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Now that's more like it, Rusty. I do find it
interesting the you get less rpm with the sceet tubing. I gain approx 200
rpm when I use it, but that may be because it gets its air from my chin scoop
for the oil cooler and I suspect the prop helps stuff a little more air in the
tube. But, in any case, your RV-3 should do very nicely with
that static rpm - using Tracy's prop I presume?
A plenum may or may not assist with the airflow,
convention wisdom is that it does, but I think it depends on the rest of your
intake, they have to play as a team or else they can hurt performance. Be
interesting to see what difference it makes.
Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
Sent: Sunday, May 30, 2004 10:22 PM
Subject: [FlyRotary] intake #3 +150
rpm
Greetings,
I installed the 3rd
intake today, and got it
running. It looks great to me, but you'll have to
take my word for it, because I forgot my
camera. I could maintain 5000-5050 static, and saw
brief flashes of 5100, so this is a good improvement. I ended up gaining an honest 150 rpm. I played with the timing some,
and maybe gained 50 rpm. I
think the gain from timing has more to do with how well you’re timed
statically to start with.
This rpm was with the TB
open, rather than ducted to the radiator intake with 1.75” sceet tubing for each barrel. Before, when I removed the duct from
the old intake, I only gained about 50 rpm. Now, I get 5000 without the duct, and 4600
with it. Ain’t gonna be using
that duct. Overall, the intake is
a keeper, and I still need to do a few final tasks, such as adding a brace for
the TB, so it isn’t supported by my poor welds of the intake pipe. I also need to make a heat shield to
go between the intake/fuel rails and the exhaust. Full tuning is of course in order, but
the biggest thing remaining is some sort of plenum upstream of the TB. At the
moment, I haven't a clue what I'll do with this.
The stock Mazda 550
injectors still require about 180 degrees less mixture knob, than the MSD 525
injectors that are being used as secondaries. I'll end up using those
440's that Tommy sent for the primaries, but not until I have some other
reason to remove the intake. Still, it will idle fine down to 1200 rpm,
which may be just fine for a ported engine.
Cheers,
Rusty (No flying
until I get inspired about the
plenum)
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