DIY cold air box
Thread Starter
Joined: Mar 2008
Posts: 8,718
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From: San Diego, CA
Thread Starter
Joined: Mar 2008
Posts: 8,718
Likes: 6
From: San Diego, CA
I went ahead and replaced the more detailed drawings on the first page with simpler ones. If anyone would like to make a box like this one, PM me and I'll send you the full drawings. I want keep a little control over where the specs end up since I spent so much time on this.
Last edited by RotaryRocket88; Jun 7, 2010 at 02:51 PM. Reason: no longer relevant
Smoke moar
Joined: Aug 2006
Posts: 2,530
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From: The yay, California
That's probably one of the nicest airboxes I have seen on this forum.
Now, about this...
Remember that the compressor is heating the air charge coming into the compressor not to a specific temperature, but a specific amount. Thus if the air charge is at 10 degrees (random number) and the compressor adds 50 degrees, you have 60 degrees heading into the intercooler. If the intake temps at the compressor are at 0 degrees then you are only seeing 50 degrees into the intercooler.
A lower temp into the intercooler means it has to reject less heat and will ultimately lead to lower intake temps at the engine.
Now, about this...
Remember that the compressor is heating the air charge coming into the compressor not to a specific temperature, but a specific amount. Thus if the air charge is at 10 degrees (random number) and the compressor adds 50 degrees, you have 60 degrees heading into the intercooler. If the intake temps at the compressor are at 0 degrees then you are only seeing 50 degrees into the intercooler.
A lower temp into the intercooler means it has to reject less heat and will ultimately lead to lower intake temps at the engine.
My question is - how come no one uses the stock air box intake snorkel and attaches it to the custom cold air box?
Are you all running FMIC's that get in the way? I want to use a Mariah box, but if it is just sucking hot air from around the gaps, what's the point of running the box anyway?
Jim
Are you all running FMIC's that get in the way? I want to use a Mariah box, but if it is just sucking hot air from around the gaps, what's the point of running the box anyway?
Jim
Thread Starter
Joined: Mar 2008
Posts: 8,718
Likes: 6
From: San Diego, CA
My question is - how come no one uses the stock air box intake snorkel and attaches it to the custom cold air box?
Are you all running FMIC's that get in the way? I want to use a Mariah box, but if it is just sucking hot air from around the gaps, what's the point of running the box anyway?
Jim
Are you all running FMIC's that get in the way? I want to use a Mariah box, but if it is just sucking hot air from around the gaps, what's the point of running the box anyway?
Jim
Thread Starter
Joined: Mar 2008
Posts: 8,718
Likes: 6
From: San Diego, CA
I knew someone would ask right away about those hoses, haha. That's my overkill MBC. Consists of a ball-n-spring relief valve and a brass check valve to vent pressure from inside the lines once the wastgate closes. I know, it's ugly right now. I'm actually going to make a little enclosure for it that mounts near the boost sensor.
Ok I see now where you are getting air. I'm going to do a set of mods exactly like yours listed (RB turbo back, Rtek, injectors etc) this June on my car, I'l love to have one of your boxes. I'll PM you
Jim
Jim
So, here they are finally. It actually took me a long time to get these right. It's been years since I used AutoCAD, so I had to relearn it, haha. Sorry about the widescreen format. I run 1600 x 1000 resolution.
All measurements are in inches. And I didn't note the width of all the tabs in the drawing, but they're 0.75". It'd get too cluttered with them in there too. Also, if you have A/C in your car, you'll need to bend the hardline that runs to the condenser in order to fit the box in. And a 5" filter will fit just barely, as long as the connector section is about 1" or less. If more room is needed, you can move the AFM attachment point closer to the passenger-side of the car.
blueprints
All measurements are in inches. And I didn't note the width of all the tabs in the drawing, but they're 0.75". It'd get too cluttered with them in there too. Also, if you have A/C in your car, you'll need to bend the hardline that runs to the condenser in order to fit the box in. And a 5" filter will fit just barely, as long as the connector section is about 1" or less. If more room is needed, you can move the AFM attachment point closer to the passenger-side of the car.
blueprints
Just angles. no one else noticed this? Am I not seeing something?edit: never mind, I missed page 2
Thread Starter
Joined: Mar 2008
Posts: 8,718
Likes: 6
From: San Diego, CA
Thread Starter
Joined: Mar 2008
Posts: 8,718
Likes: 6
From: San Diego, CA
Full Member
Joined: Jun 2008
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From: on a twisty road somewhere...
im working on adapting this design to my n/a right now. its a little different but not too bad. im also adapting the design to seal against the hood with weatherstripping instead of using a cover.
Thread Starter
Joined: Mar 2008
Posts: 8,718
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From: San Diego, CA
I made the idler pulley instead of using a double alternator pulley because every single one out there underdrives it. Of course, this past weekend I finished putting an FD alternator in the car, which has a double pulley. Unfortunately it underdrives too, but I just bumped the idle speed up to compensate. Oh well. So, the idler has been shelved. It didn't cost me anything anyway.