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Post by racket on Jan 16, 2021 16:07:56 GMT -5
Hi Paul
OK , turbos it is .
900C is what I normally use as a max T I T for my engines , though I've seen that as a TOT on many occassions for short periods of several seconds ( drag strip duration times ) , whereas 500C is what our engines will run at without any backpressure ( no jet nozzle /freepower wheel) , that 400C difference would be used to compensate for the bleed air mass flow loss through the turb stage.
Yep , at say a 3:1 PR the temps should be lower , but a lot will depend on the comp map efficiency island "widths" , but as most maps get "fatter" in the 2-3 PR range it shouldn't be a problem , I used the narrower range at 4:1 PR to test for worst case scenario , which you might just explore one day ;-)
The removal of exhaust manifold pressure will certainly improve your power output , to get 40 psi of boost you'd be needing 30 psi+ of exhaust manifold pressure feeding your turbo, thats a lotta backpressure which certainly wouldn't help cylinder scavenging.
Cheers John
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Post by paulthepilot5 on Jan 18, 2021 0:23:30 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 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 Hi Richard, I didn’t really notice your post before. If you can find out some more info about that Saphir and what the setup is I might be interested, and what he would sell it for? even without the test stand. cheers Paul
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Post by paulthepilot5 on Jan 22, 2021 15:29:02 GMT -5
Hi Paul OK , turbos it is . 900C is what I normally use as a max T I T for my engines , though I've seen that as a TOT on many occassions for short periods of several seconds ( drag strip duration times ) , whereas 500C is what our engines will run at without any backpressure ( no jet nozzle /freepower wheel) , that 400C difference would be used to compensate for the bleed air mass flow loss through the turb stage. Yep , at say a 3:1 PR the temps should be lower , but a lot will depend on the comp map efficiency island "widths" , but as most maps get "fatter" in the 2-3 PR range it shouldn't be a problem , I used the narrower range at 4:1 PR to test for worst case scenario , which you might just explore one day ;-) The removal of exhaust manifold pressure will certainly improve your power output , to get 40 psi of boost you'd be needing 30 psi+ of exhaust manifold pressure feeding your turbo, thats a lotta backpressure which certainly wouldn't help cylinder scavenging. Cheers John Hi John i found some better priced Saphirs for sale, so going to go down that path. Still pretty expensive with import duty and tax but probably not more than I would have had to spend on the other system. Specs on the Saphir are pretty impressive for its size and weight. Will provide 25kg/min at 45psi which is more than I need but leaves room to adapt to a bigger setup. I’ll put up a thread when I get the unit cheers Paul
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Post by wannabebuilderuk on Jan 22, 2021 16:45:12 GMT -5
What are the prices you've gotten out of interest?
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Post by racket on Jan 22, 2021 17:35:55 GMT -5
Hi Paul
Thats great news :-)
Look forward to pics etc
Cheers John
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ebweiss2
New Member
Joined: March 2021
Posts: 4
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Post by ebweiss2 on Mar 8, 2021 14:21:06 GMT -5
Is this for racing? There are better ways to go about it.
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