snips...

 Also, I am sorry to say, those Seimans injectors do not fit the
 injector holders or the fuel rail.  My mistake. I'll buy them
from you
 and keep them around. However you need four RX8 yellow fuel
injectors.

 Paul Lamar

Paul,
Bill Bradbury described what's happening with his engine, and it sounds
pretty much the same as what's going on with mine. Below staging, it's
smooth, but above, it runs rich and in flight there's a lot of popping
and surging.

He then reports that he has had good results by switching his stock red
and blue injectors to the yellow ones, that  I 'm assuming, but I'll
check are yellow  RX-8 injectors. Will they fit my 93 13 BREW and where
can I get them for as little $ as possible, and how much would that be?

On another note, I still have not gotten the last few pages of the plans
for my RV off to you, I still have to get up to the hangar and get them
off to you.

Brian Trubee


I have not researched the supply yet but Michael Hart is about to do
that so
he will let us know.

Sounds to me like the trim map is wrong on the top end. You could have
one or more partially clogged injectors. It takes a special circuit
and a burette to test injectors. The fuel coming out should be
directly proportional to the pulse width.

Here is a schematic of a DIY test device.

Also you could sample the air pressure in the runner with a couple
of pressure sensors and a data acq system. If my plate was not running
over I could come up and do that. It will be the end of April before
I am free enough to do that.

I don't think the RX8 injectors  will fit your current injector holders.
You could get RX8 injectors and they might not change things. If not
it is the trim map. If they do you may currently have one or more bad
injector. Getting them tested may be the first thing to do.
There are some companies around that specialize in cleaning and
calibrating. Paul Yaw may still do it. http://www.yawpower.com/ New
ones are getting so
cheap it might not be worth it.

Where are Bill's injectors mounted?

I see your secondary injectors are on the outer tubes a foot or so
from the port. What happens when you lean them out?

Is that a damper I see on the end of the secondary fuel rail?

Take some closer pictures of the EFI system.

Don't worry about the plans. Michael White kindly made me a gift of
a set he was not using. Thank you Michael. They came in.

Paul Lamar


I had the injectors cleaned and flow tested just prior to engine start.
The thing you see on the end of the secondary rail is the fuel pressure
regulator.

The other day I went out and ran the engine up on the ground,
specifically looking at EGTs for a mis-match of EGTs above the staging
point. What I saw was that the EGTs were pretty consistent all the way
up and down the RPM range. So, I'm thinking that I'm just rich up in the
areas above staging. Well, the EC2 should be able to compensate if I
tune it right, so I'll keep twiddling the program knob. When it runs
smoothly, it's like silk. I"m just a bit tired of the tower getting
calls from the local communities about a plane in distress overflying
them. Also developing a crease in the bottom seat cushion from excessive
pinching.

Brian Trubee

Well when I get time I am going to work on the engine monitoring
system that will read and store the history of the injector pulse
widths using a USB port to a PC. I think that is going to help trouble shoot these kinds of problems.  Should be about the end of April.

Paul Lamar