flyrotary@lancaironline.net Mailing List Archive

No secret really, just a microtech ECU which is Australian! (Had to get that one in!) I can only go by the A/F ration as per fuel burn. With tracy’s I kept it at around 12.5 as the engine seemed happier there, while the microtech is running great at 13.5 to 14. However I must add there that I have now been advised to richen that to a max of 13.5, so have to make a few further adjustments there. Knowing fuel burn other than that is impossible as Tracy’s engine monitor does not recognise the pulse from the injectors, or I have probably stuffed up the wiring somewhere. I also had to put a thermostat back in the line as the ECU works from water temp, MAP, a fuel map and a TPS. You have to set an idle map, a load map, then a WOT map. Tracy’s is easier to map, but needs the knob to continually fine tune the mix which was very useful. Having finally got the ECU map right in the new ECU (I hope) it is simply just a transfer of the numbers to any other similar engine. The final setting I have to set is the automatic lean out in cruise. Once you no longer fiddle with the throttle for a few minutes the ECU says, I can lean this out for cruise, so does so to what you have set (adjustable). It automatically richens for start and progressively leans as the engine warms up. Once you hit the magic 85 degrees then the fuel map is as programmed. I have had grief with blowing the main fuse to the ECU by turning off at the master switch. Simple cure is to now kill the engine with the coil isolation switchs. My new EGT of 1725 is at an A/F ratio of almost 14, so can be lowered further by more fuel and possibly advancing ignition by a degree or two. A local rotary racing bloke tells me that he gets up to 45 degrees BTDC. AS usual, so much to learn. Neil.

From: Thomas Giddings

Sent: Saturday, April 12, 2014 8:56 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Switcheroo from turbo to not

Ok...We all gotta know..which ECU and did your fuel burn increase>:)

KIND REGARDS

Thomas Giddings

n360tg@earthlink.net

727 858 1772

On Apr 11, 2014, at 6:28 PM, Neil Unger wrote:

Your EGT is interesting. I could easily get up to 1850 degrees at WOT. over about 5 hours I managed to burn out 2 sets of EGT probes due to heat. Then I managed to stuff up Tracy;s ECU which mandated a return for repair. While waiting for it’s return I had the offer of a different ECU. Once wired in and set I found that the max EGT that I now get is 1725 degrees. Nothing else has been changed. The only difference between this unit and Tracy’s is that this has a trigger box which I suspect gets the spark away just that fraction quicker and may in fact make the spark advanced over Tracy’s. The new unit sits at 27 degrees BTDC at WOT. Would like Tracy to chime in on this one as my expertise is mechanical, certainly not electrical. It may also be imagination, but the exhaust seems quieter. Neil.

From: Mark Steitle

Sent: Saturday, April 12, 2014 8:14 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Switcheroo from turbo to not

Sounds like a prudent plan to me.

Sent from my iPad

On Apr 11, 2014, at 4:51 PM, shipchief@aol.com wrote:

I went out to the Hangar last Tuesday to start installing the intercooler. Well, at least to fit a few tubes and hoses, then hold up some parts and make plans.

As I took the air discharge tube off the compressor, I noticed the whole turbo compressor & bearing assembly wiggling around on the turbine housing!

I checked all the mounting bolts and clips, everything was tight.

So I took the turbo off the engine, and realized that I probably cooked the turbine housing. I did see EGT excursions to 1800F. What's worse, I had a new turbo blanket. I think a heat shield would have been better, so some cooling air could pass over the housing, but still block radiant heat.

Bummer.

So I decided to go with Plan B: I ordered the bits and tube bends to switch to naturally aspirated operation. I'm keeping the exhaust header that the turbo sat upon, and replacing everything else past the bottom of the firewall, to the new pipe & muffler I recently added.

I'm retaining the ability to 'Go Turbo' later, but I've become curious about what the turbo must boost to equal full throttle of 'Naturally Aspirated'.

I did build and have been running a tuned intake manifold. The exhaust won't be a tuned header, but it is pretty good, possibly better than the stock exhaust reactor and a whole lot lighter. It has port discharge nozzles (reversion cones) EGT probes and a gentle sweeping shape. Plus it's proven strong while carrying the weight of the turbo beyond 1800F, and it passed inspection. I trust it.

So I hope to run it, find the performance satisfactory, the fuel consumption significantly reduced, and use 87 octane ethanol free mogas instead of 92. (low compression rotors)

Also, I can advance the timing to the NA spec.

Anyone see a problem or have advise?