Bill,

First off I’m running an Eaton MP90 root super charger. I’m just researching what would be required for a turbo swap. I would request Dave L. and John Slade’s input for best installation methods. There’s a lot more variables in an aircraft turbo system than I anticipated. My super charger is simple in comparison.

So, oil feed, I suppose I could either put in a “T” fitting at the oil pressure sender, or I could use the original oil pressure tap under the filter stand with an elbow to feed the turbo.

The turbo feed is actually in the front iron and not the rear as I indicated earlier. It’s in the area above where the AC compressor would mount. Anywhere after the cooler and filter should work. I think Dave L. has an electric valve that allows him to shut down the oil feed in case of a turbo failure.

Then some questions about your chart.  I have not seen 7125 rpm on my engine, but I am pretty certain that I am not getting 175 HP at 5700 rpm.  In fact, I doubt that I am getting much more than that at 6500 rpm.  Where did you get your numbers and do you think that these hp numbers are what you are really getting while NA and while boosted?

I have an MT electric prop and can easily hit 7500+ rpm if I feed boost in too quickly during takeoff roll. I dial in 2400 / 6800 rpm for takeoff and see 7100 rpm until the electric controller catches up. The prop moves slow.  Renesis HP numbers are extrapolated from a dyno chart and I believe they are very close. The other chart data is only an estimate to help identify air density, pressure ratios and discharge temperatures without an intercooler. Some of the values were estimated using “rules of thumb” instead of calculated formulas. The workbook needs a lot of work to be user friendly and more accurate.

You are not spraying it into the intake???

Yes, after the super charger and before the engine.  I’ve been run 30-32” MP / 2000 rpm for cruise climb, rich of peak at around 12.5 F/A. No water.

Please direct me to some info on the “surge line”.  I have heard of it, but don’t understand it or really know what it is.

http://www.turbobygarrett.com/turbobygarrett/sites/default/files/catalog/Garrett_Catalog_V5.pdf

Look at the catalog section that explain how to select a turbo. My chart uses an estimate of 1 pound of air per minute for 10 HP. So 25 lbs/min of air is roughly 250 HP. Plot the air flow and pressure ratios on the turbo map and stay between the surge and choke lines. Operating in higher efficiency areas of the map will lower the intake temperature. Higher pressure ratios will increase the intake temperature. Pressure ratio increases with altitude thus the need for an intercooler. 

Surge Line

Surge is the left hand boundary of the compressor map.

Operation to the left of this line represents a region of flow

Instability. This region is characterized by mild flutter to wildly

fluctuating boost and “barking” from the compressor. Continued

operation within this region can lead to premature turbo failure

due to heavy thrust loading.

I have installed the older 13B pan under the mount plate, and my engine holds about 8 qts of oil up to just below the bottom of the mount plate

My pan will hold 6-7 quarts. I would need to limit the oil level to 4.5 quarts plus oil cooler, filter and hose volume.

Bobby

Bobby,

Thanks for this info.  I had originally decided that I would stay away from a turbo on the Renesis, but I have come to realize that I will not be happy with the current power output.  My plane is heavier than the RVs that most are using and as a result, I just need a little more punch.  Actually, I would rather go with a 20b, but the expense and the size of the job kind of get in the way.  I think I could add a turbo a little easier and cheaper than changing to a 20B.  But, having never considered a turbo, I am starting from scratch on what and how to do it.

So, oil feed, I suppose I could either put in a “T” fitting at the oil pressure sender, or I could use the original oil pressure tap under the filter stand with an elbow to feed the turbo.

Then, oil drain, I don’t see how a turbo could be mounted high enough on the rotary to provide a gravity drain into the oil pan.  I have installed the older 13B pan under the mount plate, and my engine holds about 8 qts of oil up to just below the bottom of the mount plate.  Even if I somehow modified the oil pan and lowered the oil level, it seems that it would still not gravity feed from the turbo because of how low it seems that the turbo would have to be mounted.  I would really like to see some pictures of how the turbo was mounted.

Then, water cooling of the turbo,  I have a heater hose set up that I am not currently using that I suppose I could run thru the turbo to cool it.  I have read that it may not be necessary to do this.  What are people doing about the water cooling?  Use it or not?

Then some questions about your chart.  I have not seen 7125 rpm on my engine, but I am pretty certain that I am not getting 175 HP at 5700 rpm.  In fact, I doubt that I am getting much more than that at 6500 rpm.  Where did you get your numbers and do you think that these hp numbers are what you are really getting while NA and while boosted?  It may just be that my plane is about 500 lbs heavier than the RVs, but back when I was trying to turn the same prop that Ed has, I could only get about 5300 static where he was getting 6000 with that prop.

I don’t understand how you are cooling the intake charge if you don’t have an intercooler??  What are you putting the water injection on?  Radiator??  You are not spraying it into the intake???

Please direct me to some info on the “surge line”.  I have heard of it, but don’t understand it or really know what it is.

If I could get the HP numbers that you show below a sea level under boost, I would be a happy camper!!

Bill B