The original thread on the old forum was AeroVee Performance (Cold Air Induction) started by our mad scientist friend Wes. Most of my pictures didn’t make make it from the wayback machine import, so I thought I would re-roll the topic. This is the single best mod I’ve done to my motor. I’m going to do an abbreviated writeup but include lots of pictures.
Here is the can I wrapped around my filter. You can see it’s nice and leaky - we don’t want to pressurize the aeroinjector because that impedes fuel flow.
One of the problems I had was the turbulent air coming up to the carb seemed to divert a lot of the fuel to one side of the Y pipe. I went through a bunch of iterations - are they all required? Not sure but this is what I’ve got.
Initially I had one inlet, then went to 2 which is sort of a pain. I wonder if the later stuff I added makes this dual inlet unimportant. I’ve got these blockers to keep the high velocity air from jamming right into the filter - bounces off and goes around the can.
This is what the air sees.
I still had issues, so I made a flow straightener that jams into the air filter.
Then I still had issues, and added a tricky one in my elbow.
I messed around with the ends of that to put some swirl into the flow. Totally trial and error, but got the left-right mixture a lot more balanced.
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So after I had the can, I needed to get air to it. I glued together some pink foam I had laying around and did a rough saw job.
Off to the Craftsman vertical lathe and drilling machine.
In that picture the arbor is the holesaw I used to punch the hole through the stack. Then I sanded it roundish.
I did a little hacking to get it to sort of fit on the cowl. You can see I’m going for the Rutan asymmetry look. Besides the cowl splits in the middle.
Time for fiberglass.
I made a tube to go in the inlet - that’s what my scat ducting will slip onto later.
Then it gets bonded on - just bodywork and paint to go.
I added a rubber flap to my designed in leak.
The idea is it can flap out if there is too much air, or in if there is not enough.
Here’s my hose connected to the air filter can.
I put the right side cowl on first, and hook up the hoses. The second short hose in the back goes to my oil cooler exit reverse scoop.
So - was it worth it? OH YEAH! On my first flight with this I picked up something like 150 static and climb RPM. Definitely better climb performance. Originally I had a climb prop and after doing this plus a few other mods, I was under-propped. Would climb awesome - I’d see 3300-3400 in climb. But we were stuck at 100kts cruise. These days I’m seeing a little under 3100 in climb, but we have seen a 500 fpm average to 7500’, and we are getting 120kts in normal cruise.
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I have found one issue with the fresh air induction though. The first time I flew when it was really cold, like 0-10F, it ran really poorly. Still made RPM but was missing badly. What I have figured out, I think, is that a lot of really cold air makes the 100LL vaporize poorly. It’s probably being ingested into the engine as little blue ice cubes. So I tried a few blockoff options for the inlet, from 100% blocked to the two configurations shown above. Still fine tuning, and we are done with 0F for now, but I did get the airplane to run well in cold temperatures. The rubber flaps & built in leaks allow the engine to pull warm air from under the cowl.
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Pretty awesome stuff Bryan.
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Thanks Dan!
Also if anyone wants to post their solution in this thread, feel free. There were a few good ones on the old forum. That’s where I got my ideas from.
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I second Dan. Terrific info. Thanks for posting Bryan!
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Is your elbow 3-D printed? If not, where did you source it?
