ENGINE WORK April, 2007
If it's strictly engine wiring, it's on this page. If it's more general supporting wiring, it's on the avionics/electric page, so be sure to check there for details.
April 1 - trim wastegate, plan for and make wastegate actuating arm (4 times!). After finally getting actuating arm just right, put duct tube back into plane and realized this method isn't going to work, because the heater is right in the way of where the cable would run. Grrrr. Back to the drawing board. 5.0 hr
This is my new supercharger plumbing piece from Eggenfellner. I am moving the wastegate adapter, from the tube with the ell welded onto it, to this straight piece that is directly after the supercharger. That will let me point the outlet right at the center cowl air exit.
I made a new actuating lever for the wastegate 4 times. On LT is the stock one. It was made to be used with a servo, and is much too small to use with a clevis end on a Bowden cable. Then, left to right, I made it over and over, milling the slot and hand fitting it, changing it a little each time, until I had it just right; the one on the RT.
Here is the wastegate mounted on the tubing, with the Bowden cable clevis end attached to the final version of the lever. Perfect. Until I went to mount it. Seems I overlooked the HEATER in the way. No way can I run the cable that way. This HAD been a great idea, because it would have let me keep the cable in the center of the plane, and just run it straight from the quadrant to the wastegate. Now, I'll have to go back to running the cable out the RT side of the firewall, then lengthwise along this tubing. I'll turn the wastegate mounting 90 degrees, back to being similar to how it was mounted on the stock duct. I may still be able to use this arm or the previous version, though. This whole wastegate actuation thing is totally "roll your own" with this engine, and I've spent a huge amount of time on it.
April 4 - worked on trying to figure out a new way to control the wastegate and how to get the Bowden cable smoothly to the butterfly valve. I am getting VERY pissed about this. On the wastegate control, probably more than any other aspect of this "complete FWF engine", we are on our own to try to figure out how to make something work. That, exacerbated by the crap and attacks Jan gave me a month ago for changing the wastegate opening size (after I'd talked about it for months on the STi list), is making me especially frustrated about this. 1.0 hr
April 5 - emailed STi list about how others are doing the wastegate. Got a quick reply from Chuck Chappell that reminded me I already have 4 pics from Richard Reid's install and 2 from Mickey Coggins HERE, from nearly a year ago, when I first started working on the wastegate issues. These are helpful. I'll try again tonight, and maybe I won't be as frustrated by this as I got last night. Later on, got more good replies from Robert Paisley, Jim Skala, Ziggy, Randy Crothers, and a couple others.
April 10 - Been too busy working on panel wiring to get back to the wastegate yet. Here is a picture of John Moody's RV-8A wastegate installation:
April 18 - resumed laying out wastegate control, cable routing, and wastegate cable clamp mount 2.0 hr
Here, I used RTV silicone seal to temporarily glue the proposed bracket into place, so I could put the tubing into the plane and do a clearance check that the cable would work laid out like this. I used a 2.125" metal holesaw in my mill to cut the aluminum angle so it followed the curve of the tubing at this angle. I made a couple of these, at different angles and depths.
April 19 - final layout, positioning, and test fit of wastegate control cable clamp mount bracket 3.25 hr
Once I was confident the path I'd chosen for the cable and bracket would work, I drilled the bracket and attached the cable and cable clamp hardware to it. The cable also helped a lot to keep the bracket from sliding around. Then, I duct taped the bracket into place. The bracket will be tack welded with the tape holding it right where I want it, then all the tape and hardware removed and the bracket welded into position.
April 20 - get wastegate control cable clamp bracket welded onto supercharger tubing. Drill and ream one-hole firewall eyeball fitting (aka spherical metal grommet) to hold the cable as it passes thru the firewall. These fitting are available at Avery and ACS. I have both the one-hole and the multiple hole versions. I think the one-hole versions are easier to install, although the fit of the hole to the object going through the hole seems to be more critical with the one-hole version. I got the 0.188 model, and drilled it out to #3 (0.2130"). I need to ream it just a tad bigger, so I'm getting 0.2135 and 0.2140 reamers from MSC. I have a 0.2165 reamer (I got it for the Bowden cable clamps at each end), but it makes too big a hole for the eyeball fitting to grasp the cable tightly. 2.0 hr
All welded and ready to install onto the engine and the cable run laid out. This is the wastegate fully closed position. I have 1.375" cable travel with this setup.
