badger
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Joined: August 2020
Posts: 17
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Post by badger on Aug 24, 2020 16:50:42 GMT -5
Greetings all! I've been kicking around the idea of a DIY ' turbo-charger' turbo-jet project for quite a few years, however. I've not yet built one, " nor have I been able to let go of the idea of someday doing such!" I suppose that means that I need to finally get off of my ol' ' Rusty-Dusty' and get on with building one of these darned things! I'm hoping that you folks can steer me in the proper direction, in hopes of my eventually realizing at least a 'somewhat' successful first attempt. "Fingers Crossed!" About me... I've been in the precision metal trades for pushing 50 years, now. I'm an accomplished machinist, sheet metal mechanic and TIG welder. I also have access to a fully equipped shop. Equipment and skills will not be an issue. What 'IS' an issue, at 'this' stage of my knowledge, is that I am totally 'IGNORANT' as to where to start, ie... What type of turbo-charger to purchase, suitable oil pumps, cooling systems, etc., "yadda, yadda, yadda!" "Did I mention that I am totally 'ignorant'? My build will be a static, bench mounted system only. I'll not be trying to power any vehicles with it. I just want to build a decent power-plant and produce a respectable amount of thrust. Why? I have no real ' worthy' reason. I just want to see how well I can do in building one of these things! For starters, I've been reading that bigger is better when it comes to turbo size. It makes sense to me, due to the induced drag produced by the bearings, oil pressure, etc. that a larger diameter compressor/turbine will more easily spool up, with less of a ' huffer' needed to start it... and thus reduce the adverse effects of drag produced by the bearings/oil. Easier start and smoother operation once running. This will be my starting point. The Turbo-Charger! I've been looking at a few turbo's, reading the specs, and finding less than any really informative spec's for ' any' of the turbo's! I don't care what car/truck they are designed to bolt onto. I don't care how much that turbo will boost that vehicles horsepower... and I 'also' don't care what the O.D. dimensions of the inducer and exhaust are. I need I.D. dimensions in order to do the math. That being said, and in hopes of not being woefully disappointed after my package arrives... who can give me good choices for a decent sized turbo that will not break the bank nor destroy itself on its first successful run? I'll worry about all the other 'support' systems later. For now, I'm just looking for a good quality, proven turbo for a project like this...
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Post by racket on Aug 24, 2020 17:16:33 GMT -5
Hi Welcome to the Group :-) Have a read of the info here jetandturbineowners.proboards.com/thread/680/diy-turbines just click on the icon/s in each section for the info . LOL.........we all start off "ignorant" , its not an impediment to success :-) Yeh , go for a larger diesel truck turbo without any sort of wastegate/controls so that the flow dimensions of the turb stage are a better match to the comp , the hole out of the turb wheel( exducer) needs to be ~20% bigger in area than the hole in to the comp wheel(inducer), most auto turbos have "undersized" turbine stages for our use , but OK on a SI engine equiped with a wastegate on the turbo . Try and use a turbo with a comp inducer greater than 3" , the Garrett TV81-84 range are good candidates as well as the Holset/Cummins HX80 -82, maybe try some truck wreckers for a reasonable secondhand unit preferably one without a divided turbine scroll housing , the "open" single hole entry variety is better for us . Cheers John
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badger
Member
Joined: August 2020
Posts: 17
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Post by badger on Aug 24, 2020 18:18:22 GMT -5
Many thanks, John. I'm on it and will start shopping!
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Post by racket on Aug 24, 2020 20:45:23 GMT -5
LOL..............heres a couple of HUGE turbo cores www.ebay.com/itm/333593326625 , might be worth talking to the seller to see if they're useable , they're made in Switzerland , so probably ABB derivative , very expensive turbos when new
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Post by wannabebuilderuk on Aug 25, 2020 14:59:50 GMT -5
As others have said all over the forum John is the guru, just follow what he says and you'll get on great ha.
Have a look at all the other build threads for general knowledge and handy tips, you'll be surprised at some things you might not realise work rather well.
Also have a look at the software jetspecs for a rough idea on turbo performance if you find one you think might work, but since you're in the US you'll find some fairly decent scrapyards or ebay bargains where you'll get a decent turbo and other parts you need.
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badger
Member
Joined: August 2020
Posts: 17
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Post by badger on Aug 25, 2020 16:33:57 GMT -5
John, I checked your ebay link. Yes, those are 'HUGE' turbo's indeed! Quite a bit more than I think I want to tinker with for a first time project. "The search continues..;" I'm curious. What would the expected life of a 'turbo-charger' turbo-jet be if all is done well? Would its life be based upon run time in total hours, or what? In addition. Just how tough are these turbo's, in general, when used for such an extreme application as this? Is it possible to overheat them, over 'rev' them, etc.? If there is a flaw in the turbo, itself, are 'CATO's' with shredded parts/shrapnel flying everywhere a possibility? I think a catastrophic failure, as such, would look pretty sweet on video, however. I wouldn't want to fork over $900 bucks for a 60 second turbo-charged hand grenade show! Are used turbo's really a good idea, not knowing the turbo's true history? I found another large, used turbo for sale. It is listed as being in 'GOOD' condition, however. It came out of a wrecked truck! What if the casting(s) were clandestinely cracked via the wreck? I don't think I'd trust buying such a thing 'sight unseen'. I'd rather be able to examine it in person.
