DIY Cold Airbox Save $$$$
 

I got so sick of reading about $600 airboxes, that I decided to build one from the OEM stuff. It is almost like GM designed the parts for it. Just pull the airbox off, swap the left/right filter holders (mounting them upside down of the other side), cut 2 holes in the shroud, and voila.

The air filters hang down in the top of the shroud, catching tons of cool air. My accelerometer is dead, so I coulnd't get any before/after testing, but my MAF and air inlets are DEAD COLD after a hot run, and were always quite warm before.

I actually considered buying one of the high $$ intakes, but since none of the vendors here have ever helped my racing efforts, I'd rather help myself.

I was a little rushed today, but once I get an airtight seal, I put it within 90% of any of the aftermarket kits!

Interesting idea. Any thoughts of changing out the filter for a K&N now, or do you think they flow better?

Thanks for the post.

I was sizeing up the exact same thing today! Go figure!! All I need is the shroud part number???

I built my own for my C4. I like this approach :thumbs:

intake...
 

don't forget some pictures!!sounds very cool!

:thumbs:

David,

How about a nice write up with instructions and pics? That would be very much appreciated by a lot of us.

It's a work in progress, and I want to clean up my cutting before posting. Just cut of the original shroud, then buy a replacement for later. The shroud needs to be in place to cut properly, anyway.

The only real problem is deciding how you want the filter's to sit. If you drop them all the way down into the shroud, they can actually touch the condenser.

I got mine to a good, working point, and will refine it later. btw, the previous owner had already put gauze-style filters in the car, so I'm just using them.

My kind of mod. :thumbs:

Just remember that the stock filters are paper and you are exposing them to water. Paper filters and water don't mix, the paper will either expand and block airflow or worst case the paper will dissolve and allow water, paper from the filter and any foreign matter (sand, gravel, rocks, etc.) to get into the valves and cylinders.

Hydrolock +++.

Sounds like this has potential. Would love to see some good photos.

Like I Said in my follow up, I already had gauze filters in the car.

Here are some shots. I'll clean up my cuts, and build an aluminum shroud to seal off the outer edges. And/or, I'm thinking or trimming the area where the outer parts bolt to the primary, therefore narrowing the entire assembly slightly.

Already, it's working well, and I think with a little work, it will be great. I'm running the long course at VIR next month, and if there are any problems, that is where they would happen (nothing will).

http://www.davidfarmerracing.com/cold1.jpg
http://www.davidfarmerracing.com/cold2.jpg
http://www.davidfarmerracing.com/cold3.jpg
http://www.davidfarmerracing.com/cold4.jpg

Thanks!

http://www.DavidFarmerRacing.com/

Very cool, nice work.

Cajun

Thanks for the pics. Yep, this has some potential! Nice job.

Can't wait to see some numbers :cheers:

box
 

that's pretty friggin sweet!!Good job!Now,what filters will you be using,or will you be keeping the stock ones??Are you worried about water coming up from under??Oh,and what you're doing is flipping the unit (filters)upside down?

What year is that filter mod for?
Didnt look like my filter (06)

This seems like a nice mod.

A few questions...

1) Any idea what the shroud part number is?
2) What kind of perfomance gains can we look forward to with this cutting procedure?

Good job. :thumbs:

If I were buying the filters, I would buy GREEN filters. They are excellent quality, using SS mesh, and often have less of the rubbery stuff around the edges, basically giving more exposed surface area (both via more area and more pleats).

Believe it or not i had the same idea a few weeks ago but I thought the angle of the filters when they were turned over was too great and would cause them to hang down. Also, I didn't know how to seal them to the shroud. When you finish and have some pics i'm going to try it.
Thanks :cheers:

You can actually rotate the filter housings in the main body quite a bit. Even thought the openings are "shaped", they are flexible, and have enough play to make adjustments.

I don't know if I'll get to work on the project further this week (on vacation next week), but will update when I can.

Playing around last night, I heated the Filter holders in a 140 deg. oven for 10 min and they force fit just fine.
It would be great to have a kit that had filters, templates, an add on shroud and instructions for this for say $199.00. If there were real gains I bet it would sell !!!

