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Post by racket on Aug 24, 2021 16:48:27 GMT -5
Hi Joe
We always end up with less power using "cold " air rather than hot gases , simply because less fuel is being burnt .
Yep , the gas producer will need to use full expansion to drive the comp , substituting pressure for the lack of mass flow because of the dump from the wastegate .
Any high pressure air used will require a smaller freepower which invariably means higher rpm and gearing difficulties , it can be done , but its a compromise and theres a price to pay :-(
Cheers John
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dieselguy86
Veteran Member
Joined: September 2014
Posts: 186
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Post by dieselguy86 on Aug 24, 2021 20:24:31 GMT -5
John,
What about a next size down a/r housing? The turb isn't being forced to power an over-sized compressor that way. I realize the nozzle would choke, but wouldn't the w/g alleviate that to a small degree? I believe borg warner paper said that a wastegate is only good till ~40% of its stroke, then it chokes. In my experience it doesn't take much to really "wake" things up down stream. Just curious if there was a way to eek out a bit more power when running a small-ish gas producer.
-joe
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Post by racket on Aug 24, 2021 21:22:32 GMT -5
Hi Joe
LOL, I wish there was a way around things , but once we deviate from "standard practice" we end up with less output , something always seem to rear its ugly head and bite off the hoped for increases.
Ideally the gas producer is a good match of components running high efficiencies and exhausting optimum energy , both in terms of temp and pressures, which are then fed into the correctly sized freepower stage to exploit those energies.
A small gas producer probably needs the largest diameter freepower as possible to maximise tip speed for minimal rpm to make gearing easier , even to the point of only having partial entry to the freepower .
Cheers John
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