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Post by racket on Aug 25, 2020 17:11:45 GMT -5
Heh heh , yep , they're very large turbos and VERY HEAVY
A turbo from a reputable manufacturer when converted into a gas turbine should be able to have the same life expectacy as the turbo had on the original diesel engine as long as temperatures and pressures are also replicated .
All we do is replace the piston engine with a combustor , a turbocharger is already a "gas turbine" , its compressor wheel compresses air which is supplied to multiple "combustors/cylinders" which when the exhaust valve opens supplies hot gases to the turbine scroll housing and wheel.
A large diesel gen set will operate continuously for thousands of hours , its turbo/s all the while supplying compressed air to the engine whose exhaust will power the turbine stage.
We need to match the flow from the compressor with the "voluntary" swallowing capacity of the turbine stage so that the compressor flows in the high efficiecy region of its map , sorta midway between surge line and choke line , the higher efficiency region means less power required to power the comp leaving more power in the "exhaust" for creating thrust or shaft horsepower, generally diesel turbos have that match of componentry as they are concerned with optimising fuel efficiency from minimal backpressures on the engine whilst still producing relatively high boost levels compared to petrol/gas engines.
Turbos are pretty tough creatures , but they do have limitations with regards wheel tip speeds/RPM and turbine operating temperatures , exactly the same whether used as a turbo or DIY gas turbine , often when used as a turbo they can have life limited compressor wheels when used in things like suburban buses where the engine and turbo is going from idle to max power/RPM every few minutes.
A good quality secondhand truck turbo should be OK to use as long as one didn't want to explore the outer reaches of performance , keep the pressures and temperatures at modest levels and all should be fine , if you wanted to replace the comp and turb wheel with new parts then higher performance could be explored.
Cheers John
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badger
Member
Joined: August 2020
Posts: 17
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Post by badger on Aug 25, 2020 17:42:47 GMT -5
Many thanks, John! You're making me feel more comfortable in possibly spending more greenbacks on a used turbo. While I have no intentions of pushing any limits, at this time, who's to say what the future may bring if I really get into this...
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Post by racket on Aug 25, 2020 18:10:28 GMT -5
LOL..........beware , it can be an addictive hobby :-)
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badger
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Joined: August 2020
Posts: 17
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Post by badger on Aug 26, 2020 15:02:57 GMT -5
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Post by sauerkraut on Aug 26, 2020 15:17:14 GMT -5
I couldn't find any "important" info on that ebay listing... there is no info on A/R ratio of comp or turbine scroll, no information about the compressor or turbine wheel sizes. Just looking at it, the turbine exducer does appear to be larger than the comp inducer, so that's a good sign. I would be a little cautious about dropping $300 on a "non-name brand" turbo when I don't really know what I'm getting. I recently finished my first build using this turbo, which is half the price and is a good fit for this application. The A/R on both the turb and compressor are a bit on the low end if you want the most thrust, but that means that the engine will be easier to start and will generally be more "forgiving". At only $150 it isn't a huge hurt on the wallet if you accidentally destroy it on the first go around, which is easier to do than you may think. www.ebay.com/i/254041402664?chn=ps&mkevt=1&mkcid=28Here is my build thread, and another thread featuring another build with the same turbo. jetandturbineowners.proboards.com/thread/1385/suitable-replacement-turbojetandturbineowners.proboards.com/thread/1279/diesel-powered-aliexpress-gt45-special
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badger
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Joined: August 2020
Posts: 17
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Post by badger on Aug 26, 2020 16:13:07 GMT -5
Thanks, sauerkraut! Nice to know! I'll definitely check out the build threads! Tom...
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Post by racket on Aug 26, 2020 17:20:07 GMT -5
Thats a good price for what looks like a decent sized turbo, my only concern is the compressor inducer size as it looks a bit small for the size of the turb stage ..................maybe ask the seller for actual wheel diameters
AiResearch are an old company so often their units weren't meant for high boost applications unlike more modern designs, hence they ran overly large turb stages
Cheers John
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badger
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Joined: August 2020
Posts: 17
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Post by badger on Aug 26, 2020 19:41:27 GMT -5
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badger
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Joined: August 2020
Posts: 17
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Post by badger on Aug 28, 2020 14:30:12 GMT -5
The more I shop for turbo's, the more I realize that I don't know what the h*ll I'm really looking for. It's getting a bit confusing and also quite frustrating. Would someone please give me a guideline of 'proper-things' to look for, in a turbo... and/or steer me towards some reputable reading/educational materials? I truly want to get started, but also want to get this thing going via proper methods and a proper turbo. A/R ratios? I know what they mean, however. I don't know how those ratios should be considered in the design and building of a turbo-charger jet engine. There's much more to consider, I'm sure, than A/R ratios. I simply do not yet know of all those things. I'm just wanting to get a good start via a good foundation upon which to build and learn upon. "Please, help!" Tom...
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