I found a rough how-to of this elsewhere so I set out to try it for my new build.
Materials:
PVC pipe. (I bought a 5 foot section of 4 inch PVC for $7)
Blow torch or a Heat Gun
A hose or some source of cold water to cool the PVC with
Metal bowls. Like this:
And this:
First: Bust out your supplies. Make sure you have enough propane in the torch. Make sure the pipe is long enough and give yourself enough extra length to trim for tuning. Also make sure you use the precut end of the pipe or cut it very straight or youll have a wavy port.
Second: Sit the PVC on the bowl. I started with the smaller bowl. The bowl you choose depends on the radius and shape you want. Make sure you have plenty of room around the pipe so you can walk around the bowl and pipe while heating and so you dont light anything on fire.
Third: Heat the pipe. This is the most difficult part of the process. You want to heat it slowly. It took me between 5 and 10 minutes to get th pipe where I wanted it
You dont want to heat the pipe too quickly as this will cause the pipe to burn and bubble. Once the pipe burns it will no longer stretch. And you end up with this:
Fourth: Once the pipe becomes pliable start to push it down onto the pipe. Do it slowly and dont press too hard or the pipe will start to kink. Keep pushing until the flare is to where you want it. I did the two ports of my box with just the small bowl but for the one I did for this write up I experimented with using the small bowl and then the larger one. Im pretty pleased with how the two bowl method turned out. Mostly here is where youll do you experimentation.
Fifth: Once the curve is where you want it take your hose and spray the pipe down so it can cool. Be sure to hold the pipe where you want it until it cools completely as the pipe will contract back if you dont and youll lose your curve. When its cool, take it off and take a look at what you have. I ended up with this:
The radius was actually a lot deeper and wider but I messed up and let the port go to go grab the hose and it contracted up the bowl and shrank.
Im glad how it turned out and it seems to be a good alternative to mass produced Aeros. I need to do more experimenting but hopefully this gives you the basics for the process so you can try it out yourself.
Couple of problems. If you're going to use it like that, there's no way to mount it. And it doesn't look uniform.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
I mounted it with L brackets from the back. That piece doesnt look straight because its a from a scrap piece I used so the cut isnt straight on the end.
I thought these had to be very carefully designed or they would sound like garbage. Or am I confused with something else? Or would this only be used if you weren't concerned with sq?
becarful cooling the pipe too fast it may crack.... and i would try to find a way to get a flat face to mount them like lanman said. need more curve!
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I have to experiment with it some more. It takes me like 15 minutes to do I flare so I havent had the time to mess around with it. I have three bowl of that shape. I had the lat one I made with two bowls flared out and close to flat but I had to let it go to grab the hose and it contracted and slid up the bowl.
Ill have to take a picture of how I mounted them but I think will a bit of rounding on the hole for the port that it can sit flush. I just liked how they looked sitting out a bit.
I also dont have any issues with port noise or SQ. There is a bit of an air leak around one of them but Im going to seal it up better when I pull the box for paint and carpet.
