Don:

I've had high and erratic EGT readings on my Renesis since I started flying it early last year.  I've tried changing ground paths and replaced one EGT wire with no change.  I get readings varying as much as 75 deg. F. over 15 seconds with no change in engine operation.  My EGT temps. go as high as 1800 deg F.!  If these were correct my muffler would not have lasted.  I'm still trying to figure out what is causing the unstable and high numbers.

Can you post some pictures of your installation?  I'm wanting to build a new intake and your post shows a tuned 17.5 in intake.  That probably is what I need also.  My intake is an RX-8, 4 port unit which I cut off just below the first rotary valve.  It's runner length is closer to 10 inches.  I estimate I'm equivalent to a 175 to 180 hp lyc. in performance with my current intake and exhaust.

Dennis Haverlah

Don Walker wrote:

> Rotorians,
> Now that the airplane is painted, weighed, prop ballenced and etc.  > I'm into tuning and getting comfortable with the engine.  Yesterday I > noticed that as I ran the engine up, #1 rotor EGT trailed #2 by 20 to > 30 degrees and then at about 20 inches of manifold, #1 started > climbing rapidly!   At max static throttle 5828 rpm (prop speed of > 2045) or so,  #1 runs to 1640 degrees while #2 maxes at 1480 degrees.  > I played with the mixture etc.  No difference.  I have checked the > plugs and swaped them.  No difference.  Stock RX-7 plugs.  Pulled one > and then the other secondary inj. connector.  It starts and runs and > then drops off as RPM gets high.  Same on both #1 and 2.  Swapped > injectors.  No difference.  Tryed using Mode 4, both to increase > mixture and then to decrease.  No difference.  Reset Mode 4 back to > default.  Swapped EGT probes.  High temps showed up on #2 on EM-2.  > Swapped back.  Checked the archives.  Nothing.  The EGT probes are > installed through holes in the exhaust 5 inches from the engine > outlet.   So I am at a loss.  Any thoughts on what might be causing > this?  Engine basically running smooth and strong.  Months ago, I > remember getting 6150 RPM, but couldn't get it to run long enough to > check out EGTs.  Cooling problems.  A couple of other things that may > or may not have anything to do with this. Manifold display on EM-2 > sometimes jumps around some.  I have tried porting to the front of the > intake and to the rear.  Now I have it teed to both.  Auto tune tries > to work, but does not.  (O2 sensor installed at end of tangenial)  I > ran it almost 2.5 hours total yesterday.  11.7 hours total. since last > December.  Quietest airplane on the field.  Lots of attention from > other pilots.
>  > Don Walker
> RV-8 N113BR
> Renesis 4 port. RD-1c
> EC-2 EM-2
> Tuned 17.5 inch intake.
> Tuned 24 inch exhaust into tangetial premuffler
> catto 76/88.  Field elevation 5000 ft.  density 6200