Those are some great data points Bobby. I think it shows that either of those compressors are a good fit. Note that 6 PSI is not a lot of boost for higher altitudes. That is not even turbo normalizing. If you are going to turbo, you want to normalize, plus a little bit. Say, 35"MAP at 18k MSL. That would increase your P/R to 2.5 or something, while keeping the mass flow less changed. At that working-the-turbo-hardest situation you would land near the upper end of the peak efficiency island of either compressor. Which is what you want.
I’ll muddy the water a little. This is a scatter plots for a TO-4E-50 and a GT3076R 56 trim. The plots shows extreme operating conditions at altitude. PR remained 2.0 or lower. I purchased the GT 3076R with a Tial 1.06 housing for the RV10. I’m a little bummed I can’t use it for the Rans S21 even for a muffler. FWF weight limit is 350# and I’m hoping to use a constant speed prop. Bobby From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Tuesday, August 04, 2020 2:58 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Turbos for 13b's in aircraft In that spreadsheet there is a stack of turbine maps laid on top of each other. you can right click, stack, "send to back" to see some of the other maps. I was told that the T3-50Trim was very close to the stock Hitachi. Good average numbers for our use would be a P/R of 2.0 to 2.5 and a "mass" flow (at sea level) of about 30 lbs/min. The best compressors seem to be the TO4 - with trim of 40-60. The TO4 E50 seems about perfect. You can send your old core to BNR Supercars. For about $1 AMU (Aviation Monetary Unit) they will bore out the turbine housing and install a TO4 turbine wheel (ask for an aggressive trim/clip). They enlarge the wastegate hole and install a 360 degree bearing, install the compressor of your choice and matching new compressor housing. Also, you can upgrade the wastegate actuator if you want. There will be almost nothing left of your core except the turbine housing that fits into the stock location. Its an excellent solution I highly recommend. They may try to talk you into a smaller turbo, but only because they dont understand high altitude applications. Also, we don't care about spool up time. Check our their website, BNRsupercars Thanks for sharing that spreadsheet Dave. It has been an educational tool. When I first built and got this stock turbo, I did buy a couple of recommended books on turbocharging, but due to a shortage of time and resources I really didn't pay them as much attention as I should've. Instead I just told myself that I wasn't going to be a Reno racer and I just wanted to use it to get off the ground quickly and to give me a little safety margin flying in mountain valleys. But with the abundance of good YouTube videos and tools such as this spreadsheet available today, it is pretty easy to see that even when I'm taking it easy, I'm still asking alot of this turbo. About 2 years ago, nearing the end of one short (40 minute) but fast speed run I did have a low sump oil alarm come on and I'd already noticed a lower than normal oil pressure. I landed at my home airport without issue. This was before I'd installed a orfice restriction in the turbo oil feed line. On an inspection the next day, I found a little excess play on the turbo shaft. I just chalked this up to normal wear and tear as the turbo had never been rebuilt, so I ordered a rebuild kit and oil usage and pressure have returned to normal. There are some things that I don't know about my turbo, such as the compressor wheel trim size so I'll have to take it apart to measure this. So I'm not certain exactly which compressor map I should be using. However, playing with this spreadsheet has shown that I'm clearly running in the "choke zone" regardless of which T3 map table I use. This is certainly not acceptable to continue on this path, so I'm beginning to dive a little deeper into this to find affordable options to improve this. Thanks Dave; I was expecting that you would've had something a little more purpose-built for the task, however the fact that you accomplished that with an industrial solenoid valve is interesting. It looks like they have a minimum size of 1/4" NPT, with a 1/8' port size. I have a few of these as we used to use these in an effluent sampling system but we have now changed to a different system so no longer use them. This is the same valve used by my TurboSmart electronic boost controller and are available cheap on Amazon. It is a 3-way valve but a pipe plug in port #1 will make it a 2-way NO valve. They are designed for air use, but are tolerant of lube service, and using it as a safety shut off valve, will subject it to almost zero cycles (other than test), so it won't see much wear. I did a google search. there was a company in FL that made valves to spec. I got a normally open, 12v, electric valve with oil tolerant innards and NPT fittings. cost about $120 at the time. Cant remember the name of the company.... Hi Dave; What did you use for a shut-off valve for your oil? Kelly, you are right. I even mentioned the TO4-E50 in my post above. Mark, its not about the horsepower so much as keeping the turbo in its proper operating environment for the conditions you are going to be giving. You mentioned "300-400hp" in your post, but it seem that perhaps you dont have a specific target in mind. Thats fine, but you are not going to land much above 180hp unless you have a specific target and a plan to achieve it. The stock hitachi you mention is a T3 turbine. It and the 2nd gen 13b it ran with were only rated at 200hp in the car - and only for short bursts. I did what you are thinking about doing. I ran the stock turbo to see what I would get. I was making a little over 200hp and the turbo lasted for about 70 flight hours. Looking at its turbo map, the impeller was running over 100k RPM. It's very surprising it lasted 70 hours. It probably only lasted that long because most of the time I was not running full power. The turbo imploded on my first long cross country. I was almost home and decided to let it loose a little. I was running about 30" MAP at 17.5k altitude. It lasted about 30 min doing that. My advice, if you want to experiment with turbos, is to install a shut-off valve on the oil feed line to the turbo. I now have one in my installation. When the turbo goes it will be hemorrhaging oil into the exhaust. Without a shut-off valve, you will run out of oil before you can get very far. With the valve, you can continue to fly n/a as long as you need. Play around with that spreadsheet I sent you. Make up numbers that are realistic for how much boost at what altitude you realistically want to fly, then find a turbo to fit those parameters. You can cut and paste various turbo maps onto the spreadsheet. They are available on the internet but most of the relevant ones are there on the spreadsheet. Try to keep the turbo in its center island of efficiency while staying away from the 'surge' line. Also, keep the RPM under 60k if possible. You will find that Kellys suggestion of the TO4-E50 is a good choice and readily available. You will also see that the stock T3 does not belong in an aircraft. Group, I have no running experience yet but when I purchased my turbo I settled on a "Turbonetics" TO4-E50 with a 1.15 a/r turbine housing so as to not get into any overspeed problems..........FWIW Dave, Just how much extra Hp do you think you got withy the upgraded Turbo? I will be happy with 250 to 300 HP from the stock Hitachi. Am I off with the fairys having this expectation? Neil. James, I had my stock housing upgraded to TO4 by BNR Supercars. They also have options for the Renisis. http://bnrsupercars.com/ Cost is $950 for the level 4 upgrade. Makes a nice tight fit. I had a big discussion about Turbo maps that you can find in the archives. I settled on a TO4-H or TO4-E50 to top out around 350hp at sea level. Attached is a turbo excel spreadsheet that you can use to evaluate various parameters in selecting a turbo. James, 2 flying that I know of – Todd Bartrim and Dave leonnard. Think they have the standard RX7 Hitachi turbo. Just been around the world trying to get an affordable turbo for my renesis which does not exist if you talk to drag racers etc., Quotes between $4500 and $6500. Bought 2 hitachi turbos for $125 and one looks set to go while the other will need bearings. There was an offer of one in south Africa for freight only. Would be a bargain. Just hooking mine up now, but as usual much to go that I have not factored as usual. Finally found an intercooler that may fit. Best, Neil. Does anyone out there have any recommendations for a turbo (brand and size) for a 13b in an aircraft? 300-400 hp range. Reasons or experience is appreciated! Auto racers have their needs but are different from aircraft... or so I've heard. My 13b's are nearing the decision stage for turbos. Thanks, James Whitehurst
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