April 21 - update web site 1.0 hr doc
April 22 - drill 1 1/16" hole in firewall for eyeball fitting for wastegate cable. Drill & ream eyeball fitting to 0.213". Still a bit too tight. Will have to order a bit larger reamer; 0.214 or 0.215. The 5.5mm (0.2165") reamer I have for the Bowden cable clamps is a bit too big for the eyeball fitting, as it clamps differently from the way the cable clamp does. 1.5 hr
April 24 - I forgot to order the reamer I need, so I got that on order, from MSC. I decided to get just one, in 0.2145". $10 in shipping. UPS's minimum shipping charge now seems to be $10, which is a lot for something weighing a couple ounces.
April 25 - got my MSC order. Reamed eyeball fitting to 0.2145". Perfect fit for Bowden cable eyeball fitting (perfect fit for cable end clamps was 0.2165", due to difference in how the two clamp the cable). Spent an inordinate amount of time (to 0400) screwing around installing, rigging, securing cable for wastegate. After redoing it a couple times, I finally got it mostly completed to my satisfaction. 4.25 hr
This is the routing I ended up with for my wastegate control cable.
Here is another view of how the wastegate control cable comes out of the firewall and is routed to the wastegate in the center of the plane. I had to try a few different variations on this before getting it to be as smooth a run as possible. I'm using one of the duct clamps as a mount for an Adel clamp to hold the cable in the middle of the routing. Looks pretty simple, but I spent HOURS planning, laying out, and executing this. This is the second layout path I tried. The first one was binding the cable too much.
April 26 - finish up wastegate control cable installation. Tweak cable adjustment until I was satisfied. Mark and drill throttle quadrant for a positive stop for wastegate lever. Fully install & seal wastegate butterfly valve. Fine-tune cable adjustments & alignments to 0200. 3.25 hr
I wanted a positive stop for when the wastegate is fully opened, so I am not stressing the cable installation when I pull back on the lever, so I added this 3/32" roll pin in the middle of the wastegate lever's travel path on the throttle quadrant.
I had a late night visit from this big Spotted Salamander.
And, speaking of nature pics, I've also been busy lately, watching and taking lots of pictures of the flock of 25 or so turkeys that spend most of all day, every day, in our back yard. I put out about 6-8 quarts of cracked corn and some sunflower seeds for them every day. Click HERE for a few of the hilights.
April 29 - make up engine test run plan and run engine. Overall, the engine ran MUCH better with this new wastegate. I'm not getting nearly as much supercharger howl as I was with the 1/2" wastegate. It turns out that the old 1/2" one was way too small. The 1.25" butterfly valve supplied by Eggenfellner seems to be the perfect size. I got 0 psi at idle. The butterfly valve wastegate starts making pressure as soon as the valve starts to close, so this 1.25" valve size is the minimum. All my engine warning alarms worked properly. The low fuel pressure alarms worked OK. I am seeing 27-28 psi with the main pump, 26-27 psi with the aux pump, and about 35 psi with both pumps on. I'll ask STi list if the 35 psi with both pumps is normal. There's a slight change in idle speed when selecting both fuel pumps. I marked the quadrant where the SC pressure starts hitting 3 psi, and I will use this setting to make sure my EIS SC pressure sensor is set correctly and reading the same value at that point. The cooling fans seemed to work well, and allowed me to run the engine longer. The temp went up to 180s then climbed slowly into the upper 190s, at which point I shut the engine down. Even though I set my EIS tach P/R setting to "2", I am still seeing about 1500 rpm at startup and about 1100 rpm after it warms up a bit. I don't think the engine is really idling at that speed, so I will ask about this on the STi list, too. 0.5 hr
April 30 - Emailed questions to STi list about fuel pressure changes and about idle speed. I was going to do a quick engine run to test the supercharger pressure transducer installation and related EIS settings. But the engine wouldn't start. I tried again later and it eventually fired, after cranking a long time. It ran very rough for a few seconds, then cleared out. In retrospect, I think it was because usually I turn on the main fuel pump, then immediately start the engine. This evening, I had been fooling around with the fuel pump switches, noting pressures and flow with either one on and with both on. I think I also left them on much longer than previously, before I tried to start it. I suspect I had flooded the engine. I used that experience to develop a written start and stop sequence: 0.5 hr
main battery on
aux battery switch to ON
main fuel pump on
check oil pressure
aux battery switch to AUTO
aux battery off
main battery off
fuel pump off
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