Didn't think of heating them-good idea! I bet it would sell too.
:thumbs:

I've made my templates (out of stiff paper), and will hit the sheet metal brake when time allows. I don't think I'll go to the trouble to make a perfect seal, but should be able to contain most of the air. Personally, I'm more concerned with losing precious air to the radiator, than "ramming" air into the intake. As most of us already know, "ram air" is usually very small compared to the benifits of "cold air". I already know my mod is good for making "cold air"

Why do you think GM wouldn't do something like this from the factory?
It seems so simple, no added cost, clear benefits.

Probably for fear of someone hydrolocking their engine and GM having to replace it on their dollar. If you do this yourself and they hydrolock the engine, it's on your dollar.

water, AND the filter get dirty faster when they can get fresh air. I know that sounds stupid, but everything must fit into their "recommend service interval"

From past experience, one weekend at the track can fill your filter full of debris if you travel aggressively behind competitors (isn't that the point?).

system...
 

So David,how's the system working for u so far??

I did it last night then drove about 50 miles to check it out. First impression is no SOTP difference but i did stop and feel the intake and it was cold. Not cool, but COLD. Everything from the filters to the manifold was cold. This has got to improve performance but not enough that I could sense it. The filters are high enough that I'm not worried about water. In fact they are about the same height as stock just upside down. My only complaint is my workmanship. I am not skillfull enough to have done this well. The shroud is pretty butched up-not something I'm proud of but it was difficult to cut in place.

same here, good results, but ugly construction. Once I build my templets to rivet to the tops/sides, I'll likely pull the shroud off and clean up my cuts., even though you won't be able to see it

thanks for the idea! I just completed and can easily tell a difference. The car simply pulls much harder and breaks the tires loose like never before. Though I've not dyno'd, I can say I have picked up a few free ponies...

My Imagination?
 

The only thing I've done is this CAI and removed the screen. I didn't notice any improvement but I liked the idea. It's been just over a week and the car seems stronger but I chalked that up to my imagination. Today on my way to work I needed to change lanes and gave it a bit too much gas, the tires broke loose (TC/AH on) unintentionally. That has never happened before. It took me by surprise. Is it the colder weather, my imagination or is the car running better? :willy:

I did something very similar but used cone K&N's. If someone wants to host/post the pictures I will e-mail them to you. My entire set-up cost 110 bucks and looks awesome with a chrome pipe, clean cuts, and the stock air bridge was adapted to fit the peices. I have no desire to change what I have especially due to the looks of the system.

My main goals were to get away from having to use paper filters and to get some cool air in the engine compartment/filters. I cut the shroud in a way that the flaps hang down blocking water from hitting the filters. I never drove in rain but I'm sure its as good as any other that breaths from the bottom.

Can't wait to se the pics.

:iagree: :iagree: :iagree: :thumbs:

I'll host your photos if you'd like. PM me and I give you an address you can send the photos too. I'll set it up and then send you a link.

I just finished removing the shroud and flipping over the stock air filter holders. And there is definately a difference in the acceleration of the car! In my mind seat of pants is all that matters. Now this would not be good to drive in the rain but is an improvement in breathing. Much more air gets into the engine comp. and she runs 10-15% cooler too!

u can host pics on www.tinypic.com

Let us see what you did. :cheers:

PM sent. Please just give me your e-mail address and take care of the rest. I don't have much in the way of computer know how or interest.

If anyone else beats him to the punch I'll send the Pictures to the first e-mail address I get. You take care of it from there.

pictures
 

if the other email address doesn't get to you,send me a couple of pictures and i'll put them on here for you [email]tonight. jessetheoutlawoutlaw@yahoo.com

E-mail sent.

Essentially this is the same concept as Dave's mod. Both intakes use the bottom breather concept that is where any intake is likely to make any gains.

My intent is not to hijack but to reinforce Dave's point: 400-600 for an air cleaner is insane and not necessary.

:iagree:
I am waiting for more pic's before I work on mine. Look's good so far. :thumbs:

Photos From SpinMonster
 

Here are a couple of photos of the way SpinMonster modified his air cleaners.

http://pages.sbcglobal.net/awne/vette/KN filters.jpg

looks good. I hope to get around to making shroud/covers for mine, and will post templets for the shrouds and for cutting the holes when done.

Dave, I made a template out of cardboard peices but was still debating the material to make it out of.

