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Post by racket on Jan 12, 2021 22:46:54 GMT -5
Hi Richard
Ideal :-)
You guys in the UK have so much available "on your doorstep ", us colonials envy you .
Cheers
John
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Post by paulthepilot5 on Jan 13, 2021 1:08:51 GMT -5
That’s pretty much what I was thinking 🤔 need to look at big turbos I guess. If he’s at 35lb up to 9000 rpm in an OHC petrol he would be dealing with some much higher mass flow than I, so it’s all possible. |
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Post by paulthepilot5 on Jan 13, 2021 1:14:47 GMT -5
Hi John/Paul, The gas turbine air producer engine that was used in the manic beatie was manufactured by a UK company that was called TTL (turbine technology limited) and used the core (including bearing housing) from a Holset Hx82 turbo with a bespoke vaned compressor and turbine housing and a tiny combustion chamber. Personally I would use a microturbo saphir gas turbine air producer to produce the 45psi of boost pressure that you require as this engine will flow more air bleed volume than the TTL engine and is also more compact, Both types of engines are available from my pal at jetenginetrader.co.uk Hope this helps, Richard S. Hi Richard. yes I would love a saphir turbine, I’ve always thought of using one. Used to work on L39s so was familiar with them, but they are expensive in Australia $15-20k plus I think. They are the perfect solution for what I want to do though. A big turbo setup is more within my scope though I think |
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Post by paulthepilot5 on Jan 13, 2021 5:04:49 GMT -5
Hi Paul You don't need a fancy ball bearing turbo , just a regular cheaper "brass bush" one , it'll need to be pretty big , 98mm plus inducer , the bigger the better as your bleed will represent a smaller fraction of total flow . The "average" Garrett turbo has an "undersized" turbine stage suitable for wastegate operation , but for your application it'll not be needed as your mass flow through the turb stage will be reduced by your bleed . 45 psi of boost won't be a problem with a large turbo, and at reasonable efficiency . Cheers John John, Garrett GT6041 looks like a nice big option 🤔 (if I can find one) Compressor Specs Wheel Inducer Diameter: 105.7mm Wheel Exducer Diameter: 141mm Trim: 56 A/R: 1.25 Turbine Specs Wheel Diameter: 84.0mm Trim: 84 A/R: 1.25 Has some pretty massive flow compressor and turbine numbers, might have the capacity to bleed off the 14-15 kg/min I might need, the Holset HX82 seems to have quite a large turbine wheel an housing for the compressor size, so probably not really ideal. Just another idea (because it’s not complex enough yet 😆) Is there any reason I couldn’t run two smaller turbos in parallel for the gas turbine? A twin HX 52 or hx50 might be a good match, they are common and I can get them pretty cheap. How would a parallel set of turbos behave of the same burner do you think?, only complexity i see is extra pipework (which I enjoy fabricating) a bit of a loss in efficiency I guess too cheers Paul |
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Post by pitciblackscotland on Jan 13, 2021 7:10:46 GMT -5
I have a large frame T30 turbocharger for sale, been rebuilt. Cheers, Mark.     |
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Post by wannabebuilderuk on Jan 13, 2021 9:10:29 GMT -5
Hi John/Paul, The gas turbine air producer engine that was used in the manic beatie was manufactured by a UK company that was called TTL (turbine technology limited) and used the core (including bearing housing) from a Holset Hx82 turbo with a bespoke vaned compressor and turbine housing and a tiny combustion chamber. Personally I would use a microturbo saphir gas turbine air producer to produce the 45psi of boost pressure that you require as this engine will flow more air bleed volume than the TTL engine and is also more compact, Both types of engines are available from my pal at jetenginetrader.co.uk Hope this helps, Richard S. Saw one of those sell recently for a low price www.ebay.co.uk/itm/SEPCAT-JAGUAR-MICROTURBO-SAPHIR-STARTER-TURBINE-JET-ENGINE-AIRCRAFT-PARTS-/124472805137 |
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Post by racket on Jan 13, 2021 15:30:32 GMT -5
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Post by paulthepilot5 on Jan 14, 2021 2:34:41 GMT -5
Thanks John, good to know this might be a viable option. Two smaller turbos is definitely an easier thing to make fit. There are some Aeroflow Boosted turbos that seem to be reasonably priced The aeroflow7588 is a pretty close match to that gt4202 bit bigger turbine though. I’ll have to see if they publish maps and have AR options. Compressor: Inducer - 75mm Exducer - 100.32mm Extended Tip - 105.9mm A/R - Inlet - 5" Outlet - V Band Turbine: Inducer - 95.71mm Exducer - 88mm A/R - 1.32 Inlet Flange - T6 Outlet Flange - V Band Wastegate - External Reselling the smaller sized turbos is also easier if sizing is not correct. cheers Paul |
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Post by racket on Jan 14, 2021 3:53:12 GMT -5
Hi Paul
Those turbos have a fairly large turbine wheel exducer at 88mm vs 75 mm comp inducer , getting close to 40% larger area , they'd be OK for a normal gas turbine conversion , but with the bleed air removed they'll be grossly oversized with low gas speeds and not enough power produced to power the comps .
