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Hi Neil; Are you getting anything special done to it in the shop? Because if its just a rebuild, then that's a pretty easy job to do yourself. And I don't believe that Mazda used the same turbo as I have for long, so you may not have that damn special graphite seal that was hard to find. If you're lucky then you can just use an easy to find T3 kit. If you do need anything special then these guys seem to have pretty much everything. I recall it was a few extra bucks to ship up here to Canada, so I imagine you can double that to get it down under. But after wasting my time with a generic kit they did get me the one I needed. Porting the waste-gate was also pretty easy. I would also recommend replacing the actuator. When mine failed it was as I was taking off and it was very impressive performance. If I recall correctly I think I was around 16psi when I caught it. Fun and I wish I could reliably do that all the time without worry about detonation. This is the actuator that I bought
I forget, but what plane are you building again. And what is your planned flight profile?
Thanks Todd, I already have the info from Dave, which is similar to yours. I have the offer of the stock intercooler from a bloke here, so will get it from him as it just fits with little mods to the cowl. I have sent the stock turbo to a shop in OZ to get it checked, but they to date have done nothing that I know of. Could be the virus as it has apparently affected the phones as well with no reply!! Will advise progress when it eventually happens, Neil. Hi Neil; First I gotta apologize as I know you sent me a message early last winter that I read and meant to get back to, but got too busy and forgot about it. I started playing beer league hockey again after a few years off, with games 3 nights a week, along with my sons hockey and back-country alpine skiing every chance I get and well I'm sorry but I just kinda forgot about you. Sorry mate. This damn virus cut our season short just before the play-offs which is a shame as we had a strong team, but considering how others are suffering, that's not much to complain about. And I'm still working as much as ever since our pulp is used in medical supplies as well as toilet paper, so fortunate on that front as well (see pic). Last week my son & I even climbed a mountain and had a fantastic ski down, so yeah we're fortunate up here as you are way down there. But last month I pulled the wings off my plane to put it here in the shop at home just in-case things took a drastic turn for the worse, I figure I could do some upgrades if I got stuck at home. So as is the life of an experimenter, I seem to have traded sleep for the opportunity to implement my latest half-baked ideas. Things are looking good and I'm so far on schedule to return it to the airport at the beginning of June. I'll make a few posts soon showing my work for peer review. Anyways, sorry for the long-winded prelude, but on to your questions.... My turbo is simply a stock Mazda turbo that I ported the wastegate myself. I believe it came off of a 1990 RX-7, but I'm not sure. I got it used from RX7 Specialties in Calgary. The turbo model is an Hitachi 18S-2S. I rebuilt it after I started to loose a lot of oil through the worn bearings. The rebuild kit was only available from G-Pop Shop. The bearings are actually exactly the same as available in a $15 kit that fits almost all turbochargers, but it's that damn seal that's hard to find. The wastegate was pathetically small so I ported it out to the maximum diameter that could be covered with the stock flapper gate, which more than doubled the area. As well, I also smoothed and flared the inlet to this port. As a result, it easily controls the boost levels. The stock turbo was known for boost creep (or so I've read) I replaced the wastegate actuator with a piston type actuator after the diaphragm failed on the stock actuator. I use a 6psi spring, so under normal use that is the most boost that I use. I also have a TurboSmart electronic boost controller, so at the push of a button, I can have 9psi or 12psi (you know when you are flying up a blind mountain valley and realize you've really screwed up and need a little extra power to clear that ridge, never happened yet, don't ever plan for it to happen, but I'm glad I've got it). The set-points are user programmable. A/R ratio, no idea. Whatever it came with, but I'm certain it is not optimum for the use that I'm using it for. The stock turbo is not really ideal for aircraft use at all and many aftermarket turbos would work better except installation is unfriendly. The greatest weakness of an aftermarket turbo IMO is the oil return which would require a scavenger pump.. no thanks. The stock turbo is a compact installation with a no-issue gravity oil return. Now this works for me, but I'm really not using continuous boost to go fast. I use it for short duration for take-off and climb. If you are looking for continuous duty use for high speed cruise, then you need to talk to Dave Leonard as he used a stock turbo as well, but first I think his is a later model year that was regarded as better, and second, he sent it off to a company that ported it as I did, but also changed out the turbine and compressor wheel to something suited to his desired use. Most of that info is in the archives, but if Dave is listening, maybe he'll chime in. Intercooler.... I was just using a stock intercooler that I got from RX Specialites, but while I manged to squeeze it all in there, I always doubted it's effectiveness and then confirmed it with a the extra EM2 air temp sensors. It was interfering with my new curved rad placement, so I just removed it all and am in the midst of fiberglassing the cowl which will eliminate the intercooler in/out. If it later turns out that I need one then I'm going to go a different route and have some ideas, but right now I'm happy to loose that weight. EGT. When I'm running around 14.5:1 air/fuel I usually see around 870 on each rotor as measured in the turbo manifold with another a few inches later at the turbine inlet is always about 50 degrees cooler which has been confirmed by switching probes around. Turbine outlet is measure about 18" downstream and is usually around 450. Two years ago I began working on a prototype data-logger, but after a few moderately successful tests I never did take it to the next level and work out the bugs to make it a permanent install. I wish I had so that I could give you better data, as I'm just going by memory at this point. One of your questions from last fall was about my muffler. I was using an AeroExhaust and I got many comments around the airport about how quiet my plane was. Cockpit noise was very low, but I'm far less concerned about cockpit noise than noise on the ground. I always wonder why pilots want to put a muffler on their head instead of the engine. But then last summer I pulled the muffler off for another reason (another long story) and just using a cell phone app (not very accurate I know), I was surprised to measure barley 5db increase in the cockpit. It seems that the turbo is doing a far better job at muffling than I'd expected. One of old friends lives below the departure end of one of the runways, so I asked him and he says it's still quieter than the other planes that fly out of there. So I've bought an actual decibel meter and this summer I'll get him to make some actual measurements from the ground and I'll get some from the cockpit. I'll also get some from a few other planes for comparison. Anyways, last night was a 5am finish on a big fiberglassing job with a 9am wake up call to go to work for a break-in repair and it's after midnight now with a 0630 start tomorrow, so I'm going to sign off now to grab a little sleep. I hope this helps. Have a good day. Todd, What turbo did you fit to your rotary? Do you recall the size of the intercooler, and just what boost are you running at and do you know what EGFT you are getting? Just heading down that path now, so too lazy to start from scratch, Neil. Good to hear from you Ed; I'm starting to feel old as I clearly remember your initial report on this long past incident! But your sharing of this and other stories has had a positive impact on me. In the 3 times that I've rebuilt a rotary engine since your report I always recall this story in my mind and pay special attention as I'm installing the oil pump gear and have noticed how easy it is to accidentally push that key out of place. Another change I've made due to your experiences is my brake lines. After your incident someone on this list suggested using a grease gun hose for the final loop to the wheel. So this is what I've been using without issue since then. I'm currently doing an annual inspection that has expanded to doing various system upgrades and I've got some shiney new red hoses that were given to me by an Oiler at work. I'm going to replace the old ones as the outer rubber layer has some unsightly surface cracks from the weather and this new style won't do that. The list has been too quite as of late so I've been meaning to share some of my updates to get the conversations going again. But I'm off to the shop right now to play with expanding foam as I build a new set of intake ducts to match up to my new curved radiators taken from a Kawasaki Ninja as suggested by another list member.
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