I was able to make perfect cuts in the shroud with a sharp utility knife that came out amazingly good....looks stock. I cut the shape of a "U" and pushed the flap down to deflect water from the K&N's.

To be fair to the manufacturers of the aftermarket air cleaner assemblies, the air bridge may be a restriction and the coupler is definitely a POS. If you take into accound the cost of a coupler....50, the airbridge 150?, the K&N used, and the time to make the system, it is easy to see where 300-400 comes into play. I have since that picture was taken, made a smooth coupler -$11-and was looking into a better airbridge.

Not bad home grown MOD. Could you sell a DIY kit? How much ?

Not what I'm about. If there is some part of the process you need help with you got it for free.

The area that is hard for the average guy would be making the connection to the stock airbridge. I'm not going to fool you; while this mod was cheap....$110.00, the amount of time prohibits it being any cheaper than any other air cleaner assembly. Mine was just a protest as my exhaust will be. 2 pipes and 2 mufflers= 1000 bucks and 1200 if I want quad tips?? As soon as I get the time to use my friends mandrel bender, I will have a 3" catback for 200 bucks....unless a used corsa sport set appears for cheap.

:thumbs:Glad to see there are some of us left:thumbs:

All PM's returned for the dimensions and parts.

:iagree: :iagree: :iagree: :iagree: :thumbs: :flag:

Cajun

Thanks for the pics! :thumbs:

No, you want to travel aggressively in front of competitors. Sorry, could not help myself.

Interesting idea for the intake.

:cheers: I think it looks pretty good :yesnod: Some times I try it my self and I end up spending more time and money than I wished. Then again, that is where the fun is. :grouphug:

Thanks. That's how i feel. Some guys don't even wash their own cars. They pay someone else to do the simplest things. OK, whatever bakes your cookie. I like to tinker. Sure I could buy someone else's work but I get a lot of satisfaction out of doing my own. Sometimes I screw up. Sometimes I spend a lot more time than if I bought finished components. It's not always the money, It's doing it myself. I put the A&A exhaust by-pass mod on my C5-really cool! A little work and two pieces of pipe.
It's good to see that there's still some old hot rodders out there!
:cheers:

ttt

Without the holes, where do the stock airboxes breathe from?

And can someone post the dimensions of the parts spin monster used?
I was at a Corvette meet this weekend and a few C5's had a similar mod done, although it didn't look like they needed a bridge, just a T shaped PVC pipe and two filters.

$110 sounds a lot better than $400.

LOL!!! I had my air intake off a dozen times trying to figure out how I wanted to build my own. I had Spin's idea, then switched to the upside down stockers, then I said the heck with it and built a cat-back.

Spin, I just cut up the factory pipes and welded in Flows. Sounds pretty mean and even with pretty oval tips I'm in for under $200.

I wish I could build my own headers.........

codes
 

with all i read about codes being thrown after mods get done,how are you doing,David??Any codes at all??

JEEEZ, does anyone tune a car these days?

:cheers:

I haven't gotten any codes on my car. I'm still wondering why so many people are having problems, but it sounds like the newer PCM's are ridiculously sensitive.

I've been running my car for a couple weeks with the open cold-box and NO mufflers (for a track event), and no codes.

Dave, I don't think its more sensitive, they just took so many precautions with safe tuning that the PCM is set to dump a ton of extra fuel Via the high LTFT's be tuned to near +20. The tripping ofa SES light is usually with a combination of mods not a singe one.

Airflow with your air cleaners wouldn't change flow, it is just letting in denser cold air which is still correctly measured by the MAF. Add headers and an intake manifold and you may be at +23 with no code or +24.5 on peaks and set it off at closed loop driving or idle. Its just normal tuning.

You wouldn't think there was something wrong with the design of a cam if it didnt idle with the factory tune so why would anyone think think there is a design flaw with headers or/and intake if it didnt run with the stock volumetric efficiency table?

Someone just e-mailed me telling me that Kooks is working on the 'problem'. There isn't a problem....they need a tune.

I don't know that I agree with your logic, or may not understand it. If the OEM program throws out +20ltrms, then it is running very lean. I understand how going to +25 would cause a problem, but it would have made more sense for GM to fatten up the VE table in the first place. Running the table lean and compensating with extra fuel (via ltrms) is not the way GM usually does things.