Leave it with me , I'll do some numbers for the Garrett units I mentioned earlier , their turbine flow maps should be invaluable , I get around to it in the morning when my heads awake :-)
Cheers
John
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Post by paulthepilot5 on Jan 14, 2021 7:07:16 GMT -5
Hi Paul Those turbos have a fairly large turbine wheel exducer at 88mm vs 75 mm comp inducer , getting close to 40% larger area , they'd be OK for a normal gas turbine conversion , but with the bleed air removed they'll be grossly oversized with low gas speeds and not enough power produced to power the comps . Leave it with me , I'll do some numbers for the Garrett units I mentioned earlier , their turbine flow maps should be invaluable , I get around to it in the morning when my heads awake :-) Cheers John Hi John, I think get the turbine compressor ratio now, 20%ish bigger turbine is optimum for normal turbine setup right? so something with an equal or slightly smaller turbine will suit. I guess ideally the percentage of compressor mass flow that is lost from bleed air needs to be removed from mass flow we are targeting the turbine to get an optimum outcome. Cant find much in the way of maps for the Aeroflow range, I know they are intended to be similar to some Garrett types. Ill send some emails to them and see what I can come up with. Their sizing nomenclature is easy at least, They have a few other options 8075, 7875, 7675 all journal so pretty cheap  I may also be able to get away with a lower PR as well compared to what I originally had planned, if I'm not getting the pumping losses through the engine should be seeing much more mass flow with less boost. Getting more excited about this project the more I think about it  Really appreciate the assistance with this John. I can understand most of the theory to this and can physically fabricate components and systems without a drama, but struggle with the thermodynamics calculations Thanks Paul |
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jetric
Veteran Member
Joined: December 2014
Posts: 149 
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Post by jetric on Jan 14, 2021 14:41:56 GMT -5
Hi Paul, Asked my pal how much he would sell a saphir for and he said around £4000 for a complete running engine on a test frame turnkey setup and around £200/£300 for the shipping to Australia, Let me know if you are interested then I can get the precise prices from him for you. Richard S. Hi Paul Those turbos have a fairly large turbine wheel exducer at 88mm vs 75 mm comp inducer , getting close to 40% larger area , they'd be OK for a normal gas turbine conversion , but with the bleed air removed they'll be grossly oversized with low gas speeds and not enough power produced to power the comps . Leave it with me , I'll do some numbers for the Garrett units I mentioned earlier , their turbine flow maps should be invaluable , I get around to it in the morning when my heads awake :-) Cheers John Hi John, I think get the turbine compressor ratio now, 20%ish bigger turbine is optimum for normal turbine setup right? so something with an equal or slightly smaller turbine will suit. I guess ideally the percentage of compressor mass flow that is lost from bleed air needs to be removed from mass flow we are targeting the turbine to get an optimum outcome. Cant find much in the way of maps for the Aeroflow range, I know they are intended to be similar to some Garrett types. Ill send some emails to them and see what I can come up with. Their sizing nomenclature is easy at least, They have a few other options 8075, 7875, 7675 all journal so pretty cheap I may also be able to get away with a lower PR as well compared to what I originally had planned, if I'm not getting the pumping losses through the engine should be seeing much more mass flow with less boost. Getting more excited about this project the more I think about it Really appreciate the assistance with this John. I can understand most of the theory to this and can physically fabricate components and systems without a drama, but struggle with the thermodynamics calculations Thanks Paul |
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Post by racket on Jan 14, 2021 17:20:04 GMT -5
