simple air-filter replacement, you won't be seeing any noticeable benefit.

With the ported/polished LIM and some exhaust work you may see some gains - but you will also need to get rid of the accordian piping like you said.

Damn straight. THe stock airbox is incredibly restrictive. I sure don't think the filter medium would have any effect on the performance.

The airbox gutting makes a heck of a difference because of the restriction. You may notice a slight increase from a K&N . Now..let's talk about that accordian piece. It migth allow for non laminar airflow.. and the MAF screen takes care of this... but it's not a restriction.

I replaced mine with a piece of smooth INTENSE wall tubing and noticed no difference.

When I gutted my air box and dropped in a K&N I noticed an immediate increase in HP, I have no way to tell how much but it was quite noticeable.

Sorry Bill. Wrong choice of words. The accordion tube will certainly not restrict air, but it ain't doing much good to the flow. MAF screen wmight smooth out the flow, but it should be damn turbulent ahead of it.
I guess it is all about where the restrictions make the biggest difference.

Totally understand what you are saying and wanted to give you my real world experience. Snoothing that 4" section did nothing at all for me. Nice thing is it didn't cost me anything to find out.

Bill,
Thanks for "coming out" on this. I've been a non-believer in the accordian being a restriction for some time. It's minimum inner diameter is just too big for it to be a significant issue.


Erik,

In my opinion/experience...
Your biggest intake restriction is your TB bore (at the butterfly). Your second biggest is the airbox. You took care of the airbox, a bigger TB would be next up. On your OBD-I '95, how you'll scale the MAF input to get the A/F correct while being in the right place in the spark table, I don't know...AFC device?
(I believe TJsBlackBonne has some experience with that device)

After that, maybe the K&N will be beneficial.

That's the benefit to the club I can provide. I tried most low cost mods one at a time and noticed changes.

For those of you that are arbitrarily negating the use of a K&N cotton filter by assuming that they "can't really flow any better than a paper filter", be aware that you have not done any research. Research done by any number of companies, both those that are selling high-performance alternatives and a number of independant sources, has shown, beyond a doubt, that the high performance filters (of which K&N is the most well known) flow better and actually still offer better filtration than OEM paper filters and their replacements.

Indeed, the K&N website only claims that the standard panel replacement filters will offer somewhere between a 1-4 HP increase. This is certainly not enough for the average "butt dyno" to feel, but is nice nonetheless. When combined with the much more noticeable increase from a gutted airbox, the gain is even better. Other high performance air filters offer similar gains. Why wouldn't one choose to do this simple power adder?

This is not my attempt to begin a huge discussion or argument. I only wish to help educate those that may not be aware of the facts or those that have not had the opportunity to research this information for themselves.

Make no mistake about it, you absolutely CAN do better than OEM replacement paper filters. ;)

lash,

I don't think anyone's disputing that the K&N flows more air. The real issue is, is the stock air filter a huge restriction on our cars?

Surely there are cars here and there where the stock air filter is the biggest restriction in the intake....but show me the data proving a hp increase with a high-flow filter on an otherwise essentially stock n/a 3800 H-body.

On a s/c 3800 application (with gutted airbox), I could see it helping. On the n/a, I believe the TB would need to be bigger (and the airbox gutted) before the K&N would be a performance benefit.

The first "mod" I tried on the '98 LeSabre was a K&N, then the K&N with gutted airbox. They did absolutely nothing to my scans. Now I have the modded L67 TB, gutted airbox and K&N...and I have an unmodified airbox and stock filter in the shed. One of these days I should swap around the unmodified airbox / stock filter in various configurations and see what it does to my scans now.

agrazela,

I don't have any data to prove what you asked about, nor do I believe that the airbox is the biggest restriction in the H-body N/A 3800 intake system.

For that matter, I also don't think that the TB is the biggest restriction in the stock N/A H-body 3800 intake system either. Even your data hasn't shown that to be the case so far.

What I do believe is that, when in search of increases in engine breathing (and therefore potential for more power), one should start with the simplest and fairly low cost items and work progressively toward the more involved/difficult/expensive items. There is little doubt that one must balance all the air volume/velocity components, going both in and out of the engine, before you will realize a balanced "full" potential.

As such, we're really talking semantics and/or personal preferences when we discuss what should be done first.

Further to that, I would ask, what is the goal or purpose behind a person's "improvements" or question? For the vast majority of those on this site, I would bet that it may be mild gains at a relatively low cost and with minimal mechanical work or knowledge required. That alone is why the bolt-on industry does so well, even when offering garbage and scam stuff.

You have higher goals and capabilities than that and have done a pretty good job of documenting your tests and providing data as much as possible. But that is somewhat moot in this thread, IMO.

When a person asks for information regarding gutting an airbox, filter media, and the accordian hose, my usual focus is to stay within those parameters unless he/she has hinted that they are interested in more involved improvements.

That is really where I was coming from when I made that post. Hope this helps. ;)

I understand what you're saying, lash. Maybe instead of hi-jacking this thread, I should have just said, "my testing showed that neither K&N nor gutting the airbox (nor both together) did anything to improve performance on my otherwise stock '98 LeSabre L36. IMO, spend what you would have spent on a K&N filter elsewhere, until you're more modded."

PS, I agree that neither the airbox nor the TB is the biggest restriction in the entire intake system...I think that would be the heads, followed by the LIM.

Thanks for all the advice Andrew. I guess I picked up the tip about the accordion tube around these parts and bought it. But nothing like some real world feedback to show it ain't the case.
Makes me wonder how different a CAI would be? Should flow a bit better. Sound nicer too, I bet! :)

No clue on the TB. Getting the A/F right would be a bugger on a 95. I just haven't seen any tools available that would let me do that. Not saying there aren't any, but just that I have not seen them. Best thing I can imagine is cleaning up the TB.
Wonder what info my "new" super duper Actron scanner will give me...

New scanner eh?

I wonder if it could tell me why my engine is making a sewing machine noise at 100km/h and above

Ghost..that may be best handled with a pm.

Overall..my findings are that yes...laminar flow is good. However the MAF screen corrects any turbulance that my supercharger was attempting to pull through it. I would believe that your NA does the same. Now..trying to run w/o the screen .. I wasn't able to because there simply wasn't the right amount of laminar flow with my smooth wall 4" piece of tubing.

appologies :)

I think I may gut the box today and see what happens :)