A tune can definitely fix anything, but I sort-of agree with ??(kooks, halltech etc) that the items should work without a tune. I would think anything short of a cam should not cause a problem, yet it is (intake and headers) for some. Some people seem to be having problems with nothing more than an airbox.

Thanks for your insight! I've got a scanner coming so that I can check my ltrms. No problems, but I'm awefully damn curious!

Dave

Actually at +20 it is at 14.7 and not lean but allows for a ton of fuel to be dumped. At +24.8 or so it throws a code. Like I said it is a combination of mods that throws the code. Especially ones that make unpredictable airflow changes after the MAF of if you relocate the MAF. A ported TB or intake manifold would be suspect since they get air inot the cylinders differently than the MAF/ve tables predict. Now for the guy that made an exhaust change AND put on a air cleaner.....you made a big change there.

If GM made the LTFT's zero then there was one less way of getting fuel in under adverse conditions so to allow for the biggest control/variance they made it run at the higher end of things since the casual driver doesn't car what the PCM is doing as long as it runs smoothly in all types of weather and in all altitudes. On high altitude places air is less dense and since they don't know where a car is going after they make it, they must make all PCM's operate a car in all conditions. High altitude cars have less range capability.

ok, i just did a dry run using davidfarmer method...without cutting up anything and the filter boxes switch sides and upside down....now the whole intake tubing sits much higher to the point of the hood will not close. i am assuming where the holes are cut the actually air filter boxes are sticking out pass / or hanging pass the fan shroud by an inch or so. can someone that has done this confirm this?

yes, mine hangs down "just enough". You don't want it resting against the radiator, but low enough that the air-bridge will sit in the factory latches.

It's not necessary to switch sides. I first tried this too but had the same clearence problem you have. Just rotate the filter boxes 180. After you cut the shroud they will be lower and no interference. :thumbs:

I cheated and bought a K & N kit..........

I'll have my AutoXRay scanner on Thursday, hopefully, and am curious to see how far my ltrms are off. I've also got a set of straight pipe (cats, but no muffler) for track events, and I've had no codes so far. I'm really curious to see how whacked the OEM tune is.

Who makes it and is there a site where I can see the product software? I like the HPtuners especially for the logging of the timing advance cells that show the exact cell being used when you get knock retard. Makes tuning the spark advance so much easier than auto-tap.

http://www.autoxray.com/

it is a hanheld that can offload to a laptop. I imagine it will be similar to Autotap, only the convenience of not draggin my laptop everytime I go for a ride. You can buy the cheaper version from tooltopia.com, then add the PC cable and enhanced GM stuff direct from them.

Looks good but if you paid 399 ...

HPtuners is 1000 for the tuner versions and has the scanner built in. Single users will be 500-550. That is what LS2edit costs.

I like the portability and not worrying about laptops and batteries.

Let us know how it works out :thumbs:

I would really like to see a before and after dyno on this mod if any of you have done it? If the intake feels cold then I am guessing it is getting something done. I would guess 10-12 HP and similiar TQ gains but it is all conjecture until we get some numbers. I love this idea and am planning to do it (once I get a C6). Hell by that time there will definitely be some conclusive data on this mod..............just cant wait to see if the freebie work?

Cajun

WOW!! That's something that I'm going to have to do! Thanks for the VERY COOL info!! :thumbs: :flag:
Bill

Added to the C6 FAQ.

With VIR next weekend (THSCC HPD event), I finally finished off my DIY airbox.

Here are the two aluminum shroud extentions I made up. Pardon my fabricating skills, but I don't have a metal "box break" for making compound bends. Therefor, this is the best I can do with shears and a pair of pliars!

Anyway, I'm pretty pleased with it. I'll pull the pieces off, rivet it all together, and spray it black.

**I do not have a template to give away or sell, so what you've seen here is all there is. IMHO, if you have the initiative/skill to do this, you also have the skill to figure it out for yourself.

http://www.davidfarmerracing.com/aba.jpg
http://www.davidfarmerracing.com/abb.jpg

ttt, want to make sure everyone sees this final chapter before I let it dye!

david...
 

SO,any issues since you put it on a few months ago??Have you noticed a more responsive throttle??LASTLY,Can you make me one?? :D

no issues, runs great, nice clean cold air. Haven't really noticed throttle response, but I've put less than 500miles on the car the 6 months I've had it.