Hi Paul I've done some numbers for the GTX42 www.garrettmotion.com/racing-and-performance/performance-catalog/turbo/gtx4202r/ , I used a 4:1 PR on their comp map www.garrettmotion.com/wp-content/uploads/2018/05/Comp-Map-GTX4202R.jpg with a flow of 98 lbs/min , then I removed 25 lbs/min bleed air for a minimum flow of 73 lbs/min used in the turb flow map www.garrettmotion.com/wp-content/uploads/2018/05/Turbine-Flow-GT42.jpg in conjunction with the "small" 1.01 A/R scroll which has a max CORRECTED FLOW of 38 lbs/min , I used a 3.75 PR going into the scroll to account for losses through the combustor and a T I T of 900C -1173K The result was a Corrected Flow of 39 lbs/min which is close enough to the 38 lbs/min on the map . I then did a set of numbers for 98 lbs/min of flow ( no bleed) at the same PR but at only 500C T I T, a temp more likely with full flow going to/thru the turb stage, and that came back at ~43 lbs/min ,but considering your engine would be consuming some of the 98 lbs/min even when idling , the comp could easily accomodate further reductions without surging . I hope this helps to provide an alternative option to the Saphir , my personal thoughts would be to go with Richards option of the Saphir, thats a good price as it'll come with all the "extras" that take time and money to source/construct/develop, and it would easily be resalable here in Oz ....................the decision will be yours to make,.... if you like tinkering , go the turbos , if you want a quick solution, then the Saphir. Cheers John |
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miuge
Veteran Member
Joined: March 2014
Posts: 200
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Post by miuge on Jan 14, 2021 17:25:01 GMT -5
Take a look at Subaru "Rocket anti-lag system" if not familiar:
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Post by paulthepilot5 on Jan 16, 2021 5:27:35 GMT -5
Hi Paul I've done some numbers for the GTX42 www.garrettmotion.com/racing-and-performance/performance-catalog/turbo/gtx4202r/ , I used a 4:1 PR on their comp map www.garrettmotion.com/wp-content/uploads/2018/05/Comp-Map-GTX4202R.jpg with a flow of 98 lbs/min , then I removed 25 lbs/min bleed air for a minimum flow of 73 lbs/min used in the turb flow map www.garrettmotion.com/wp-content/uploads/2018/05/Turbine-Flow-GT42.jpg in conjunction with the "small" 1.01 A/R scroll which has a max CORRECTED FLOW of 38 lbs/min , I used a 3.75 PR going into the scroll to account for losses through the combustor and a T I T of 900C -1173K The result was a Corrected Flow of 39 lbs/min which is close enough to the 38 lbs/min on the map . I then did a set of numbers for 98 lbs/min of flow ( no bleed) at the same PR but at only 500C T I T, a temp more likely with full flow going to/thru the turb stage, and that came back at ~43 lbs/min ,but considering your engine would be consuming some of the 98 lbs/min even when idling , the comp could easily accomodate further reductions without surging . I hope this helps to provide an alternative option to the Saphir , my personal thoughts would be to go with Richards option of the Saphir, thats a good price as it'll come with all the "extras" that take time and money to source/construct/develop, and it would easily be resalable here in Oz ....................the decision will be yours to make,.... if you like tinkering , go the turbos , if you want a quick solution, then the Saphir. Cheers John Thanks for the number crunching John. I think I will pursue the turbo based system, just for the challenge, probably still keep an eye out for a cheap Saphir. There would be a few other options with air start carts for small bleed air turbines as well, probably not that expensive given the lack of air start these days. Those T I Ts sound like they are on the max side of things am I right? Running the same numbers on a lower PR would likely see lower T I T correct? The manifold pressure required for my setup is likely to be less than I originally calculated, not having drive pressures to work against. Ill keep looking at options for turbos with similar sizing and Inducer/Exducer ratios. Cheers Paul |
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Post by paulthepilot5 on Jan 16, 2021 5:42:55 GMT -5
Take a look at Subaru "Rocket anti-lag system" if not familiar: Miuge, Yep have see that setup, actually saw that concept in a model gas turbine book published 1992 that I have had since high School. Was going to do a similar system, but decided to take it further with a stand alone turbine. A bit of Napier Nomad engine concept as well. Eliminating those turbo drive pressures will yield more power, and much less thermal load on the engine, allowing even more fuelling and power on top of that. Thanks Paul |
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