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Discussion Starter #1
I know the factory K&N replacement is E1009, and a few people have used E0773 successfully by also removing the factory "Neck", but both have their "disadvantages"....

Replacing the stock filter with E1009 does nothing to eliminate the factory necked-section and the in-airbox resonator. The necked section has an 80mm ID, but then opens up to the MAF ID of 85mm, followed then downstream with an "accordian" hose ID of ~90mm and the hard-plastic TB duct (and TB) of ID 90mm. The biggest restriction in this system is still the 80mm opening at the neck...BUT, the airbox remains "sealed" as best as possible with the blockoff flange extending from the bottom of the Neck, keeping the intake charge as cool as possible.

Replacing the filter with E0773 eliminates the factory Neck and the in-box Resonator, as the filter connects directly to the MAF-end. However, the airbox is no longer sealed due to the blockoff flange (molded on the Neck) also being removed. This opening will then allow more underhood heat to propogate into the intake airtract than the factory setup originally allowed. You will get more flow, but you may get more heat. In addition, its been said that the E0773 filter takes a bit of effort to get it to "fit" (deform) underneath the factory airbox lid.

Well, I removed the stock intake system today to have a bit of a look-see. There's a couple possibilities that I am looking into, but there's one pretty simple, cheap, and likely effective alternative to getting the extra flow while still using the factory Neck & OEM sealing capabilities:

1) Remove the airlid, and remove the in-airbox Resonator from the round 48mm OD "auxiliary" hose that extends from the Neck.

2) Remove the factory air filter.

3) Install E1009 to the factory Neck.

4) Install RU-1280 -or- RU-0400 to the 48mm OD hose. My quick calculations show that they will fit where that rectangular resonator once was.

5) Reinstall the factory airlid, using the factory Neck's flange as the seal, and enjoy the hopefully newfound power with your *two* (well, a fullsize and a midget) K&N filters installed.

What this setup enables is the inlet flow from the 80mm ID opening (factory air-filter), AND also inlet flow from the 43mm ID opening that once connected to the Resonator....while still completely sealing your airbox from sucking-in the engine heat. RU-1280 is about $30 from Jegs, so it could be a very CHEAP flow-enhancer, combined with the FREE mod of enlargening the headlight opening (call it the EHO mod).

My next step is to purchase the two filters, and then do some before-after flow testing with my homemade manometer.... Stay tuned....!


Also, for anyone doing a homebrew CAI w/ hoses & whatnot, be sure to USE some sort of accordian (or hump) hose for a section. The motor DOES torque-over upon heavy throttle, so you need to have an accordian section to accomodate this. Otherwise, I'd say you will run a pretty good risk of pulling-apart one of your clamp-joints, and/or splitting a section of ducting. Just a PSA.
 

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Discussion Starter #4
Its just so amazingly simple and obvious that it blew all of yer minds! (Whoever thinks to look for the easiest solution anymore!?!)
 

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Discussion Starter #5
ludicrist said:
I do like your idea and would love to here the outcome but I think you'll have more of a problem with the lid with two filters then one .

Shouldn't, in theory. The dimensions of the mini-filter are shorter/skinnier than the rectangular resonator it replaces, so there should be no interference to the lid whatsoever. :thumbsup:
 

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Discussion Starter #7
Ok boys and girls, here ya go.....

I first started by removing the airbox, air-filter, and the in-airbox resonator. The resonator is just pressed onto the neck-tube, with a tight rubber grommet sealing it. Just wiggle it off.

Then take the tube leading to the resonator, and cut off 1.5" from the end. This leaves enough tube to reinstall the resonator (if ever needed), but also is short enough to not interfere with the incoming flow from our soon-to-be-installed auxiliary K&N filter.




I then slid on K&N filter P/N RU-1280 as far as it would go onto the tube, and tightened the clamp.



Then, of course, install E1009 onto the main-filter attachment.



Install the entire assembly back onto the truck..... The RU1280 Aux Filter is a PERFECT fit within the boundaries of the stock airbox's lid.



Then I reinstalled the airbox's cover..... But, not done yet! Notice that with the E1009 filter installed, the airbox no longer is sealed along the upper radius. This is due to the inherent difference in how the stock filter attaches to the neck, versus the K&N. The stock filter used to act as the seal in this area, but the flange-attachment on the K&N negates this as an option. Soooo....



....I added a strip of closed-cell foam weatherstripping to seal this section off.



...and we're done!




Now, I'm sure the first question will be - any SOTP difference? My answer: I HAVE NO IDEA. I have NOT driven it with this setup yet. Based upon the info regarding the neck-down removal skewing the fueling and some advice from GTPprix privately, I'm not going to run it like this until my CAN-compliant scanning software (HPTuners) arrives. Chris has said that even this configuration WILL send the MAF-signal aloof, and with a Vector-optimized tune already in my truck for the stock airbox, I'm not about to "chance it" by leaving the aux-filter installed - until I have my own software to scan my truck and see how bad it is, and if it can be readjusted with a custom Vector tune.... So after doing this little "install" above, I then went back and reinstalled my in-airbox resonator for the time being.

Methinks that a MAF-relocate would help the situation out immensely; that is, moving the MAF further towards the TB (flip-flopping the MAF & accordian hose). This extra distance in theory would help give the airflow a chance to "stabilize" and result in a more laminar airflow across the MAF wires. Just a thought, but if there's any astute folk out there (and running the Colorado K&N) that wants to tinker with it (MAF relocate), I'd be curious to see its results.

