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Post by racket on Apr 5, 2020 23:53:12 GMT -5
Your 4.8" is ~122 mm , this is "impossible" ...............what are you measuring ?? The exducer is the outlet diameter of the turbine wheel blades, it would normally be ~3.2 - 3.5" dia at most with a 2.8" comp inducer . A 4.8" ID jetpipe is what I'm using on my engine with a 4.65" comp inducer , its far too large for your engine , the gases exiting the turbine wheel will be "diffused ??", with losses , then accelerated through the jet nozzle with its losses , you end up with twice the losses ...............you need a jetpipe with an ID the same diameter as the scrolls exducer shroud which will be ~1 mm bigger in diameter than the turb wheel exducer. With a jetpipe ID of the right diameter , the jet nozzle axial length will probably only be 1-1.5" long , the jetnozzle in the GT6041 link was fitted to a turbo with a 119 mm exducer Buy this book www.ebay.com/itm/Turbochargers-by-MacInnes-Hugh/392749228608?epid=439493&hash=item5b71ada240:g:imwAAOSwdGFYrkoA
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Post by aquaticharpy on Apr 6, 2020 0:17:37 GMT -5
I was measuring the outside of the exducer, the pipe around it. I was planning on that being the main outside jetpipe with a cone inside, and a secondary pipe to press air against the cone before being let out via a convergent nozzle at the end of the main pipe~ ie divergent-convergent nozzle.
The blades are 88mm diameter for the exducer with 72mm inducer blade area diameter. I'll get that book.
I'll remeasure the jet pipe to fit on the inside, rather than the outside of the exducer, though it's a little hard as theres a lip on the exducer piping coming out of the turbo.
Thanks for setting me straight again.
John
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Post by racket on Apr 6, 2020 1:32:54 GMT -5
OK
Use a 90 mm ID tube , this will provide a small amount of extra diameter for any mounting inaccuracy , your turbo scroll has an inbuilt "diffuser" in the outlet , this is OK for when on a diesel engine as the sudden expansion has "benefits", but not for a turbine , theres no point slowing the gases down just to speed them back up again, on my TV84 scroll I machined a short step in the scroll at the wheel exducer area that the jetpipe located into to provide accurate radial alignment, A 10 degree taper will mean a jet nozzle ~2" long , add on a max of ~7" of 90mm ID jetpipe and your max total exhaust will be ~9", don't be concerned about the ~1" dia exducer hub area by trying to add a downstream fairing inside the jetpipe, keep it simple
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Post by aquaticharpy on Apr 6, 2020 8:50:06 GMT -5
Ok! Thanks for the information.
I just drew it out and tapering from 90mm to 72mm at a 10 degree angle takes 3 inches. Making a 10 inch long jetpipe. Is that alright?
Thanks John
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Post by racket on Apr 6, 2020 17:44:23 GMT -5
10 degrees each side , 20 degrees included ??
It can be even a tad greater angle , the GT6041 one in the Link was at ~34 degrees included angle ( 17 deg each side) .
Theres compromises as with everything we do , a tighter/steeper angle has certain losses , a shallow angle is more efficient in some areas but the extra metal surface friction produces losses , so which one is best , ............if it looks "right" , then I use it
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Post by aquaticharpy on Apr 6, 2020 18:25:47 GMT -5
Loevly, I'll get everything cut and rolled and update you soon.
Thanks John
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Post by aquaticharpy on Apr 6, 2020 21:03:17 GMT -5
Actually~ How do you reccomend getting a 2d sheet pattern to roll a steel cone? I havent found any ways, though I probably havent been searching the right things. Is there a calculator somewhere on the internet that can tell me about rolling tapered pipe or cones?
Thanks John
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Post by racket on Apr 6, 2020 22:40:49 GMT -5
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Post by aquaticharpy on Apr 15, 2020 22:29:14 GMT -5
I recently purchased picked up some 410 Stainless Sheet for the exhaust. Do you think it will do well? The rest of everything is 310..
Thanks John
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Post by racket on Apr 15, 2020 22:49:36 GMT -5
Mild steel is adequate for the exhaust as the temps are a lot lower
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Post by aquaticharpy on Apr 16, 2020 22:36:16 GMT -5
I was looking at running an afterburner. I dont know if I want to or not. Would that just be putting another convergent nozzle in the exhaust and putting fuel injectors around that? Does the afterburner need a flame tube to be efficient? Or just 400% more fuel and a variable nozzle on the end? Add one way check valves near the fuel nozzles to provide a ring of fresh air for better combustion?
Perhaps a sort of venturi vaccuum could provide fresh air from the accelerated exhaust gasses?
Thanks John
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Post by racket on Apr 17, 2020 1:32:57 GMT -5
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Post by aquaticharpy on Aug 15, 2020 12:30:43 GMT -5
Well, after a short hiatus I came back with stainless steel tubes, a nozzle, and an idea. What would you think about very thick mild steel end caps on the flame tube? I have some water valve covers/rangepoint box covers that look like they'd do but I wanted a second opinion. Thanks. John
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Post by racket on Aug 15, 2020 18:00:12 GMT -5
Mild steel endcaps are OK , but they don't need to be quite that thick
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Post by aquaticharpy on Aug 15, 2020 21:12:32 GMT -5
It's just what I have on hand, I suppose I'll weld them up
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