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Post by azwood on Mar 18, 2019 0:28:15 GMT -5
One question when you say .68 radial clearance do you mean 1.38mm total or is the .68 divided between both sides of the wheel.
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Post by racket on Mar 18, 2019 3:16:36 GMT -5
Hi Aaron
The "radial" clearance between exducer and its shroud needs to take into account the differences in expansion coefficients between the two materials as well as the possible speed of expansion due to relative thicknesses .
The Garrett GT6041 which has a 119mm exduce with high coeffic , running in a pretty thick scroll with a lower coeffic, has 0.030"- 0.75mm radial clearance, so 0.060" - 1.5 mm diametric clearance , the exducer bore of the scroll is 119 +1.5 mm = 120.5 mm .
Often tech data gives a "radial ??" clearance without specifying whether its radial or diametric , which can be confusing , but err on the large side as it will at least stop the wheel impacting the housing even though there'll be a slight loss penalty .
The turbine wheel will expand faster and greater than its shroud , so plenty of clearance required , I give my TV94 turb wheels exducer 0.025" radial - 0.050" diametric
Cheers John
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Post by azwood on Mar 18, 2019 3:49:19 GMT -5
Thanks I get it now jhon
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Post by azwood on Mar 18, 2019 4:25:56 GMT -5
The exit portion is 150mm if I make the shroud say 8mm thick a overall clearance of around 1.5/1.6mm might be ok.but I fully understand that there will be different expansion rates so that would be a wild guess I could always make one with loads of clearance 1.8mm and make a new one when I know a bit more about how it behaves I guess
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Post by racket on Mar 18, 2019 18:25:27 GMT -5
Hi Aaron
Yep , with a homemade scroll theres always going to be unforeseen expansions in different directions compared to the cast variety , a weldmet is inherantly "mobile" so I wouldn't skimp on clearances, 1.8 mm diametricly bigger wouldn't be unreasonable over a 150 mm exducer
Cheers John
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Post by azwood on Mar 18, 2019 21:34:48 GMT -5
Hi Aaron Yep , with a homemade scroll theres always going to be unforeseen expansions in different directions compared to the cast variety , a weldmet is inherantly "mobile" so I wouldn't skimp on clearances, 1.8 mm diametricly bigger wouldn't be unreasonable over a 150 mm exducer Cheers John Yeah I'd hate to damage the wheel it took way to long to find and I think they are like $2000 to replace so I'll proceed with caution Afterall a new shroud is easy to make.
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Post by azwood on Mar 18, 2019 23:24:15 GMT -5
While I'm on the subject of exhausts I'd like to experiment with some kind of muffler has anyone tried doing this I know that it cannot obstruct the outwood flow in any way but a 150mm purferated tube with a outer casing could help I know volume is the key factor with damping sound.
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Post by racket on Mar 19, 2019 0:27:04 GMT -5
Hi Aaron
LOL..............then you'll need one at the other end to keep the intake sucking noise under control ;-)
Cheers John
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Post by azwood on Mar 19, 2019 0:29:27 GMT -5
Hi Aaron LOL..............then you'll need one at the other end to keep the intake sucking noise under control ;-) Cheers John It's definitely opening a new can of worms haha
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Post by turboron on Mar 19, 2019 5:21:58 GMT -5
azwood, truck mufflers are available with up to 5" in diameter in/out flanges. Price is around $100 US each. Could you use two with a wye?
Thanks, Ron
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Post by azwood on Mar 20, 2019 5:30:19 GMT -5
azwood, truck mufflers are available with up to 5" in diameter in/out flanges. Price is around $100 US each. Could you use two with a wye? Thanks, Ron Yep I was looking at stainless sports mufflers the kind you see on imports covered in stickers of products they don't even have on their car (a shopping list) a fart Cannan but anyway that tend to be cheap and light weight I've found 4in ones but I'm sure they'd make 5s.
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Post by turboron on Mar 20, 2019 6:53:53 GMT -5
azwood, I found tw0 5" in/out diesel stainless sports mufflers.
1. Quiet Tone, 8" Diameter Body, 31" OAL, $184.99 US Dollars 2. Diamond Eye, ? Diameter Body, 27" OAL, $107.99 US Dollars - Sold by Summit Racing.
We have a lot of large diesel pickups that owners drag race(and pretend) which is probably the market.
Thanks, Ron
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Post by azwood on Mar 21, 2019 1:54:33 GMT -5
I'm thinking a insulated alloy box over the intake would go a long way toward ruduceing the noise along with a muffler.id like to experiment with this because one day I'd like to put a engine in a road bike but without dropping the noise it would never pass the vac test's apart from that an engineer told me there is no emitions leval for bikes here.
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Post by turboron on Mar 21, 2019 4:33:33 GMT -5
azwood, there are several papers on the internet that show silencing the inlet by the use of an insulated inlet box with insulated axial splitters. My understanding is that the insulated panels and splitters have numerous small holes to reduce the noise.
Thanks, Ron
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Post by azwood on Mar 22, 2019 0:53:43 GMT -5
azwood, there are several papers on the internet that show silencing the inlet by the use of an insulated inlet box with insulated axial splitters. My understanding is that the insulated panels and splitters have numerous small holes to reduce the noise. Thanks, Ron Cool I'll look into that more
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