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My DIY cold air box - all but done

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Old 03-01-03, 09:11 PM
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Refined Valley Dude

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Talking My DIY cold air box - all but done

I've been wanting to do this pretty much since I got my 7. Now that I finally have time I've hit it twice in the last two weeks and I'm nearly done. Just have to grab some more bolts and washers (didn't buy enough -duh,) finish painting the box and replace the stock duct (from the AFM to the UIM) with something that will put less stress on the box.


Pics can be seen here:
http://groups.msn.com/Amur/g2.msnw

You shouldn't have to 'join' to view them. Lemme know if it does ask you to...


Two thursdays ago I cut the steel and welded the pieces in place (not easy with a TIG welder that used to belong to the Flintstones.) Did the painting and added the hinged lid today. Ran out of time so the paint wasn't exactly dry when I put it together. Look for fingerprints. That'll be taken care of when I finish it.

The air inlet is a hole I cut in the forward bulkhead. Look at the 3rd pic - 'airbox open no filter.' The thick white line that I added is to show where I welded/RTV'ed the edge of one steel piece. The thinner white line is to show the boundaries of the other two sides of the cut in the wall (I knew I should have put a light source by the oil cooler. )
Directly below that hole is a rectangle of steel mounted (more like wedged) parallel to the ground. The intent there is for it to act as something of a shield and deflect any stones and such that might otherwise bounce up and into the box (the plastic undertray is off right now - hoping to get it on tomorrow.)

Yes, that is duct tape on the fan shroud. **** off. I'll be dealing with that when I've finished up the big stuff.

Oh, and the car is pulling with much more strength. I can't WAIT to get a catback on this girl!

So, whadda ya think?
Old 03-01-03, 10:34 PM
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Atleast you have a tig
Old 03-01-03, 11:12 PM
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Refined Valley Dude

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Gonna have a MIG soon, too.
Old 03-02-03, 12:00 AM
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now
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I assume that the air flow meter is not connected in
that one picture, and its just sitting there, or can you
mount them not level?
rivets might be a better choice for the hindges, they
dont come loose, and look better I think. but thats just me.


matt

Last edited by now; 03-02-03 at 12:03 AM.
Old 03-02-03, 12:03 AM
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Refined Valley Dude

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Which picture (they're titled, y'know?)

I *hope* the AFM can be mounted off-angle, cuz right now mine's at about 80 degrees with a forward tilt.
Old 03-02-03, 12:04 AM
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now
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air box open side
Old 03-02-03, 12:06 AM
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now
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i always thought the air flow meter had to have the
checkered side down and level.

matt
Old 03-02-03, 12:17 AM
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I put lock washers ahead of the nuts. I used rivets temporarily on the hinges but I thought that they looked like ****.

That pic was the last one I took before I drove away. The AFM and everything else is hooked up. You can see the AFM just to the left (our left) of the lid. That grid-like pattern is its underside.



edit: Just changed the pic to point out the AFM.

Last edited by Amur_; 03-02-03 at 12:21 AM.
Old 03-02-03, 12:23 AM
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now
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just thought it needed to be more level than that
the flap / door inside if it is hanging down it will run lean
and it the door is pointing up it will be rich, the effect of gravity on the weight of the door.
btw good quality "water tight rivets" look nice, the Canadian tire rivets look like ****.

matt
Old 03-02-03, 12:28 AM
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Refined Valley Dude

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Okay, so in that position the door is hanging down. Which would mean that I am running lean (if you're right.)

The car seems to be running normally. What are the symptoms of a lean condition?

Btw, my 7 mechanic had a look at this setup earlier this week and didn't say anything about the AFM's position being a concern (just FYI.)
Old 03-02-03, 12:33 AM
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now
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i know its a factor, i just dont know how much of a factor.
sorry i am not more help

matt
Old 03-02-03, 12:34 AM
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It has to be level like now said, to function correctly. High EGTs are an easy way to tell if you're lean.
Old 03-02-03, 12:39 AM
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****.

I already have an idea on how to fix it. I'll keep you posted...
Old 03-02-03, 10:14 AM
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Now just a damn minute here.

I've got a spare AFM that I saved from my last 7. I just grabbed it. It's door is spring-loaded, and it's a good, strong spring. Tilting this AFM does not open the door.

Unless the spring on my 'in-use' AFM is pooched, I'm having trouble believing that its being angled would have any impact on the door's behaviour or readings...

Yes? No? Where are the cookies?
Old 03-02-03, 10:36 AM
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now
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there must be someone here who can answer this other than me.
I know the cone style afm doesn't matter for level
but remember that the flapper door style should be level.
matt
Old 03-02-03, 10:56 AM
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make one for me too?
Old 03-02-03, 11:20 AM
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Sure. When will you next have time?
Old 03-02-03, 02:44 PM
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Having the AFM angled will cause an error in the reading.
If it is angled down, there will be an additional force of gravity acting to close the door, meaning the air has to push harder on the door, meaning that more air is actually flowing through than the ECU thinks (according to a table of AFM values related to air flow)
If it angle up, gravity will be acting to open the door (even if it doesn't) meaning the ECU thinks there is more air coming through than what really is coming through.
Old 03-03-03, 12:35 AM
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Yeah in this picture (if it links), you can see that the AFM is at a 90 degree angle to what it should be:
http://groups.msn.com/Amur/g2.msnw?a...oto&PhotoID=22

That would (even with the spring inside) give you inaccurate readings. Probably it would read rich as the flapper must go up.

Last edited by Icemark; 03-03-03 at 12:41 AM.
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