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)