For what I'd charge, you might as well spend the big money on a honker :)

metal
 

What's the metal strip for??

There is no way to get a good seal between the air boxes and the shroud without either taping it up, OR adding a fabricated shroud. I made an aluminum shroud for each side to seal off most of the area between the air boxes and the shroud. With a little foam added to the spots that need them, I should now be able to get 99% of the airflow either to the radiators or the air intake.

Just painted it, and its now ready to put on for good.

How about using some weather stripping (car or home) rubber around the square cut out holes in the shroud to seal against the airfilters/airboxes? Wouldnt that work? Plus, once pressed around the edge of the cut shroud, it would hide any uneven or rough cuts! Have seen it at autoparts stores, JC Whitney has some with different profiles and attachment point shapes.

It really doesn't need it now, as my final trimming and shaping is giving a good seal. I did put some foam around the bottom corners, but I'm pretty happy with the seal. Also, painted, it looks quite nice. I'll post better photos later.

btw, now that I have the airbox done and the Cat-back on (CORSA), I'll log some LTFT's and see if there are any issues.

What about driving in the rain?/ Would that be an issue??

Looks like a really good CAI. A home made honker. :)

I have a VARARAM on my C5 Z06. It is a daily driver and I do drive it in the rain. I have driven it in some really heavy down pours. The only issue that I had are a few DTC codes due to the ingestion of some rain water through the MAF. It gave me P0172 & 0175 Rich codes. I guessing it cause of the water. I didn't hit any deep puddles and that is the only time that I get these codes.

If you hit a really deep puddle, it could cause some issues. Just guessing though. If there wasn't a chance that there could be water ingestion GM would have made it that way in the first place. :lol:

If you make the change, you just have to know your limitations.

BC

Ran at VIR in the monsoon yesterday, and while I did put the OEM box back on, just in case (got it for next to nothing on ebay), I left the hole open in the shroud. To my surprise, very little water came up into the engine compartment, leading me to think that it would be very hard to gulp enough water to actually damage anything. The day included one extrememly high speed off, when I hydroplaned off the track at about 100mph, and drove half the length of the front straight bouncing through the "lawn", and again, very little water made it up into the engine bay, even with the big hole cut in the shroud.

The DIY box will go back on today!

BRAkes
 

David,those stoptech brake setups fit the 05 z51's??

I have heard this as well
That is why i put the LPE Cai on
It is near impossible to ingest water
unless you try to be a submarine commander ! :rofl:

Dave

What air filters are those that you are using on your new set-up?? Where did you get them and how much are they?

I admire all all of the cool ground breaking stuff your doing! :flag: Keep up the great work!

Racing in the rain!!! :eek: You got some HUGH nads!!!!!!!! Have fun and be safe! :flag:

Bill C

I think my filters are Holley (they are blue), but I'm not sure. They came with the car. Personally, I think GREEN Filters are the best quality on the market.

Stoptechs will fit C6 wheels, IF you install longer studs. That is a PITA, but cheaper than getting new wheels.

Hi David,

Some of us who admire your work are waiting for the final pictures of the DIY CAI. Thanx in advance,

roger, will do. Looks much better painted. I'll shoot some today.

Can you make a ramair?
Also you should take the screen out,if you havent already.

http://www.davidfarmerracing.com/Img_7293.jpg
http://www.davidfarmerracing.com/Img_7294.jpg
http://www.davidfarmerracing.com/Img_7295.jpg

Yep,,,,,,,,,,,,Ide call that RAM AIR!!!!!!!! :thumbs: :D :smash:

Dave ROCKS!

BC

More of a "cold air" since it is sharing air with the radiators, but cheap and effective nonetheless

This is a great idea and I'm sure will help with getting cold air in. My only comment would be that in looking at the stock system, the biggest airflow restriction appears to be where the two airboxes connect to the main tube. At those points, the air tubes are pinched down to quite a small diameter and by just eyeballing them (meaning I admit I'm making an assumption), that pinch-down should create both turbulence and restriction. I think that's where a completely redesigned CAI might give you some additional benefit (an extra few horses maybe). None of the aftermarket CAI's have restricted pinched down areas like this and most of them flow straighter as well which should also improve flow.

My .02

:cheers:

Mike