If you want to run your truck with the above config, do it at your own risk. Same rules likely apply here as for anyone running the Colorado-filter w/out the neckdown....


Ok, with that little writeup over, let's hear your thoughts....
 

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I can assure you that will do nothing but sound only for your SS. Better off caping it with a rubber cap at your local hardware store. Our SS's are begging for more power. Look at VM CAI + Tune, that will solve your problem. I made my CAI take a look its in the picture and videos thread. Some things are better left untouched.
 

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Discussion Starter #10
tBSSOldblue said:
I can assure you that will do nothing but sound only for your SS. Better off caping it with a rubber cap at your local hardware store. Our SS's are begging for more power. Look at VM CAI + Tune, that will solve your problem. I made my CAI take a look its in the picture and videos thread. Some things are better left untouched.

I can assure you that manometer testing has confirmed that it improves airflow; I forget offhand what the delta in pressure-drop was (at work right now). Sucking from the TB-side the aux-filter does reduce the restriction. Also do a x-sectional area check w/ and w/out the opened aux-filter attachment, for comparative purposes.

And in case you didn't read my thread, I already have the Vector tune. :thumbsup:
 

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Mike we tried moving the MAF up the tube to stabilize the flow but the stock cal still wants to see the "neckdown" piece in place it seems :( That was one of the things we tried to get it to stay at a safe AFR when making the CAI kits.
 

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Discussion Starter #13
GTPprix said:
Mike we tried moving the MAF up the tube to stabilize the flow but the stock cal still wants to see the "neckdown" piece in place it seems :( That was one of the things we tried to get it to stay at a safe AFR when making the CAI kits.

Again, as usual - great info to have from Chris. :thumbsup:
 

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Ok, I am a little bit confused - what is the "neck down" piece?

So far, all that I have done is replace the stock filter with the 1009 - where is the risk in replacing the resonator with the 2nd filter as shown...we are not removing any of the tubing associated with the MAF?

I am a bit new to all this stuff so bear with me.
:thumbsup:
 

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Discussion Starter #15
FastFL said:
Ok, I am a little bit confused - what is the "neck down" piece?

So far, all that I have done is replace the stock filter with the 1009 - where is the risk in replacing the resonator with the 2nd filter as shown...we are not removing any of the tubing associated with the MAF?

I am a bit new to all this stuff so bear with me.
:thumbsup:
You're fine with only the 1009. The neck-down piece is the hard-plastic coupler that attaches the MAF to the filter. Looks like a funnel in the pics I have shown above. Some persons remove this piece and directly attach an air-filter to the MAF.

The 'risk' with removing the other pieces resides in the fact that those modifications cause additional turbulence in the intake-tract, enough that the MAF sensor cannot accurately gage the airflow & thus order the appropriate fueling. Then, really bad-yams could be the end result.
 

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So, is it fair to say that if I replace the resonator with the aux filter as you have shown and leave the "neck" piece alone - I should be ok and the result will be a little bit of an improved sound and possibly a slight improvement in air flow?

Chris: Do you think that there is any real danger in this small adjustment?

Obviously, I will not hold anyone to anything but since I know less than zero about most of this stuff:duh: , your input is valued.

Thanks!:)
 

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FastFL said:
Chris: Do you think that there is any real danger in this small adjustment?
In that setup, nah it caused some ripples in the A/F but they werent the huge changes we've see on other CAI setups. You'll gain a little flow and some sound it's a good mod ;)
 

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FastFL said:
So, is it fair to say that if I replace the resonator with the aux filter as you have shown and leave the "neck" piece alone - I should be ok and the result will be a little bit of an improved sound and possibly a slight improvement in air flow?

Chris: Do you think that there is any real danger in this small adjustment?

Obviously, I will not hold anyone to anything but since I know less than zero about most of this stuff:duh: , your input is valued.

Thanks!:)
anything done in front of the neck down, which is in front of the MAF shouldn't affect the A/F, in fact I still can't understand how when the MAF and screen are in place (which reduces even more CFM, probably the same as the neckdown) any mod to the intake tract ie: enlarging the tubing.that would be like saying the MAF isn't doing its job?? that's the function of the MAF to monitor airflow isn't it..
 

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Yes Tony that is it's job however it's programmed to only know the volume of air that can pass through the SMALL opening at a given frequency. When you remove the neck down the frequency will of course go up but so will the volume of air the ECM "thinks" it sees. It sees what should be say for arguments sake 300 g/sec at 9,500Hz but in acutuality the MAF is now flowing 330 g/sec at 9,500Hz and thus not providing enough fuel for the mixture it thinks it should have at WOT. It can trim out or add during Trim (closed loop) operations but trims arent used during WOT (open loop)

Make sense?
 

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GTPprix said:
Yes Tony that is it's job however it's programmed to only know the volume of air that can pass through the SMALL opening at a given frequency. When you remove the neck down the frequency will of course go up but so will the volume of air the ECM "thinks" it sees. It sees what should be say for arguments sake 300 g/sec at 9,500Hz but in acutuality the MAF it now flowing 330 g/sec at 9,500Hz and thus not providing enough fuel for the mixture it thinks it should have at WOT. It can trim out or add during Trim (closed loop) operations but trims arent used during WOT (open loop)

Make sense?

You lost me at yes Tony!!:rotfl:
 
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