Air Intake Question...
06-26-2003, 11:47 AM
#1
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Air Intake Question...
When i drove around without a headlight, as Hokie_90 mentioned, the car was noticeably quicker at all RPM's.
Just wondering if increasing the diameter of the pipe behind the headlight would make any worth while gains. peace.
Just wondering if increasing the diameter of the pipe behind the headlight would make any worth while gains. peace.
06-26-2003, 12:23 PM
#2
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The race teams put a ram-air tube in their headlights to "boost" pressure in the air intake
so, while diameter matters, you must consider whether you can meaningfully use the extra volume. A ram-air system will improve the air volume in any intake system, because it pressurizes the incoming air based on the velocity of the car.
06-26-2003, 01:42 PM
#4
Absolutely, yes!! Especially on the 90 series 2.8 and other that use that system...
We're doing it on my sons 90 with an aluminum tube into the airbox that's 3" diameter with a HUGE 4" velocity stack opening behind the headlight. Only piece eliminated is the stock 2" diameter air horn that goes to the airbox. Does require removing the airbox and cutting a larger diameter hole near where the top of the inlet hole is in there now and plugging a small lower portion of that same hole due to it's stock oval shape. But only takes about an hour to modify and is a HUGE HUGE increase over stock when used with the matching internal velocity stack.
But you're right about one thing: when we take my sons headlight out his car with automatic transmission it starts to run like that 94 90Q with my throttle body on it. Of coarse my sons car has my throttle body on it too but that intake mod with the headlight out transforms the whole car into a new dimension... VERY quick!! I think he could take me in a 25mph rolling start all the way to the speed controller.
I've got a pic of that inlet around here somewhere... one of the the prototypes we made. I'll see if I can't find it and post back here in an hour or so.
But you're right about one thing: when we take my sons headlight out his car with automatic transmission it starts to run like that 94 90Q with my throttle body on it. Of coarse my sons car has my throttle body on it too but that intake mod with the headlight out transforms the whole car into a new dimension... VERY quick!! I think he could take me in a 25mph rolling start all the way to the speed controller.
I've got a pic of that inlet around here somewhere... one of the the prototypes we made. I'll see if I can't find it and post back here in an hour or so.
06-26-2003, 02:37 PM
#6
Ok, here ya go. Not the pic I wanted but it'll give you an idea...
<center><img src="http://pictureposter.audiworld.com/711/90scai.jpg"></center><p>
this was our the very first attempt a couple months ago. A failure because I annealed the entire length and the walls buckled under the pressure of flairing the velocity stack into the end. Subsequent ones I only annealed the tips by holding the bodies in water and heating the velocity stack end with a torch then quenching in the water below.
The finished kit also has two 1/2" wide x 1/4" thick black PVC machined collars that each have a stainless set screw in them to hold them in place on the O.D. of the aluminum tubing. Their purpose is to keep the new velocity stack sleeve from sliding fore/aft within the plastic behind the headlight and in front the airbox entry wall.
Sorry I can't find the disk that the REALLY nice one is on. Maybe my son knows where it is. I'll ask next time I see him.
We tossed the idea as too labor intensive and expensive. Would've cost in the $160-$175 range and I didn't want to do only onesie-twosies of them as they're a monumental pain in the *** unless there's half a dozen so a production line of sorts can be applied. But feel free to use the idea or any variation thereof as I have no plans to run with it. It will flow over 400% more than the stock plastic tube. And it is slightly louder.
this was our the very first attempt a couple months ago. A failure because I annealed the entire length and the walls buckled under the pressure of flairing the velocity stack into the end. Subsequent ones I only annealed the tips by holding the bodies in water and heating the velocity stack end with a torch then quenching in the water below.
The finished kit also has two 1/2" wide x 1/4" thick black PVC machined collars that each have a stainless set screw in them to hold them in place on the O.D. of the aluminum tubing. Their purpose is to keep the new velocity stack sleeve from sliding fore/aft within the plastic behind the headlight and in front the airbox entry wall.
Sorry I can't find the disk that the REALLY nice one is on. Maybe my son knows where it is. I'll ask next time I see him.
We tossed the idea as too labor intensive and expensive. Would've cost in the $160-$175 range and I didn't want to do only onesie-twosies of them as they're a monumental pain in the *** unless there's half a dozen so a production line of sorts can be applied. But feel free to use the idea or any variation thereof as I have no plans to run with it. It will flow over 400% more than the stock plastic tube. And it is slightly louder.
06-26-2003, 03:59 PM
#7
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Ever thought of doing something like this?....i am having some problems...
I am trying to find a funel thin enough, so i can modify it to fit it under the head light instead of a little trim piece....maybe yo could fbricate something?...well, I have a cone so it might not work too good with a air box...anyway see my older post about it<ul><li><a href="https://forums.audiworld.com/9080/msgs/99028.phtml">https://forums.audiworld.com/9080/msgs/99028.phtml</a</li></ul>
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06-26-2003, 04:08 PM
#8
That's beyond my capabilities and field of expertise...
I have no in-house molding capabilities and a die to stamp something like that out of metal would probably run in the $5k range and require a 50 ton hydraulic press to stamp it. Cool looking but WAY outta my league!
06-26-2003, 04:35 PM
#10
JustDave had a nice setup on his Audi! ;O)
<center><img src="http://pictureposter.audiworld.com/8297/scoop_pipe.jpg"></center><p>It grabbed air from the lower right side grill, & piped it under the cone.
<img src="http://pictureposter.audiworld.com/8297/mvc-010f.jpg" border="0">
<img src="http://pictureposter.audiworld.com/8297/scoop_day_full_view.jpg" border="0">
Maybe you could ask him for details? ;o)<ul><li><a href="http://pictureposter.audiworld.com/users/8297.phtml">http://pictureposter.audiworld.com/users/8297.phtml</a</li></ul>
<img src="http://pictureposter.audiworld.com/8297/mvc-010f.jpg" border="0">
<img src="http://pictureposter.audiworld.com/8297/scoop_day_full_view.jpg" border="0">
Maybe you could ask him for details? ;o)<ul><li><a href="http://pictureposter.audiworld.com/users/8297.phtml">http://pictureposter.audiworld.com/users/8297.phtml</a</li></ul>